diff --git a/applications/solvers/combustion/fireFoam/createClouds.H b/applications/solvers/combustion/fireFoam/createClouds.H
index 8ea23b2181..702f1a4651 100644
--- a/applications/solvers/combustion/fireFoam/createClouds.H
+++ b/applications/solvers/combustion/fireFoam/createClouds.H
@@ -1,2 +1,2 @@
 Info<< "\nConstructing clouds" << endl;
-parcelCloudList parcels(rho, U, g, slgThermo);
+parcelCloudList parcels(rho, U, g, thermo);
diff --git a/applications/solvers/combustion/fireFoam/createFields.H b/applications/solvers/combustion/fireFoam/createFields.H
index d615250c18..954848f3fb 100644
--- a/applications/solvers/combustion/fireFoam/createFields.H
+++ b/applications/solvers/combustion/fireFoam/createFields.H
@@ -3,8 +3,6 @@ autoPtr<fluidReactionThermo> pThermo(fluidReactionThermo::New(mesh));
 fluidReactionThermo& thermo = pThermo();
 thermo.validate(args.executable(), "h", "e");
 
-SLGThermo slgThermo(mesh, thermo);
-
 basicSpecieMixture& composition = thermo.composition();
 PtrList<volScalarField>& Y = composition.Y();
 
diff --git a/applications/solvers/combustion/fireFoam/fireFoam.C b/applications/solvers/combustion/fireFoam/fireFoam.C
index 215bfa3055..9770d21c2f 100644
--- a/applications/solvers/combustion/fireFoam/fireFoam.C
+++ b/applications/solvers/combustion/fireFoam/fireFoam.C
@@ -35,7 +35,6 @@ Description
 #include "fluidReactionThermophysicalTransportModel.H"
 #include "parcelCloudList.H"
 #include "surfaceFilmModel.H"
-#include "SLGThermo.H"
 #include "fluidReactionThermo.H"
 #include "combustionModel.H"
 #include "pimpleControl.H"
diff --git a/applications/solvers/lagrangian/reactingParticleFoam/buoyantReactingParticleFoam/buoyantReactingParticleFoam.C b/applications/solvers/lagrangian/reactingParticleFoam/buoyantReactingParticleFoam/buoyantReactingParticleFoam.C
index cce0d1029d..ad6f3b646d 100644
--- a/applications/solvers/lagrangian/reactingParticleFoam/buoyantReactingParticleFoam/buoyantReactingParticleFoam.C
+++ b/applications/solvers/lagrangian/reactingParticleFoam/buoyantReactingParticleFoam/buoyantReactingParticleFoam.C
@@ -37,7 +37,6 @@ Description
 #include "parcelCloudList.H"
 #include "surfaceFilmModel.H"
 #include "combustionModel.H"
-#include "SLGThermo.H"
 #include "fvModels.H"
 #include "fvConstraints.H"
 #include "pimpleControl.H"
diff --git a/applications/solvers/lagrangian/reactingParticleFoam/buoyantReactingParticleFoam/createFields.H b/applications/solvers/lagrangian/reactingParticleFoam/buoyantReactingParticleFoam/createFields.H
index 487eb1ae4a..fcd3e601b8 100644
--- a/applications/solvers/lagrangian/reactingParticleFoam/buoyantReactingParticleFoam/createFields.H
+++ b/applications/solvers/lagrangian/reactingParticleFoam/buoyantReactingParticleFoam/createFields.H
@@ -5,8 +5,6 @@ autoPtr<fluidReactionThermo> pThermo(fluidReactionThermo::New(mesh));
 fluidReactionThermo& thermo = pThermo();
 thermo.validate(args.executable(), "h", "e");
 
-SLGThermo slgThermo(mesh, thermo);
-
 basicSpecieMixture& composition = thermo.composition();
 PtrList<volScalarField>& Y = composition.Y();
 
diff --git a/applications/solvers/lagrangian/reactingParticleFoam/createClouds.H b/applications/solvers/lagrangian/reactingParticleFoam/createClouds.H
index afdbf46543..5376aaf445 100644
--- a/applications/solvers/lagrangian/reactingParticleFoam/createClouds.H
+++ b/applications/solvers/lagrangian/reactingParticleFoam/createClouds.H
@@ -1,2 +1,2 @@
 Info<< "\nConstructing clouds" << endl;
-parcelCloudList clouds(rho, U, g, slgThermo);
+parcelCloudList clouds(rho, U, g, thermo);
diff --git a/applications/solvers/lagrangian/reactingParticleFoam/createFields.H b/applications/solvers/lagrangian/reactingParticleFoam/createFields.H
index 6d77cf9a7e..f92845bf10 100644
--- a/applications/solvers/lagrangian/reactingParticleFoam/createFields.H
+++ b/applications/solvers/lagrangian/reactingParticleFoam/createFields.H
@@ -5,8 +5,6 @@ autoPtr<fluidReactionThermo> pThermo(fluidReactionThermo::New(mesh));
 fluidReactionThermo& thermo = pThermo();
 thermo.validate(args.executable(), "h", "e");
 
-SLGThermo slgThermo(mesh, thermo);
-
 basicSpecieMixture& composition = thermo.composition();
 PtrList<volScalarField>& Y = composition.Y();
 
diff --git a/applications/solvers/lagrangian/reactingParticleFoam/engineFoam/engineFoam.C b/applications/solvers/lagrangian/reactingParticleFoam/engineFoam/engineFoam.C
index 1a95a0f692..0be3ce9f88 100644
--- a/applications/solvers/lagrangian/reactingParticleFoam/engineFoam/engineFoam.C
+++ b/applications/solvers/lagrangian/reactingParticleFoam/engineFoam/engineFoam.C
@@ -37,7 +37,6 @@ Description
 #include "parcelCloudList.H"
 #include "surfaceFilmModel.H"
 #include "combustionModel.H"
-#include "SLGThermo.H"
 #include "fvModels.H"
 #include "fvConstraints.H"
 #include "pimpleControl.H"
diff --git a/applications/solvers/lagrangian/reactingParticleFoam/reactingParticleFoam.C b/applications/solvers/lagrangian/reactingParticleFoam/reactingParticleFoam.C
index 0ee97a2f1b..cec2704ff9 100644
--- a/applications/solvers/lagrangian/reactingParticleFoam/reactingParticleFoam.C
+++ b/applications/solvers/lagrangian/reactingParticleFoam/reactingParticleFoam.C
@@ -37,7 +37,6 @@ Description
 #include "parcelCloudList.H"
 #include "surfaceFilmModel.H"
 #include "combustionModel.H"
-#include "SLGThermo.H"
 #include "fvModels.H"
 #include "fvConstraints.H"
 #include "pimpleControl.H"
diff --git a/applications/solvers/lagrangian/simpleReactingParticleFoam/createClouds.H b/applications/solvers/lagrangian/simpleReactingParticleFoam/createClouds.H
index afdbf46543..5376aaf445 100644
--- a/applications/solvers/lagrangian/simpleReactingParticleFoam/createClouds.H
+++ b/applications/solvers/lagrangian/simpleReactingParticleFoam/createClouds.H
@@ -1,2 +1,2 @@
 Info<< "\nConstructing clouds" << endl;
-parcelCloudList clouds(rho, U, g, slgThermo);
+parcelCloudList clouds(rho, U, g, thermo);
diff --git a/applications/solvers/lagrangian/simpleReactingParticleFoam/createFields.H b/applications/solvers/lagrangian/simpleReactingParticleFoam/createFields.H
index 6ef519f19e..ba6461ab38 100644
--- a/applications/solvers/lagrangian/simpleReactingParticleFoam/createFields.H
+++ b/applications/solvers/lagrangian/simpleReactingParticleFoam/createFields.H
@@ -5,8 +5,6 @@ autoPtr<fluidReactionThermo> pThermo(fluidReactionThermo::New(mesh));
 fluidReactionThermo& thermo = pThermo();
 thermo.validate(args.executable(), "h", "e");
 
-SLGThermo slgThermo(mesh, thermo);
-
 basicSpecieMixture& composition = thermo.composition();
 PtrList<volScalarField>& Y = composition.Y();
 
diff --git a/applications/solvers/lagrangian/simpleReactingParticleFoam/simpleReactingParticleFoam.C b/applications/solvers/lagrangian/simpleReactingParticleFoam/simpleReactingParticleFoam.C
index 74e7299336..ecda0d7e6f 100644
--- a/applications/solvers/lagrangian/simpleReactingParticleFoam/simpleReactingParticleFoam.C
+++ b/applications/solvers/lagrangian/simpleReactingParticleFoam/simpleReactingParticleFoam.C
@@ -39,7 +39,6 @@ Description
 #include "IOporosityModelList.H"
 #include "fvModels.H"
 #include "fvConstraints.H"
-#include "SLGThermo.H"
 #include "simpleControl.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
diff --git a/src/lagrangian/parcel/Make/files b/src/lagrangian/parcel/Make/files
index 776de27fa1..097de52c9f 100644
--- a/src/lagrangian/parcel/Make/files
+++ b/src/lagrangian/parcel/Make/files
@@ -7,7 +7,7 @@ BASECLOUDS=$(CLOUDS)/baseClasses
 DERIVEDCLOUDS=$(CLOUDS)/derived
 
 # Thermo
-SLGThermo/SLGThermo.C
+parcelThermo/parcelThermo.C
 
 # parcel cloud
 parcelCloud/parcelCloudBase.C
diff --git a/src/lagrangian/parcel/clouds/Templates/CollidingCloud/CollidingCloud.C b/src/lagrangian/parcel/clouds/Templates/CollidingCloud/CollidingCloud.C
index f82e77e244..cdcf95e25f 100644
--- a/src/lagrangian/parcel/clouds/Templates/CollidingCloud/CollidingCloud.C
+++ b/src/lagrangian/parcel/clouds/Templates/CollidingCloud/CollidingCloud.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -127,11 +127,11 @@ Foam::CollidingCloud<CloudType>::CollidingCloud
     const volScalarField& rho,
     const volVectorField& U,
     const dimensionedVector& g,
-    const SLGThermo& thermo,
+    const fluidThermo& carrierThermo,
     const bool readFields
 )
 :
-    CollidingCloud(cloudName, rho, U, thermo.thermo().mu(), g, readFields)
+    CollidingCloud(cloudName, rho, U, carrierThermo.mu(), g, readFields)
 {}
 
 
diff --git a/src/lagrangian/parcel/clouds/Templates/CollidingCloud/CollidingCloud.H b/src/lagrangian/parcel/clouds/Templates/CollidingCloud/CollidingCloud.H
index 857c4ae20e..a88ddbdd40 100644
--- a/src/lagrangian/parcel/clouds/Templates/CollidingCloud/CollidingCloud.H
+++ b/src/lagrangian/parcel/clouds/Templates/CollidingCloud/CollidingCloud.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -40,7 +40,7 @@ SourceFiles
 #include "fvMatricesFwd.H"
 #include "dimensionedTypes.H"
 #include "fvMesh.H"
-#include "SLGThermo.H"
+#include "fluidThermo.H"
 #include "Cloud.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
@@ -151,7 +151,7 @@ public:
             const volScalarField& rho,
             const volVectorField& U,
             const dimensionedVector& g,
-            const SLGThermo& thermo,
+            const fluidThermo& carrierThermo,
             const bool readFields = true
         );
 
diff --git a/src/lagrangian/parcel/clouds/Templates/MPPICCloud/MPPICCloud.C b/src/lagrangian/parcel/clouds/Templates/MPPICCloud/MPPICCloud.C
index d434e75836..3d8173f4b5 100644
--- a/src/lagrangian/parcel/clouds/Templates/MPPICCloud/MPPICCloud.C
+++ b/src/lagrangian/parcel/clouds/Templates/MPPICCloud/MPPICCloud.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2013-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2013-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -104,11 +104,11 @@ Foam::MPPICCloud<CloudType>::MPPICCloud
     const volScalarField& rho,
     const volVectorField& U,
     const dimensionedVector& g,
-    const SLGThermo& thermo,
+    const fluidThermo& carrierThermo,
     const bool readFields
 )
 :
-    MPPICCloud(cloudName, rho, U, thermo.thermo().mu(), g, readFields)
+    MPPICCloud(cloudName, rho, U, carrierThermo.mu(), g, readFields)
 {}
 
 
diff --git a/src/lagrangian/parcel/clouds/Templates/MPPICCloud/MPPICCloud.H b/src/lagrangian/parcel/clouds/Templates/MPPICCloud/MPPICCloud.H
index c0052cdcae..b4e9a1ccd0 100644
--- a/src/lagrangian/parcel/clouds/Templates/MPPICCloud/MPPICCloud.H
+++ b/src/lagrangian/parcel/clouds/Templates/MPPICCloud/MPPICCloud.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2013-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2013-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -40,7 +40,7 @@ SourceFiles
 #include "fvMatricesFwd.H"
 #include "dimensionedTypes.H"
 #include "fvMesh.H"
-#include "SLGThermo.H"
+#include "fluidThermo.H"
 #include "Cloud.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
@@ -146,7 +146,7 @@ public:
             const volScalarField& rho,
             const volVectorField& U,
             const dimensionedVector& g,
-            const SLGThermo& thermo,
+            const fluidThermo& carrierThermo,
             const bool readFields = true
         );
 
diff --git a/src/lagrangian/parcel/clouds/Templates/MomentumCloud/MomentumCloud.C b/src/lagrangian/parcel/clouds/Templates/MomentumCloud/MomentumCloud.C
index a202ac0fe8..b2449f62e4 100644
--- a/src/lagrangian/parcel/clouds/Templates/MomentumCloud/MomentumCloud.C
+++ b/src/lagrangian/parcel/clouds/Templates/MomentumCloud/MomentumCloud.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -409,11 +409,11 @@ Foam::MomentumCloud<CloudType>::MomentumCloud
     const volScalarField& rho,
     const volVectorField& U,
     const dimensionedVector& g,
-    const SLGThermo& thermo,
+    const fluidThermo& carrierThermo,
     const bool readFields
 )
 :
-    MomentumCloud(cloudName, rho, U, thermo.thermo().mu(), g, readFields)
+    MomentumCloud(cloudName, rho, U, carrierThermo.mu(), g, readFields)
 {}
 
 
diff --git a/src/lagrangian/parcel/clouds/Templates/MomentumCloud/MomentumCloud.H b/src/lagrangian/parcel/clouds/Templates/MomentumCloud/MomentumCloud.H
index 50e0978e42..89fcf83045 100644
--- a/src/lagrangian/parcel/clouds/Templates/MomentumCloud/MomentumCloud.H
+++ b/src/lagrangian/parcel/clouds/Templates/MomentumCloud/MomentumCloud.H
@@ -60,7 +60,7 @@ SourceFiles
 #include "volFields.H"
 #include "fvMatrices.H"
 #include "cloudSolution.H"
-#include "SLGThermo.H"
+#include "fluidThermo.H"
 
 #include "ParticleForceList.H"
 #include "CloudFunctionObjectList.H"
@@ -290,7 +290,7 @@ public:
             const volScalarField& rho,
             const volVectorField& U,
             const dimensionedVector& g,
-            const SLGThermo& thermo,
+            const fluidThermo& carrierThermo,
             const bool readFields = true
         );
 
diff --git a/src/lagrangian/parcel/clouds/Templates/ReactingCloud/ReactingCloud.C b/src/lagrangian/parcel/clouds/Templates/ReactingCloud/ReactingCloud.C
index 713abb2159..495dbd8610 100644
--- a/src/lagrangian/parcel/clouds/Templates/ReactingCloud/ReactingCloud.C
+++ b/src/lagrangian/parcel/clouds/Templates/ReactingCloud/ReactingCloud.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -91,19 +91,20 @@ Foam::ReactingCloud<CloudType>::ReactingCloud
     const volScalarField& rho,
     const volVectorField& U,
     const dimensionedVector& g,
-    const SLGThermo& thermo,
+    const fluidThermo& carrierThermo,
     const bool readFields
 )
 :
-    CloudType(cloudName, rho, U, g, thermo, false),
+    CloudType(cloudName, rho, U, g, carrierThermo, false),
     cloudCopyPtr_(nullptr),
     constProps_(this->particleProperties()),
     compositionModel_(nullptr),
-    phaseChangeModel_(nullptr),
-    rhoTrans_(this->thermo().carrier().species().size())
+    phaseChangeModel_(nullptr)
 {
     setModels();
 
+    rhoTrans_.setSize(compositionModel_->carrier().species().size());
+
     if (readFields)
     {
         parcelType::readFields(*this, this->composition());
@@ -113,7 +114,7 @@ Foam::ReactingCloud<CloudType>::ReactingCloud
     // Set storage for mass source fields and initialise to zero
     forAll(rhoTrans_, i)
     {
-        const word& specieName = this->thermo().carrier().species()[i];
+        const word& specieName = compositionModel_->carrier().species()[i];
         rhoTrans_.set
         (
             i,
@@ -156,7 +157,7 @@ Foam::ReactingCloud<CloudType>::ReactingCloud
 {
     forAll(c.rhoTrans_, i)
     {
-        const word& specieName = this->thermo().carrier().species()[i];
+        const word& specieName = compositionModel_->carrier().species()[i];
         rhoTrans_.set
         (
             i,
diff --git a/src/lagrangian/parcel/clouds/Templates/ReactingCloud/ReactingCloud.H b/src/lagrangian/parcel/clouds/Templates/ReactingCloud/ReactingCloud.H
index d1fdf420a1..42268f4082 100644
--- a/src/lagrangian/parcel/clouds/Templates/ReactingCloud/ReactingCloud.H
+++ b/src/lagrangian/parcel/clouds/Templates/ReactingCloud/ReactingCloud.H
@@ -44,7 +44,7 @@ SourceFiles
 #include "fvMatricesFwd.H"
 #include "dimensionedTypes.H"
 #include "fvMesh.H"
-#include "SLGThermo.H"
+#include "fluidThermo.H"
 #include "Cloud.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
@@ -162,7 +162,7 @@ public:
             const volScalarField& rho,
             const volVectorField& U,
             const dimensionedVector& g,
-            const SLGThermo& thermo,
+            const fluidThermo& carrierThermo,
             const bool readFields = true
         );
 
diff --git a/src/lagrangian/parcel/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.C b/src/lagrangian/parcel/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.C
index 7ead2306b3..90b4f3f60d 100644
--- a/src/lagrangian/parcel/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.C
+++ b/src/lagrangian/parcel/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -78,11 +78,11 @@ Foam::ReactingMultiphaseCloud<CloudType>::ReactingMultiphaseCloud
     const volScalarField& rho,
     const volVectorField& U,
     const dimensionedVector& g,
-    const SLGThermo& thermo,
+    const fluidThermo& carrierThermo,
     const bool readFields
 )
 :
-    CloudType(cloudName, rho, U, g, thermo, false),
+    CloudType(cloudName, rho, U, g, carrierThermo, false),
     cloudCopyPtr_(nullptr),
     constProps_(this->particleProperties()),
     devolatilisationModel_(nullptr),
diff --git a/src/lagrangian/parcel/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.H b/src/lagrangian/parcel/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.H
index 75480e1c03..64332c4a2f 100644
--- a/src/lagrangian/parcel/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.H
+++ b/src/lagrangian/parcel/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -45,7 +45,7 @@ SourceFiles
 #include "fvMatricesFwd.H"
 #include "dimensionedTypes.H"
 #include "fvMesh.H"
-#include "SLGThermo.H"
+#include "fluidThermo.H"
 #include "Cloud.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
@@ -161,7 +161,7 @@ public:
             const volScalarField& rho,
             const volVectorField& U,
             const dimensionedVector& g,
-            const SLGThermo& thermo,
+            const fluidThermo& carrierThermo,
             const bool readFields = true
         );
 
diff --git a/src/lagrangian/parcel/clouds/Templates/SprayCloud/SprayCloud.C b/src/lagrangian/parcel/clouds/Templates/SprayCloud/SprayCloud.C
index 0ff3125f2d..dc6a446610 100644
--- a/src/lagrangian/parcel/clouds/Templates/SprayCloud/SprayCloud.C
+++ b/src/lagrangian/parcel/clouds/Templates/SprayCloud/SprayCloud.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -26,6 +26,7 @@ License
 #include "SprayCloud.H"
 #include "AtomizationModel.H"
 #include "BreakupModel.H"
+#include "parcelThermo.H"
 
 // * * * * * * * * * * * * * Protected Member Functions  * * * * * * * * * * //
 
@@ -74,11 +75,11 @@ Foam::SprayCloud<CloudType>::SprayCloud
     const volScalarField& rho,
     const volVectorField& U,
     const dimensionedVector& g,
-    const SLGThermo& thermo,
+    const fluidThermo& carrierThermo,
     bool readFields
 )
 :
-    CloudType(cloudName, rho, U, g, thermo, false),
+    CloudType(cloudName, rho, U, g, carrierThermo, false),
     cloudCopyPtr_(nullptr),
     averageParcelMass_(0.0),
     atomizationModel_(nullptr),
diff --git a/src/lagrangian/parcel/clouds/Templates/SprayCloud/SprayCloud.H b/src/lagrangian/parcel/clouds/Templates/SprayCloud/SprayCloud.H
index 33956601b4..a35ea319f8 100644
--- a/src/lagrangian/parcel/clouds/Templates/SprayCloud/SprayCloud.H
+++ b/src/lagrangian/parcel/clouds/Templates/SprayCloud/SprayCloud.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -40,7 +40,7 @@ Description
 #include "fvMatricesFwd.H"
 #include "dimensionedTypes.H"
 #include "fvMesh.H"
-#include "SLGThermo.H"
+#include "fluidThermo.H"
 #include "Cloud.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
@@ -136,7 +136,7 @@ public:
             const volScalarField& rho,
             const volVectorField& U,
             const dimensionedVector& g,
-            const SLGThermo& thermo,
+            const fluidThermo& carrierThermo,
             bool readFields = true
         );
 
diff --git a/src/lagrangian/parcel/clouds/Templates/ThermoCloud/ThermoCloud.C b/src/lagrangian/parcel/clouds/Templates/ThermoCloud/ThermoCloud.C
index f2b96c40fb..92d1f87c88 100644
--- a/src/lagrangian/parcel/clouds/Templates/ThermoCloud/ThermoCloud.C
+++ b/src/lagrangian/parcel/clouds/Templates/ThermoCloud/ThermoCloud.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -25,7 +25,6 @@ License
 
 #include "ThermoCloud.H"
 #include "integrationScheme.H"
-
 #include "HeatTransferModel.H"
 
 // * * * * * * * * * * * * * Protected Member Functions  * * * * * * * * * * //
@@ -133,16 +132,17 @@ Foam::ThermoCloud<CloudType>::ThermoCloud
     const volScalarField& rho,
     const volVectorField& U,
     const dimensionedVector& g,
-    const SLGThermo& thermo,
+    const fluidThermo& carrierThermo,
     const bool readFields
 )
 :
-    CloudType(cloudName, rho, U, g, thermo, false),
+    CloudType(cloudName, rho, U, g, carrierThermo, false),
     cloudCopyPtr_(nullptr),
     constProps_(this->particleProperties()),
-    thermo_(thermo),
-    T_(thermo.thermo().T()),
-    p_(thermo.thermo().p()),
+    carrierThermo_(carrierThermo),
+    thermo_(carrierThermo_),
+    T_(carrierThermo.T()),
+    p_(carrierThermo.p()),
     heatTransferModel_(nullptr),
     TIntegrator_(nullptr),
     radiation_(false),
@@ -207,6 +207,7 @@ Foam::ThermoCloud<CloudType>::ThermoCloud
     CloudType(c, name),
     cloudCopyPtr_(nullptr),
     constProps_(c.constProps_),
+    carrierThermo_(c.carrierThermo_),
     thermo_(c.thermo_),
     T_(c.T()),
     p_(c.p()),
@@ -316,6 +317,7 @@ Foam::ThermoCloud<CloudType>::ThermoCloud
     CloudType(mesh, name, c),
     cloudCopyPtr_(nullptr),
     constProps_(),
+    carrierThermo_(c.carrierThermo_),
     thermo_(c.thermo()),
     T_(c.T()),
     p_(c.p()),
@@ -444,7 +446,7 @@ void Foam::ThermoCloud<CloudType>::preEvolve()
 {
     CloudType::preEvolve();
 
-    this->pAmbient() = thermo_.thermo().p().average().value();
+    this->pAmbient() = carrierThermo_.p().average().value();
 }
 
 
diff --git a/src/lagrangian/parcel/clouds/Templates/ThermoCloud/ThermoCloud.H b/src/lagrangian/parcel/clouds/Templates/ThermoCloud/ThermoCloud.H
index 8693c1992f..d5e0feb822 100644
--- a/src/lagrangian/parcel/clouds/Templates/ThermoCloud/ThermoCloud.H
+++ b/src/lagrangian/parcel/clouds/Templates/ThermoCloud/ThermoCloud.H
@@ -43,7 +43,7 @@ SourceFiles
 #include "fvMatricesFwd.H"
 #include "dimensionedTypes.H"
 #include "fvMesh.H"
-#include "SLGThermo.H"
+#include "parcelThermo.H"
 #include "Cloud.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
@@ -108,8 +108,11 @@ protected:
 
         // References to the carrier gas fields
 
+            //- Thermophysical properties of the carrier fluid
+            const fluidThermo& carrierThermo_;
+
             //- SLG thermodynamics package
-            const SLGThermo& thermo_;
+            const parcelThermo thermo_;
 
             //- Temperature [K]
             const volScalarField& T_;
@@ -180,7 +183,7 @@ public:
             const volScalarField& rho,
             const volVectorField& U,
             const dimensionedVector& g,
-            const SLGThermo& thermo,
+            const fluidThermo& carrierThermo,
             const bool readFields = true
         );
 
@@ -235,8 +238,11 @@ public:
             //- Return access to the constant properties
             inline typename parcelType::constantProperties& constProps();
 
+            //- Return const access to carrier thermo package
+            inline const fluidThermo& carrierThermo() const;
+
             //- Return const access to thermo package
-            inline const SLGThermo& thermo() const;
+            inline const parcelThermo& thermo() const;
 
             //- Return const access to the carrier temperature field
             inline const volScalarField& T() const;
diff --git a/src/lagrangian/parcel/clouds/Templates/ThermoCloud/ThermoCloudI.H b/src/lagrangian/parcel/clouds/Templates/ThermoCloud/ThermoCloudI.H
index eafae99de3..0fc1c5f54f 100644
--- a/src/lagrangian/parcel/clouds/Templates/ThermoCloud/ThermoCloudI.H
+++ b/src/lagrangian/parcel/clouds/Templates/ThermoCloud/ThermoCloudI.H
@@ -55,7 +55,15 @@ Foam::ThermoCloud<CloudType>::constProps()
 
 
 template<class CloudType>
-inline const Foam::SLGThermo& Foam::ThermoCloud<CloudType>::thermo() const
+inline const Foam::fluidThermo&
+Foam::ThermoCloud<CloudType>::carrierThermo() const
+{
+    return carrierThermo_;
+}
+
+
+template<class CloudType>
+inline const Foam::parcelThermo& Foam::ThermoCloud<CloudType>::thermo() const
 {
     return thermo_;
 }
@@ -236,7 +244,7 @@ Foam::ThermoCloud<CloudType>::Sh(const volScalarField& hs) const
     {
         if (this->solution().semiImplicit("h"))
         {
-            const volScalarField Cp(thermo_.thermo().Cp());
+            const volScalarField Cp(carrierThermo_.Cp());
             const volScalarField::Internal
                 Vdt(this->mesh().V()*this->db().time().deltaT());
 
diff --git a/src/lagrangian/parcel/parcelCloud/ParcelCloudBase.H b/src/lagrangian/parcel/parcelCloud/ParcelCloudBase.H
index 255179b3f4..d69103678e 100644
--- a/src/lagrangian/parcel/parcelCloud/ParcelCloudBase.H
+++ b/src/lagrangian/parcel/parcelCloud/ParcelCloudBase.H
@@ -43,7 +43,7 @@ Description
 namespace Foam
 {
 
-class SLGThermo;
+class fluidThermo;
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -87,7 +87,7 @@ public:
             const volScalarField& rho,
             const volVectorField& U,
             const dimensionedVector& g,
-            const SLGThermo& thermo,
+            const fluidThermo& carrierThermo,
             const bool readFields = true
         )
         :
diff --git a/src/lagrangian/parcel/parcelCloud/parcelCloud.H b/src/lagrangian/parcel/parcelCloud/parcelCloud.H
index 0885ce9156..6ea60b3f49 100644
--- a/src/lagrangian/parcel/parcelCloud/parcelCloud.H
+++ b/src/lagrangian/parcel/parcelCloud/parcelCloud.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2020-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -48,7 +48,7 @@ SourceFiles
 namespace Foam
 {
 
-class SLGThermo;
+class fluidThermo;
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -89,9 +89,9 @@ public:
             const volScalarField& rho,
             const volVectorField& U,
             const dimensionedVector& g,
-            const SLGThermo& thermo
+            const fluidThermo& carrierThermo
         ),
-        (name, rho, U, g, thermo)
+        (name, rho, U, g, carrierThermo)
     );
 
 
@@ -123,7 +123,7 @@ public:
             const volScalarField& rho,
             const volVectorField& U,
             const dimensionedVector& g,
-            const SLGThermo& thermo
+            const fluidThermo& carrierThermo
         );
 
 
diff --git a/src/lagrangian/parcel/parcelCloud/parcelCloudNew.C b/src/lagrangian/parcel/parcelCloud/parcelCloudNew.C
index df22a6f54a..dd45c79ce9 100644
--- a/src/lagrangian/parcel/parcelCloud/parcelCloudNew.C
+++ b/src/lagrangian/parcel/parcelCloud/parcelCloudNew.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2020-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -74,7 +74,7 @@ Foam::autoPtr<Foam::parcelCloud> Foam::parcelCloud::New
     const volScalarField& rho,
     const volVectorField& U,
     const dimensionedVector& g,
-    const SLGThermo& thermo
+    const fluidThermo& carrierThermo
 )
 {
     IOdictionary dict
@@ -105,7 +105,7 @@ Foam::autoPtr<Foam::parcelCloud> Foam::parcelCloud::New
             << exit(FatalError);
     }
 
-    return cstrIter()(name, rho, U, g, thermo);
+    return cstrIter()(name, rho, U, g, carrierThermo);
 }
 
 
diff --git a/src/lagrangian/parcel/parcelCloudList/parcelCloudList.C b/src/lagrangian/parcel/parcelCloudList/parcelCloudList.C
index c4f67b03df..7b675c7d31 100644
--- a/src/lagrangian/parcel/parcelCloudList/parcelCloudList.C
+++ b/src/lagrangian/parcel/parcelCloudList/parcelCloudList.C
@@ -109,13 +109,13 @@ Foam::parcelCloudList::parcelCloudList
     const volScalarField& rho,
     const volVectorField& U,
     const dimensionedVector& g,
-    const SLGThermo& thermo
+    const fluidThermo& carrierThermo
 )
 :
     PtrList<parcelCloud>(),
     mesh_(rho.mesh())
 {
-    initialise(rho, U, g, thermo);
+    initialise(rho, U, g, carrierThermo);
 }
 
 
diff --git a/src/lagrangian/parcel/parcelCloudList/parcelCloudList.H b/src/lagrangian/parcel/parcelCloudList/parcelCloudList.H
index 5668f0ad37..05b0d98310 100644
--- a/src/lagrangian/parcel/parcelCloudList/parcelCloudList.H
+++ b/src/lagrangian/parcel/parcelCloudList/parcelCloudList.H
@@ -90,7 +90,7 @@ public:
             const volScalarField& rho,
             const volVectorField& U,
             const dimensionedVector& g,
-            const SLGThermo& thermo
+            const fluidThermo& carrierThermo
         );
 
         //- Disallow default bitwise copy construction
diff --git a/src/lagrangian/parcel/SLGThermo/SLGThermo.C b/src/lagrangian/parcel/parcelThermo/parcelThermo.C
similarity index 59%
rename from src/lagrangian/parcel/SLGThermo/SLGThermo.C
rename to src/lagrangian/parcel/parcelThermo/parcelThermo.C
index 4a92e55b58..de5c655c51 100644
--- a/src/lagrangian/parcel/SLGThermo/SLGThermo.C
+++ b/src/lagrangian/parcel/parcelThermo/parcelThermo.C
@@ -23,55 +23,22 @@ License
 
 \*---------------------------------------------------------------------------*/
 
-#include "SLGThermo.H"
-
-// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
-
-namespace Foam
-{
-    defineTypeNameAndDebug(SLGThermo, 0);
-}
-
+#include "parcelThermo.H"
 
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
-Foam::SLGThermo::SLGThermo(const fvMesh& mesh, const fluidThermo& thermo)
+Foam::parcelThermo::parcelThermo(const fluidThermo& carrierThermo)
 :
-    regIOobject
-    (
-        IOobject
-        (
-            SLGThermo::typeName,
-            mesh.polyMesh::instance(),
-            mesh
-        )
-    ),
-    thermo_(thermo),
-    carrier_(nullptr),
     liquids_(nullptr),
     solids_(nullptr)
 {
     Info<< "Creating component thermo properties:" << endl;
 
-    if (isA<basicSpecieMixture>(thermo))
-    {
-        const basicSpecieMixture& mcThermo =
-            refCast<const basicSpecieMixture>(thermo);
-        carrier_ = &mcThermo;
-
-        Info<< "    multi-component carrier - " << mcThermo.species().size()
-            << " species" << endl;
-    }
-    else
-    {
-        Info<< "    single component carrier" << endl;
-    }
-
-    if (thermo.properties().found("liquids"))
+    if (carrierThermo.properties().found("liquids"))
     {
         liquids_ = liquidMixtureProperties::New
         (
-            thermo.properties().subDict("liquids")
+            carrierThermo.properties().subDict("liquids")
         );
         Info<< "    liquids - " << liquids_->components().size()
             << " components" << endl;
@@ -81,11 +48,11 @@ Foam::SLGThermo::SLGThermo(const fvMesh& mesh, const fluidThermo& thermo)
         Info<< "    no liquid components" << endl;
     }
 
-    if (thermo.properties().found("solids"))
+    if (carrierThermo.properties().found("solids"))
     {
         solids_ = solidMixtureProperties::New
         (
-            thermo.properties().subDict("solids")
+            carrierThermo.properties().subDict("solids")
         );
         Info<< "    solids - " << solids_->components().size()
             << " components" << endl;
@@ -99,32 +66,13 @@ Foam::SLGThermo::SLGThermo(const fvMesh& mesh, const fluidThermo& thermo)
 
 // * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
-Foam::SLGThermo::~SLGThermo()
+Foam::parcelThermo::~parcelThermo()
 {}
 
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-const Foam::fluidThermo& Foam::SLGThermo::thermo() const
-{
-    return thermo_;
-}
-
-
-const Foam::basicSpecieMixture& Foam::SLGThermo::carrier() const
-{
-    if (carrier_ == nullptr)
-    {
-        FatalErrorInFunction
-            << "carrier requested, but object is not allocated"
-            << abort(FatalError);
-    }
-
-    return *carrier_;
-}
-
-
-const Foam::liquidMixtureProperties& Foam::SLGThermo::liquids() const
+const Foam::liquidMixtureProperties& Foam::parcelThermo::liquids() const
 {
     if (!liquids_.valid())
     {
@@ -137,7 +85,7 @@ const Foam::liquidMixtureProperties& Foam::SLGThermo::liquids() const
 }
 
 
-const Foam::solidMixtureProperties& Foam::SLGThermo::solids() const
+const Foam::solidMixtureProperties& Foam::parcelThermo::solids() const
 {
     if (!solids_.valid())
     {
@@ -150,33 +98,7 @@ const Foam::solidMixtureProperties& Foam::SLGThermo::solids() const
 }
 
 
-Foam::label Foam::SLGThermo::carrierId
-(
-    const word& cmptName,
-    bool allowNotfound
-) const
-{
-    forAll(carrier().species(), i)
-    {
-        if (cmptName == carrier_->species()[i])
-        {
-            return i;
-        }
-    }
-
-    if (!allowNotfound)
-    {
-        FatalErrorInFunction
-            << "Unknown carrier component " << cmptName
-            << ". Valid carrier components are:" << nl
-            << carrier_->species() << exit(FatalError);
-    }
-
-    return -1;
-}
-
-
-Foam::label Foam::SLGThermo::liquidId
+Foam::label Foam::parcelThermo::liquidId
 (
     const word& cmptName,
     bool allowNotfound
@@ -201,7 +123,7 @@ Foam::label Foam::SLGThermo::liquidId
 }
 
 
-Foam::label Foam::SLGThermo::solidId
+Foam::label Foam::parcelThermo::solidId
 (
     const word& cmptName,
     bool allowNotfound
@@ -226,22 +148,4 @@ Foam::label Foam::SLGThermo::solidId
 }
 
 
-bool Foam::SLGThermo::hasMultiComponentCarrier() const
-{
-    return (carrier_ != nullptr);
-}
-
-
-bool Foam::SLGThermo::hasLiquids() const
-{
-    return liquids_.valid();
-}
-
-
-bool Foam::SLGThermo::hasSolids() const
-{
-    return solids_.valid();
-}
-
-
 // ************************************************************************* //
diff --git a/src/lagrangian/parcel/SLGThermo/SLGThermo.H b/src/lagrangian/parcel/parcelThermo/parcelThermo.H
similarity index 50%
rename from src/lagrangian/parcel/SLGThermo/SLGThermo.H
rename to src/lagrangian/parcel/parcelThermo/parcelThermo.H
index 2ada95600b..6459d5d17a 100644
--- a/src/lagrangian/parcel/SLGThermo/SLGThermo.H
+++ b/src/lagrangian/parcel/parcelThermo/parcelThermo.H
@@ -22,32 +22,28 @@ License
     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
 Class
-    Foam::SLGThermo
+    Foam::parcelThermo
 
 Description
     Thermo package for (S)olids (L)iquids and (G)ases
     Takes reference to thermo package, and provides:
-    - carrier : components of thermo - access to elemental properties
     - liquids : liquid components - access  to elemental properties
     - solids  : solid components - access  to elemental properties
 
-    If thermo is not a multi-component thermo package, carrier is nullptr.
-    Similarly, if no liquids or solids are specified, their respective
-    pointers will also be nullptr.
+    If no liquids or solids are specified, their respective pointers will also
+    be nullptr.
 
     Registered to the mesh so that it can be looked-up
 
 SourceFiles
-    SLGThermo.C
+    parcelThermo.C
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef SLGThermo_H
-#define SLGThermo_H
+#ifndef parcelThermo_H
+#define parcelThermo_H
 
-#include "regIOobject.H"
 #include "fluidThermo.H"
-#include "basicSpecieMixture.H"
 #include "liquidMixtureProperties.H"
 #include "solidMixtureProperties.H"
 
@@ -57,21 +53,13 @@ namespace Foam
 {
 
 /*---------------------------------------------------------------------------*\
-                          Class SLGThermo Declaration
+                          Class parcelThermo Declaration
 \*---------------------------------------------------------------------------*/
 
-class SLGThermo
-:
-    public regIOobject
+class parcelThermo
 {
     // Private Data
 
-        //- Thermo package
-        const fluidThermo& thermo_;
-
-        //- Reference to the multi-component carrier phase thermo
-        const basicSpecieMixture* carrier_;
-
         //- Additional liquid properties data
         autoPtr<liquidMixtureProperties> liquids_;
 
@@ -81,78 +69,37 @@ class SLGThermo
 
 public:
 
-    //- Runtime type information
-    TypeName("SLGThermo");
-
     // Constructors
 
-        //- Construct from mesh
-        SLGThermo(const fvMesh& mesh, const fluidThermo& thermo);
+        //- Construct from carrier thermo
+        parcelThermo(const fluidThermo& carrierThermo);
 
 
     //- Destructor
-    virtual ~SLGThermo();
+    virtual ~parcelThermo();
 
 
     // Member Functions
 
-        // Access
+        //- Return reference to the global (additional) liquids
+        const liquidMixtureProperties& liquids() const;
 
-            //- Return reference to the thermo database
-            const fluidThermo& thermo() const;
+        //- Return reference to the global (additional) solids
+        const solidMixtureProperties& solids() const;
 
-            //- Return reference to the gaseous components
-            const basicSpecieMixture& carrier() const;
+        //- Index of liquid component
+        label liquidId
+        (
+            const word& cmptName,
+            bool allowNotFound = false
+        ) const;
 
-            //- Return reference to the global (additional) liquids
-            const liquidMixtureProperties& liquids() const;
-
-            //- Return reference to the global (additional) solids
-            const solidMixtureProperties& solids() const;
-
-
-            // Index retrieval
-
-                //- Index of carrier component
-                label carrierId
-                (
-                    const word& cmptName,
-                    bool allowNotFound = false
-                ) const;
-
-                //- Index of liquid component
-                label liquidId
-                (
-                    const word& cmptName,
-                    bool allowNotFound = false
-                ) const;
-
-                //- Index of solid component
-                label solidId
-                (
-                    const word& cmptName,
-                    bool allowNotFound = false
-                ) const;
-
-
-        // Checks
-
-            //- Thermo database has multi-component carrier flag
-            bool hasMultiComponentCarrier() const;
-
-            //- Thermo database has liquid components flag
-            bool hasLiquids() const;
-
-            //- Thermo database has solid components flag
-            bool hasSolids() const;
-
-
-        // IO
-
-            bool writeData(Foam::Ostream&) const
-            {
-                return true;
-            }
+        //- Index of solid component
+        label solidId
+        (
+            const word& cmptName,
+            bool allowNotFound = false
+        ) const;
 };
 
 
diff --git a/src/lagrangian/parcel/parcels/Templates/ReactingMultiphaseParcel/ReactingMultiphaseParcel.H b/src/lagrangian/parcel/parcels/Templates/ReactingMultiphaseParcel/ReactingMultiphaseParcel.H
index ee2e785bec..ccc3147f0a 100644
--- a/src/lagrangian/parcel/parcels/Templates/ReactingMultiphaseParcel/ReactingMultiphaseParcel.H
+++ b/src/lagrangian/parcel/parcels/Templates/ReactingMultiphaseParcel/ReactingMultiphaseParcel.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -39,7 +39,7 @@ SourceFiles
 #define ReactingMultiphaseParcel_H
 
 #include "particle.H"
-#include "SLGThermo.H"
+#include "fluidThermo.H"
 #include "demandDrivenEntry.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
diff --git a/src/lagrangian/parcel/parcels/Templates/ReactingParcel/ReactingParcel.C b/src/lagrangian/parcel/parcels/Templates/ReactingParcel/ReactingParcel.C
index 88008a20d3..c10984170e 100644
--- a/src/lagrangian/parcel/parcels/Templates/ReactingParcel/ReactingParcel.C
+++ b/src/lagrangian/parcel/parcels/Templates/ReactingParcel/ReactingParcel.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -302,14 +302,14 @@ void Foam::ReactingParcel<ParcelType>::correctSurfaceValues
         return;
     }
 
-    const SLGThermo& thermo = cloud.thermo();
+    const basicSpecieMixture& carrier = cloud.composition().carrier();
 
     // Far field carrier  molar fractions
-    scalarField Xinf(thermo.carrier().species().size());
+    scalarField Xinf(carrier.species().size());
 
     forAll(Xinf, i)
     {
-        Xinf[i] = thermo.carrier().Y(i)[this->cell()]/thermo.carrier().Wi(i);
+        Xinf[i] = carrier.Y(i)[this->cell()]/carrier.Wi(i);
     }
     Xinf /= sum(Xinf);
 
@@ -331,7 +331,7 @@ void Foam::ReactingParcel<ParcelType>::correctSurfaceValues
         const scalar Csi = Cs[i] + Xsff*Xinf[i]*CsTot;
 
         Xs[i] = (2.0*Csi + Xinf[i]*CsTot)/3.0;
-        Ys[i] = Xs[i]*thermo.carrier().Wi(i);
+        Ys[i] = Xs[i]*carrier.Wi(i);
     }
     Xs /= sum(Xs);
     Ys /= sum(Ys);
@@ -346,14 +346,14 @@ void Foam::ReactingParcel<ParcelType>::correctSurfaceValues
 
     forAll(Ys, i)
     {
-        const scalar W = thermo.carrier().Wi(i);
+        const scalar W = carrier.Wi(i);
         const scalar sqrtW = sqrt(W);
         const scalar cbrtW = cbrt(W);
 
         rhos += Xs[i]*W;
-        mus += Ys[i]*sqrtW*thermo.carrier().mu(i, td.pc(), T);
-        kappas += Ys[i]*cbrtW*thermo.carrier().kappa(i, td.pc(), T);
-        Cps += Xs[i]*thermo.carrier().Cp(i, td.pc(), T);
+        mus += Ys[i]*sqrtW*carrier.mu(i, td.pc(), T);
+        kappas += Ys[i]*cbrtW*carrier.kappa(i, td.pc(), T);
+        Cps += Xs[i]*carrier.Cp(i, td.pc(), T);
 
         sumYiSqrtW += Ys[i]*sqrtW;
         sumYiCbrtW += Ys[i]*cbrtW;
diff --git a/src/lagrangian/parcel/parcels/Templates/ReactingParcel/ReactingParcel.H b/src/lagrangian/parcel/parcels/Templates/ReactingParcel/ReactingParcel.H
index 637ef6bb3a..45d8c65bcd 100644
--- a/src/lagrangian/parcel/parcels/Templates/ReactingParcel/ReactingParcel.H
+++ b/src/lagrangian/parcel/parcels/Templates/ReactingParcel/ReactingParcel.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -40,7 +40,7 @@ SourceFiles
 
 #include "particle.H"
 #include "interpolation.H"
-#include "SLGThermo.H"
+#include "fluidThermo.H"
 #include "demandDrivenEntry.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
diff --git a/src/lagrangian/parcel/parcels/Templates/ThermoParcel/ThermoParcel.H b/src/lagrangian/parcel/parcels/Templates/ThermoParcel/ThermoParcel.H
index 69d08803a6..9a66d1840b 100644
--- a/src/lagrangian/parcel/parcels/Templates/ThermoParcel/ThermoParcel.H
+++ b/src/lagrangian/parcel/parcels/Templates/ThermoParcel/ThermoParcel.H
@@ -40,7 +40,7 @@ SourceFiles
 
 #include "particle.H"
 #include "interpolation.H"
-#include "SLGThermo.H"
+#include "fluidThermo.H"
 #include "demandDrivenEntry.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
diff --git a/src/lagrangian/parcel/parcels/Templates/ThermoParcel/ThermoParcelTrackingDataI.H b/src/lagrangian/parcel/parcels/Templates/ThermoParcel/ThermoParcelTrackingDataI.H
index 76668961b6..7120122666 100644
--- a/src/lagrangian/parcel/parcels/Templates/ThermoParcel/ThermoParcelTrackingDataI.H
+++ b/src/lagrangian/parcel/parcels/Templates/ThermoParcel/ThermoParcelTrackingDataI.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -31,8 +31,8 @@ inline Foam::ThermoParcel<ParcelType>::trackingData::trackingData
 )
 :
     ParcelType::trackingData(cloud),
-    Cp_(cloud.thermo().thermo().Cp()),
-    kappa_(cloud.thermo().thermo().kappa()),
+    Cp_(cloud.carrierThermo().Cp()),
+    kappa_(cloud.carrierThermo().kappa()),
     TInterp_
     (
         interpolation<scalar>::New
diff --git a/src/lagrangian/parcel/submodels/Momentum/SurfaceFilmModel/SurfaceFilmModel/SurfaceFilmModel.H b/src/lagrangian/parcel/submodels/Momentum/SurfaceFilmModel/SurfaceFilmModel/SurfaceFilmModel.H
index da969b82ba..4e6308fbf5 100644
--- a/src/lagrangian/parcel/submodels/Momentum/SurfaceFilmModel/SurfaceFilmModel/SurfaceFilmModel.H
+++ b/src/lagrangian/parcel/submodels/Momentum/SurfaceFilmModel/SurfaceFilmModel/SurfaceFilmModel.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -231,17 +231,17 @@ public:
 
 #define makeSurfaceFilmModel(CloudType)                                        \
                                                                                \
-    typedef Foam::CloudType::momentumCloudType momentumCloudType;            \
+    typedef Foam::CloudType::momentumCloudType momentumCloudType;              \
     defineNamedTemplateTypeNameAndDebug                                        \
     (                                                                          \
-        Foam::SurfaceFilmModel<momentumCloudType>,                            \
+        Foam::SurfaceFilmModel<momentumCloudType>,                             \
         0                                                                      \
     );                                                                         \
     namespace Foam                                                             \
     {                                                                          \
         defineTemplateRunTimeSelectionTable                                    \
         (                                                                      \
-            SurfaceFilmModel<momentumCloudType>,                              \
+            SurfaceFilmModel<momentumCloudType>,                               \
             dictionary                                                         \
         );                                                                     \
     }
@@ -249,11 +249,11 @@ public:
 
 #define makeSurfaceFilmModelType(SS, CloudType)                                \
                                                                                \
-    typedef Foam::CloudType::momentumCloudType momentumCloudType;            \
-    defineNamedTemplateTypeNameAndDebug(Foam::SS<momentumCloudType>, 0);      \
+    typedef Foam::CloudType::momentumCloudType momentumCloudType;              \
+    defineNamedTemplateTypeNameAndDebug(Foam::SS<momentumCloudType>, 0);       \
                                                                                \
-    Foam::SurfaceFilmModel<momentumCloudType>::                               \
-        adddictionaryConstructorToTable<Foam::SS<momentumCloudType>>          \
+    Foam::SurfaceFilmModel<momentumCloudType>::                                \
+        adddictionaryConstructorToTable<Foam::SS<momentumCloudType>>           \
             add##SS##CloudType##momentumCloudType##ConstructorToTable_;
 
 
diff --git a/src/lagrangian/parcel/submodels/Reacting/CompositionModel/CompositionModel/CompositionModel.C b/src/lagrangian/parcel/submodels/Reacting/CompositionModel/CompositionModel/CompositionModel.C
index 0b8ee5cbdf..963e3333a3 100644
--- a/src/lagrangian/parcel/submodels/Reacting/CompositionModel/CompositionModel/CompositionModel.C
+++ b/src/lagrangian/parcel/submodels/Reacting/CompositionModel/CompositionModel/CompositionModel.C
@@ -31,6 +31,13 @@ template<class CloudType>
 Foam::CompositionModel<CloudType>::CompositionModel(CloudType& owner)
 :
     CloudSubModelBase<CloudType>(owner),
+    carrierThermo_(owner.carrierThermo()),
+    carrierMixture_
+    (
+        isA<basicSpecieMixture>(carrierThermo_)
+      ? &refCast<const basicSpecieMixture>(carrierThermo_)
+      : nullptr
+    ),
     thermo_(owner.thermo()),
     phaseProps_()
 {}
@@ -45,11 +52,13 @@ Foam::CompositionModel<CloudType>::CompositionModel
 )
 :
     CloudSubModelBase<CloudType>(owner, dict, typeName, type),
+    carrierThermo_(owner.carrierThermo()),
+    carrierMixture_(&refCast<const basicSpecieMixture>(carrierThermo_)),
     thermo_(owner.thermo()),
     phaseProps_
     (
         this->coeffDict().lookup("phases"),
-        thermo_.carrier().species(),
+        carrierMixture_->species(),
         thermo_.liquids().components(),
         thermo_.solids().components()
     )
@@ -63,6 +72,8 @@ Foam::CompositionModel<CloudType>::CompositionModel
 )
 :
     CloudSubModelBase<CloudType>(cm),
+    carrierThermo_(cm.carrierThermo_),
+    carrierMixture_(cm.carrierMixture_),
     thermo_(cm.thermo_),
     phaseProps_(cm.phaseProps_)
 {}
@@ -78,7 +89,7 @@ Foam::CompositionModel<CloudType>::~CompositionModel()
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class CloudType>
-const Foam::SLGThermo& Foam::CompositionModel<CloudType>::thermo() const
+const Foam::parcelThermo& Foam::CompositionModel<CloudType>::thermo() const
 {
     return thermo_;
 }
@@ -88,7 +99,14 @@ template<class CloudType>
 const Foam::basicSpecieMixture&
 Foam::CompositionModel<CloudType>::carrier() const
 {
-    return thermo_.carrier();
+    if (carrierMixture_ == nullptr)
+    {
+        FatalErrorInFunction
+            << "carrier requested, but object is not allocated"
+            << abort(FatalError);
+    }
+
+    return *carrierMixture_;
 }
 
 
@@ -160,14 +178,22 @@ Foam::label Foam::CompositionModel<CloudType>::carrierId
     const bool allowNotFound
 ) const
 {
-    label id = thermo_.carrierId(cmptName);
+    label id = -1;
+
+    forAll(carrierMixture_->species(), i)
+    {
+        if (cmptName == carrierMixture_->species()[i])
+        {
+            id = i;
+        }
+    }
 
     if (id < 0 && !allowNotFound)
     {
         FatalErrorInFunction
             << "Unable to determine global id for requested component "
             << cmptName << ". Available components are " << nl
-            << thermo_.carrier().species()
+            << carrierMixture_->species()
             << abort(FatalError);
     }
 
@@ -245,7 +271,7 @@ Foam::scalarField Foam::CompositionModel<CloudType>::X
             forAll(Y, i)
             {
                 label cid = props.carrierIds()[i];
-                X[i] = Y[i]/thermo_.carrier().Wi(cid);
+                X[i] = Y[i]/carrierMixture_->Wi(cid);
                 WInv += X[i];
             }
             break;
@@ -291,7 +317,7 @@ Foam::scalar Foam::CompositionModel<CloudType>::H
             forAll(Y, i)
             {
                 label cid = props.carrierIds()[i];
-                HMixture += Y[i]*thermo_.carrier().Ha(cid, p, T);
+                HMixture += Y[i]*carrierMixture_->Ha(cid, p, T);
             }
             break;
         }
@@ -340,7 +366,7 @@ Foam::scalar Foam::CompositionModel<CloudType>::Hs
             forAll(Y, i)
             {
                 label cid = props.carrierIds()[i];
-                HsMixture += Y[i]*thermo_.carrier().Hs(cid, p, T);
+                HsMixture += Y[i]*carrierMixture_->Hs(cid, p, T);
             }
             break;
         }
@@ -391,7 +417,7 @@ Foam::scalar Foam::CompositionModel<CloudType>::Hc
             forAll(Y, i)
             {
                 label cid = props.carrierIds()[i];
-                HcMixture += Y[i]*thermo_.carrier().Hf(cid);
+                HcMixture += Y[i]*carrierMixture_->Hf(cid);
             }
             break;
         }
@@ -441,7 +467,7 @@ Foam::scalar Foam::CompositionModel<CloudType>::Cp
             forAll(Y, i)
             {
                 label cid = props.carrierIds()[i];
-                CpMixture += Y[i]*thermo_.carrier().Cp(cid, p, T);
+                CpMixture += Y[i]*carrierMixture_->Cp(cid, p, T);
             }
             break;
         }
diff --git a/src/lagrangian/parcel/submodels/Reacting/CompositionModel/CompositionModel/CompositionModel.H b/src/lagrangian/parcel/submodels/Reacting/CompositionModel/CompositionModel/CompositionModel.H
index cbc7c36737..8b89551c88 100644
--- a/src/lagrangian/parcel/submodels/Reacting/CompositionModel/CompositionModel/CompositionModel.H
+++ b/src/lagrangian/parcel/submodels/Reacting/CompositionModel/CompositionModel/CompositionModel.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -39,14 +39,10 @@ SourceFiles
 #define CompositionModel_H
 
 #include "CloudSubModelBase.H"
-#include "IOdictionary.H"
-#include "autoPtr.H"
-#include "runTimeSelectionTables.H"
-
-#include "PtrList.H"
-#include "SLGThermo.H"
-
+#include "parcelThermo.H"
+#include "basicSpecieMixture.H"
 #include "phasePropertiesList.H"
+#include "runTimeSelectionTables.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -64,8 +60,14 @@ class CompositionModel
 {
     // Private Data
 
+        //- Reference to thermophysical properties of the carrier fluid
+        const fluidThermo& carrierThermo_;
+
+        //- Pointer to the multi-component carrier composition
+        const basicSpecieMixture* carrierMixture_;
+
         //- Reference to the thermo database
-        const SLGThermo& thermo_;
+        const parcelThermo& thermo_;
 
         //- List of phase properties
         phasePropertiesList phaseProps_;
@@ -127,7 +129,7 @@ public:
         // Access
 
             //- Return the thermo database
-            const SLGThermo& thermo() const;
+            const parcelThermo& thermo() const;
 
 
             // Composition lists
diff --git a/src/lagrangian/parcel/submodels/Reacting/PhaseChangeModel/LiquidEvaporation/LiquidEvaporation.C b/src/lagrangian/parcel/submodels/Reacting/PhaseChangeModel/LiquidEvaporation/LiquidEvaporation.C
index 9afda88e83..daa306ae10 100644
--- a/src/lagrangian/parcel/submodels/Reacting/PhaseChangeModel/LiquidEvaporation/LiquidEvaporation.C
+++ b/src/lagrangian/parcel/submodels/Reacting/PhaseChangeModel/LiquidEvaporation/LiquidEvaporation.C
@@ -37,13 +37,13 @@ Foam::tmp<Foam::scalarField> Foam::LiquidEvaporation<CloudType>::calcXc
     const label celli
 ) const
 {
-    scalarField Xc(this->owner().thermo().carrier().Y().size());
+    scalarField Xc(this->owner().composition().carrier().Y().size());
 
     forAll(Xc, i)
     {
         Xc[i] =
-            this->owner().thermo().carrier().Y()[i][celli]
-           /this->owner().thermo().carrier().Wi(i);
+            this->owner().composition().carrier().Y()[i][celli]
+           /this->owner().composition().carrier().Wi(i);
     }
 
     return Xc/sum(Xc);
diff --git a/src/lagrangian/parcel/submodels/Reacting/PhaseChangeModel/LiquidEvaporationBoil/LiquidEvaporationBoil.C b/src/lagrangian/parcel/submodels/Reacting/PhaseChangeModel/LiquidEvaporationBoil/LiquidEvaporationBoil.C
index 8b3ef66282..ce2feb76fe 100644
--- a/src/lagrangian/parcel/submodels/Reacting/PhaseChangeModel/LiquidEvaporationBoil/LiquidEvaporationBoil.C
+++ b/src/lagrangian/parcel/submodels/Reacting/PhaseChangeModel/LiquidEvaporationBoil/LiquidEvaporationBoil.C
@@ -37,13 +37,13 @@ Foam::tmp<Foam::scalarField> Foam::LiquidEvaporationBoil<CloudType>::calcXc
     const label celli
 ) const
 {
-    scalarField Xc(this->owner().thermo().carrier().Y().size());
+    scalarField Xc(this->owner().composition().carrier().Y().size());
 
     forAll(Xc, i)
     {
         Xc[i] =
-            this->owner().thermo().carrier().Y()[i][celli]
-           /this->owner().thermo().carrier().Wi(i);
+            this->owner().composition().carrier().Y()[i][celli]
+           /this->owner().composition().carrier().Wi(i);
     }
 
     return Xc/sum(Xc);
@@ -178,13 +178,13 @@ void Foam::LiquidEvaporationBoil<CloudType>::calculate
     scalar Hc = 0.0;
     scalar Cpc = 0.0;
     scalar kappac = 0.0;
-    forAll(this->owner().thermo().carrier().Y(), i)
+    forAll(this->owner().composition().carrier().Y(), i)
     {
-        scalar Yc = this->owner().thermo().carrier().Y()[i][celli];
-        Hc += Yc*this->owner().thermo().carrier().Ha(i, pc, Tc);
-        Hsc += Yc*this->owner().thermo().carrier().Ha(i, ps, Ts);
-        Cpc += Yc*this->owner().thermo().carrier().Cp(i, ps, Ts);
-        kappac += Yc*this->owner().thermo().carrier().kappa(i, ps, Ts);
+        scalar Yc = this->owner().composition().carrier().Y()[i][celli];
+        Hc += Yc*this->owner().composition().carrier().Ha(i, pc, Tc);
+        Hsc += Yc*this->owner().composition().carrier().Ha(i, ps, Ts);
+        Cpc += Yc*this->owner().composition().carrier().Cp(i, ps, Ts);
+        kappac += Yc*this->owner().composition().carrier().kappa(i, ps, Ts);
     }
 
     // calculate mass transfer of each specie in liquid
diff --git a/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationDiffusionLimitedRate/COxidationDiffusionLimitedRate.C b/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationDiffusionLimitedRate/COxidationDiffusionLimitedRate.C
index 08faacf284..d9e2ff8ec6 100644
--- a/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationDiffusionLimitedRate/COxidationDiffusionLimitedRate.C
+++ b/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationDiffusionLimitedRate/COxidationDiffusionLimitedRate.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -52,11 +52,11 @@ Foam::COxidationDiffusionLimitedRate<CloudType>::COxidationDiffusionLimitedRate
     CsLocalId_ = owner.composition().localId(idSolid, "C");
 
     // Set local copies of thermo properties
-    WO2_ = owner.thermo().carrier().Wi(O2GlobalId_);
-    const scalar WCO2 = owner.thermo().carrier().Wi(CO2GlobalId_);
+    WO2_ = owner.composition().carrier().Wi(O2GlobalId_);
+    const scalar WCO2 = owner.composition().carrier().Wi(CO2GlobalId_);
     WC_ = WCO2 - WO2_;
 
-    HcCO2_ = owner.thermo().carrier().Hf(CO2GlobalId_);
+    HcCO2_ = owner.composition().carrier().Hf(CO2GlobalId_);
 
     if (Sb_ < 0)
     {
@@ -131,10 +131,11 @@ Foam::scalar Foam::COxidationDiffusionLimitedRate<CloudType>::calculate
         return 0.0;
     }
 
-    const SLGThermo& thermo = this->owner().thermo();
+    const parcelThermo& thermo = this->owner().thermo();
+    const basicSpecieMixture& carrier = this->owner().composition().carrier();
 
     // Local mass fraction of O2 in the carrier phase
-    const scalar YO2 = thermo.carrier().Y(O2GlobalId_)[celli];
+    const scalar YO2 = carrier.Y(O2GlobalId_)[celli];
 
     // Change in C mass [kg]
     scalar dmC = 4.0*mathematical::pi*d*D_*YO2*Tc*rhoc/(Sb_*(T + Tc))*dt;
diff --git a/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationHurtMitchell/COxidationHurtMitchell.C b/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationHurtMitchell/COxidationHurtMitchell.C
index b462aec1b7..3ab28866e7 100644
--- a/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationHurtMitchell/COxidationHurtMitchell.C
+++ b/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationHurtMitchell/COxidationHurtMitchell.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2012-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2012-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -52,11 +52,11 @@ Foam::COxidationHurtMitchell<CloudType>::COxidationHurtMitchell
     ashLocalId_ = owner.composition().localId(idSolid, "ash", true);
 
     // Set local copies of thermo properties
-    WO2_ = owner.thermo().carrier().Wi(O2GlobalId_);
-    const scalar WCO2 = owner.thermo().carrier().Wi(CO2GlobalId_);
+    WO2_ = owner.composition().carrier().Wi(O2GlobalId_);
+    const scalar WCO2 = owner.composition().carrier().Wi(CO2GlobalId_);
     WC_ = WCO2 - WO2_;
 
-    HcCO2_ = owner.thermo().carrier().Hf(CO2GlobalId_);
+    HcCO2_ = owner.composition().carrier().Hf(CO2GlobalId_);
 
     const scalar YCloc = owner.composition().Y0(idSolid)[CsLocalId_];
     const scalar YSolidTot = owner.composition().YMixture0()[idSolid];
@@ -130,10 +130,11 @@ Foam::scalar Foam::COxidationHurtMitchell<CloudType>::calculate
         return 0.0;
     }
 
-    const SLGThermo& thermo = this->owner().thermo();
+    const parcelThermo& thermo = this->owner().thermo();
+    const basicSpecieMixture& carrier = this->owner().composition().carrier();
 
     // Local mass fraction of O2 in the carrier phase
-    const scalar YO2 = thermo.carrier().Y(O2GlobalId_)[celli];
+    const scalar YO2 = carrier.Y(O2GlobalId_)[celli];
 
     // No combustion if no oxygen present
     if (YO2 < small)
diff --git a/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationIntrinsicRate/COxidationIntrinsicRate.C b/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationIntrinsicRate/COxidationIntrinsicRate.C
index d1b98a7377..6018ce254b 100644
--- a/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationIntrinsicRate/COxidationIntrinsicRate.C
+++ b/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationIntrinsicRate/COxidationIntrinsicRate.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2014-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2014-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -58,11 +58,11 @@ Foam::COxidationIntrinsicRate<CloudType>::COxidationIntrinsicRate
     CsLocalId_ = owner.composition().localId(idSolid, "C");
 
     // Set local copies of thermo properties
-    WO2_ = owner.thermo().carrier().Wi(O2GlobalId_);
-    const scalar WCO2 = owner.thermo().carrier().Wi(CO2GlobalId_);
+    WO2_ = owner.composition().carrier().Wi(O2GlobalId_);
+    const scalar WCO2 = owner.composition().carrier().Wi(CO2GlobalId_);
     WC_ = WCO2 - WO2_;
 
-    HcCO2_ = owner.thermo().carrier().Hf(CO2GlobalId_);
+    HcCO2_ = owner.composition().carrier().Hf(CO2GlobalId_);
 
     if (Sb_ < 0)
     {
@@ -143,10 +143,11 @@ Foam::scalar Foam::COxidationIntrinsicRate<CloudType>::calculate
         return 0.0;
     }
 
-    const SLGThermo& thermo = this->owner().thermo();
+    const parcelThermo& thermo = this->owner().thermo();
+    const basicSpecieMixture& carrier = this->owner().composition().carrier();
 
     // Local mass fraction of O2 in the carrier phase []
-    const scalar YO2 = thermo.carrier().Y(O2GlobalId_)[celli];
+    const scalar YO2 = carrier.Y(O2GlobalId_)[celli];
 
     // Quick exit if oxidant not present
     if (YO2 < rootVSmall)
diff --git a/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationKineticDiffusionLimitedRate/COxidationKineticDiffusionLimitedRate.C b/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationKineticDiffusionLimitedRate/COxidationKineticDiffusionLimitedRate.C
index 92820a94ea..d3584bbd9b 100644
--- a/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationKineticDiffusionLimitedRate/COxidationKineticDiffusionLimitedRate.C
+++ b/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationKineticDiffusionLimitedRate/COxidationKineticDiffusionLimitedRate.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -53,11 +53,11 @@ COxidationKineticDiffusionLimitedRate
     CsLocalId_ = owner.composition().localId(idSolid, "C");
 
     // Set local copies of thermo properties
-    WO2_ = owner.thermo().carrier().Wi(O2GlobalId_);
-    const scalar WCO2 = owner.thermo().carrier().Wi(CO2GlobalId_);
+    WO2_ = owner.composition().carrier().Wi(O2GlobalId_);
+    const scalar WCO2 = owner.composition().carrier().Wi(CO2GlobalId_);
     WC_ = WCO2 - WO2_;
 
-    HcCO2_ = owner.thermo().carrier().Hf(CO2GlobalId_);
+    HcCO2_ = owner.composition().carrier().Hf(CO2GlobalId_);
 
     const scalar YCloc = owner.composition().Y0(idSolid)[CsLocalId_];
     const scalar YSolidTot = owner.composition().YMixture0()[idSolid];
@@ -128,10 +128,11 @@ Foam::scalar Foam::COxidationKineticDiffusionLimitedRate<CloudType>::calculate
         return 0.0;
     }
 
-    const SLGThermo& thermo = this->owner().thermo();
+    const parcelThermo& thermo = this->owner().thermo();
+    const basicSpecieMixture& carrier = this->owner().composition().carrier();
 
     // Local mass fraction of O2 in the carrier phase
-    const scalar YO2 = thermo.carrier().Y(O2GlobalId_)[celli];
+    const scalar YO2 = carrier.Y(O2GlobalId_)[celli];
 
     // Diffusion rate coefficient
     const scalar D0 = C1_/d*pow(0.5*(T + Tc), 0.75);
diff --git a/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationMurphyShaddix/COxidationMurphyShaddix.C b/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationMurphyShaddix/COxidationMurphyShaddix.C
index ecf669dc42..c27ff1a83c 100644
--- a/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationMurphyShaddix/COxidationMurphyShaddix.C
+++ b/src/lagrangian/parcel/submodels/ReactingMultiphase/SurfaceReactionModel/COxidationMurphyShaddix/COxidationMurphyShaddix.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -65,11 +65,11 @@ Foam::COxidationMurphyShaddix<CloudType>::COxidationMurphyShaddix
     CsLocalId_ = owner.composition().localId(idSolid, "C");
 
     // Set local copies of thermo properties
-    WO2_ = owner.thermo().carrier().Wi(O2GlobalId_);
-    const scalar WCO2 = owner.thermo().carrier().Wi(CO2GlobalId_);
+    WO2_ = owner.composition().carrier().Wi(O2GlobalId_);
+    const scalar WCO2 = owner.composition().carrier().Wi(CO2GlobalId_);
     WC_ = WCO2 - WO2_;
 
-    HcCO2_ = owner.thermo().carrier().Hf(CO2GlobalId_);
+    HcCO2_ = owner.composition().carrier().Hf(CO2GlobalId_);
 
     const scalar YCloc = owner.composition().Y0(idSolid)[CsLocalId_];
     const scalar YSolidTot = owner.composition().YMixture0()[idSolid];
@@ -142,10 +142,11 @@ Foam::scalar Foam::COxidationMurphyShaddix<CloudType>::calculate
         return 0.0;
     }
 
-    const SLGThermo& thermo = this->owner().thermo();
+    const parcelThermo& thermo = this->owner().thermo();
+    const basicSpecieMixture& carrier = this->owner().composition().carrier();
 
     // Cell carrier phase O2 species density [kg/m^3]
-    const scalar rhoO2 = rhoc*thermo.carrier().Y(O2GlobalId_)[celli];
+    const scalar rhoO2 = rhoc*carrier.Y(O2GlobalId_)[celli];
 
     if (rhoO2 < small)
     {
diff --git a/src/lagrangian/parcel/submodels/Spray/StochasticCollision/ORourkeCollision/ORourkeCollision.C b/src/lagrangian/parcel/submodels/Spray/StochasticCollision/ORourkeCollision/ORourkeCollision.C
index 263058aff9..5341a68e56 100644
--- a/src/lagrangian/parcel/submodels/Spray/StochasticCollision/ORourkeCollision/ORourkeCollision.C
+++ b/src/lagrangian/parcel/submodels/Spray/StochasticCollision/ORourkeCollision/ORourkeCollision.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -24,7 +24,7 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "ORourkeCollision.H"
-#include "SLGThermo.H"
+#include "parcelThermo.H"
 #include "CompactListList.H"
 #include "mathematicalConstants.H"
 
@@ -299,7 +299,7 @@ Foam::ORourkeCollision<CloudType>::ORourkeCollision
     StochasticCollisionModel<CloudType>(dict, owner, modelName),
     liquids_
     (
-        owner.db().template lookupObject<SLGThermo>("SLGThermo").liquids()
+        static_cast<const ThermoCloud<CloudType>&>(owner).thermo().liquids()
     ),
     coalescence_(this->coeffDict().lookup("coalescence"))
 {}
diff --git a/src/lagrangian/parcel/submodels/Thermodynamic/SurfaceFilmModel/ThermoSurfaceFilm/ThermoSurfaceFilm.C b/src/lagrangian/parcel/submodels/Thermodynamic/SurfaceFilmModel/ThermoSurfaceFilm/ThermoSurfaceFilm.C
index c3a80118b3..ce59593999 100644
--- a/src/lagrangian/parcel/submodels/Thermodynamic/SurfaceFilmModel/ThermoSurfaceFilm/ThermoSurfaceFilm.C
+++ b/src/lagrangian/parcel/submodels/Thermodynamic/SurfaceFilmModel/ThermoSurfaceFilm/ThermoSurfaceFilm.C
@@ -143,7 +143,7 @@ void Foam::ThermoSurfaceFilm<CloudType>::absorbInteraction
     const liquidProperties& liq = thermo_.liquids().properties()[0];
 
     // Local pressure
-    const scalar pc = thermo_.thermo().p()[p.cell()];
+    const scalar pc = carrierThermo_.p()[p.cell()];
 
     filmModel.addSources
     (
@@ -213,7 +213,7 @@ void Foam::ThermoSurfaceFilm<CloudType>::drySplashInteraction
     const vector& nf = pp.faceNormals()[facei];
 
     // Local pressure
-    const scalar pc = thermo_.thermo().p()[p.cell()];
+    const scalar pc = carrierThermo_.p()[p.cell()];
 
     // Retrieve parcel properties
     const scalar m = p.mass()*p.nParticle();
@@ -269,7 +269,7 @@ void Foam::ThermoSurfaceFilm<CloudType>::wetSplashInteraction
     const vector& nf = pp.faceNormals()[facei];
 
     // Local pressure
-    const scalar pc = thermo_.thermo().p()[p.cell()];
+    const scalar pc = carrierThermo_.p()[p.cell()];
 
     // Retrieve parcel properties
     const scalar m = p.mass()*p.nParticle();
@@ -470,10 +470,11 @@ Foam::ThermoSurfaceFilm<CloudType>::ThermoSurfaceFilm
 :
     SurfaceFilmModel<CloudType>(dict, owner, typeName),
     rndGen_(owner.rndGen()),
-    thermo_
+    carrierThermo_
     (
-        owner.db().objectRegistry::template lookupObject<SLGThermo>("SLGThermo")
+        static_cast<const ThermoCloud<CloudType>&>(owner).carrierThermo()
     ),
+    thermo_(static_cast<const ThermoCloud<CloudType>&>(owner).thermo()),
     TFilmPatch_(0),
     CpFilmPatch_(0),
     interactionType_
@@ -513,6 +514,7 @@ Foam::ThermoSurfaceFilm<CloudType>::ThermoSurfaceFilm
 :
     SurfaceFilmModel<CloudType>(sfm),
     rndGen_(sfm.rndGen_),
+    carrierThermo_(sfm.carrierThermo_),
     thermo_(sfm.thermo_),
     TFilmPatch_(sfm.TFilmPatch_),
     CpFilmPatch_(sfm.CpFilmPatch_),
diff --git a/src/lagrangian/parcel/submodels/Thermodynamic/SurfaceFilmModel/ThermoSurfaceFilm/ThermoSurfaceFilm.H b/src/lagrangian/parcel/submodels/Thermodynamic/SurfaceFilmModel/ThermoSurfaceFilm/ThermoSurfaceFilm.H
index 819c01001b..d54540e42b 100644
--- a/src/lagrangian/parcel/submodels/Thermodynamic/SurfaceFilmModel/ThermoSurfaceFilm/ThermoSurfaceFilm.H
+++ b/src/lagrangian/parcel/submodels/Thermodynamic/SurfaceFilmModel/ThermoSurfaceFilm/ThermoSurfaceFilm.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -100,8 +100,11 @@ protected:
         //- Reference to the cloud random number generator
         Random& rndGen_;
 
+        //- Thermophysical properties of the carrier fluid
+        const fluidThermo& carrierThermo_;
+
         //- Reference to the cloud thermo package
-        const SLGThermo& thermo_;
+        const parcelThermo& thermo_;
 
 
         // Cached injector fields per film patch