diff --git a/src/lagrangian/intermediate/submodels/Thermodynamic/HeatTransferModel/HeatTransferModel/HeatTransferModel.C b/src/lagrangian/intermediate/submodels/Thermodynamic/HeatTransferModel/HeatTransferModel/HeatTransferModel.C
index 93a621d0980a5afc2d3bf9f88218fed5caa7b284..37b5276269d3f01e9563f6f4b087c13afc63647a 100644
--- a/src/lagrangian/intermediate/submodels/Thermodynamic/HeatTransferModel/HeatTransferModel/HeatTransferModel.C
+++ b/src/lagrangian/intermediate/submodels/Thermodynamic/HeatTransferModel/HeatTransferModel/HeatTransferModel.C
@@ -118,7 +118,7 @@ Foam::scalar Foam::HeatTransferModel<CloudType>::Cu
     const scalar muc
 ) const
 {
-    const scalar Re = rhoc*mag(Ur)*dp/(muc + SMALL);
+    const scalar Re = rhoc*mag(Ur)*dp/(muc + ROOTVSMALL);
 
 //    const scalar Pr = muc/alphac;
     const scalar Pr = this->Pr();