Jonathan Park

Yes, the block is present in both cases. Both the reactor (larger rectangle) and substrate (smaller rectangle) are cylindrical cross sections. The substrate has a thickness of 5 mm, so it's thin. Is there a way to apply source into the solid volume (W/m^3) if I only have the non-uniform heat flux profile (W/m^2)? The reason I can't apply the heat flux is because the external surface of the substrate is the internal surface of the CFD model of the reactor. Therefore I must convert my heat flux distribution into a volumetric heat source.