In this question I showed images of a smoke simulation with Flow Type = Fire and Flow Type = Fire+Smoke. It seems that these two flow types have very little difference in their effects on the simulation.
But I guess the developers had reasons to create those two flow types. What is the nature of these two flow types and how do these flow types influence the smoke simulation ? I also mean how do these flow types influence the voxel data / simulation fields (availability, strength) ? So where do these flow types really have a different impact on your simulation ?