15.3.6 Dense Discrete Phase Model Drag Laws

The drag laws that are suitable for dense gas-solid flow are the Wen and Yu, the Gidaspow, and the Syamlal-O'Brien drag model. A detailed theoretical background to the correlations, along with a recommendation of when to use each model, can be found in Section  16.5.4 (see also this section in the separate User's Guide). All three correlations incorporate group effects and therefore are dependent on the particle phase volume fraction. Thus, the new drag models are only available when the DPM volume fraction is computed, i.e. in conjunction with the Dense Discrete Phase Model.