Filtered drag coefficient

Fig. 31. Filtered drag coefficient (in CGS units) extracted from simulations over 16 x 16cm domain using 128 x 128 cells. Source Andrews and Sundaresan (2005).

Strictly speaking, one should use 2D bins involving particle volume fraction and a Reynolds number based on slip velocity to classify the filtered drag coefficient however in these simulations, the Reynolds number effect was found to be weak and hence the data were collapsed to just volume fraction bins. 

The term essentially a drag coefficient for the dust cake particles, should be a function of the median particle size and particle size distribution, the particle shape, and the packing density. Experimental data are the only reflable source for predicting cake resistance to flow. Bag filters are often selected for some desired maximum pressure drop (500—1750 Pa = 3.75-13 mm Hg) and the cleaning interval is then set to limit pressure drop to a chosen maximum value. 

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