I was hoping someone here could clarify a few formulas for me.

With regards to the dispersed solids density. Is it (weight of solids in test area/volume of test area) or (mass of solids in test area/volume of test area)? I seem to be getting conflicting reports from the books I have read.

Also, with regards to Hinkle's correlation used to obtain the superficial gas velocity from gas velocity. Is it only applicable to dilute phase flow?

Any help you could offer would be appreciated.