Ergun equation for beds + rising fluid + potential energy

[maistral]

TL;DR

Do I add the potential energy term?

I am quite familiar with the Ergun equation's formulation.

My question is, do I need to subtract the potential term ΔP/Δz = -ρg/g_c after the Ergun equation's own ΔP/Δz , assuming that the fluid is to be pumped upward, from the bottom of the bed to the top of the bed? I was thinking it should be negative because the fluid is counteracting gravity (fluid is flowing upward), which means that the pressure drop is greater.

Thanks.

 

[Chestermiller]

Yes, that needs to be included.