[Dereje]

Hello everyone!

I'm studying the effect of liquid holdup on flow of gas in packed bed. I am using Eulerian multiphase model in 3D in Fluent.

In my control volume, gas is initially patched uniformly in the flow control volume at 60% as liquid is primary phase. Gas is injected from below and discharged at the top. I used velocity inlet and degassing boundary conditions at outlet so that liquid never leaves the control volume. I was continuously monitoring the liquid mass flux at inlet and outlet and it was zero always. However, when I check the volume fraction of liquid and gas gradually, liquid volume fraction decreases and gas increases. I am confused why liquid is decreasing even though degassing BC is used.

Could anyone give me any advice why liquid volume fraction is decreasing? Any form of idea is highly appreciated. For better understanding, I attached the volume fraction decreasing of liquid.

Thank you so much !!!
Dereje