Eulerian multiphase model momentum divergence
 

Dear friends

I am trying to simulate PEM water electrolysis with Eulerian multiphase model, where anode side is fed with liquid water and oxygen is the product at anode and hydrogen at cathode. Based on this, I defined inlet at anode as liquid water which is defined as the primary phase and oxygen as the secondary phase. Since there is no oxygen inlet, my inlet boundary condition is primary phase (water) inlet velocity and the secondary phase (oxygen) volume fraction is defined as 0 and velocity is also 0. Based on the faradaic law, I defined the mass source term for both primary phase (water) and the secondary phase (oxygen) as -j/2F and j/4F respectively. When I run the fluent, the volume fraction of secondary phase instantly reaches 1 and primary phase as 0 causing momentum divergence. I have attached the screenshot of model I am using. Please help me fix it.

viscous: laminar:
model: Eulerian (2 phases) Implicit formulation
Drag: schiller-naumann
Lift: saffman-mei
Wall Lubrication: antal-et-al
Heat, Mass: none
surface tension: 0.072
Interfacial Area: ia-particle

Attachment 95099

Attachment 95100

Attachment 95101

Attachment 95102
Thanks
Faizan