[piyuhota17]

Hi all,
I have a cylindrical reaction chamber with a pressure inlet(atm pressure) and an outlet (pressure outlet at vacuum). The cylinder is only partially filled with liquid (ammonium ion), the rest on the top is air.

Now this liquid is mixed with a hydroxide base flowing in through the inlet.
I have successfully set up the liquid mixing with a multiphase VOF (with 2 phases of air and mixture template) and species transport with ammonium and hydroxide. This is with no reaction. I am getting the correct results validated by experimental data.

Now I would like to set up the reaction chemistry. When the initial liquid(NH4+) in the reaction chamber is mixed with hydroxide (OH-) -two liquids mixing - leads to the production of ammonia (NH3) gas and water (H2O). I have tried to switch on the volumetric reaction on the species transport with adding all reactants and products correctly. Also, in the multiphase I have added a mass transport of Nh3 production from the mixture template to air; since NH3 is a gas that will escape from the liquid; I have accounted for the mass transport mechanism as evaporation/condensation.

My simulation is blowing up instantly with chemical reactions. Does anyone have any experience modeling such kind of chemical reaction flows? what models/schemes can be used to model such flow in Ansys fluent?