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Im September 3, 2001 22:33

material mass imbalance
Hi everyone.. Nowadays I have been tried to solve acrylate mixer. The used components in this problem are C3h402, c4h10o, h2o,c7h12o2. I used MRF to simulate rotating of agitator. When I solve it as single species, it was converged and showed good result. But I try to solve it as multi-species, it doesn't converged. Eventhough total mass flow rates at inlet, outlet are exactly same, material balance of each species doesn't make sense. Especially, the last species in material table shows lagerest mass imbalance. The latest material c7h12o2 totally disappeard at the outlet. I try to change the order of material in material table. but it shows same result. if I put c3h4o2 to the last position in material table, c3h4o2 goes nearly zero at the outlet. I try to remove MRF, but the result is same. I put pseudo-material in material table, but I have same results. I don't know what I to do to fix this error. Please show me the way to solve this probelm.

Thanks in adavnce.

Y. H. Im

david September 5, 2001 05:29

Re: material mass imbalance
A) When the solution does not converge, there is no point of checking the material balance of each component :) B) why don't u start with 2 components and see how it goes (50% and 50%)? DC

Im September 5, 2001 20:15

Re: material mass imbalance
Thank you for your response. I have been tried with 2 components. The result was same. But there is something particular features. In my case, there is 2 inlets. If the mass fractions are same at 2 inlets, then the solution going to converge. but if the mass fractions are different, the solution didn't converge. And, as mass fraction difference between two inlet increase, mass imbalance increase.

david September 5, 2001 22:47

Re: material mass imbalance
I think there is no steady state solution for your case. DC

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