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Error: Divergence detected in AMG solver: x-momentum |
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#1 |
Senior Member
Gustavo
Join Date: Jun 2015
Posts: 121
Rep Power: 11 ![]() |
Hi,
I´m trying to simulate the gas (O2 + N2) flow inside a low pressure chamber. In this moment I´m not interested in reactions. I´m using steady state, laminar model (Low Pressure boundary slip), activated energy equation and species Transport (inlet Diffusion, Diffusion energy source, Thermal Diffusion enabled). Operating conditions - 1Pa inlet (mass-flow-rate) = 4.26e-6 outlet (pressure-outlet) = 0Pa When I start Simulation the message error appears "Error: Divergence detected in AMG solver: x-momentum" and I´m not able to solve it. I tried to reduce the Relaxation factors... but didn´t worked. Anyone has a hint? thanks in advance |
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#2 |
Member
Jim
Join Date: May 2015
Posts: 47
Rep Power: 11 ![]() |
try the following:
- don't use mass flow; stick to velcity inlet and pressure outlet. do a back-of-the-envelope calc to find velocity from continuity. - don't mess with the URFs justnow; stick to the defualt settings. - don't start with mixtures; start with the defualt air. keep going more and more simple until it works. also, could be an issue with the mesh. have you named the inlet & outlets etc ? |
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#3 |
Senior Member
Gustavo
Join Date: Jun 2015
Posts: 121
Rep Power: 11 ![]() |
Thank you so much for your suggestions. I will try it and let you know. Regarding your questionar I named The outlet and outlet. Should I named walls too?
How can I find The velocity from The continuou equation using mass flow rate? The Knudsen number is 0,038 Thanks |
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#4 |
Member
Jim
Join Date: May 2015
Posts: 47
Rep Power: 11 ![]() |
Hi gustavo,
sorry, I shouldn't have called it a "continuity equation", the term is ambiguous in this context. I meant: Q=rho*u*CSA mass fr = density * velocity * cross sectional area for flow. and rearrange for velocity. |
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divergence amg solver |
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