{"id":368773,"date":"2024-05-27T17:50:11","date_gmt":"2024-05-27T17:50:11","guid":{"rendered":"\/forum\/forums\/topic\/cese-chemistry-solver-fails-in-2d-axisymmetric-case\/"},"modified":"2024-06-03T10:15:14","modified_gmt":"2024-06-03T10:15:14","slug":"cese-chemistry-solver-fails-in-2d-axisymmetric-case","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/cese-chemistry-solver-fails-in-2d-axisymmetric-case\/","title":{"rendered":"CESE Chemistry solver fails in 2D Axisymmetric case"},"content":{"rendered":"

Hello, I’m trying to set up a simple 2D axisymmetric simulation using the compressible CESE Chemistry (inviscid). I defined an H2-O2 reaction mechanism with 8 reactions and gave the thermodynamic input file.<\/p>\n

Background:
The simulation domain is a rectangle with solid walls and an ignition zone with high pressure and temperature. When I use a 2D planar simulation (igeom=2), a shock wave develops and propagates in the H2-O2 mixture. The temperature, pressure and speed of the shock wave closely match the theoretical CJ values for hydrogen detonation, so I assume the simulation is correct (see the image below). <\/p>\n

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Problem: 
However, when I switch to the 2D Axissymetric simulation the simulation doesn’t converge and weird\/non-physical values show up in the results. Instead of a uniform propagation of the shock wave, I get random spots with non-sense values (even away from the ignition point), as shown below. The only difference to the 2D planar simulation is that I define the *CESE_BOUNDARY_AXISYMMETRIC in the y-axis and change the *CESE_CONTROL_SOLVER card to perform a 2D axisymetric simulation (igeom=101). <\/p>\n

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The error message is:
 *** Error 150209 (CHEM+209)
     Chemistry EOS nonlinear temperature solver failed to converge.
     Error code = 50 Last iterate temperature = -0.21165E+04<\/p>\n

I tried to simplify the problem by reducing the reaction mechanism and removing the ignition but the problem persists. Additionally, I reduced the mesh size and the time step and still doesn’t converge. However, if I run the CESE axisymmetric simulation without the chemistry cards the results are okay.<\/p>\n

Has anyone faced similar problems or has any idea on how to approach these issues?? 
I need to set up the axisymmetric case since my next step is to run a simulation of a cylinder with bigger dimensions. <\/p>\n","protected":false},"template":"","class_list":["post-368773","topic","type-topic","status-closed","hentry","topic-tag-2d-axisymmetric","topic-tag-CESE-1","topic-tag-cfd-convergence","topic-tag-chemistry","topic-tag-detonation-1","topic-tag-hydrogen-combustion","topic-tag-ls-dyna"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t