Learning Forum

[DENG]

1. The input parameters defined by keywords CESE_MAT_GAS and CESE_EOS_IDEAL_GAS specify which regions exactly, and aren’t the initial conditions for the entire fluid defined by CESE_INITIAL_CHEMISTRY?

2. If there are mixed gases with different temperatures, pressures, or compositions within the same fluid domain, should different SET_SOLID definitions be used, represented by different CESE_INITIAL_CHEMISTRY_SETS, and will multiple defined SETs overlap?

3. What is the maximum number of grids that the CESE solver can compute, and can the number or size of grids lead to result errors?

4. I encountered a detonation using the same CESE parameters with fewer grids and only CESE grids, but when I increased the grids and added aluminum alloy, I got the following errors: Error 150209 (CHEl+209) Chemistry EOS nonlinear temperature solver failed to converge. Error code=50 Last iterate temperature = -0.10209E+04 Error 150210 (CHEI+210) Nonlinear chemistry EOS temperature solver returned a negative value. CHEM_COMBUST_I: Failed to converge What could be causing this error?

 

[Ashish Khemka]

Hello,

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Regards,

Ashish Khemka

[Atish Gawale]

Hello,

1) If you have defined composition of fluid using *CHEMISTRY keywords, then you need to use CESE_INITIAL_CHEMISTRY otherwise use CESE_INITIAL. Then you must also specify the CESE_MAT_GAS and CESE_EOS. 

2) Yes, you need to create the SET_SOLID for each composition and they should not overlap.

3) Grid size should be very small. Min size can be less than 1cm in the combustion domain. I will recommend structured hex mesh. 

4) Error is typical with CESE solver. If solver finds anything non-physical then it gives only one typical error for any problem. Be is related to mesh size, time step size, non-physical pressure, temperatures, boundary conditions or any other problems. 

Regards,
Atish