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Old   October 14, 2018, 12:13
Default EDC convergence problems
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Andy
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Hi,
I'm using Ansys fluent to simulate methane-oxygen combustion at 10-20bar using:
-Turbulence: RANS (standard k-epsilon)
Scheme: coupled
-Combustion model: EDC
- Reaction mechanism: 17 Species, 50 REactions

The convergence of the transport equations is ok (10^-6). Also the mass conservation shows a very low descrepancy of 10^-9.

BUT the monitored "Total Heat Transfer Rate" (THTR)-difference between the incoming and outflowing energy got stucked at around 1% of the total incoming THTR:

(THTR[out]-THTR[in])/(THTR[in])=0.01

In an ideal case this value should be close to 0, since the energy getting in the system also has to leave (especially in a stady state simulation). So it is an exclusivly numerical error.
I heared that this is a typical problem of the EDC but I don't know why, or how to deal with it. Which parameter can be altered to reduce this discrepancy?

Thanks!
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convergence, edc, fluent, thtr, total heat transfer rate

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