View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0002730 | OpenFOAM | Contribution | public | 2017-10-20 10:26 | 2017-11-01 18:23 |
| Reporter | fxzf | Assigned To | wyldckat | ||
| Priority | normal | Severity | minor | Reproducibility | have not tried |
| Status | closed | Resolution | no change required | ||
| Summary | 0002730: heat flux boundary condition for incompressible flow with radiation | ||||
| Description | Hi, I am trying to develop heat flux boundary condition for incompressible heat transfer solver. e.g. BuoyantBoussinesqSimpleFoam. In some case, I need to specify heat flux at wall. The current externalWallHeatFluxTemperature is only for compressible heat transfer solver. So basically, I derived this boundary condition from fixedGradientFvPatchScalarField type. It take user specified HeatFlux_ (in 0/T) , CpRef, RhoRef (in transportProperties), and grab alphaEff from solver. Then, it fixed gradient use gradient() = (heatFlux_) / (alphaEff * CpRef.value() * rhoRef.value() ); if there is radiation involved, it grab radiation heat flux qr from field and do gradient() = (heatFlux_ + qr) / (alphaEff * CpRef.value() * rhoRef.value() ); Now, it is working well when radiation is off. The results is also match with Fluent. However, when radiation is on, qr is normally large like 10^6 to 10^8 (when one side is 2000K)level at beginning, this will lead gradient goto 10^8 to 10^9 level. Then, my temperature goto 10^5 and then solver divergence very quickly. I tried the same mesh and same case in Fluent, it has high qr at beginning as well. But the temperature in next step got in Fluent is only upto 4000K, and it eventually converged back to sensible number. Could you please give me any advice if there is anything wrong here? I can provide my code and test case if required. Thanks very much. Best Regards, Feng | ||||
| Tags | No tags attached. | ||||
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As of OpenFOAM 4.0, the Boussinesq approximation is done with compressible solvers, as indicated in: - the release notes... it's only mentioned in OpenFOAM 5.0: https://openfoam.org/release/5-0/ - but it was already implemented for 4.0... - in this commit: https://github.com/OpenFOAM/OpenFOAM-dev/commit/dfecb23b08c04c92401bc0bdf904ed0793c3be66 - and is documented here: https://cfd.direct/openfoam/user-guide/thermophysical/#equation-of-state This makes it a lot easier to maintain and keep the implementations generic. See the comments on the following report for more details on this development choice: https://bugs.openfoam.org/view.php?id=1856 Therefore, adding further support for radiation to the incompressible implementation (which is limited to the Boussinesq approach) is redundant and makes this report fall within the term of "user support". Please see the rules guidelines for more details: https://bugs.openfoam.org/rules.php I'm closing this report as "no change required". |
