compressibleInterFoam incl. viscous dissipation heating
Hello Foamers!
I am working on a modification of compressibleInterFoam, more specifically, I am trying to implement the term for viscous dissipation into TEqn.H in order to take viscous dissipation heating of highly viscous fluids (i.e. oil) into account. I managed to extend the source code of the TEqn.H file according to this thread: http://www.cfd-online.com/Forums/ope...n-heating.html Code:
volScalarField muEff(turbulence->muEff()); The results so far: T_aw = 305.4 K | standard compressibleInterFoam T_aw = 328.7 K | modified compressibleInterFoam Somehow, it seems to be working, however, it's strange that T_aw of the standard solver is almost 3 K higher than T_jet. Theoretically, it should be the same, right? The wall and outlet patches all have zeroGradient BCs. Another thing which makes me second-guessing my above mentioned implementation of the viscous terms, is a CFX simulation of the same problem. With viscous dissipation heating, it yields a adiabatic wall temperature of T_aw = 305.9 K which is significantly lower than the result of the modified solver. My question is quite simple: Did I miss something during the implementation of the viscous term? I tend to think that my definition of muEff is not completely right. AFAIK, it's muEff = mu + mut, which should hold since I'm using the kOmegaSST model. But I think, I made a mistake regarding the multiphase character of the case. If anyone has experience with this, your help will be greatly appreciated :) |
hello,
Did you get any good result ? Because i need to do the same. Did you take a look at this: http://www.cfd-online.com/Forums/ope...tml#post428926 By the way, you use muEff from turbulence->muEff(), but this is multiphase: this should be something like mixture.muEff instead ? regards, olivier |
Salut Olivier,
I'm not able to access my final version of the modified solver or my data, however, the results were pretty good compared to the CFX solution I used as reference. Maybe, with a bit of fine tuning, they would be extremely good ;) Let get back to you as soon as I can access my stuff again (I am moving at the moment :D) Regards, Victor |
Hello Victor,
Did you find your final version of your modified solver ? regards, olivier |
Hello Olivier,
sorry for the delay, setting up everything took a bit longer than expected :) In fact, I used the code from my first post and did a re-run of the exact case. The only thing I did was implementing a ramp for my mass flow rate. The modified solver now yields a T_aw = 306.7K, compared to T_aw = 305.9K from the CFX run. For the time being, it's sufficiently exact, but your point regarding the muEff is completely valid. I'm gonna check up on that, when I find the time ;) Best regards, Victor |
Quote:
Are you sure that viscous dissipation is calculated by: Code:
( tau && gradU ) Code:
0.5 * ( tau && gradU+gradU.T() ) |
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