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lonestarstraits September 24, 2021 10:52

Temperature issue in cavitation simulations
 
Hi all


I am working on a cavitation problem involving water flow through an annular duct with a restriction, with a large pressure drop across the geometry (50 bar inlet to 0.5 bar outlet).



The case converges successfully as a single-phase problem (running energy equation, and k-w SST turbulence model).

However when I then attempt to switch on a multiphase model (mixture model, with Schnerr-Sauer cavitation mechanism), after a few iterations (starting from the converged single-phase result) the temperature in cavitated regions, which do start to form where I would expect them to, drops to a very low level causing "temperature in XX cells limited to 1 K" warnings etc. I have tried changing the lower temperature limit closer to the boundary condition value i.e. ~280 K but without success - temperature in vapor regions is still limited to this new low value.

As this seems to be the only issue I am encountering I was suspicious as to whether it was a simple case of having missed a required thermal boundary condition setting, but looking through various online tutorials I have found nothing.
Does anyone have any suggestions? Currently trying to converge the case with multiphase/cavitation model switched on, but energy equation switched off, which appears that it will eventually be possible, before re-activating energy equation at the end to see what happens. Is this a good approach?


Many thanks for any advice / suggestions.


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