Mass imbalances

Timmy

Hi everybody,

I have a problem concerning the convergence of my simulation. I modelled a steamflow through a very thin gap between two casings of a turbine. The interesting part of my simulation should be the influence of the steamflow on the heat flux between both casings. Through a few boreholes the steem gets into the domain (total pressure at inlet) and leaves it through some other boreholes (massflow at outlet). These boreholes are orientated perpendicular to the gap. Because the gap is so thin but widely expanding I chose a hex-grid for meshing. The quality of the mesh is as good as possible for my geometry. Now as I started the calculation it seems that my p-mass imbalances and the h-energy imbalances are far from good. They fluctuate stochasticly on a very high level (+/- 10%). The RMS residuals look fine though. I use the SST-modell.

Maybe there is someone who can give me a good advice what I could do to get rid of these imbalance fluctuations.

Thanks in advance,

Timmy