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k residual goes up after temperature limitation warning???

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Old   November 24, 2010, 17:48
Default k residual goes up after temperature limitation warning???
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Dear all,

I am modelling the combustion of methane-air in a stirling engine burner and after, say, 65 iterations and while all residuals decrease i get the temperature limitation (limited to 1K) warning and once I get it the k residual starts to increase (while all the rest keep going down).
At the moment the warning is restricted to 1 to 3 cells.

What I am using is the species transport with no reactions yet activated and the realizable k-ε turbulence model.

The solution is steady state.

I can tell that solution is at an early stage by a velocity monitor in my outlet which has not yet stabilised.

I understand it might be too early to worry but I think whatever is wrong has started affecting other cells

I am using a very fine tetra mesh with prism layers on the walls.

my bocos are:

mass flow inlet for my air and gas inlets with turbulence specification set to intensity and ratio - default values of 10% for both

outflow for my exhaust

coupled walls for components inside the burner where I must later compute conjugate heat transfer

0 heat flux for all other walls (e. g. the base of the burner)

I am running this huge case on a super computer facility and I am a bit pressed in time so any suggestions would be most appreciated


All the best
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