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Elizabet April 13, 1999 20:15

internal combustion engines with FLUENT

I'm trying to simulate an internal combustion engine, with FLUENT, but I don't obtain convergence for the pressure..

I thought that perhaps FLUENT is not prepare to work with compressible flows, because all of the examples they gave are with entrances and outlets defined perfectly.

the simplified ICE I tryed to simulate was a rectangle, with one entrance to fuel, another to ar and one outlet. and they have boundary conditions varying with time.

really I don't get anything..

Is there anybody that get something and how??

thanks a lot

Melanie April 14, 1999 13:10

Re: internal combustion engines with FLUENT
I have been working with fluent 4 and fluent 5 for about a year simulating scram jet combustion chamber. 2d and 3d. I have always had a difficult time obtaining convergence for pressure. It is extemely grid dependent. I have found that using a low underrelaxation approx 0.2 for velocity and pressure help also. Ussually i use 0.5 for species,viscosity, etal.

any more questions please email me at

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