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atlantis83 April 25, 2010 05:18

Intake Flow Simulation Accuracy
Good Morning

This is my first time in this forum and also my first time with Fluent.
I'm trying to simulate flow thoru the intake duct and valve of a gasoline engine to calculate the direct discharge coefficient with fluent and I procided in this way:

1 - mesh with workbench with y-plus between 30-300
2 - boundary condition:

2.1 - First Approach: - pressure inlet 101325 Pa total pressure
- pressure outlet 86325 Pa static pressure
this setup take to instable and non phisical solution

2.2 - Second Approach: - velocity inlet
- pressure outlet -15000 Pa relative to atmosperic pressure

in both cases I set a T.I. of 5% at inlet and 4% at outlet with relative hydraulic diameter.
As Solver i use Simple with Momentum Second Upwind and I initialize with inlet condition.

With second approach I obtain coherent values but the matching with experimental values of discharge coefficent was affected by at least 10% of relative error.

Have you any suggestion to improve the accuracy of this model??

Thank you very much.

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