[tomding0107]

Hello,

I have a question about the pressure boundary condition at the inlet.

I have been trying to do a motoring engine case in Converge, and I have pressure measuments for both inlet and outlet, P_in(CAD) and P_ex(CAD), howerver they are both static pressures.

So for the boundary conditions, I have tried to impose a P_in for inlet as static pressure and the same for outlet with P_ex.

The result is very strange, especially in the admission pipe where the velocity and temperature have very large values after 1 cycle, and finally the simulation can't continue as temperature goes beyond 5000K.

So I'm wondering if a correction/modification that we need to do on the P_in in order to convert it into total pressure. If yes, how shouldI do it?

Thanks for your help !

[Yaju]

Hi,


Engine cases generally do not have very high velocities at the inlet, so the difference between total and static pressure would not be very significant. So, the temperature should not be going to 5000 K.



Please check if appropriate grid sizes are used, you can look at the SI8 example case to see the base grid sizem, fixed embedding strategy for valve seat area and cylinder embedding, and velocity amr settings. Also, check if the pressure conditions you are giving is cyclic and the units are in pascals. Make sure that the events are set correctly between the intake-cylinder regions and exhaust-cylinder regions.