Flow in a thin nozzle

Saso Prijatelj

Hi.

I'm working on simulation of air-flow through an inlet duct and a valve into a cylinder of a diesel engine. I'm trying to determine the flow coefficient (that's ratio between actual and theoretical air-flow through a nozzle) and compare it with experimental results I have obtained. I use CFX5.5. Simulation are static (they are done for different openings of valve). Does anyone have any experience with modelling flow in very thin nozzle (when the valve openening is less than 0.5mm) where "happening" in boundery layer has great effects on overall mass flow.

Any help will be appreciated.

Best regards,

Sašo Prijatelj.