Exhaust Valve Geometry and Its Effect on Gas Velocity and Turbulence in an Exhaust Port

The influence of fluid flow phenomenon in the exhaust valve and port region on available energy at the turbine of a turbocharged diesel engine is discussed. Zones of high fluid shear, recirculation and vortex shedding all increase fluid entropy and heat transfer and reduce turbine available energy.

Detailed measurement of fluid velocity and turbulence intensity downstream of the exhaust valve have been made for six valve designs. The fluid flow characteristics are discussed and the influence of geometric design changes presented. Overall discharge coefficients are included.

The data will also be useful for validation of detailed fluid dynamic models of flow through valves.