Numerical analysis of the jet issuing from a poppet valve

The present study describes the numerical analysis of the jet issuing from a poppet valve together with the now inside it using a streamline-coordinate system. In this system, the flows with free surface and inside the complex geometrical shapes of poppet valves can be analysed, because the boundary conditions are easily satisfied. Parameters used in this analysis are poppet shape (cone angle for conical type and radius for spherical type), seat chamfer width, seat chamfer angle, valve lift and now rate. Pressure distributions and now forces acting on poppets were analysed in detail. The computed results were in good agreement with the experimental ones. It is shown that now force is almost independent of now rate for sharp edge seat, but strongly dependent for chamfered seat.