Hi All
when the number of intake or exhaust valves is increased from 1 to 2 the discharge coefficient seems to increase by about 1.41 X the flow coefficients in the valve data. This leads to sonic flow in the port because the Effective_Section_Valve is more than the port.
The data that I have used to model the valves seems reasonable with a Cd of 0.6 based on the valve diameter, the port diameter used seems correct, it was measured directly on a cylinder head.
There is also a small increase in the Cd value (1.05 x approximately) when modeling only 1 valve. This is probably to account for differences between measuring Cd at lower Reynolds numbers and with ambient air, but I would like to understand how OpenWAM calculates this better.
I have “cheated” the input flow coefficients lower, or used a smaller reference calculation diameter to get the flow Cd approximately correct, and the results seem reasonable.
Thanks so Much
Tod
