Cavitation in a non-circular opening spool valve with U-grooves

Abstract

A numerical method and an experimental analysis were applied to obtain a better understanding on the characteristics of cavitation inside the non-circular opening spool valve with U-grooves. The relationship between structural parameters and cavitating flow inside the valve, as well as acoustic noise, are studied. A two-staged flow resistance model was brought forward for the qualitative prediction of the cavitation intensity and incipient cavitation number inside the valve. The throttling effect of the first throttling stage plays an important role in the incipience and development of cavitation inside the valve. The reduction of pressure loss caused by the first throttling stage benefits to the cavitation resistance. With the decrease of cavitation number, the acoustic noise level increases until the former reaches the critical value (σ=0.04). Once cavitation number is below the critical value, the flowrate of the valve is choked, and the acoustic noise level decreases instead.