円筒形絞りのキャビテーション特性 : 第2報,非定常流における臨界キャビテーション係数

抄録

This paper deals with an experimental study on the unsteady performance in cylindrical choke of the oil hydraulic equipment. Experiments are performed under unsteady flow in which the outlet pressure P₂ of the cylindrical choke takes the form of a trapezoid varying with time, keeping the inlet pressure p₁ constant. It is found that as the absolute values of the rates of pressure change dp₂/dt increase, the incipient cavitation number k_ci shows a tendency to decrease, and the desinent one, k_cd, shows a tendency to increase with three geometric parameters : diameter, length and chamfered length of the choke. The values of k_ci, and k_cd with the chamfered length of chokes are smaller than those with the sharp edge of chokes for various dp₂/dt. As the larger absolute values o dp₂/dt further increase, the hysteresis between k_ci and k_cd becomes larger for each combination of the cylindrical choke.