油圧作動油のキャビテーション
(第5報 絞り部キャビテーションに及ぼす液体特性と絞り材質の影響)
1982 年 13 巻 4 号 p. 269-275
詳細
1982 年 13 巻 4 号 p. 269-275
In this report, effects of the fluid properties and orifice plate materials on the cavitation characteristics of long orifices are presented. The cavitation characteristics were evaluated by the cavitation number corresponding to the disappearance of the choking. The fluids tested were two kinds of hydraulic fluid (petroleum base), a water-glycol, a spindle oil, five kinds of high water base fluid (HWBF), a tap water and a n-hexane. The orifices 2.5mm in diameter and 20.0mm in length were made of brass, acrylic resin, stainless steel and carbon steel.
The results obtained are as follows.
(1) Desinent cavitation number of choking kd for the hydraulic fluids, the water-glycol and the spindle oil, where orifice Reynolds Number Re has a magnitube of 103, increases with an increase in Re. kd for the water and the HWBF, where Re has a magnitude of 104, is nearly constant, and kd for the n-hexane, where Re has a magnitude of 105, decreases rapidly with an increase in Re.
(2) For the test where the outlet pressure is constant and the inlet pressure is varied, kd is less than that for the test in a reverse pressure condition, with a difference up to 0.1 at the same Re.
(3) Difference in kd in terms of the orifice plate material is less than 0.05, and in the case of a material easily wettable with the fluid, kd has a tendency to be smaller.
