Development of gaseous cavitation model in hydraulic oil flow considering the effect of dynamic stimulation

Abstract

Hydraulic equipment is widely used in the industrial eld. For example, driving equipment such as power steering of automobiles, and construction machinery such as hydraulic excavators, and so on. The oil used in these machines is called hydraulic oil. In hydraulic oil system, the cavitation has an in uence on its durability and efficiency, therefore the prediction of cavitation phenomena has an important meaning for the design of hydraulic equipment. However, experimental prediction is difficult because hydraulic equipment is used under severe conditions of high pressure. Generally, cavitation is classi ed in two types. One is caused by evaporation of working uid which occurs when the local static pressure goes lower than the local saturated vapor pressure, called vaporous cavitation. The other is by the liberation of dissolved air, called gaseous cavitation. Among these two types, the vaporous cavitation is considered predominant in the water. On the other hand, in hydraulic oil, the saturated vapor pressure in the standard state is usually assumed to be close to 0 Pa. Therefore, in hydraulic oil, gaseous cavitation due to air dissolved in oil at a relatively high volume ratio is considered to be predominant and the mechanism of occurrence, which is completely different from cavitation occurrence with water. In the past researches, in order to understand the characteristics of gaseous cavitation, a number of studies has been conducted. However, regarding a speci c cause of the liberation of dissolved air, the threshold values and formulas that serve as criteria are not proved. In this paper, the cavitation phenomena in hydraulic oil is investigated, and a new gaseous cavitation model based on the dynamic stimulation is presented.