液压系统气穴实验的相似设计

On the Design of Cavitation—Similitude Experiments in Fluid Power Transmission and Control Systems

本文从控制气穴的运动微分方程及其解出发,导出了扩散型气穴的相似准数,讨论了液压系统中气穴实验的相似设计问题,指出气穴起始与液压油本身的压力关系不大,主要取决于介质中溶解气体含量的状态参数λ_c及等效降压比λ_(pw),从而在满足Euler相似准数Eu,Reynolds相似准数Re及本文导出的气穴相似准数A的条件下,可用低压系统模拟高压系统中的气穴现象。文中还对气穴判据等问题进行了探讨,并给出了一个气穴机理实验系统设计的实例。

Based on the governing equation and its solution of gaseous cavitation in FPTC systems, the similitude number for cavitation of this type is derived in the paper, the design of cavitation—similitude, experiments in FPTC systems is discussed. It is pointed out that cavitation onset in FPTC systems is mainly controled by the dissolved gas content, gas nuclei density and the equivalent pressure—drop ratio in the system, while the pressure in the liquid medium does not take a directly influence on it. The results make it possible to model cavitation phenomenon in a FPTC system of higher pressure with a lower pressure system, to do so, in addition to Euler number Eu and Reynolds number Re, the cavitation similitude nurnber A derived in this paper should be equal in both systems. The principle for assessment of cavitation inception in FPTC systems is also discussed. Finally, an example for designing the experimental set—up for cavitation modelling in FPTC systems is given.