高速重载液压系统气体溶解理论分析

Theoretical analysis of gas dissolution in high-speed and heavy-load hydraulic systems

针对液压系统中阀口空化后的气泡进入液压缸对液压缸表面造成气蚀以及对液压系统造成振动、噪声、不稳定等问题,以滚切剪液压系统为例,以液压油有效体积模量为桥梁,建立了阀口初始含气量和气泡运动距离之间的数学模型。通过不同的液压阀口后的初始含气量,得到孔道中气泡运动的最佳溶解距离,从而使更少的气体进入液压缸,并用Fluent进行仿真验证。研究表明:随着初始含气量的变化,孔内气体溶解的距离也在发生变化;并且分析发现数学模型和仿真模型误差在10%以下。该模型的研究有助于防止空化后更多的气泡进入液压缸,防止液压缸造成气蚀及密封装置出现断裂等问题,更有提高液压系统的稳定性。

In order to explore the cavitation phenomenon on the surface of a hydraulic cylinder and the instability of a hydraulic system caused by air bubbles entering into the hydraulic cylinder through pipelines after the cavitation at valve mouth,an effective volume modulus of hydraulic oil was taken as a bridge and a mathematical model was established to analyse the relationship between the initial air content at valve mouth and the distance of air bubbles movement.The travel length of the bubble movement in the channel was obtained according to the initial gas content after the gas passing through different hydraulic valve ports.The simulation was verified by using the software Fluent.The results show that as the initial gas content changes,the distance of gas dissolution in the pores also changes.It is found that the error caused by the mathematical model and the simulation model is less than 10%.The study of this model is helpful to prevent more air bubbles from entering the hydraulic cylinder after cavitation,and is benefitial to avoid causing cavitation in the hydraulic cylinder and breaking of the sealing device.It is more conducive to improve the stability of the hydraulic system.