多柱塞阀配流往复式容积泵流量脉动的理论研究与仿真分析

Theoretical Study and Simulation Analysis of Flow Fluctuation of Reciprocating⁃type Positive Displacement Pump with Multi Plunger and Check Valve

多柱塞阀配流往复式容积泵的排液流量存在脉动现象是由这类泵的结构特点及工作原理决定的,是这类泵的固有属性。在忽略配流阀动力学过程及柱塞副泄漏效应前提下,建立了三柱塞泵及五柱塞泵量纲一化瞬时排液流量理论模型,并分析了这两类泵排液过程的循环工作节拍以及流量脉动发生机制;引入上流量脉动率与下流量脉动率来量化衡量流量脉动程度,并分析柱塞数量以及曲轴旋转半径与连杆长度比值这两项指标对流量脉动率的影响规律;借助AMESim软件搭建了未包含蓄能器的三柱塞泵液压仿真模型,并在仿真数据量纲一化处理基础上开展了与理论分析结果的对比研究。研究结果表明:这类泵的每个循环周期内,排液流量曲线出现了两次波峰、一次波谷,并由此造成上流量脉动率较小、而下流量脉动率较大;对于奇数数目柱塞泵而言,流量脉动率随着曲轴旋转半径与连杆长度比值的增大而增大;对于偶数数目柱塞泵而言,流量脉动率均较高,且与这一比值无关;这类泵进液阀关闭滞后将诱发流量曲线波谷位置滞后、深度加深,并导致同一个循环周期内的两个波峰位置不再对称、高度不再相等。此研究成果可为这类泵的变排量改进设计及面向负载工艺过程的稳压供液技术研究提供参考。

The fluctuation of outlet flow of reciprocating⁃type positive displacement pump with multi plunger and check valve is determined by the structural characteristics and operational principle of this kind of pump,which is the inherent property of this kind of pump.In this study,the theoretical model of dimensionless instantaneous outlet of 3-plunger and 5-plunger reciprocating positive dis⁃placement pump were established without considering the dynamic process of valve and leakage effect of plunger pair,and the cycle working rhythm and flow fluctuation mechanism of these two kinds of pump were analyzed;the upper and lower flow fluctuation rates were introduced to quantitatively measure the flow fluctuation,and the influence of the number of plunger and the ratio of crankshaft ro⁃tation radius to connecting rod length on the flow fluctuation rate was analyzed;the hydraulic simulation model of 3-plunger pump with⁃out accumulator was built based on AMESim,and a comparative study with the theoretical analysis results was carried out on the base of dimensionless process of the simulation data.The results show that:there are two peaks and one trough in the outlet flow curve among every working cycle of this kind of pump,which results in smaller upper flow fluctuation rate and bigger lower flow fluctuation rate;for odd number plunger pump,the flow fluctuation rate increases with the increase of the ratio of crankshaft rotation radius to con⁃necting rod length;for even number plunger pump,the flow fluctuation rate is higher and independent of this ratio;the inlet valve clos⁃ing lag of this kind of pump causes the position lag and depth deepening of the flow curve trough,and leads to the position of the two peaks in the same cycle is no longer symmetrical and the height is no longer equal.The results of this study can be used as reference for the improvement design of this kind of pump with variable displacement and the research of fluid supply with steady pressure tech⁃nology oriented to the action process of hydraulic loading.