超高压往复泵液力端的流体激振力研究

Research on fluid excitation force at the hydraulic end of ultra-high pressure reciprocating pump

目前,针对往复泵的振动研究主要集中在动力端的曲轴以及曲柄连杆机构上,缺乏对液力端流致振动的研究。然而,超高压负载下的流致振动会影响往复泵的可靠性。为此,基于UDF(user define function,用户自定义函数)和Scheme脚本语言建立了能完整模拟吸入冲程和排出冲程的往复泵单缸仿真模型,并以流量和阀盘位移的理论曲线验证了仿真模型的正确性。同时,对不同的弹簧预紧力、弹簧刚度、限位器高度、曲柄转速和排出压力下往复泵单缸所受的流体激振力、腔内压力及阀盘运动随时间的变化情况进行了研究。结果表明,往复泵液力端的流体激振力是由柱塞腔内压力超调量瞬间释放所导致的;流体激振力最值出现在吸入阀开启之后,而非排出阀开启之后;现有结构参数下液力端最大的压力超调量和流体激振力分别为6.75 MPa和15.3 kN。基于往复泵单缸仿真模型的分析方法可用于往复泵流体激振力、阀盘运动和工作性能的预测,能有效减少超高压往复泵的研发周期和试验成本。

At present,the vibration research for reciprocating pumps mainly focuses on the crankshaft and the crank connecting rod mechanism at the power end,with a lack of research on fluid-induced vibration at the hydraulic end.However,the fluid-induced vibration under ultra-high pressure load will affect the reliability of reciprocating pumps.Therefore,based on UDF(user define function)and Scheme scripting language,a reciprocating pump single-cylinder simulation model that could completely simulate the suction and discharge strokes was established,and the correctness of the simulation model was verified by the theoretical curves of flow and valve disc displacement.At the same time,the changes in fluid excitation force,chamber pressure and valve disc movement over time for a single cylinder of the reciprocating pump under different spring preload force,spring stiffness,limiter height,crank speed and discharge pressure were studied.The results showed that the fluid excitation force at the hydraulic end of reciprocating pump was caused by the instantaneous release of pressure overshoot in the plunger chamber;the maximum fluid excitation force occurred after the suction valve was opened rather than after the discharge valve was opened,and the maximum pressure overshoot and fluid excitation force at the hydraulic end were 6.75 MPa and 15.3 kN,respectively.The analysis method based on reciprocating pump singlecylinder simulation model can predict the fluid excitation force,valve disc movement and working performance of reciprocating pumps,which can effectively reduce the development cycle and test cost of ultra-high pressure reciprocating pumps.