油气混输泵单向球阀启闭瞬态性能试验研究

为了研究变工况来流环境下各参数变化对单向球阀的启闭迟滞性影响,针对3DP-60/3.0型往复式混输泵单向球阀的启闭瞬态过程及往复运动特征,运用UDF动网格技术计算气液单向阀启闭高度-时间函数,重点分析启闭瞬时2种极限情况下入口流体速度、压力及动能损失.揭示了不同入口流量、开启高度、含气率等工况参数对单向球阀内部压力场、气液两相分布的影响规律,并通过试验数据和模拟结果进行对比,验证数值模拟的可靠性.研究结果表明:无论是在纯液相还是低含气率下,随着入口流量的增加,球阀压降增加,而且增加幅度比较均匀.在含气率分别为80%,60%,40%时,开启高度从2~6 mm过程中入口压差逐步减小,呈现递减分布规律;20%至纯液工况(含气率为0)时,开启高度越低入口压差变化越大,体现球阀界面气液逐步分离产生界面压差也更大.含气率从0增加到0.9,球阀压降的降低幅度非常明显,随着含气率的进一步增加,压降不断减小.

Study on transient opening and closing performance of one-way ball valve in oil-gas multiphase reciprocating pump

The transient opening and closing processes and reciprocating motion characteristics of the one-way ball valve in the 3DP-60/3.0 type oil-gas multiphase reciprocating pump were simulated by using user-defined functions(UDF)and dynamic mesh model in Fluent to investigate the influence of different parameters on hysteresis in the processes under variable flow conditions.The opening height-time function of the valve was involved in a UDF and the inlet fluid velocity,static pressure and kinetic energy loss under two limit conditions of opening and closing moments were focused.The influences of inlet flow rate,opening height and gas content on the pressure field and gas-liquid two-phase volumetric fraction distribution in the valve were revealed.Experimental data were compared with simulated results to verify the reliability of numerical simulations.The results show that the pressure drop across the valve rises with increasing inlet flow rate whether under pure liquid or low gas content two-phase flow condition,particularly with a more uniform increment.The inlet pressure difference gradually decreases when the opening height increases to 6 mm from 2 mm,presenting a decreasing trend with the gas content being 80%,60%and 40%,respectively.When the gas content is reduced to 0%(pure liquid condition)from 20%,the smaller the opening height is,the greater the inlet pressure varies,showing a gradual phase separation on the valve surface and a larger interfacial pressure difference.The decrease of pressure drop across the valve is very significant as the gas content varies from 0%to 90%,especially,the pressure drop decreases steadily with further increasing gas content.