混输泵气液单向阀启闭瞬态空化流动机理研究

Gas-liquid check valve was a key hydraulic components in oil-gas mixture pump, whose poor ability to anti-cavitation erosion and short lifetime, would decrease the production efficiency of oil and gas engineering. In order to solve the key scientific problems which include the opening and closing transient cavitation mechanism and the measurement technology of flow structure in time and space, the basic theory and experimental research on opening and closing transient cavitation flow of gas-liquid check valve in mixture pump was breakthrough point. The nonlinear dynamics behavior and the forming process of cavitation of unsteady turbulent flow field at opening and closing moment were investigated to explore pressure load and flow pulsation characteristics distribution rule in high pressure flow areas under intermittent cavitation. Then vortex cavitation mechanism model of gas-liquid two-phase separation flow of check valve was established to discover the interaction mechanism between the open/close step movement and cavitation migration flows. The expected results will provide theoretical foundation for development and application of anti-cavitation erosion design system of efficient oil-gas transportation equipment.

混输泵气液单向阀作为油气混输设备中关键水力部件，在高压差、高含气率条件下抗空蚀能力差、使用寿命短的问题严重制约了油气开采工程的生产效率。为解决单向阀启闭瞬态动力学特性诱导内部空化发生与构建空化-流动结构响应关系等关键科学问题。本项目以混输泵气液单向阀启闭瞬态空化流动问题为切入点开展基础理论与实验研究，考察启闭瞬间非稳态湍流场下非线性动力学行为和空化形成过程，揭示阀体高压区间歇性空蚀作用下压力载荷、流量脉动特征及分布规律，建立单向阀气液两相绕流分离流动诱发旋涡空化机理模型，探讨单向阀启闭阶跃运动与气穴迁移流动的相互作用机制，为抗空蚀的气液混输产品设计体系的开发及应用奠定理论基础。

为解决单向阀启闭瞬态动力学特性诱导内部空化发生与构建空化-流动结构响应关系等关键科学问题。本项目以混输泵气液单向阀启闭瞬态空化流动问题为切入点开展基础理论与实验研究；（1）分析阿道尔夫微分方程不能直接描绘泵阀启动、闭合过程的原因，构建适宜于描述往复泵启闭瞬态流体动力学的运动方程。对比不同类型单向阀所受滞后性影响，确定锥阀作为气液混输泵主要阀芯原件。（2）根据推导的动力学特性方程开展实验验证研究，对比相关核心数据辨别启闭瞬态特性对空化诱发准则。考虑气泡为弹状、泡状特征，发展了一种两组双流体模型。基于当地流动结构的空化预测模型修正及验证。（3）搭建两相混输性能测试平台，调试进口混合器输送效果，优化局部结构。结合实验数据对比压力、功率、含气率、开启高度等技术指标及性能曲线。研究瞬态流场流动结构的变化与流体动力之间的关系。最后，根据核心泵阀结构影响参数确定空化影响大小，提出抑制空化流动的结构选型。

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