井下螺旋轴流式混抽泵增压单元流场仿真分析

Flow field simulation analysis of pressurized unit on the downhole helicon-axial multiphase pump

为了对井下螺旋轴流式混抽泵增压单元内部流场及相应的运行特性进行数值分析,建立了增压单元的CFD分析模型,将试验结果与仿真结果进行对比。计算时将叶轮区域设在运动坐标系,其余静止区域设在固定坐标系,紊流计算采用标准κ-ε模型和非结构网格,速度压力耦合计算采用SIMPLE算法,非定常计算采用一阶精度的时间项,使用标准壁面方程以考虑边界层。结果表明,应用Fluent仿真软件进行数值模拟能够获得叶轮、导轮及整个泵的外特性,还可以直观地认识泵内部流动的耦合与干涉机理,指导水力模型设计;通过数值模拟不但可以比较初始模型和优化模型,还可对不同的优化模型进行比较,对混抽泵的结构进行优化,从而完善设计模型。

In order to complete the numerical simulation on internal flow and operating characteristics of downhole multiphase pump pressurized unit, the CFD analysis model of the unit is established and the test result and simulation result are compared. In calculation, the impeller region is set at the motion coordinate system, and the rest static region is set at the fixed coordinate system. In turbulent calculation, the standard κ-ε model and unstructured grid are used. In velocity-pressure coupling calculation, the SIMPLE algorithm is used. And in non fixed calculation, the one-step accuracy time term is used. The standard wall equation is adopted for considering the boundary zone. The result shows that the application of Fluent simulation software to carry out the numerical simulation can obtain outer feature of impeller, guide pulley and the whole pump and can visually know the coupling and interference mechanism of flow inside the pump for guiding hydraulic model design. By numerical simulation, the initial model and optimized model can be compared, and in addition, the different optimized models can be compared to optimize the structure of multiphase pump and improve the design model.