流固耦合作用对螺旋离心泵流场影响的数值分析

Numerical Analysis for Effect of Fluid-structure Interaction on Flow Field in Screw Centrifugal Pump

摘要:

为研究流固耦合作用对螺旋离心泵内部流场的影响，以ZJ200—25型螺旋离心泵为研究对象，应用计算流体力学软件CFX12.1和有限元软件ANSYS Workbench对螺旋离心泵进行了考虑内部流场和结构相互作用的两场交替联合求解，并以相同的设置对不考虑流固耦合作用的内部流场进行了计算。对比分析两种计算方法得到的流场发现，考虑流固耦合作用后：泵进口处的压力波动加剧，出口压力波动强度降低，进出口波动频率不变，但相位有改变；速度分布满足共同的规律，但在小流量工况下差别最大，同时在叶片与隔舌处于相干位置时，隔舌附近流动也受到明显影响；径向力大小随时间变化规律一致，但波动范围减小；考虑流固耦合作用后叶轮流道内流动更加不对称。

Abstract:

In order to analyze the effect of fluid-structure interaction (FSI) on flow field in screw centrifugal pump, a ZJ200—25 screw type centrifugal pump with double screw blades was chosen as the study subject. The two-way coupling method was established to study the effect of FSI of impeller on flow field in screw centrifugal pump. CFX12.1 and ANSYS Workbench were used to the combined calculation for turbulent flow and structure response of impeller. And the unsteady flow field of the pump was simulated numerically under several operating conditions without effect of FSI. Compared the result of the two calculation methods, it’s found that, with the effect of FSI, pressure fluctuations in pump inlet intensified. The dominant frequency of pressure in inlet and outlet do not change but the phase position was different after FSI. The inner velocity distributions satisfy the common characteristic, but the largest differences were appeared under the condition of small flow rate. The flow field near volute tongue was affected by FSI most obviously when blades passing by the tongue. Magnitude of radial trust changing with time has similar regularities, but the fluctuation range with FSI method was reduced. Flow filed in impeller was more dissymmetrical under the effect of fluid-structure interaction. The conclusion obtained in this investigation will provide an essential guide to analyze the inner flow filed and master characteristics of rotor vibration characters and inducing factors of the pressure fluctuation in the screw type centrifugal pump.