喷射泵内部流动模拟与其扩散角优化

Optimization of Divergence Angle of Jet Pump Based on Numerical Simulation of Interior Flow Field

扩散管的扩散角是喷射泵的重要结构参数之一。采用SIMPLE算法和Realizable k-ε湍流模型,应用FLUENT软件计算了不同扩散角下某型喷射泵的性能,对轴线速度、沿程压力及扩散管进出口的动能与动量修正系数进行了计算与分析。结果表明:扩散角的变化对扩散管上游部分的流场几乎不产生影响,只对下游产生影响;扩散角对喷射泵性能和效率的影响是通过扩散管的阻力和流动损失来施加的;最优扩散角的取值范围应从经济和效率两方面综合考虑,以9.2°扩散角所对应的喷射泵为基准,以最高效率相对变化2.5%为原则,结合泵的外形尺寸和制造成本,认为最优扩散角的取值范围为8°～11°。

The divergence angle of a diffuser is one of the important structure parameters of the jet pumps,which has effect on the performance,interior flow field distribution and manufacture cost of the jet pump.In this paper,SIMPLE arithmetic and Realizable k-ε turbulence model is adopted to simulate the flow field and performance of jet pump of various divergence angles.The analysis on the centerline velocity,wall pressure distributions as well as the momentum correction coefficient and dynamic energy correction coefficient in the inlet and outlet of diffuser indicate that the divergence angle has less effect on the flow upstream the diffuser.It influences greatly the flow in the diffuser and downstream pipe.The effect of divergence angle on the performance and efficiency of jet pump is imposed by the resistance loss in the diffuser.Both the manufacture cost and pump efficiency should be considered together in the optimization of the divergence angle.Under a guideline of relatively changing 2.5% from the maximum efficiency point,the optimal divergence angle is proposed as 8°-11° considering the overall dimension and manufacture cost.