射流泵内压力分布研究

本文采用CFD模拟了射流泵中的流动情况,并对射流泵结构进行优化设计以抑制空化。采用不同湍流模型发现计算结果类似,雷诺应力模型相对来说与实验数据更为相符。随着流量比的增大,最低压力点位置由喷嘴出口平直段衔接处向喉部衔接处转移。随后本文对这两处位置进行优化,取消喷嘴出口平直段,采用渐缩喷嘴,模拟结果显示该方案能有效消除喷嘴处的静压低压区;对喉部衔接处进行光顺化处理能有效提高该处的最低静压值。本文的计算结果能为射流泵优化设计提供参考。

CFD simulations for the optimization of jet pumps

The 3-D flow inside the jet pump was simulated in this paper. The static pressure distribution, which isre-lated to the cavitation phenomenon occurring inside the jet pump, was analyzed. It was found that different turbulencemod-els lead to similar simulation results, and the Reynolds stress model offers the best efficiency prediction comparing with the experimental data. The simulation results show that the location of minimum static pressure moves from the nozzle exitre-gion to the connection between the suction chamber and throat when increasing the flow rate ratio. Then two optimizations have been proposed: 1. adopting the convergent conical nozzle design and removing the straight zone at the nozzle exit. 2. Using the smooth curve instead of the sharp connection between the suction chamber and throat. Those two optimizations could both significantly improve the minimum static pressure, which further suppression the cavitation phenomenon. The simulation results could provide theoretical support for the jet pump designs.