喉管长度对环形射流泵性能影响的数值模拟

基于有限体积法和Realizablek-ε紊流模型,应用Fluent软件对环形射流泵内部流场进行数值模拟,并对计算的可靠性进行验证.由射流泵内部流场可以看出,环形射流泵射流的扩展混合在喉管和扩散管中均存在.针对不同喉管长度下环形射流泵内部射流扩展和壁面压力分布情况,模拟分析了不同喉管长度对环形射流泵性能和效率的影响.结果表明,喉管长度对喉管内射流扩展、环形射流泵性能和效率均有一定影响.喉管越长,射流扩展混合程度越好,但过长的喉管会带来较大的摩阻损失.根据效率最高原则,环形射流泵喉管长度Lt应符合Lt/Dt=2.17-2.89,其中当喉管长度为喉管直径2.69倍时效率最高,可达到35.6%.

Numerical simulation for influence of throat length on annular jet pump performance

The flow inside an annular jet pump was investigated numerically by Fluent based on finite volume method and Realizable k-ε turbulent model,and the reliability of calculations was examined and validated.From the flow field of the jet pump,the expansion and mixing of two streams in the annular jet pump exist in both throat pipe and diffuser.The development of jet flow and wall pressure distribution under different length of the throat pipe was discussed and the effect of throat length on performance and efficiency of annular jet pump was also compared and analyzed.The results show that the throat length has some influence on the expanding of jet flow inside the throat,as well as the performance and efficiency of annular jet pump.The longer throat length,the better expanding and mixability of jet,but over-long throat length will result in more friction loss.According to the principle of best efficiency,the range of throat length is Lt/Dt=2.17～2.89,and when the throat length is 2.69 times of throat diameter,the efficiency achieves its maximum value of 35.6%.