多孔喷嘴射流泵流动模拟与涡结构分析

基于有限体积法和Realizablek—s湍流模型，对多孔喷嘴射流泵内部流场进行数值模拟和分析，并与试验结果进行对比，验证了数值模拟的可靠性．引入涡动力学理论对喉管内部工作流体和被吸流体的混合机理进行分析，研究了喉管内部流向涡和展向涡的分布及其峰值沿流向的变化．结果表明：多孔喷嘴结构能够加快工作流体和被吸流体的混合，提高射流泵的效率；射流泵喉管内的涡结构对工作流体和被吸流体的混合有重要影响，相对流向涡而言，展向涡的强度较大，在喉管内的衰减较为平缓；在射流泵中，对两股流体起主要掺混作用的是流向涡，其强度和衰减的速率决定了混合效率；在涡量一定的情况下，流向涡越强，衰减越快；展向涡结构越小，越能加速喉管中的混合，从而提高泵的效率；喉管内涡的分布表明，位于喷嘴中心的出口可能导致较大的损失，各孔喷嘴出口应优先沿圆周方向布置．

Flow simulation and vortex structure analysis of multi-nozzle jet pumps

Based on the finite volume method and Realizable k - s turbulence model, the flow field inside multi-nozzle jet pumps was investigated numerically. The calculation reliability was validated by experimental data. Based on the simulation results of streamwise and spanwise vorticity distribution and their peak value variation, the mixing mechanism of the two fluids was analyzed. The results show that the multi-nozzle could promote the mixing and improve pump efficiency. The vortex has great effects on the mixing. Relative to the streamwise vorticity, the spanwise vorticity value is large and the attenuation becomes fiat. The streamwise vortex plays a major role in the mixing. The value and attenuation rate of streamwise vorticity determine the effect of the mixing in the throat. For a definite vorticity value, the greater the streamwise vortieity value is, the faster it decays. The smaller the spanwise vortex size, the faster the mixng, and the higher the pump efficiency. The vorticity distribution in the throat indicates a central nozzle may lead to greater losses. The optimum distribution is that all the nozzles are on a circle.