气液两相喷射器喷嘴型线优化设计

Optimal design of nozzle profile for gas-liquid two phase ejector

采用均相流模型一维计算方法,优化设计两相喷射器的工作喷嘴型线,与对应工况锥形喷嘴的流动参数进行对比。运用流体动力学方程,先使用等压降方法计算喷嘴型线,进而采取更适合两相流动的等速度梯度数学方法来优化型线。结果表明:在流场出口压力以及出口速度差值在1%以内的情况下,相较于锥形结构喷嘴,此方法得到的喷嘴结构贴合两相流膨胀加速过程,关键位置压力降变化稳定,膨胀波发生位置后移90%,喉部后的流体平稳区域是其5倍,加强对超音速流体的适应能力,得到良好品质的出口流场,使喷射器中工作流体和引射流体的初步混合不偏离理想混合压力,降低对喷射系数的影响。

A one - dimensional calculation method of homogeneous flow model was used to optimize the design of the work ing nozzle line of the two - phase ejector, and the flow parameters of the conical nozzle were compared with the corresponding working conditions. Using the hydrodynamic equation, the nozzle type line was calculated first by using the equal pressure drop method, and then the equal velocity gradient mathematical method which was most suitable for two - phase flow was adopted to optimize the line. The results show that under the condition that the outlet pressure of the flow field and the difference of outlet speed is less than 1 %, compared with the conical structure nozzle, the pressure drop at the critical position is stable, the position of the expansion wave is shifted by 90%, and the fluid stable area behind the throat is 5 times, which enhances the adaptability to supersonic fluid. The good quality outlet flow field is obtained, so that the initial mixing of working fluid and ejection fluid in the ejector does not deviate from the ideal mixing pressure and reduces the influence on the injection coefficient.