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为了研究削弱微型离心叶轮内损失、提高其性能的方法,采用S-A湍流模型对微型涡喷发动机离心叶轮流动进行了三维数值模拟。分析表明流场中存在的三个主要涡流区是显著的损失源,它们的形成机理与通道内展向静压分布不均匀性造成的压力梯度有关。因此,从改善展向压力分布的角度对叶轮进行了改进设计以削弱流动损失。结果表明通过改进叶轮轴向长度、分流叶片前缘的位置和形式以及主叶片的叶片角分布可改善子午流道、分流叶片吸力面和通道内S2流面等处的展向静压分布,使之变化减缓、梯度降低,从而削弱了涡流的损失,使堵塞流量增加了约15%,叶轮峰值效率提高约7%,压比提高约6%。
In order to study the method to weaken the loss and improve the performance of micro-centrifugal impeller, the S-A turbulence model was used to simulate the centrifugal impeller flow of micro-turbojet. The analysis shows that the three major vortex regions existing in the flow field are significant sources of losses, and their formation mechanism is related to the pressure gradient caused by the non-uniform distribution of static pressure in the channel. Therefore, the impeller has been improved from the perspective of improving the spread of pressure to reduce the flow loss. The results show that by improving the axial length of the impeller, the location and form of the leading edge of the splitter blade and the blade angle distribution of the main blade, the static pressure distribution in the meridional flow path, the suction surface of the splitter blade and the S2 flow surface in the passage can be improved. The change slows down and the gradient decreases, thus reducing the eddy current loss, increasing the clogging flow rate by about 15%, the impeller peak efficiency by about 7% and the pressure ratio by about 6%.