Numerical Simulation of Flow Fields in Circularly Lobed Ejectors With/Without Central Plug Sudden Expansion
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摘要: 对中心锥有无内突扩的波瓣引射器内流场进行了CFD仿真模拟和比较分析.对比了两者下游流场流向涡的大小和分布,并以热混合效率和总压恢复系数为性能参数,分析了截锥内突扩对此类引射器性能的影响.结果表明:中心锥内突扩结构能有效降低流动损失,可大幅度提高总压恢复系数.中心锥内突扩结构的扩压作用导致主流的速度降低,使引射器下游的流向涡量降低,但其能给下游流场带来额外的流动扰动,使整个流场的混合效率增加.Abstract: The models of lobed ejectors with/without central plug sudden expansion were built. The flow fields by CFD simulation were compared and analyzed with focuses on the sizes and distributions of the downstream streamwise vorticities. Thermal mixing efficiency and total pressure recovery coefficient were used to judge the performances of the two kinds of ejectors. The results show that the central plug with sudden expansion can effectively reduce flow loss and significantly improve the total pressure recovery coefficient. As the central plug sudden expansion causes the mainstream velocity to slow down, the vorticity of the ejector declines in the downstream flow field; but on the other hand, the central plug sudden expansion brings additional flow disturbances to the flow field and makes the mixing efficiency of the whole field increase.
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