轴向引气口位置及进口条件对可控涡扩压器流场的影响分析

Influence of axial bleed slot and inlet conditions on the vortex controlled diffuser flow field

采用黏性定常不可压缩Navier-Stokes方程及Realizable k-ε两方程湍流模型研究了可控涡扩压器轴向引气口位置及进口条件变化对流场的影响。结果表明:轴向引气口在突扩台阶处时,扩压效率为39.5%,比无开口情况(36.6%)有所提高,但不及在突扩喉部开口情况(78.5%),从提高扩压效率角度考虑,选取开口位置时应取突扩喉部;气体入口速度增大时,扩压器扩压效率增大约0.3%,总压损失减小约0.4%,扩压性能变化不明显;气体入口湍流度增加时,扩压性能变化较为明显,扩压效率减小约3%,总压损失增大约3%;引气量增加时,扩压性能变化最为显著,扩压效率增大约37%,总压损失减小约34%。

To investigate the flow performance of a vortex controlled diffuser, viscous steady incompressible Navier-Stokes equation and Realizable k-ε turbulence model are employed to numerical simulate flow field under the changing axial bleed slot and inlet conditions. When axial bleed slot is located in the sudden expansion step, its diffuser efficiency is 39.5%, better than no bleed slot's 36.6%, but worse than sudden expansion throat's 78.5%. With the increase of the inlet velocity, the diffuser efficiency increases about 0.3%, and the total pressure loss decreases about 0.4%, but the difference is not obvious. With the increase of turbulence, diffuser efficiency decreases about 3%, the total pressure loss increases about 3%, and the difference is more obvious. With the increase of bleed fraction, diffuser efficiency increases about 37%, total pressure loss decreases about 34%, and the effects of bleed fraction on diffuser performance are most obvious.