S型收缩流道对涡轮通流能力影响的研究

为进一步提高航空发动机涡轮通流能力，以小型跨声速涡轮为原型，研究了静子S型收缩流道对涡轮通流能力的影响。将S型流道直线段长度和收缩段内外圆半径比作为流道造型参数，分别针对原型涡轮静子内外端壁进行调整造型，得到一系列不同参数组合的S型内外端壁涡轮算例。保持膨胀比为设计值不变，利用CFD软件对原型和S型流道涡轮进行设计点模拟分析。结果表明，S型流道涡轮流量提升的原理在于增大的静子喉道面积。在相同造型参数下，S型外端壁涡轮的静子叶根损失被有效降低，流量提升明显，且流量高于S型内端壁涡轮1%左右，但由于最大外径增大使其质量通量提升效果减弱；与之相反，S型内端壁涡轮的质量通量提升明显，且高于S型外端壁涡轮3%左右。从提升涡轮质量通量并保证效率不低于原型的角度看，S型外端壁造型参数选取范围更广。

Influence on Turbine Through Flow Capability by S-Shaped Convergent Flow Path

In order to promote turbine through flow capability of aeroengine, the influence of stator S shape convergent flow path on turbine through flow capability is studied with a small transonic turbine taken as the original model. Straight segment length L?b and inner/outer circle radius ratio R_i?R_o in convergent segment are regarded as design factors of S shape flow path. Next a set of modified turbine examples with hub or tip stator S shape wall are designed, according to different L?b and R_i?R_o combinations. CFD software is used to simulate and analyze original and S shape flow path turbines on design point with expansion ratio equal to design value. The results have found that the theory of mass flow improvement by S shape flow path lies in the larger stator throat area. When given the same geometry profiling parameters, loss at S tip wall turbine stator hub is effectively reduced. Meanwhile, mass flow ratio of S tip wall turbine is remarkably improved and higher than S hub wall turbine by around 1%. However, due to increased outer radius, its mas flux improvement is counterbalanced to some degree. One the contrary, S hub wall turbine mass flux is effectively promoted and about 3% higher than S tip wall turbine. Finally, to increase turbine mass flux with efficiency not lower than the origin, there are more design parameter options for S tip wall profiling.