带处理机匣的跨声速风扇非定常数值模拟

对带背腔的斜缝式处理机匣的三级跨声速风扇第一级转子进行了非定常的全三维时间精确的数值模拟计算,研究了机匣处理前后转子稳定裕度和性能的变化。结果表明,这种带背腔的斜缝式机匣可以大幅度地提高转子的稳定工作裕度,同时也会造成效率的降低。通过与光壁机匣对比以及分析处理机匣与转子通道之间的非定常干涉现象,本文认为该处理机匣在跨声速条件下的扩稳机理是激波在处理机匣内沿轴向静压差形成一股吹向转子叶尖前缘的非定常气流,改变了前缘气流的攻角所致。比较机匣处理后定常计算与非定常计算的结果,说明了处理机匣对转子有非定常的作用。

Unsteady Numerical Simulation of Transonic Fan with Casing Treatment

The 3-D time-accurate unsteady numerical simulation of the first-stage rotor of a three-stage transonic fan with oblique slots and cavity treatment of casing is performed.By studying the stall margin and the performance of the rotor,results show that the casing treatment can substantially extend the stall margin of the rotor and decrease isentropic efficiency in all of the operating range.The proposed rotor is compared with the one with no casing treatment.And the unsteady interaction between the casing treatment and the rotor blade rows under the transonic condition is analyzed.The simulation result shows that the physical reason of the extending stall margin by using this casing treatment is the unsteady flow.The flow can inject to the leading edge of the tip by the difference of the static pressure in the slots.The difference between the steady simulation and the unsteady simulation shows that the interaction between the casing treatment and blade rows is unsteady.