跨音轴流压气机转子叶尖喷气扩稳机理分析

Mechanism Analysis of Stability Improvement with Tip Injection in a Transonic Axial-Flow Compressor Rotor

对跨音压气机Rotor35进行了多通道全三维定常/非定常叶顶喷气数值模拟。数值计算所获得实壁机匣总性能与试验结果符合良好。计算表明使用3.6%转子堵塞流量的叶顶喷气量可以获得21.4%的扩稳效果。定常计算结果显示叶顶喷气重点影响0.9叶展以上区域,使得该区域进气攻角和扩散因子减小,从而降低叶顶载荷,减小了由激波和泄漏涡相互作用形成的通道堵塞。非定常计算结果显示,叶尖喷气的扩稳效果来自两方面:一是对某一叶片叶顶的卸载作用;二是对激波/泄漏涡干扰形成的低能区重新注入轴向动量。后者对通道流通的改善作用大于前者。非常高的喷射频率使得叶顶喷气能够抑制每个通道中低速区的进一步增长,从而实现了对压气机的扩稳。

Multichannel,full three-dimensional,steady/unsteady numerical simulation with tip injection was carried out for NASA Rotor 35.The predicted overall performance of solid casing agreed very well with the experimental data.Predicted result showed that the stall margin could be improved by 21.4%when the jet amount was equal to 3.6%of choke mass flow of the rotor. The steady calculations showed that nearly 10%outerspan of flow annulus was influenced by tip injection.The high axial momentum introduced by injection decreased the flow incidence angle and diffusion factor,thus reducing near-tip blade loading,and accordingly the blockage region arising from the interaction between passage shock and tip leakage vortex.Unsteady simulation showed that stall margin improvement attribute to two aspects：one is reducing the loading on a certain blade,and the other is reinjection axial momentum into the low energy region formed by the interaction between shock/leakage vortex.The latter improved the passage flow to larger extent than that of the former.The higher jet frequency can make the tip injection restrain further development of low-speed area in each passage so as to achieve the stability improvement of compressor.