非对称处理机匣周向分区数的实验

Experiment on treating block number of non-axisymmetric casing treatment

关键词:  压气机  非对称处理机匣  非定常信号

Key words:  Compressor  Non-axisymmetric casing treatment+  Unsteady signal

摘要:

为了改善传统的对称处理机匣对压气机"扩稳降效"的普遍现象,设计了五种周向分区数的非对称处理机匣。实验结果显示,非对称处理机匣的分区数对压气机的稳定裕度影响不大;而对效率和总压升影响较大:随着分区数增加,压气机的性能先增加后降低。其中一种优选结构的非对称处理机匣能使压气机的稳定裕度扩大13%,同时使其峰值效率提高0.8%。这种非对称处理机匣能取得明显优于轴对称处理机匣的"扩稳增效"的原因是它改变了处理槽对压气机叶尖作用的非定常信号。根据非定常耦合流动理论,其产生的独特的低频激励信号能够对压气机叶尖复杂的非定常流场产生耦合整流效果。

Abstract:

Traditional axisymmetric casing treatment always reduces the efficiency while improving the stall margin of a compressor.Five non-axisymmetric casing treatments with different circumferential block numbers were designed.It was proved that different numbers of treating blocks influence compressor stall margin little,but obviously change the efficiency and total pressure rise.Both of which rise is followed by a gradual decline at the process of increasing the number of treating blocks.An optimized non-axisymmetric casing treatment can not only increase the stall margin of compressor by 13%,but also raise the max efficiency by 0.8%.The cause for this is analyzed as that non-axisymmetric distributed treating slots change the unsteady exciting signal for the tip flow.Based on the Unsteady Cooperative Flow theory,the low-frequency exciting signal from the optimized non-axisymmetric casing treatment can coupled with the complicated vortex tip flow in the compressor.