脉动背压离心压气机动态特性及稳定性

Compressor transient responses and stability at pulsating backpressure conditions

试验研究了脉动背压对离心压气机动态响应及喘振特性的影响规律。结果表明:脉动背压条件时压气机性能存在明显非定常特征,高频大幅脉动背压和陡峭的压比流量特性均可强化该非定常特征。基于试验结果,提出了脉动背压压气机非定常性能与脉冲特性及运行工况的关联模型。脉动背压导致压气机喘振边界左移,稳定运行范围最高拓宽12.3%。压气机向小流量工况趋近时,脉动背压引起的流场振荡减弱,但喘振所致的流场振荡逐步强化,致使流场振荡强度呈V型变化特征,表明了脉动背压与压气机气动稳定性之间存在耦合关系。研究探明了脉动背压条件对压气机动态响应和喘振特性的影响规律,对帮助真实运行环境压气机设计理论的发展具有重要意义。

The influence of pulsating backpressure on compressor transient responses and surge characteristics was investigated experimentally.The results showed that the compressor responses were highly unsteady at pulsating conditions.The unsteadiness of compressor performance was stronger at high frequency,high magnitude pulsating conditions,or steep pressure ratio-flow rate characteristic curves.A correlation among compressor unsteadiness,pulsating strength,and operating condition was proposed based on the results.Surge was postponed at pulsating conditions,with improvement by 12.3%of compressor stable operating range.The strength of fluctuation caused by pulsating decreased with the reduction of flow rate,while the fluctuation due to aerodynamic instability increased.The V-shaped trend of the strength of flow fluctuation was caused by the interaction between pulsating backpressure and compressor instability.The influence of pulsating backpressure on dynamic response and surge characteristics of compressor was studied.This study can be helpful to improve compressor design methodology at unsteady operating conditions.