基于喘振频域特性的失稳预警技术研究

为了寻求离心压缩机喘振发作的早期征兆,利用相关积分法结合细化快速傅里叶变换,研究了完整记录喘振发展变化的压力信号的频域特性,并根据喘振产生的物理机制提出了一种新的喘振预警方法.该方法采用与监测频带能量相对应的参数,来度量喘振过程中离心压缩机内部流动特性的变化.分析结果表明,在离心压缩机完全进入喘振前,喘振频带能量有明显的增长过程,增长时刻距喘振完全发作有1~2 s的时间间隔,这对实现离心压缩机安全高效运行具有十分重要的意义.

Instability Early Warning Based on Frequency-Domain Characteristic of Surge

To seek the incipient symptom of surge in the centrifugal compressor,the frequency-domain characteristics of the pressure signal from the state far from surge to the state of full developed surge are analyzed by correlation integral method combining with zoom fast Fourier transform,and a new surge early warning method defining a parameter related with the frequency band energy as the measure is proposed according to the fact that the perturbed energy increases nonlinearly during the surge process.It is illustrated that the frequency band energy of surge is endowed with a visible increase process,and the time delay of 1 - 2 s between the initial rise and the full onset of surge is long enough to allow the effective response of the controller.The investigation offers a powerful support for the compressor to operate under safe and high-efficient condition.