三级离心压缩机非定常流动与交变应力的数值研究

Numerical Investigation of Unsteady Flow and Alternating Stress of a Three-Stage Centrifugal Compressor

以三级天然气离心压缩机为研究对象,采用非定常流动和流固耦合方法,研究了离心压缩机在三种转速、多个流量工况下的内部非定常流动和叶片交变应力。研究表明:流场关键监测点处的压力脉动以叶片通过频率为主,在偏离设计工况下压力脉动频率成分较复杂,但是以叶片通过频率为主导;同一工况下,监测点压力脉动幅值逐级增加;同一转速下,随着流量增大,叶片交变应力幅值呈现出先减小后增加的趋势,并且随着转速提高而增大。

In this paper,unsteady flow simulation and fluid-structure interaction methods are adopted to investigate the internal unsteady flow and blade alternating stresses of a three-stage natural gas centrifugal compressor at three rotational speeds and multiple flow rates.The results show that the frequencies of static pressure fluctuations mainly consist of blade passing frequencies even at off-design conditions.Under the same working conditions,the amplitudes of static pressure fluctuations increase from the first stage to the third stage.The amplitudes of blade alternating stresses first decrease and then increase as the flow rate increases at a given rotational speed.Moreover,the blade alternating stresses increase with the increase of the rotational speed.