考虑气流激振效应的离心式压缩机叶轮强度分析*

摘要

以往离心式压缩机的叶轮强度设计主要基于静力分析结果，忽略了非定常气动力引起的脉动应力。工程实际表明，许多叶轮的破坏并非静强度不足，而是材料的高周疲劳破坏。考虑离心式压缩机叶轮的非定常气流激振效应，给出了动应力计算和结果后处理过程中应注意的几个问题。气流激振下的动应力分析可以确定叶轮在气动荷载和机械荷载联合作用下的交变应力，为疲劳分析和可靠性设计打下基础。%Previous stress-based designs of centrifugal compressor impellers were mostly based on static analysis without considering the fluctuating stress caused by unsteady aerodynamic pressures. However, many practical failures of impellers were found not because of lack of static strength but the high-cycle fatigue failures. In this paper, the effect of vibratory stress induced by unsteady airflows of centrifugal compressor impellers is investigated with emphasis on computation of dynamic stress and post processing of results. The analysis methodology for dynamic stress considering transient airflow effect can be applied to determine the alternative stress of impellers jointly excited by pneumatic and mechanical loadings and hence be able to serve as a foundation of fatigue analysis and reliability-based designs.