Reliability Research On Impeller Of Centrifugal Compressors

The impeller is the core component of centrifugal compressor high-speed rotors,whose structure,service status and working environment are very complicated.The reliability of the impeller directly affects the normal operation or even the safety of the whole compressor unit. It can be said that the reliability of the impeller basically represents the reliability of the centrifugal compressor.Therefore,it is absolutely necessary to carry out the research and analysis on the reliability of the impeller.Firstly,the mechanical analysis of the impeller is carried out based on ANSYS software. Our numerical results can give some reasonable suggestions for optimization of the impeller. Mechanics calculation analyses of the impeller in normal overloading and over-speed pre-over loading condition have been taken with ANSYS software.The distribution of the Von Mises stress and equivalent plastic strain in over-speed pre-over loading have been discussed and compared to the case in normal overloading.The numerical results can well show the mechanical mechanism of the over-speed pre-over loading process.By the numerical analysis,it's found that the maximum Von Mises stress of the impeller under normal operation has little change whether it has over-speed pre-over loading history or not, while the equivalent plastic strain after overloading is far more than that of non-overload, indicating an obvious self-enhancement.Then,effect of the assembly magnitude of interference and the elastic modulus on assembly performance and reliability has been discussed.What's more,the relation curve between magnitude of interference value and static strength reliability and anti-slide reliability of impeller and the relation curve between elastic modulus and static strength reliability and anti-slide reliability of impeller have been studied out.The research curve indicated that, static strength reliability is decreasing with the magnitude of interference value increasing, while anti-slide reliability is increasing with the magnitude of interference value increasing. That is to say,the stress in wheel disk and the friction torque produced by magnitude of interference assemble are increasing with elastic modulus increasing.The influence on the elastic modulus of the impeller is relatively larger,when the magnitude of interference value is Common value 0.2mm and 0.3mm,elastic modulus has no significant effect on static strength,and anti-slide reliability is increasing with elastic modulus increasing in larger working torque,the influence on the elastic modulus of the impeller is still relatively larger. So we can select suitable assembly magnitude of interference value and elastic modulus based on its own needs and make engineering design keep economical simultaneously under the premise of meeting the two reliability requirements.