Reliability Analysis Of Centrifugal Compressor Impeller Considering Fluid-solid Coupling Effect

The centrifugal compressor as a turbine machine is the most commonly used equipment for transporting and compressing gas in the chemical industry.The compressor impeller is the core component of the entire equipment,and the safety and reliability of the impeller are particularly important.The flow of fluid inside the compressor is a complex three-dimensional turbulent flow,and the working environment of the impeller is extremely complicated.In order to ensure the safe and reliable operation of the impeller,it is necessary to perform fluid-structure coupling and reliability analysis.This paper takes the centrifugal compressor impeller as the research object,and uses Ansys software to perform flow field simulation,fluid-structure coupling analysis and reliability calculation analysis of the compressor impeller.(1)This paper uses Ansys workbench CFX software to perform flow field simulation calculations to obtain the temperature,pressure and flow rate of the compressor.The analysis results show that the internal flow of the compressor is good,the pressure changes significantly in the radial direction,and the speed distribution conforms to the basic law.The aerodynamic load obtained by extracting the results of the flow field analysis is applied to the impeller blades for unidirectional fluid-solid coupling simulation.The analysis results show that under the action of fluid-solid coupling,the largest deformation occurs at the outer edge of the disc.Very small,accounting for about 1.5% of the deformation of the fluid-solid coupled impeller.The maximum equivalent stress of the impeller occurs at the shaft hole,and the maximum equivalent stress on the blade is at the root of the leading edge of the blade.The maximum equivalent stress produced by aerodynamic loads is two orders of magnitude smaller than the maximum equivalent stress produced by inertial centrifugal loads.(2)The modal analysis of the impeller was carried out using Ansys workbench software.The prestressed modal analysis of three different loads of aerodynamic load,inertial centrifugal force load and coupled load were carried out.Drawing the Campbell diagram of the natural frequency of the impeller.The vibration mode of the impeller is mainly fan-shaped vibration,and the aerodynamic load has little effect on the natural frequency of the impeller.The impeller has a resonance point near 70%,78%,and 93% of the rotation speed.(3)Considering the results of fluid-solid coupling effect impeller stress calculation,the first-order second-moment method is used to analyze the reliability of the impeller.Calculate the reliability of the impeller at multiple speeds and draw a reliability curve.Change the two parameters of gas density and kinematic viscosity to analyze the change of impeller reliability.The reliability of the impeller with different mean and standard deviation at design speed varies from 1 to 0.7244.Change the gas parameter,the maximum change range of reliability is 0.94%.