Research On Redesign And Performance Of Centrifugal Compressor Impeller Under Variable Flow Conditions

The general impeller design requires complex type selection of impeller and performance verification,which needs a large amount of work and costs of enterprises,therefore,based on the flow rate provided by users,reasonable cutting of the original model stage impeller to meet the needs of new working conditions will greatly reduce the labor and manufacturing costs of enterprises,as well as provide guidance for the development of new compressor model stage impeller.Based on the idea above,the cutting scheme of the impeller is determined in this thesis,according to different flow rate on the basis of the original impeller model parameters and with premise of satisfying the efficiency and performance of the compressor.And then the results are analyzed and verified to make the selection of impeller cutting scheme universal and serial.In this thesis,three-dimensional models of centrifugal compressor blade and diffuser are built by SolidWorks,and the calculation area is settled,then NUMECA is used for numerical calculation.In order to shorten the calculating time and get the calculation results as soon as possible,with the premise of satisfying the engineering accuracy,computational domain is set as the single channel of impeller and diffuser based on experience.The computational domain of impeller and diffuser is meshed by module Autogrid5 and solved by FINE/EURANUS.According to the requirements of working conditions,the designed flow rate is reduced from 100% to 70% gradually,and then based on the variable flow rate,the shroud of impeller is cut with different proportion coefficients.The impellers with different cutting schemes are meshed and numerical calculated respectively,and the performances under different working conditions of each cutting scheme impeller and of original impeller are compared.Moreover,the calculation results of the diffuser changed into wedge-shaped and original airfoil diffuser are compared.Finally,the impeller cutting scheme matching the operating flow rate point is obtained.And the whole machine is tested,the testing results show that the performance of the centrifugal compressor meets the technical requirements,meanwhile,the redesign scheme of impeller cutting is proved to be feasible.Impeller cutting is the extension of centrifugal compressor model application,which has important guiding significance for the serialization development of centrifugal compressor model stage.