Study On The Aerodynamic Performance Of Centrifugal Impeller With Full Range Working Conditions

In order to predict the flow loss of centrifugal compressor, the loss model of each component should be determined especially in, impeller and diffuser. Also the designers should consider the characteristics of flow phenomenon in that, such as the blade surface friction effect, the blade loading, the secondary flow, the gap effect, the separation flow and mixing effect in diffuser.Basing on the existing research results, this paper tries to build a series of loss models that were conform to the real flow and fix on accurate formula to calculate the key flow parameters. The program of calculating aerodynamic performance was carried out by using the FORTRAN and VISUAL BASIC languages in the centrifugal impeller with variable working conditions. The flow data at design point was used as the initial value to the program, the parameter values of each reference section under variable working conditions were obtained. Also the performance curves, the surge and the blocking point could be determined for the safe operating of compressor.The Eckardt impeller was chosen to predict the performance and validate the loss model in the program. The impeller and vaneless diffuser geometry models were generated and meshed firstly, then by the program the aerodynamic parameters and the performance curves were obtained. The isentropic efficiency, polytropic efficiency and pressure ratio were compared.As the present performance prediction method of centrifugal compressors come from the relations experimental data, it is inevitable that there are difference in a way between the predicting data and the real value. The aim of this paper is that designer could get a basic understanding of the performance at the beginning of design and take a short design period. It is hoped to be useful to study the aerodynamic performance of the compressors with variable operating conditions.