Effect Of Impeller Leading Edge Sweep And Meridional Profile On Aerodynamic Performance Of Centrifugal Compressor

Centrifugal compressor has compact structure,good craftsmanship and high single-stage pressure ratio.As an important equipment for high speed and precision,centrifugal compressors are widely used in aviation,petrochemical,construction,and pneumatic conveying departments.The impeller is the core part of the centrifugal compressor and its performance directly determines the overall performance and reliability.The sweeping technology of impeller blades and the optimization of meridional lines can all promote the performance of centrifugal compressors.However,the mechanism of its action in centrifugal compressors is not clear,and the influence on internal flow conditions is not clear.The meridional profile has a guiding significance for the influence of the aerodynamic performance of a centrifugal compressor.The main research contents in this study:(1)According to the structure of centrifugal compressor,a three-dimensional model was established to divide the impeller and volute into different grids.The numerical simulation of the CFX software was used to analyze the results,and the minimum accuracy of the grid was determined,and the grid accuracy was excluded.The effect of the result.(2)A high-speed and high-efficiency centrifugal compressor experimental bench was set up,and its actual characteristic curve was obtained through experiments;then the centrifugal compressor was numerically simulated and the characteristic curve of the simulation was calculated.The comparison of the two characteristic curves was performed to verify the numerical value.The reliability of the simulation method.(3)Using a non-sweeping centrifugal compressor as the initial model,by modifying the leading edge grazing angle of the splitter blade,three sets of forward swept and three sets of swept back were obtained.Numerical simulations were performed on the grazing angles of different splitting blade leading edges,and each set of pneumatics was obtained.The performance parameters were compared with the characteristics of each group,and the influence of the leading edge of the splitter blade on the aerodynamic performance of the centrifugal compressor was analyzed.(4)Four bezier curves were used to model the meridional profile of hub and shroud.By translating the positions of the three control points in the middle of meridional profile,three groups of meridional profiles of hub and shroud were obtained respectively,which were arranged and combined into nine combinations.Numerical simulations were carried out on different meridional profiles.And then the effects of translation control on the performance of centrifugal compressor were analyzed and the mechanism of the effects was studied.It is found that the forward sweep of the leading edge of the splitter blade increases the efficiency and pressure ratio,and decreases the stall margin and stable operating margin.The efficiency,pressure ratio,stall margin and stable operating margin of the splitter blade are decreased by the leading edge sweep.It is found that the pressure ratio decreases gradually when the middle control point of the meridional profile of the shroud is moved down,and the efficiency,stall margin and stable operating margin increase first and then decrease.The pressure ratio and efficiency increase,stall margin and stable operating margin decrease due to the downward movement of the middle control point of the meridional profile of the hub.By comparing and analyzing the sensitivity of the meridional profile of the shroud and hub to the performance of centrifugal compressor,it is found that the sensitivity of the meridional profile of the shroud is higher than that of the hub.The research in this paper provides a reference for the design of centrifugal impeller.