Design And Performance Analysis Of Mixed-flow Centrifugal Compressor Stages

Centrifugal compressors are widely used in various fields of the national economy.With the gradual development of industrial equipment on a large-scale,the high-volume,high-performance centrifugal compressor stage has become a hot topic for scholars.The mixed-flow stage combines the features of the traditional centrifugal stage and the axial-flow stage.It can adapt to the working requirements of large mass flow conditions under the requirement of guaranteeing the aerodynamic performance of the compressor.Therefore mixed-flow stage is more suitable for large mass flow centrifugal compressor.As a result,in order to improve the performance of centrifugal compressor with large flow coefficient,the development and research of mixed-flow stage has become a research topic with both theoretical value and application value.The design process of centrifugal compressors consists of four parts: one-dimensional design,one-dimensional performance verification,three-dimensional geometric modeling,and three-dimensional CFD numerical simulation performance analysis.The design cycle and aerodynamic performance of centrifugal compressors are directly affects the accuracy of one-dimensional performance prediction.This paper will study one-dimensional performance prediction and development and performance analysis of mix-flow stage with reference to the above design process.The main research contents are as follows:1.A large number of centrifugal compressor loss models are summarized and a one-dimensional performance prediction programs was written in C language.Several centrifugal compressors are used to verify the accuracy and universality of the one-dimensional performance prediction program.2.To design mixed-flow impellers with different exit angles by referring to the existing centrifugal stage of 0.2 flow coefficient.The variation of flow field in the impeller and aerodynamic parameters at the outlet of the impeller with the different exit lean angles is analyzed.In addition,the range of exit lean angle for a 0.2 flow coefficient impeller is explored.3.Based on the research above,complete mixed-flow impeller optimization and aerodynamic design of stage are completed.The aerodynamic performance of the designed stage is calculated with the help of one-dimensional performance prediction program and three-dimensional CFD numerical simulation.By comparing the aerodynamic performance and flow field of the mixed-flow stage and centrifugal stage,the aerodynamic performance of the designed mixed-flow model stage is evaluated.The research above provides technical support for the development of 0.2 flow coefficient centrifugal compressors.Through the research of this paper,a mixed flow compressor stage with excellent performance is finally designed.By one-dimensional performance prediction and CFD numerical simulation calculation,it turns out that aerodynamic performance of the stage is better than the original 0.2 flow coefficient centrifugal compressor stage,achieving the goal of raising the aerodynamic performance of 0.2 flow coefficient compressor stage.