Development of a Design Procedure for Contra -rotating Multi Stage Axial Flow Compressors

The current study is about developing a 3D design method to undertake a preliminary design of a multi-stage contra-rotating axial compressor to achieve a target technical specification. The term contra -rotating axial compressors refers to compressors which have not stationary stator blades and all rows are rotating blades. The procedure starts by a two dimensional pitch line design of the stages to provide velocity triangles of blades. Three dimensional geometry of stages are calculated using a certain swirl distribution. In this paper, the goal is to formulize a design methodology. The whole design procedure has been implemented in a MATLAB code, which accepts the customer target performance specification as input data, and results in complete 3D geometry of blades of various stages from hub to tip and shroud contours, which are all finally presented by CATIA. In order to evaluate the methodology, the familiar axial compressor of Siemens SGT-600 industrial gas turbine was re-designed by the aforementioned procedure to compare the resultant geometry with respect to size. Moreover, to evaluate qualitatively the level of loss, a 3D simulation of three rotor rows is undertaken which shows that high subsonic flows in aft rotor is inevitable and proper decision have to be considered.

Keywords:

2D velocity triangles , Compressor , contra-rotating , CFD , CATIA