Development of a Two-Dimensional Streamline Curvature Code

Abstract

Two-dimensional (2D) compressor flow simulation software has always been a very valuable tool in compressor preliminary design studies, as well as in compressor performance assessment operating under uniform and non-uniform inlet conditions. This type of software can also be used as a supplementary teaching tool. In this context, a new streamline curvature (SLC) software has been developed capable of analyzing the flow inside a compressor in two dimensions. The software was developed to provide great flexibility, in the sense that it can be used as: (a) a performance prediction tool for compressors of a known design, (b) a development tool to assess the changes in performance of a known compressor after implementing small geometrical changes, (c) a design tool to verify and refine the outcome of a preliminary compressor design analysis, and (d) a teaching tool to provide the student with an insight of the 2D flow field inside a compressor and how this could be effectively predicted using the SLC method combined with various algorithms and cascade models. Apart from describing in detail the design, structure, and execution of the SLC software, this paper also stresses the importance of developing robust, well thought-out software and highlights the main areas a potential programmer should focus on in order to achieve this. This text also highlights the programming features incorporated into the development of the software in order to make it amenable for teaching purposes. The paper reviews in detail the set of cascade models incorporated for subsonic and supersonic flow, for design and off-design operating conditions. Moreover, the methods used for the prediction of surge and choke are discussed in detail. The code has been validated against experimental results, which are presented in this paper together with the strong and weak points of this first version of the software and the potential for future development. Finally, an indicative case study is presented in which the shift of streamlines and radial velocity profiles is demonstrated under the influence of two sets of compressor inlet boundary conditions.