A preliminary design method for axial compressor stages

A preliminary design method for axial flow compressor stages and mean line code were developed based on steady-state energy equations and empirical correlations. Axial flow compressors typically have three common annulus shapes, which are called as the constant hub, constant tip, and constant mean diameter. Each type of design has its own specific advantages and disadvantages compared to others. Due to customer requirements, such as disk stress, space for accessories, overall length, etc. Designers sometimes need to utilize variable mean diameter annulus shape, which has no constant diameter and provides a more flexible design. In this thesis, variable mean diameter compressor calculations were done through the mean line radius then corresponding blade angles were determined by using empirical correlations. Tip and hub air angles were determined by utilizing the radial equilibrium equation. The tool is called "Axial Compressor Mean Line Calculation" (ACMC), which is a spreadsheet-based Excel VBA tool. In order to get maximum efficiency and compression ratio, an optimum combination of flow path dimensions and air angles was found by the optimization process. Design of experiment (DOE), response surface and multi-objective genetic algorithm optimization were conducted with Ansys Workbench. The first stage of an axial compressor was designed with the code and 3D CFD results were compared with ACMC results. Mass flow rate variation was 2.4600 percent, compression ratio variation was 0.1864 percent and efficiency variation was 2.1597 percent between CFD and analytical solution.