Development of an axial compressor design and blade profile generation tool

Abstract

Axial compressors are used in a wide range of applications like jet engines, ground gas turbines, and auxiliary power units. The primary function of axial compressors is increasing the pressure of the working fluid. Different design methodologies can be used for modelling axial compressors. Compressor design generally starts with one dimensional mean line calculations which is a fundamental component of the axial compressor design process. It provides essential insights before more complex calculations since flawed one-dimensional designs can compromise the effectiveness of subsequent CFD analyses. The purpose of this thesis is to develop a comprehensive axial compressor preliminary design tool that estimates aerodynamic performance and generates blade geometry for 3D CFD simulations. Python programming language is used to develop the axial compressor design tool. Euler turbomachinery equation and continuity equation are used to create compressor flow path and velocity triangles according to defined boundary conditions and design choices. Designers can check the violation of design limitations by using flow and design parameter outputs of the design tool. Axial velocities in the radial direction are calculated according to the radial equilibrium equation. Empirical loss correlations are integrated to provide a more accurate prediction of the compressor efficiency. Minimum loss incidence and deviation angle correlations are used to calculate blade angles. Axial compressor blade geometry generation process starts with 2D blade profiles. They are created by using either standard NACA profiles or a predefined thickness distribution with a selected camber line generation method. Wennerstrom thickness distribution and NACA 65 series thickness distribution are formulated in the tool. Parabolic and circular camber line generation methods are implemented in the design tool. Double circular arc and multiple circular arc blade profile generation methods are also implemented. 3D blade profiles are created by stacking 2D blade profiles using a defined stacking curve. Point cloud 3D blade profile data is given as an output by the design tool for ANSYS CFX software to perform 3D CFD calculations. Calculation methods are validated by using the Concepts NREC's commercial software Axial which has available axial compressor cases. Results show that the created design tool can accurately predict axial compressor performance and generate blade profiles to perform 3D CFD simulations.