Methodology and Experience in the Primary Designing a Transsonic Axial Compressor

Abstract

The article considers the basic principles underlying the program for the calculation and designing gas turbine engine axial compressors. Calculation of pressure losses and deflection ability of the cascades is based on the formulas of A. Komarov. The model involves empirical coefficients, the values of which were selected during program verification based on the results of testing multistage compressors and compressor stages. The basic equations and the algorithm for calculating pressures and velocities are given under the condition of radial balance. The application of computer programs based on these models in designing a gas turbine engine four-stage compressor of moderate power with a total pressure ratio of 3.2 and a given speed is shown. For the first compressor stage, two options with different flow rates are compared. The first option was designed according to the classic recommendation to get close to the same mechanical energy of the gas at the exit of the stage along the radius. The second option was designed for a lower flow coefficient, but ensuring the radial balance, requires introducing a significant non-uniformity of mechanical energy supply along the radius. Due to the lower kinetic energy, the stage efficiency of the second variant is 1.9 % higher, despite the fact that the loss coefficients of the blade cascades are lower in the first variant. The question remains as to how much the inevitable mixing losses in the second variant will reduce its efficiency in the process of equalizing the mechanical energy of the gas