Preliminary design optimization of a gas turbine multi-stage compressor

In the present study, the preliminary design optimization of an axial-compressor is considered. The axisymmetric flow solver is developed to simulate the flow field within the compressor to predict quickly some important drawbacks of the conceptual design and treat them in preliminary design phase where the conceptual design is made by the mean-line method and the free-vortex assumption is utilized to find the radial distribution of the flow deflection angles. The finite volume scheme is used in this numerical procedure of the inviscid flow simulation where the advection upstream splitting method is used to calculate the fluxes. The focus is on the axial velocity changes along the compressor, and the optimization target of the preliminary design is to increase the minimum axial velocity with the criteria of keeping the mass flow rate and the total pressure ratio constant. The results demonstrate that this target is achieved by minor modification in flow deflection angles to improve the variation of the axial velocity, which can be more important especially in off-design performance of the compressor. © 2020 Gas Turbine Society of Japan.