The Folw Mechanism Investigation And Optimum Design Of Advanced Compressor Airfoils For Ground-based Heavy-duty Gas Turbines

Optimal design method which is popular at home and abroad provides a new way for the blade design. Optimization is parametric the parameters of the blade geometry, and the performance of the blade is expressed as objective function, which changes with the design parameters. Design objective function is designed to select the best design parameters for performance, which is an automated process. From this point the work establishes aerodynamic optimization design platform that is applicable to heavy-duty gas turbine compressor by introducing optimization theory to compressor blade design. The system consists of in-house program for 2D compressor blade design, AutoGrid5 for grid generating, CFX for flow field computation and analysis and in-house codes for optimization. In the optimization process, the off-design condition and the stall margin is the main objection. Therefore, low total pressure loss, wide attainable operating range, reasonable stall margin, low loss at small incidence and stable change are taken into account in the objective function. Multi-objective and mutative condition optimization is established, expecting the improvement of cascade performance.In turbomachinery, transition has a great influence to the performance of compressor, this mainly because the boundary layer, which divided into laminar and turbulent layer, is different in boundary layer structure, velocity distribution, wall shear stress and heat transfer coefficient. On one hand, the transition directly affect the fluid dynamic of machine, in order to accurately predict the dynamic performance of fluid machinery, we must assure the state of boundary layer flow, on the other hand, the efficiency of flow and the level of design can be improved through control the starting point of the transition, the length of the transition zone. In the mid and rear part of the ground-based heavy-duty gas turbine, the high Reynolds Number together with the high turbulence levels have a great influence on the position and the development of transient. In view of this the design process in this paper, applying the one equation model of y-Ree transient model of CFX-solver, considering the influence of transient in high Reynolds and turbulence levels, so that the results of computation can reflect the real flow of turbomachinery, and get reliable results.In this paper, a compressor blade of a ground-based heavy-duty gas turbine has been optimized by the design system referred above. Multi-objective and mutative condition optimization is established, and transition is especially considered in flow field analysis. After optimization, aerodynamic performance of the blade is improved, the trailing edge loss and the total pressure loss are both decreased under this profile. On off-design condition, the work range is larger, the loss is lower to the original profile, and the optimal profile have certain stall margin.The optimized blade profile was applied to each section of the original blade. The three-dimensional numerical simulation is carried on for the original blade profile and the optimized profile with CFX. It shows that the flow angles and static pressure ratios of different blade height are increased, so the performance of optimized blade is much better than the original blade.