Optimal design of flow guide in exhaust hood based on quadratic regression orthogonal methodology

As the aerodynamic performance of exhaust hood in a 600 MW steam turbine is influenced by the structure of flow guide, the numerical calculation of the aerodynamic performance in exhaust passage under different structure of flow guide is arranged by the method of quadratic regressive orthogonal experiment. The profile parameters of flow guide are optimized by regression equation which is significant and fitting to determine the optimal solution of objective function. The result shows that the profile parameters of flow guide have an obvious nonlinear relationship with the static pressure recovery coefficient of exhaust hood. The impact of the axial flow space and profile curvature of flow guide on the static pressure recovery of exhaust hood appears the opposite change tendency. When the flow space is greater than 320 m³ and the curvature is less than 0.6, the static pressure recovery tends to be the best value within the scope of orthogonal experiment. After the optimization, the aerodynamic performance of exhaust hood and the uniformity of outlet flow field is significantly improved, which the total pressure loss coefficient decreases by 6.85%, the static pressure recovery coefficient increases by 11.35%, and the uniformity coefficient of exhaust passage increases by 6.79%. The studying results provide some references for the further optimization design on flow guide of exhaust hood.