基于二次回归正交试验的排汽缸导流环优化设计

Optimal Design of Flow Guide in Exhaust Hood Based on Quadratic Regression Orthogonal Methodology

针对某600 MW机组排汽缸导流环形状对汽轮机排汽气动性能的影响,基于二次回归正交试验方法,安排不同形状导流环时排汽通道气动性能的数值计算,通过显著不失拟的回归方程确定目标函数最优解,对低压排汽缸导流环型线参数进行优化设计。结果表明:导流环型线参数与排汽缸静压恢复系数呈明显的非线性关系。导流环轴向通流空间和型线曲率对排汽缸静压恢复作用呈现相反的变化趋势,当同时满足通流空间大于320 m^3及曲率小于0.6时,静压恢复能力趋于正交试验范围内的最佳值。优化后排汽缸的气动性能得到明显改善,出口流场均匀性得到很大的提高。排汽缸总压损失系数降低了6.85%,静压恢复系数增加了11.35%,排汽通道均匀性系数增大了6.79%。研究结果可为排汽缸导流环优化设计提供一定的参考。

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 m^3 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.