基于二次回归正交试验的汽轮机排汽缸加装导流板的研究

Study on Installing Deflector in Exhaust Hood of Steam Turbine Based on Quadratic Regressive Orthogonal Experiment

以某600 MW汽轮机为研究对象,应用计算流体力学软件CFX对低压缸末级和排汽缸的耦合模型进行了数值模拟,基于二次回归正交试验,在排汽缸上端安装导流板来削弱通道涡对排汽缸气动性能的影响,得到了导流板安装参数与静压恢复系数之间的回归方程。方程呈现非线性关系,显著不失拟,且三因素之间互不影响。求解回归方程的最优解,得出最佳的导流板安装方案。安装导流板后,通道涡被破碎,排汽缸的气动性能得到了明显的改善。排汽缸出口的静压恢复系数提高3.008%,总压损失系数降低5.789%,出口截面标准偏差降低了3.043。并且,不同负荷下优化后排汽缸出口的静压恢复系数均大于优化前。

A combined numerical simulation is conducted to couple fluid flow between exhaust hood and last-stage blades of a 600 MW steam turbine using the computational fluid dynamics software CFX.Based on quadratic orthogonal regression design,the flow guide device at the top of the exhaust hood is installed.The regression orthogonal equation between the installation parameters of the guide plate and the coefficient of static pressure recovery is obtained.The equation is remarkably unlost with nonlinear relation and there is no influence among the three factors.The optimal solution of the regression equation is solved.The channel vortex is broken and the aerodynamic performance of the exhaust hood is improved obviously after the diversion plate is installed.The static pressure recovery coefficient of exhaust hood outlet is increased by 3.008%,the total pressure loss coefficient is reduced by 5.789%and the standard deviation of the outlet is reduced by 3.043.The static pressure recovery coefficient of exhaust hood outlet under different loads after the optimization is always higher than that before the optimization.