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

Abstract

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.

Keywords

• steam turbine
• exhaust hood
• flow guide device
• quadratic regressive orthogonal experiment
• aerodynamic performance