Numerical simulation and optimization of aerodynamic performance for axial exhaust hood

CHU Peng1，2，LIU Long-hai1，2，XIN Xiao-peng1，2，MA Xin-lei1，2，SUI Yong-feng1，2，3

（1. Industrial Turbine Academy Turbomechanical Institute，Hangzhou Steam Turbine Co.，Ltd.，

Hangzhou 310022，China ；2. Zhejiang Industrial Steam Turbine Rotor Dynamics Research Key Laboratory，Hangzhou 310022，China； 3. College of Mechanical Engineering，Zhejiang University of Technology，Hangzhou 310014，China）

Abstract：Aiming at reducing the leaving velocity loss of the axial exhaust hood，improving the aerodynamic performance of the exhaust hood，numerical simulation was used to analysis the flow field of the axial exhaust hood which was designed by Hangzhou Steam Turbine Corporation considering about the influence of non-uniformity radial velocity field at the last blade exit. The axial exhaust hood was also modified for optimization. The results indicate that there are flow interactions between the exhaust system and low pressure turbine stages. There are two vortexes at the back of the exhaust hood. By changing the structure of the exhaust hood，static pressure recovery coefficient increases 40.68%，total pressure loss coefficient reduces 31.43%，by changing the cross section of the oil pipe，static pressure recovery coefficient increases 0.13%，total pressure loss coefficient reduces 2.2%，also flow condition in exhaust hood outlet is improved.