Computational study of combined effects of tip leakage jets and wetness on the performance of steam turbine exhaust system using actuator disc model

Abstract

A numerical model to study the individual and combined effects of the tip clearance jets and the presence of wetness on the performance of the steam turbine exhaust hood has been developed. The Eulerian-Eulerian wet steam flow equations along with mass, momentum, energy, and k- ε model equations are solved in the present study. An increase in inlet wetness level improves the pressure recovery capacity of the steam turbine exhaust hood by reducing the total pressure loss. The presence of moisture causes a turbulence attenuation which in turn reduces the vortex strength. The combined effect of the tip leakage jets and the presence of inlet wetness improve the performance of the exhaust system further. However, the presence of a non-uniform condenser pressure gradient caused by the temperature variation of the cooling water flow increases the level of complexity of the flow in the exhaust system deteriorating the performance.