Cooling of Steam Turbine Exhaust Hood and Last Stage Blade

Abstract

This paper describes a novel semi-numerical method of water droplets path lines calculation in steam turbine axial exhaust hood 2D space. The axial velocity profile of steam as well as droplets evaporation are taken into account. Water droplets occur in several cooling nozzles placed on the outer wall of axial exhaust hood. Mathematical model of all water nozzles used in Doosan Škoda steam turbines was developed. Position and angle of cooling nozzles towards the outer exhaust hood wall influence the possibility of last stage blade trailing edges erosion given by droplets flow from the nozzles. The turbine lifetime is prolonged as the final consequence.