Turbine cascades of last stage blades for wide range of operating conditions

Authors

Ondřej Novák - Doosan Skoda Power, Ltd.
Marek Bobčík - Doosan Skoda Power, Ltd.
Martin Luxa - Institute of Thermomechanics, CAS, v.v.i.
Jaroslav Fořt - CTU Prague, Faculty of MEchanical Engineering
Bartoloměj Rudas - Doosan Skoda Power, Ltd.
Jaroslav Synáč - University of West Bohemia, Faculty of Mechanical Engineering
David Simurda - Institute of Thermomechanics, CAS, v.v.i
Jiří Fürst - CTU Prague, Faculty of Mechanical Engineering
Jan Halama - CTU Prague, Faculty of Mechanical Engineering
Vladimír Hric - CTU Prague, Faculty of Mechanical Engineering
Jaromír Příhoda - Institute of Thermomechanics, CAS, v.v.i
Zdeněk Šimka - Doosan Skoda Power, Ltd.

Abstract

Recent trends in electric energy market such as biomass, waste incineration or combined cycle power plants require innovative solutions in steam turbine design. Variable operating conditions cause the significant changes in flow field surrounding the steam turbine last stage blades. Therefore the enlargement of operating range for last stage blades presents new challenges in design of turbine cascades. Several turbine cascades were designed and analyzed by commercial and in house software of CTU Prague. Selected profiles were experimentally validated in the high-speed wind tunnel for 2D cascade measurements of IT CAS CR which is equipped by an adjustable supersonic inlet nozzle, perforated inserts at side walls and adjustable perforated tailboard. There are presented comparisons of numerical results with optical and pneumatic measurements for wide range of inlet and outlet Mach numbers for optimized hub and tip profile cascades.