关键词: 大子午扩张涡轮;端区流动;传热特性;数值模拟;端区正弯

Abstract: In order to study the flow and heat transfer characteristics of the large meridional expansion turbine at the end-zone and the effect of end-zone positive tangential curve technology， numerical simulation of a large meridional expansion turbine vane was performed. The SST turbulence model is used to capture the flow structure accurately. The validity verification of aerodynamic and heat transfer prediction is carried out. Through simulation calculation， both the flow and heat transfer characteristics and the influence of each other were studied at the end-zone of the large meridional expansion turbine. End-zone positive tangential curve technology was analysed for the application effect of recombinant large meridional expansion turbine end-zone flow and reasonable distribution heat load. It can be concluded that the large meridional expansion end wall results in the strong separation of the boundary layer of the turbine end wall， and the separation point of the passage vortex is about 15% in advance. The high heat transfer area is strongly influenced by horseshoe vortex and passage vortex. The end-zone positive tangential curve technology can effectively improve the separation of the boundary layer， reduce the heat load of the front edge by 25%， and improve the gas thermal performance of the turbine.

Key words: Large meridional expansion turbine;Flow at the end wall;Heat transfer characteristics;Numerical simulation;End-zone positive tangential curve