Turbine blade cascade endwall

Abstract

Provided is a turbine blade cascade endwall that is capable of reducing crossflow and is capable of reducing secondary-flow loss that occurs in association with the crossflow, therefore being capable of achieving enhanced turbine performance. A convex portion ( 11 ) that is gently swollen as a whole, that has an apex (P 1 ) at a position of 0 to 20% pitch in a position of 5 to 25% Cax, that gently slopes from this apex (P 1 ) toward a downstream side and a suction side surface of an adjacently disposed turbine stationary blade (B 1 ) or turbine moving blade, and that slopes slightly steeply from the apex (P 1 ) toward an upstream side is provided between one turbine stationary blade (B 1 ) or turbine moving blade and another turbine stationary blade (B 1 ) or turbine moving blade disposed adjacent to one turbine stationary blade (B 1 ) or turbine moving blade.

1 . A turbine blade cascade endwall that is positioned on a tip side or a hub side of a plurality of turbine stationary blades or turbine moving blades arranged in the form of a ring, wherein,
 defining 0% Cax as a leading edge position of the turbine stationary blades or the turbine moving blades in an axial direction and 100% Cax as a trailing edge position of the turbine stationary blades or the turbine moving blades in the axial direction, and defining 0% pitch as a position on a pressure side surface of the turbine stationary blades or the turbine moving blades and 100% pitch as a position on a suction side surface of a turbine stationary blade or a turbine moving blade facing the pressure side surface of the turbine stationary blade or the turbine moving blade,   a convex portion that is gently swollen as a whole, that has an apex at a position of 0 to 20% pitch at a position of 5 to 25% Cax, that gently slopes from this apex toward a downstream side and the suction side surface of the adjacently disposed turbine stationary blade or turbine moving blade, and that slopes slightly steeply from the apex toward an upstream side is provided between one turbine stationary blade or turbine moving blade and another turbine stationary blade or turbine moving blade disposed adjacent to one turbine stationary blade or turbine moving blade.   
     
     
         2 . A turbine blade cascade endwall that is positioned on a tip side or a hub side of a plurality of turbine stationary blades or turbine moving blades arranged in the form of a ring, wherein,
 defining 0% Cax as a leading edge position of the turbine stationary blades or the turbine moving blades in an axial direction and 100% Cax as a trailing edge position of the turbine stationary blades or the turbine moving blades in the axial direction, and defining 0% pitch as a position on a pressure side surface of the turbine stationary blades or the turbine moving blades and 100% pitch as a position on a suction side surface of a turbine stationary blade or a turbine moving blade facing the pressure side surface of the turbine stationary blade or the turbine moving blade,   a concave portion that is gently depressed as a whole, that has a bottom point at a position of 70 to 90% pitch in a position of 5 to 25% Cax, that gently slopes from this bottom point toward a downstream side and the pressure side surface of the adjacently disposed turbine stationary blade or turbine moving blade, and that slopes slightly steeply from the bottom point toward an upstream side is provided between one turbine stationary blade or turbine moving blade and another turbine stationary blade or turbine moving blade disposed adjacent to one turbine stationary blade or turbine moving blade.   
     
     
         3 . A turbine blade cascade endwall according to  claim 1 , wherein a second convex portion that is gently swollen as a whole or a convex portion is provided near a throat. 
     
     
         4 . A turbine provided with a turbine blade cascade endwall according to  claim 1 . 
     
     
         5 . A turbine blade cascade endwall according to  claim 2 , wherein a second convex portion that is gently swollen as a whole is provided near a throat.