Axial turbine

Abstract

An axial turbine has a turbine stage including stator blades fixedly provided on a stationary section and moving blades fixedly provided on a rotating section and has a structure in which a flow blowing out from a space formed between the stator blades and the moving blades exists. In order to prevent a decrease in stage output power due to such blowout flow thereby to improve the turbine stage efficiency, the axial turbine comprises a member coupling an inner circumferential side of the stator blades, and a structure provided on a surface of the member opposed to the moving blades for bending a flow blowing out from the side of the rotating section into a space between the stator blades and the moving blades in a rotational direction of the rotating section.

1 . An axial turbine having a turbine stage including stator blades fixedly provided on a stationary section and moving blades fixedly provided on a rotating section;
 wherein said axial turbine comprises a member coupling an inner circumferential side of said stator blades, and a structure provided on a surface of said member opposed to said moving blades for bending a flow blowing out from the side of said rotating section into a space between said stator blades and said moving blades in a rotational direction of the rotating section.   
   
   
       2 . The axial turbine according to  claim 1 , wherein:
 said member coupling the inner circumferential side of said stator blades is a diaphragm disposed at the inner circumferential side of said stator blades.   
   
   
       3 . The axial turbine according to  claim 1 , wherein:
 said member coupling the inner circumferential side of said stator blades is a cover formed integrally with said stator blades.   
   
   
       4 . The axial turbine according to  claim 1 , wherein:
 said structure is a protrusion projecting from said member coupling the inner circumferential side of said stator blades towards said moving blades.   
   
   
       5 . The axial turbine according to  claim 1 , wherein:
 said structure is a brush seal having a brush portion at a side opposed to said moving blades.   
   
   
       6 . The axial turbine according to  claim 1 , wherein:
 said structure has a shape forming a flow path concaved in the rotational direction of the rotating section.   
   
   
       7 . The axial turbine according to  claim 1 , wherein said rotating section is a drum-type rotor. 
   
   
       8 . The axial turbine according to  claim 1 , wherein said rotating section has no holes at positions in which said moving blades are fixed. 
   
   
       9 . An axial turbine having a turbine stage including stator blades fixedly provided on a stationary section and moving blades fixedly provided on a rotor;
 wherein said axial turbine comprises a stator blade coupling member provided at an inner circumferential side of said stator blades, and a protrusion provided on a surface of said stator blade coupling member opposed to said moving blades and inclined in a rotational direction of said rotor such that an outer circumferential side of said protrusion shifts relative to an inner circumferential side thereof in a rotational direction of said rotor.   
   
   
       10 . An axial turbine having a turbine stage including stator blades fixedly provided on a stationary section and moving blades fixedly provided on a rotor;
 wherein said axial turbine comprises a stator blade coupling member provided at an inner circumferential side of said stator blades, and a protrusion provided on a surface of said stator blade coupling member opposed to said moving blades and having a shape curved such that an inner circumferential side thereof is oriented in a radial direction and an outer circumferential side thereof is oriented in a rotational direction of said rotor.