Turbine for converting energy and method for operating the same

Abstract

A turbine and a method for converting energy are provided, wherein an angular position of an exit of a cooling duct in the casing depends on angular positions of a downstream edge 21 of a guide vane and on an angular position of a fluid entry duct for supplying streaming fluid to the turbine. Further, unnecessary cooling of components in the turbine not subjected to high temperature and high pressure is avoided by providing a consolidated casing at particular angular and axial positions.

1 - 16 . (canceled) 
     
     
         17 . A turbine for converting energy, comprising:
 a casing;   a rotor shaft rotatably, around a rotation axis extending in an axial direction, supported within the casing;   a fluid entry duct formed in the casing for supplying streaming fluid;   a guide vane having a downstream edge, the guide vane being fixed in the casing;   a cooling duct in the casing, the cooling duct having an exit,   wherein, with respect to the rotation axis:
 an angular position of a center of the exit of the cooling duct is spaced apart from an angular position of a portion of the downstream edge of the guide vane, offset by a first offset angle, by a first angular distance, and 
 the angular position of the center of the exit of the cooling duct is spaced apart from an angular position of a center of the fluid entry duct, offset by a second offset angle, by a second angular distance, 
   wherein the first angular distance is less than 10°, and the second angular distance is less than 30°, wherein the center of the exit of the at least one cooling duct is arranged downstream of the at least one guide vane,   wherein a plurality of cooling ducts comprising the at least one cooling duct is arranged such that where streaming fluid temperature and pressure both are high a maximum cooling is provided.   
     
     
         18 . The turbine according to  claim 17 , wherein the first angular distance is less than 5°. 
     
     
         19 . The turbine according to  claim 17 , wherein the second angular distance is less than 15°. 
     
     
         20 . The turbine according to  claim 17 , wherein the first angular distance is less than 20% of an angular extent of the guide vane. 
     
     
         21 . The turbine according to  claim 20 , wherein the first angular distance is less than 10% of an angular extent of the guide vane. 
     
     
         22 . The turbine according to  claim 17 , wherein the second angular distance is less than three times an angular extent of the fluid entry duct. 
     
     
         23 . The turbine according to  claim 22 , wherein the second angular distance is less than two times an angular extent of the fluid entry duct. 
     
     
         24 . The turbine according to  claim 17 , wherein
 the first offset angle depends on a distance between an axial position of the downstream edge of the at least one guide vane and an axial position of the center of the exit of the cooling duct, and   the second offset angle depends on a distance between an axial position of the center of the fluid entry duct and an axial position of the center of the exit of the cooling duct.   
     
     
         25 . The turbine according to  claim 17 , wherein the first offset angle depends on a geometry and/or an orientation of the guide vane. 
     
     
         26 . The turbine according to  claim 17 , further comprising
 a further guide vane having a further downstream edge,   wherein an axial position of the downstream edge of the at least one guide vane equals an axial position of the downstream edge of the further guide vane,   wherein the first offset angle depends on a distance between an angular position of the downstream edge of the at least one guide vane and an angular position of the downstream edge of the further guide vane.   
     
     
         27 . The turbine according to  claim 17 , wherein the cooling duct in the casing has an entry, wherein a line defined by a center of the entry and the center of the exit of the cooling duct and projected into a plane orthogonal to a radial direction of extent of the guide vane includes an angle with a line defined by a projection of a point at the downstream edge into the plane and a projection of a point at an upstream edge of the guide vane into the plane, wherein the angle is less than 30°. 
     
     
         28 . The turbine according to  claim 27 , wherein, along the axial direction, the exit of the cooling duct is arranged downstream relative to the entry of the cooling duct. 
     
     
         29 . The turbine according to  claim 17 , wherein portions of the casing define a cooling volume for accommodating cooling fluid, the cooling fluid being in communication, via the cooling duct, with a working volume for accommodating the streaming fluid. 
     
     
         30 . The turbine according to  claim 17 , further comprising at least one rotor blade having a rotor blade tip at an radially outer end of the rotor blade, the rotor blade being fixed at the rotor shaft. 
     
     
         31 . The turbine according to  claim 30 , wherein, along the axial direction, the downstream edge of the guide vane is located at a first axial position and the rotor blade tip is located at a second axial position, wherein an axial position of a center of the exit of the cooling duct lies between the first axial position and the second axial position. 
     
     
         32 . The turbine according to  claim 31 , wherein portions of the casing defining the cooling volume are consolidated for cooling fluid at positions
 having an axial position between the first axial position and the second axial position and   having an angular position   a) farther away than 20° from the angular position of the portion of the downstream edge of the guide vane, offset by the first offset angle, or   b) farther away than 35° from the angular position of the center of the fluid entry duct, offset by the second offset angle.   
     
     
         33 . The turbine according to  claim 30 , wherein the casing comprises a tip sealing portion having an axial position being at least approximately equal to an axial position of the rotor blade tip of the rotor blade. 
     
     
         34 . The turbine according to  claim 17 , wherein at least one of the following features holds:
 exits of the plurality of cooling ducts are angularly non-equally spaced;   exits of the plurality of cooling ducts are differently dimensioned and/or shaped;   different cooling ducts of the plurality of cooling ducts are adapted to supply different amounts of cooling fluid.   
     
     
         35 . A method of converting energy, comprising:
 supplying streaming fluid via at least one fluid entry duct being fixed at a casing;   streaming the streaming fluid to at least one guide vane having a downstream edge, the guide vane being fixed at the casing;   driving, by the streaming fluid, a rotor shaft rotatably supported within the casing; and   supplying a cooling fluid through an exit of at least one cooling duct in the casing,   wherein, with respect to a rotation axis of the rotor shaft,
 an angular position of a center of the exit of the cooling duct is spaced apart from an angular position of a portion of the downstream edge of the guide vane, offset by a first offset angle, by a first angular distance, and 
 the angular position of the center of the exit of the cooling duct is spaced apart from an angular position of a center of the fluid entry duct, offset by a second offset angle, by a second angular distance, 
   wherein the first angular distance is less than 10°, and the second angular distance is less than 30°,   wherein the center of the exit of the at least one cooling duct is arranged downstream of the at least one guide vane,   wherein a plurality of cooling ducts comprising the at least one cooling duct is arranged such that where streaming fluid temperature and pressure both are high a maximum cooling is provided.   
     
     
         36 . The method according to  claim 35 , further comprising directing the cooling fluid through the cooling duct to a tip of a rotor blade fixed at the rotor shaft and to a tip sealing portion of the casing.