Patent ID: 7540158

Claim:
A multistage turbine with a single rotor blade row for causing a working fluid passing through a rotor blade row ( 3 ) to pass through the rotor blade row ( 3 ) again, and thereby subjecting the working fluid to adiabatic expansion a number of times to output power, the multistage turbine with the single rotor blade row comprising: a first stationary blade row ( 2 ) which is positioned at an upstream of the rotor blade row ( 3 ) and causes the working fluid to flow into the rotor blade row ( 3 ) while increasing the speed of the working fluid; and a second stationary blade row ( 4 ) which is positioned at a downstream of the rotor blade row ( 3 ) and separates the working fluid flowing out of the rotor blade row ( 3 ), wherein, when stationary blades which separate the high-pressure working fluid (F H ) and the low-pressure working fluid (F L ) in the first stationary blade row are taken as reference blades and some of the reference blades, which are disposed so that the high-pressure working fluid (F H ) flows in parallel with and preceding the low-pressure working fluid (F L ) with respect to a direction of movement of the rotor blade row ( 3 ) are defined as a first reference blade ( 21 a ) respectively and some of the reference blades, which are disposed so that the high-pressure working fluid (F H ) flows in parallel with and following the low-pressure working fluid (F L ) with respect to the direction of movement of the rotor blade row ( 3 ) are defined as a second reference blade ( 21 b ) respectively, the multistage turbine being characterized in that: a first corresponding blade ( 41 a ) of the second stationary blade row in relation to one of the first reference blades ( 21 a ) is disposed in the vicinity of the distance, which is determined by an expression 2×U×T, where T is the time required for the high-pressure working fluid to pass through one of the rotor blades of the rotor blade row ( 3 ) and U is traveling speed of the rotor blade in a circumferential direction, with respect to the direction of movement of the rotor blade ( 31 ) from a lower end of the rotor blade when the rotor blade makes the closest approach to the first reference blade ( 21 a ), and wherein a second corresponding blade ( 41 b ) of the second stationary blade row in relation to one of the second reference blades ( 21 b ) is disposed in the vicinity of a lower end of one of the rotor blades of the rotor blade row ( 3 ) when the rotor blade makes the closest approach to a lower end of the second reference blade ( 21 b ).