Axial flow rotating machine and diffuser

Patent metadata

Field	Value
Publication number	US-2016017734-A1
Application number	US-201414771913-A
Country	US
Kind code	A1
Filing date	Mar 20, 2014
Priority date	Mar 29, 2013
Publication date	Jan 21, 2016
Grant date	—

Abstract

An axial flow rotating machine having: a rotor that is provided with a plurality of rotor blades; a stator provided with a plurality of stator blades; an axial flow rotating portion formed by the rotor and the stator; and a diffuser connected to the axial flow rotating portion on the downstream side of the axial flow rotating portion. The final blade portion inner-circumferential inner wall, which is a portion of the inner-circumferential inner wall of the axial flow rotating portion, is formed so that the diameter thereof at the trailing edge position of the final blade is smaller than the diameter at the leading edge position of the final blade. In addition, the diameter of all or a portion of the diffuser inner-circumferential inner wall decreases in a direction of a first side in the axial direction, the first side being the downstream side.

First claim

1 . An axial flow rotating machine comprising:
a rotor that is provided with a plurality of rotor blades and that freely rotates around an axial line; a stator that is provided with a plurality of stator blades arranged adjacent to the plurality of rotor blades; an axial flow rotating portion that is formed by the rotor and the stator; and a diffuser that is connected to the axial flow rotating portion on a downstream side of the axial flow rotating portion and that extends in an axial direction to form a circular flow path; a final blade portion inner-circumferential inner wall, which is a portion of an inner-circumferential inner wall of the axial flow rotating portion corresponding to an axial-direction position of a final blade, being formed so that a diameter thereof at a trailing edge position of the final blade is smaller than the diameter at a leading edge position of the final blade, the final blade being a blade located furthest downstream among the plurality of rotor blades and the plurality of stator blades; and the diameter of all or a portion of a diffuser inner-circumferential inner wall, which is an inner-circumferential inner wall of the diffuser, decreasing in a direction of a first side in the axial direction, the first side being a downstream side.

2 . The axial flow rotating machine according to claim 1 , wherein
the diameter of the diffuser inner-circumferential inner wall starts decreasing from an end portion on a downstream side of the final blade portion inner-circumferential inner wall.

3 . The axial flow rotating machine according to claim 1 , wherein
an inclination angle of the diffuser inner-circumferential inner wall is equal to or greater than an average inclination angle from a leading edge to a trailing edge of the final blade on the final blade portion inner-circumferential inner wall and is less than 0 degrees.

4 . The axial flow rotating machine according to claim 1 , wherein
the diffuser is connected to a final-stage rotor blade of a turbine on a downstream side of the final-stage rotor blade; the final blade portion inner-circumferential inner wall is a final-stage rotor blade inner-circumferential inner wall; and a diameter of the final-stage rotor blade inner-circumferential inner wall starts decreasing from a position between a leading edge and a throat position of the final-stage rotor blade.

5 . A diffuser that is connected to a final-stage rotor blade of a turbine on a downstream side of the final-stage rotor blade, the diffuser comprising:
an outer-circumferential inner wall that is provided on an outer circumferential side of an inner-circumferential inner wall of the diffuser so that the outer-circumferential inner wall is separated from the inner-circumferential inner wall, and that defines a circular flow path between the outer-circumferential inner wall and the inner-circumferential inner wall; and a connecting member that connects the inner-circumferential inner wall and the outer-circumferential inner wall in a radial direction inside the circular flow path and that has a blade-like cross-sectional shape; a diameter of the inner-circumferential inner wall decreasing in a direction of a first side in an axial direction, the first side being a downstream side; the decrease of the diameter reaching a connecting member inner-circumferential inner wall, which is an inner-circumferential inner wall corresponding to an axial-direction position of the connecting member, and the connecting member inner-circumferential inner wall being formed by a first inclination portion located upstream of the connecting member inner-circumferential inner wall, and a second inclination portion located downstream of the first inclination portion; the first inclination portion and the second inclination portion being connected with each other at a position located downstream of a throat position of the connecting member and upstream of a trailing edge that includes a trailing edge position of the connecting member; and an inclination angle of the second inclination portion being equal to or greater than an inclination angle of the first inclination portion and being less than 0 degrees.

6 . A diffuser that is connected to a final-stage rotor blade of a turbine on a downstream side of the final-stage rotor blade, the diffuser comprising:
an inner-circumferential inner wall that has a cylindrical shape extending in an axial direction, an outer-circumferential inner wall that is provided on an outer circumferential side of the inner-circumferential inner wall so that the outer-circumferential inner wall is separated from the inner-circumferential inner wall, and that defines a circular flow path between the outer-circumferential inner wall and the inner-circumferential inner wall; and a connecting member that connects the inner-circumferential inner wall and the outer-circumferential inner wall in a radial direction inside the circular flow path; a diameter of at least a portion of the inner-circumferential inner wall in the axial direction decreasing in a direction of a first side in the axial direction, the first side being a downstream side of the circular flow path; and at least one of a leading edge and a trailing edge of the connecting member being inclined toward a second side in the axial direction, as the edge extends from the outer-circumferential inner wall to the inner-circumferential inner wall, the second side being an upstream side of the circular flow path.

7 . A diffuser that is connected to a final blade on a downstream side of the final blade located furthest downstream among a plurality of rotor blades and a plurality of stator blades of an axial flow rotating machine, the axial flow rotating machine being provided with a rotor, which is provided with the plurality of rotor blades and which freely rotates around an axial line, and a stator which is provided with the plurality of stator blades arranged adjacent to the plurality of rotor blades, the diffuser comprising:
an inner-circumferential inner wall that has a cylindrical shape extending in an axial direction; and an outer-circumferential inner wall that is provided on an outer circumferential side of the inner-circumferential inner wall so that the outer-circumferential inner wall is separated from the inner-circumferential inner wall, and that defines a circular flow path between the outer-circumferential inner wall and the inner-circumferential inner wall; a diameter of the inner-circumferential inner wall decreasing over an entire section of the inner-circumferential inner wall in the axial direction in a direction of a first side in the axial direction, the first side being a downstream side of the circular flow path; and a base end portion of the final blade being formed so that a total pressure of working fluid at an outlet of the final blade becomes high compared with a total pressure in a central portion of the final blade in the blade-height direction.

8 . The axial flow rotating machine according to claim 2 , wherein
an inclination angle of the diffuser inner-circumferential inner wall is equal to or greater than an average inclination angle from a leading edge to a trailing edge of the final blade on the final blade portion inner-circumferential inner wall and is less than 0 degrees.

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Nishimura Kazuya
• Ito Eisaku
• Iida Koichiro
• AKIMOTO Kentaro

Classifications

• F01D25/30

  Exhaust heads, chambers, or the like · CPC title

• F05D2250/324

  divergent · CPC title

• F05D2240/12

  Fluid guiding means, e.g. vanes · CPC title

• F04D29/542

  Bladed diffusers (fixing blades to stators F01D9/042) · CPC title

• F01D25/162

  Bearing supports · CPC title