Mixed flow turbine

• US 9,657,573 B2
• Filed: 09/06/2012
• Issued: 05/23/2017
• Est. Priority Date: 09/06/2012
• Status: Active Grant

• Current Assignee: Mitsubishi Heavy Industries, Ltd.
• Original Assignee: Mitsubishi Heavy Industries, Ltd.
• Inventors: Higashimori, Hirotaka
• Primary Examiner(s): Kim, Craig
• Assistant Examiner(s): Davis, Jason
• Application Number:
  US14/359,140
• Publication Number:
  US 20150218949A1
• Time in Patent Office: 1,720 Days
• CPC Class Codes: F01D 1/026 Impact turbines with buckets, i.e. impulse turbines, e.g. Pelton turbines F01D1/16, F01D1/34 take precedence
• CPC Class Codes: F01D 5/048 Form or construction
• CPC Class Codes: F01D 5/141 Shape, i.e. outer, aerodynamic form F01D5/148 - F01D5/20 take precedence; blade construction F01D5/147
• CPC Class Codes: F01D 9/026 Scrolls for radial machines or engines
• CPC Class Codes: F05D 2210/43 Radial inlet and axial outlet
• CPC Class Codes: F05D 2220/40 in turbochargers
• CPC Class Codes: F05D 2240/241 of impulse type

Abstract

An object is to provide a mixed flow turbine, wherein intermediate blades having an intermediate height are provided between main blades of the mixed flow turbine, thus improving an impulse blade turbine characteristic and reducing the moment of inertia for a rotor blade as a whole, thereby improving the efficiency and transient response. The mixed flow turbine includes: a turbine rotor blade 11; a turbine housing 3; a scroll partition wall 17 dividing a scroll chamber 13; a shroud-side inflow passageway 35 formed on the side of a shroud-side partition wall surface 25; and a hub-side inflow passageway 29 formed on the side of a hub-side partition wall surface 23, wherein the rotor blade 11 includes: main blades 37 formed with a height spanning the entire extent between a hub outer circumferential surface 31 and the inner periphery surface of a shroud portion 15; and intermediate blades 39 arranged in the circumferential direction between the main blades 37 and arranged so as to extend from the inlet portion of the main blades 37 to an intermediate portion and having an intermediate height with respect to the height of the main blades 37, wherein a fluid from the hub-side inflow passageway 29 flows in through front edges of the intermediate blades 39.

Claims

1. A mixed flow turbine comprising:

a turbine rotor having a front edge, through which a fluid flows in, the front edge being shaped so that a middle portion thereof between a hub side and a shroud side is formed so as to protrude toward an upstream side past a line extending between the hub side and the shroud side;

a turbine housing formed to cover the turbine rotor and having a scroll portion for supplying the fluid toward the front edge of the turbine rotor;

a scroll partition wall dividing the scroll portion into a shroud-side space and a hub-side space;

a shroud-side inflow passageway formed between a shroud-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the shroud-side partition wall surface, the fluid flowing through the shroud-side inflow passageway in a generally radial direction to a shroud-side inlet of the turbine rotor; and

a hub-side inflow passageway formed between a hub-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the hub-side partition wall surface, the fluid flowing through the hub-side inflow passageway in a direction generally equal to an inclination direction of a hub to a hub-side inlet of the turbine rotor,

the turbine rotor comprising;

a plurality of main blades formed to stand upright in a circumferential direction on a hub outer circumferential surface, and having a height spanning an entire extent between the hub outer circumferential surface and an inner periphery surface of a shroud portion; and

a plurality of intermediate blades each of which is arranged in the circumferential direction between two of the main blades so as to extend from an inlet portion to an intermediate portion with respect to the extension of the main blades, and has an intermediate height with respect to the height of the main blades,

the fluid from the hub-side inflow passageway being allowed to flow in through a front edge of each of the intermediate blades,

wherein the front edge of each of the plurality of intermediate blades coincides with a front edge of a corresponding one of the plurality of main blades, while a blade height of the front edge of each of the plurality of intermediate blades is set to a position substantially equal to, or higher than, a center line on a meridional plane that divides a flow along the main blade into passageway areas of a flow through a shroud-side passageway and a flow through a hub-side passageway on a basis of a ratio between the passageway width of the shroud-side inflow passageway and the passageway width of the hub-side inflow passageway, and a blade height of a rear edge of each of the plurality of intermediate blades is set to a position higher than a blade height of the front edge of the intermediate blade.

2. The mixed flow turbine according to claim 1,

wherein the intermediate blade is provided at least across an area, in a meridional shape of the turbine rotor, where an extension area of a passageway width of the hub-side inflow passageway overlaps an extension area of the shroud-side inflow passageway.

3. The mixed flow turbine according to claim 1,

wherein the plurality of the intermediate blades are arranged in the circumferential direction between the main blades.

4. The mixed flow turbine according to claim 1,

wherein a blade tip of each of the plurality of intermediate blades is formed to have an arc-shaped cross section.

5. The mixed flow turbine according to claim 1, comprising,

in the hub-side inflow passageway, a nozzle formed by a blade surface parallel to a central axis, and a guide plate arranged on a downstream side of the nozzle so that a rear edge opposes the front edge of the turbine rotor.

6. A mixed flow turbine comprising:

a turbine rotor having a front edge, through which a fluid flows in, the front edge being shaped so that a middle portion thereof between a hub side and a shroud side is formed so as to protrude toward an upstream side past a line extending between the hub side and the shroud side;

a turbine housing formed to cover the turbine rotor and having a scroll portion for supplying the fluid toward the front edge of the turbine rotor;

a scroll partition wall dividing the scroll portion into a shroud-side space and a hub-side space;

a shroud-side inflow passageway formed between a shroud-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the shroud-side partition wall surface, the fluid flowing through the shroud-side inflow passageway in a generally radial direction to a shroud-side inlet of the turbine rotor; and

a hub-side inflow passageway formed between a hub-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the hub-side partition wall surface, the fluid flowing through the hub-side inflow passageway in a direction generally equal to an inclination direction of a hub to a hub-side inlet of the turbine rotor,

the turbine rotor comprising;

a plurality of main blades formed to stand upright in a circumferential direction on a hub outer circumferential surface, and having a height spanning an entire extent between the hub outer circumferential surface and an inner periphery surface of a shroud portion; and

a plurality of intermediate blades each of which is arranged in the circumferential direction between two of the main blades so as to extend from an inlet portion to an intermediate portion with respect to the extension of the main blades, and has an intermediate height with respect to the height of the main blades,

the fluid from the hub-side inflow passageway being allowed to flow in through a front edge of each of the intermediate blades,

wherein a front edge of the intermediate blade is provided at a position less than a front edge radius of the main blade, and a blade height of the intermediate blade across an entire extent from upstream to downstream is maintained constantly at a position at a substantially equal height to, or higher than, a height of a center line on a meridional plane that divides a flow along the main blade into passageway areas of a flow through a shroud-side passageway and a flow through a hub-side passageway on the basis of a ratio between the passageway width of the shroud-side inflow passageway and the passageway width of the hub-side inflow passageway.

7. The mixed flow turbine according to claim 6,

wherein a radius of the front edge of each of the plurality of intermediate blades is set to a radius substantially equal to a radius at which the intermediate blade is attached to the hub.

8. The mixed flow turbine according to claim 6, comprising,

in the hub-side inflow passageway, a nozzle formed by a blade surface parallel to a central axis, and

a guide plate arranged on a downstream side of the nozzle so that a rear edge opposes the front edge of the turbine rotor.

9. The mixed flow turbine according to claim 6,

wherein a blade tip of each of the intermediate blades is formed to have an arc-shaped cross section.

10. A mixed flow turbine comprising:

a turbine rotor having a front edge, through which a fluid flows in, the front edge being shaped so that a middle portion thereof between a hub side and a shroud side is formed so as to protrude toward an upstream side past a line extending between the hub side and the shroud side;

a turbine housing formed to cover the turbine rotor and having a scroll portion for supplying the fluid toward the front edge of the turbine rotor;

a scroll partition wall dividing the scroll portion into a shroud-side space and a hub-side space;

a shroud-side inflow passageway formed between a shroud-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the shroud-side partition wall surface, the fluid flowing through the shroud-side inflow passageway in a generally radial direction to a shroud-side inlet of the turbine rotor; and

a hub-side inflow passageway formed between a hub-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the hub-side partition wall surface, the fluid flowing through the hub-side inflow passageway in a direction generally equal to an inclination direction of a hub to a hub-side inlet of the turbine rotor,

the turbine rotor comprising;

a plurality of main blades formed to stand upright in a circumferential direction on a hub outer circumferential surface, and having a height spanning an entire extent between the hub outer circumferential surface and an inner periphery surface of a shroud portion; and

a plurality of intermediate blades each of which is arranged in the circumferential direction between two of the main blades so as to extend from an inlet portion to an intermediate portion with respect to the extension of the main blades, and has an intermediate height with respect to the height of the main blades,

the fluid from the hub-side inflow passageway being allowed to flow in through a front edge of each of the intermediate blades,

wherein a front edge of the intermediate blade is provided at a position less than a front edge radius of the main blades, while a blade height of each of the plurality of intermediate blades across an entire extent from an upstream to downstream is set to a position higher than a center line on a meridional plane that divides a flow along the main blade into passageway areas of a flow through a shroud-side passageway and a flow through a hub-side passageway on a basis of a ratio between the passageway width of the shroud-side inflow passageway and the passageway width of the hub-side inflow passageway, and a blade height of a rear edge of each of the plurality of intermediate blades is set to a position higher than a blade height of the front edge of the intermediate blade.

11. The mixed flow turbine according to claim 10, comprising,

in the hub-side inflow passageway, a nozzle formed by a blade surface parallel to a central axis, and

a guide plate arranged on a downstream side of the nozzle so that a rear edge opposes the front edge of the turbine rotor.

12. The mixed flow turbine according to claim 10,

wherein a blade tip of each of the intermediate blades is formed to have an arc-shaped cross section.

13. A mixed flow turbine comprising:

a turbine rotor having a front edge, through which a fluid flows in, the front edge being shaped so that a middle portion thereof between a hub side and a shroud side is formed so as to protrude toward an upstream side past a line extending between the hub side and the shroud side;

a turbine housing formed to cover the turbine rotor and having a scroll portion for supplying the fluid toward the front edge of the turbine rotor;

a scroll partition wall dividing the scroll portion into a shroud-side space and a hub-side space;

a shroud-side inflow passageway formed between a shroud-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the shroud-side partition wall surface the fluid flowing through the shroud-side inflow passageway in a generally radial direction to a shroud-side inlet of the turbine rotor; and

a hub-side inflow passageway formed between a hub-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the hub-side partition wall surface, the fluid flowing through the hub-side inflow passageway in a direction generally equal to an inclination direction of a hub to a hub-side inlet of the turbine rotor,

the turbine rotor comprising;

a plurality of main blades formed to stand upright in a circumferential direction on a hub outer circumferential surface, and having a height spanning an entire extent between the hub outer circumferential surface and an inner periphery surface of a shroud portion; and

a plurality of intermediate blades each of which is arranged in the circumferential direction between two of the main blades so as to extend from an inlet portion to an intermediate portion with respect to the extension of the main blades, and has an intermediate height with respect to the height of the main blades,

the fluid from the hub-side inflow passageway being allowed to flow in through a front edge of each of the intermediate blades,

wherein the front edge of each of the plurality of intermediate blades coincides with a front edge of corresponding one of the main blades, and a blade height of each of the plurality of intermediate blades gradually decreases toward a rear edge of the intermediate blade.

14. The mixed flow turbine according to claim 13, comprising,

in the hub-side inflow passageway, a nozzle formed by a blade surface parallel to a central axis, and

a guide plate arranged on a downstream side of the nozzle so that a rear edge opposes the front edge of the turbine rotor.

15. The mixed flow turbine according to claim 13,

wherein a blade tip of each of the intermediate blades is formed to have an arc-shaped cross section.

16. A mixed flow turbine comprising:

a turbine rotor having a front edge, through which a fluid flows in, the front edge being shaped so that a middle portion thereof between a hub side and a shroud side is formed so as to protrude toward an upstream side past a line extending between the hub side and the shroud side;

a turbine housing formed to cover the turbine rotor and having a scroll portion for supplying the fluid toward the front edge of the turbine rotor;

a scroll partition wall dividing the scroll portion into a shroud-side space and a hub-side space;

a shroud-side inflow passageway formed between a shroud-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the shroud-side partition wall surface, the fluid flowing through the shroud-side inflow passageway in a generally radial direction to a shroud-side inlet of the turbine rotor; and

a hub-side inflow passageway formed between a hub-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the hub-side partition wall surface, the fluid flowing through the hub-side inflow passageway in a direction generally equal to an inclination direction of a hub to a hub-side inlet of the turbine rotor,

the turbine rotor comprising;

a plurality of main blades formed to stand upright in a circumferential direction on a hub outer circumferential surface, and having a height spanning an entire extent between the hub outer circumferential surface and an inner periphery surface of a shroud portion; and

a plurality of intermediate blades each of which is arranged in the circumferential direction between two of the main blades so as to extend from an inlet portion to an intermediate portion with respect to the extension of the main blades, and has an intermediate height with respect to the height of the main blades,

the fluid from the hub-side inflow passageway being allowed to flow in through a front edge each of the intermediate blades,

wherein

the front edge of each of the plurality of main blades and each of the intermediate blades includes a pressure surface and a suction surface,

a blade front edge wedge angle is formed between the pressure surface and the suction surface of the front edge of each of the plurality of main blades and each of the intermediate blades, and

the blade front edge wedge angle (θ

) is set so an angle corresponding to a change in an inflow angle (β

) of the fluid, following a pressure variation of the fluid, to the front edge of corresponding one of the plurality of main blades or the intermediate blades, and a blade angle (ω

) which is an angle formed between the suction surface (Z2) of the front edge of each of the plurality of main blades and each of the intermediate blades and the circumferential direction, is set to be substantially equal to or less than an inflow angle to the blade front edge when the pressure variation increases toward a high-pressure side.

17. A mixed flow turbine comprising:

a turbine rotor having a front edge, through which a fluid flows in, the front edge being shaped so that a middle portion thereof between a hub side and a shroud side is formed so as to protrude toward an upstream side past a line extending between the hub side and the shroud side;

a turbine housing formed to cover the turbine rotor and having a scroll portion for supplying the fluid toward the front edge of the turbine rotor;

a scroll partition wall dividing the scroll portion into a shroud-side space and a hub-side space;

a shroud-side inflow passageway formed between a shroud-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the shroud-side partition wall surface, the fluid flowing through the shroud-side inflow passageway in a generally radial direction to a shroud-side inlet of the turbine rotor; and

a hub-side inflow passageway formed between a hub-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the hub-side partition wall surface, the fluid flowing through the hub-side inflow passageway in a direction generally equal to an inclination direction of a hub to a hub-side inlet of the turbine rotor,

the turbine rotor comprising;

a plurality of main blades formed to stand upright in a circumferential direction on a hub outer circumferential surface, and having a height spanning an entire extent between the hub outer circumferential surface and an inner periphery surface of a shroud portion; and

plurality of intermediate blades each of which is arranged in the circumferential direction between two of the main blades so as to extend from an inlet portion to an intermediate portion with respect to the extension of the main blades, and has an intermediate height with respect to the height of the main blades,

the fluid from the hub-side inflow passageway being allowed to flow in through a front edge of each of the intermediate blades,

wherein the cross-sectional profile of a front edge portion of the main blade in a normal cross section to a rotating shaft is formed by curving the front edge portion of the main blade in a direction of rotation to have a shape which is protruded in an opposite direction to the direction of rotation.