Combustion chamber

Patent metadata

Field	Value
Publication number	US-10859271-B2
Application number	US-201816118966-A
Country	US
Kind code	B2
Filing date	Aug 31, 2018
Priority date	Sep 22, 2017
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

A combustion chamber comprises an upstream end wall structure and inner and outer annular wall structures. The upstream end wall structure comprises an upstream wall and a plurality of circumferentially arranged heat shields secured to the upstream wall. The upstream wall has a plurality of circumferentially spaced fuel injector apertures. Each heat shield has radially outer and radially inner ends and a fuel injector aperture aligned with a corresponding fuel injector aperture in the upstream wall. The radially outer and inner ends of each heat shield have outer and inner rails spacing the heat shield from the upstream wall. The radially outer and inner ends of each heat shield have first and second pluralities of circumferentially spaced apertures extending there-through and through the associated outer and inner rails to direct coolant over the surface of the outer and inner annular wall structures to form respective films of coolant.

First claim

The invention claimed is:

1. A combustion chamber comprising an upstream end wall structure, an inner annular wall structure, an outer annular wall structure spaced radially from the inner annular wall structure,
the upstream end wall structure comprising an upstream wall and a plurality of heat shields secured to and spaced axially from the upstream wall,
the inner annular wall structure being secured to the upstream wall, the outer annular wall structure being secured to the upstream wall,
the upstream wall having a plurality of circumferentially spaced fuel injector apertures, the heat shields being arranged circumferentially around the combustion chamber, each heat shield having a radially outer end, a radially inner end, a first circumferential end, a second circumferential end, and a fuel injector aperture aligned with a corresponding one of the fuel injector apertures in the upstream end wall,
the radially outer end of each heat shield having an outer rail that is monolithic, extends from the first circumferential end to the second circumferential end, and spaces the heat shield from the upstream end wall, the radially inner end of each heat shield having an inner rail that is monolithic, extends from the first circumferential end to the second circumferential end, and spaces the heat shield from the upstream end wall, a remote end of the outer rail of each heat shield having a surface abutting the upstream wall, a remote end of the inner rail of each heat shield having a surface abutting the upstream wall,
the radially outer end of each heat shield having a first plurality of circumferentially spaced apertures extending there-through and through the associated outer rail to direct coolant over the surface of the outer annular wall structure to form a film of coolant, the first plurality of circumferentially spaced apertures of each heat shield extending through the associated outer rail from respective inlets in the surface abutting the upstream wall to respective outlets in a surface of the heat shield facing away from the upstream wall, and
the radially inner end of each heat shield having a second plurality of circumferentially spaced apertures extending there-through and through the associated inner rail to direct coolant over the surface of the inner annular wall structure to form a film of coolant, the second plurality of circumferentially spaced apertures of each heat shield extending through the associated inner rail from respective inlets in the surface abutting the upstream wall to respective outlets in the surface of the heat shield facing away from the upstream wall.

2. The combustion chamber as claimed in claim 1 further comprising a third plurality of circumferentially spaced apertures extending through the heat shields to direct coolant towards a centre of the combustion chamber and the first plurality of apertures being positioned radially outwardly of the third plurality of apertures, and a fourth plurality of circumferentially spaced apertures extending through the heat shields to direct coolant towards the centre of the combustion chamber and the second plurality of apertures being positioned radially inwardly of the fourth plurality of apertures.

3. The combustion chamber as claimed in claim 2 wherein the third plurality of circumferentially spaced apertures extends through the associated outer rail to direct coolant towards the centre of the combustion chamber, and the fourth plurality of circumferentially spaced apertures extends through the associated inner rail to direct coolant towards the centre of the combustion chamber.

4. The combustion chamber as claimed in claim 1 wherein a cross-sectional area of the first plurality of apertures varies circumferentially around the combustion chamber, and a cross sectional area of the second plurality of apertures varies circumferentially around the combustion chamber.

5. The combustion chamber as claimed in claim 1 wherein each heat shield has a planar surface facing away from the upstream wall.

6. The combustion chamber as claimed in claim 1 wherein each heat shield has a flange extending radially outwardly towards the outer annular wall structure from the outer rail at the radially outer end of the heat shield and the flange extends parallel to a planar surface of each heat shield facing away from the upstream wall.

7. The combustion chamber as claimed in claim 6 wherein the flange abuts the outer annular wall structure.

8. The combustion chamber as claimed in claim 5 wherein each heat shield has a flange extending radially inwardly towards the inner annular wall structure from the inner rail at the radially inner end of the heat shield, the flange extending parallel to the planar surface facing away from the upstream wall.

9. The combustion chamber as claimed in claim 8 wherein the flange abuts the inner annular wall structure.

10. The combustion chamber as claimed in claim 1 wherein a diameter of each of the apertures of the first plurality of apertures is greater than or equal to 0.4 mm and less than or equal to 6 mm and a distance between adjacent apertures of the first plurality of apertures is greater than or equal to half the diameter of the first plurality of apertures and less than or equal to four times the diameter of the first plurality of apertures, a diameter of each of the apertures of the second plurality of apertures is greater than or equal to 0.4 mm and less than or equal to 6 mm, and a distance between adjacent apertures of the second plurality of apertures is greater than or equal to half the diameter of the second plurality of apertures and less than or equal to four times the diameter of the second plurality of apertures.

11. The combustion chamber as claimed in claim 1 wherein the apertures of the first plurality of apertures are arranged to direct the coolant circumferentially at an angle of greater than or equal to −60° to less than or equal to +60°, where a positive direction is the direction of flow from the fuel injector, and the apertures of the second plurality of apertures are arranged to direct the coolant circumferentially at an angle of greater than or equal to −60° to less than or equal to +60°, where the positive direction is the direction of flow from the fuel injector.

12. The combustion chamber as claimed in claim 1 wherein the apertures of the first plurality of apertures are arranged to direct the coolant at an angle of less than or equal to 10° towards a centre of the combustion chamber or equal to or less than 60° towards the outer annular wall structure, and the apertures of the second plurality of apertures are arranged to direct the coolant at an angle of less than or equal to 10° towards the centre of the combustion chamber or equal to or less than 60° towards the inner annular wall structure.

13. The combustion chamber as claimed in claim 12 wherein axes of the first plurality of apertures are arranged parallel to the surface of the outer annular wall structure, and axes of the second plurality of apertures are arranged parallel to the surface of the inner annular wall structure.

14. The combustion chamber as claimed in claim 1 wherein axes of the apertures of the first plurality of apertures are spaced from the surface of the outer annular wall structure by a distance equal to or greater than half the diameter of the first plurality of apertures and less than or equal to five times the diameter of the first plurality of apertures, and axes of the apertures of the second plurality of apertures are spaced from the surface of the inner annular wall structure by a distance equal to or greater than half the diameter of the

Assignees

• Rolls Royce Plc

Inventors

• Rimmer John E
• Martin Damian
• Wilson David P

Classifications

• F23R3/283 Primary

  Attaching or cooling of fuel injecting means including supports for fuel injectors, stems, or lances · CPC title

• F23R3/10

  for primary air (F23R3/06, F23R3/045 take precedence) · CPC title

• F23R3/50

  Combustion chambers comprising an annular flame tube within an annular casing (toroidal combustion chambers F23R3/52) · CPC title

• F23R2900/03042

  Film cooled combustion chamber walls or domes · CPC title

• F23R2900/00005

  Preventing fatigue failures or reducing mechanical stress in gas turbine components · CPC title