Aerofoil and method for making an aerofoil

• US 20100124484A1
• Filed: 07/27/2009
• Published: 05/20/2010
• Est. Priority Date: 07/30/2008
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: Harrogate, Ian W.R., Tibbott, Ian
• Granted Patent: US 8,596,961 B2
• Time in Patent Office: Days
• US Class Current: 415/115
• CPC Class Codes: F01D 5/188 with an insert in the blade cavity to guide the cooling fluid, e.g. forming a separation wall
• CPC Class Codes: F01D 9/041 using blades F01D5/148 takes precedence
• CPC Class Codes: F05D 2230/21 by casting
• CPC Class Codes: F05D 2240/126 Baffles or ribs

Abstract

Within aerofoils, and in particular nozzle guide vane aerofoils in gas turbine engines problems can occur with regard to coolant flows from respective inlets at opposite ends of a cavity within the aerofoil. The cavity generally defines a hollow core and unless care is taken coolant flow can pass directly across the internal cavity. Previously baffle plates were inserted within the cavity to prevent such direct jetting across the cavity. Such baffle plates are subject to additional costs as well as potential unreliability problems. Baffles formed integrally with a wall within the aerofoil allow more reliability with regard to positioning as well as consistency of performance. The baffles can be perpendicular, upward or downwardly orientated or have a compound angle.

Claims

1. An aerofoil having a radial axis and a hollow core to define a cavity with an inlet for fluid flow in use at each end of a radially inner and a radially outer end of the aerofoil, the core having a divider wall, the aerofoil wherein a baffle is integrally formed with the divider wall to extend across the cavity to present a flow restraint between the inlets wherein the baffle comprises an angled portion, the angle is between 15 and 75 degrees from the radial axis.

2. The aerofoil as claimed in claim 1 wherein the angle θ

is between 30 and 60 degrees from the radial axis.

3. The aerofoil as claimed in claim 1 wherein the angled portion is part of the baffle which is generally straight, U-, V- or W-shaped.

4. The aerofoil as claimed in claim 1 wherein coolant apertures are provided in a surface opposite the wall and are generally arranged in a line parallel to the angled portion of the baffle.

5. The aerofoil as claimed in claim 1 wherein the aerofoil has a second axis, perpendicular to the radial axis, the baffle comprises a portion angled α

to the second axis.

6. The aerofoil as claimed in claim 5 wherein the angle (α

) is between 15 and 75 degrees from the radial axis.

7. The aerofoil as claimed in claim 5 wherein the angle α

is between 30 and 60 degrees from the radial axis.

8. The aerofoil as claimed in claim 5 wherein coolant apertures are provided in the wall and at least one of the apertures is angled α

approximately parallel to the baffle.

9. The aerofoil as claimed in claim 5 wherein the baffle is orientated towards alignment with the apertures.

10. The aerofoil as claimed in claim 1 wherein the baffle extends nearly fully across the cavity to define a predetermined available cross sectional area for fluid flow exchange either side of the baffle.

11. The aerofoil as claimed in claim 1 wherein the cavity incorporates a plurality of baffles.

12. The aerofoil as claimed in claim 11 wherein the cavity has a principal baffle to substantially divide the cavity and a respective partial baffle at a relatively spaced location laterally from an inlet to define variations in the cross sectional area of the cavity across which a fluid flow in use can flow from an inlet at one of the opposed respective ends of the aerofoil.

13. The aerofoil as claimed in claim 1 wherein the baffle has a web extending to stiffen association of the baffle with the wall.

14. The aerofoil as claimed in claim 1 wherein the baffle is perforated with holes.

15. The aerofoil as claimed in claim 14 wherein the holes are orientated relative to the apertures.