FLUID SYSTEM

Abstract

A fluid system comprising a surface that is fluid washed in use by a fluid flow travelling substantially parallel to the surface is disclosed. The system has a first port through the surface and a second port through the surface, the first and second ports having respective first and second port inlets that are substantially flush with the fluid washed surface. The first and second port inlets are stacked in a direction parallel to the normal flow of fluid over the fluid washed surface such that the first port is upstream of the second port and fluid travelling closer to the fluid-washed surface entering into the first port tends to entrain fluid travelling further from the fluid-washed surface for entry into the second port.

Claims

1. A fluid system comprising a surface that is fluid washed in use by a fluid flow travelling substantially parallel to the surface, a first port through the surface and a second port through the surface, the first and second ports having respective first and second port inlets that are substantially flush with the fluid washed surface, the first and second port inlets being stacked in a direction parallel to the normal flow of fluid over the fluid washed surface such that the first port is upstream of the second port and fluid travelling closer to the fluid-washed surface entering into the first port tends to entrain fluid travelling further from the fluid-washed surface for entry into the second port.

2. A fluid system according to claim 1 where the first and second port inlets are immediately adjacent one another.

3. A fluid system according to claim 1 where the first and second ports are separated by a common wall.

4. A fluid system according to claim 1 where the second port inlet has a smaller cross-sectional area than the first port inlet.

5. A fluid system according to claim 1 where the first and second port inlets share a common axis of symmetry that is substantially parallel to the normal flow direction of fluid over the fluid washed surface.

6. A fluid system according to claim 1 where the second port inlet is narrower than the first port inlet in a direction perpendicular to the normal flow direction of fluid over the fluid washed surface.

7. A fluid system according to claim 1 where respective first and second conduits extend from the first and second ports for transporting fluid captured by the first and second port inlets for respective first and second different uses.

8. A fluid system according to claim 7 where the second use benefits from a lower temperature and/or higher pressure and/or less turbulent flow being captured by the second port inlet than is captured by the first port inlet for the first use.

9. A fluid system according to claim 1 where the surface is arranged for use in a gas turbine engine.

10. A fluid system according to claim 1 where the surface is arranged for use as a surface of a bypass duct of a gas turbine engine.

11. A fluid system according to claim 1 where the surface is arranged for use in a vehicle.

12. A fluid system according to claim 1 where the fluid washing the surface in use is gas.

13. A fluid system according to claim 1 comprising one or more additional ports each having a port inlet forming part of the stacked arrangement.

14. A gas turbine engine comprising a fluid system in accordance with claim 1.

15. An aircraft comprising a fluid system in accordance with claim 1.

Description

[0020] Embodiments will now be described by way of example only, with reference to the Figures, in which:

[0021] FIG. 1 is a sectional side view of a gas turbine engine;

[0022] FIG. 2 is a cross sectional view of part of a fluid system in accordance with an embodiment of the invention;

[0023] FIG. 3 is a plan view of first, second and third port inlets in accordance with embodiments of the invention.

[0024] With reference to FIG. 1, a gas turbine engine is generally indicated at 10, having a principal and rotational axis 11. The engine 10 comprises, in axial flow series, an air intake 12, a propulsive fan 13, an intermediate pressure compressor 14, a high-pressure compressor 15, combustion equipment 16, a high-pressure turbine 17, an intermediate pressure turbine 18, a low-pressure turbine 19 and an exhaust nozzle 20. A nacelle 21 generally surrounds the engine 10 and defines both the intake 12 and the exhaust nozzle 20.

[0025] The gas turbine engine 10 works in the conventional manner so that air entering the intake 12 is accelerated by the fan 13 to produce two air flows: a first air flow into the intermediate pressure compressor 14 and a second air flow which passes through a bypass duct 22 to provide propulsive thrust. The intermediate pressure compressor 14 compresses the air flow directed into it before delivering that air to the high pressure compressor 15 where further compression takes place.

[0026] The compressed air exhausted from the high-pressure compressor 15 is directed into the combustion equipment 16 where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines 17, 18, 19 before being exhausted through the nozzle 20 to provide additional propulsive thrust. The high 17, intermediate 18 and low 19 pressure turbines drive respectively the high pressure compressor 15, intermediate pressure compressor 14 and fan 13, each by suitable interconnecting shaft.

[0027] Other gas turbine engines to which the present disclosure may be applied may have alternative configurations. By way of example such engines may have an alternative number of interconnecting shafts (e.g. two) and/or an alternative number of compressors and/or turbines. Further the engine may comprise a gearbox provided in the drive train from a turbine to a compressor and/or fan.

[0028] Referring now to FIGS. 2 and 3 part of a fluid system is generally provided at 30. The fluid system 30 comprises an inner wall 32 of the bypass duct 22 having a surface 34. Passing through the surface 34 are a first 36, second 38 and third 40 ports. The ports 36, 38, 40 have respective first 42, second 44 and third 46 port inlets which are flush with the surface 34. The first 36 and second 38 ports and the second 38 and third 40 ports are separated by respective common walls 48. The ports 36, 38, 40 are canted at an oblique angle to the surface 34 such that air entering the ports 36, 38, 40 from the second airflow turns through less than 90°.

[0029] Respective first, second and third conduits (not shown) extend from the first 36, second 38 and third 40 ports, fluidly connecting the ports to respective distinct systems. Specifically the first conduit connects the first port 36 to a turbine case cooling system (not shown) of the gas turbine engine 10 and the second and third conduits connect the second 38 and third 40 ports respectively to a cooled cooling air system (not shown) of the gas turbine engine 10. The turbine case cooling system uses the air delivered from the first port 36 for controlling a turbine case temperature. The cooled cooling air system uses the air delivered from the second 38 and third 40 ports for cooling higher pressure air which is itself then used for cooling of nozzle guide vanes of the gas turbine engine 10.

[0030] When in use the surface 34 is air-washed by the second air flow passing through the bypass duct 22. The second airflow travels substantially parallel to the surface 34. The first 36, second 38 and third 40 ports are stacked one after the other with respect to the second airflow, with the first port 36 being furthest upstream, the third port 40 being furthest downstream and the second port 38 being between the two. Each port 36, 38, 40 is positioned immediately adjacent its neighbouring port(s). Further and as can be seen with reference to FIG. 3, each port inlet 42, 44, 46 is narrower than the last from the upstream to the downstream direction. The length of each port inlet 42, 44, 46 is greater than the last from the upstream to the downstream direction, compensating somewhat for the reduction in cross-sectional area caused by the reduction in width. Nonetheless the cross-sectional area still decreases by comparison with the previous port from the upstream to the downstream direction. The port inlets 42, 44, 46 also have a common axis of symmetry that is parallel to the flow direction of the second airflow such that the port inlets 42, 44, 46 are aligned.

[0031] In use the fluid system 30 supplies bypass duct air to the turbine case cooling system and the cooled cooling air system The second airflow travels along the bypass duct 22. As it does so a boundary layer is formed adjacent the surface 34. The boundary layer air has a higher temperature, lower pressure and greater turbulence than the main body of the second airflow. At the first port inlet 42 the majority of the boundary layer is captured and travels into the first port 36, through the first conduit and to the turbine case cooling system. For the turbine case cooling system mass flow of the air delivered may be more significant than delivery pressure and/or temperature. With the boundary layer having been largely captured, air flowing into the second port inlet 44 is drawn from further away from the surface 34 and indeed is entrained by the boundary layer flowing into the first port inlet 42. The air captured by the second port inlet 42 is therefore cooler, of higher pressure and is less turbulent than the air captured by the first port inlet 42. The air captured by the second port inlet 45 travels into the second port 38, through the second conduit and to the cooled cooling air system. Reduced temperature and increased pressure of the air delivered to the cooled cooling air system may be particularly advantageous. As will be appreciated air flowing into the third port inlet 46 is drawn from still further from the surface 34 and may therefore have still lower temperature, higher pressure and lower turbulence than the air captured by the second port. The air captured by the third port inlet 46 travels into the third port 40, through the third conduit and to the cooled cooling air system.

[0032] It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.