Particle separating fluid intake

Abstract

A fluid intake including first and second ducts and a particle separation spinner defining an interface between the first and second ducts is disclosed. Spinner includes flow passages passing from first duct side of the spinner to second duct side of the spinner and splitter bodies separating the flow passages. Flow passages and splitter bodies are arranged in thread-like screw manner about spinner. In use, the spinner is spun about an axis of rotation, axis and direction of rotation being such that, from static frame of reference with respect to first duct, splitter bodies and flow passages have a component of movement towards a main travel direction of a fluid flow incident towards spinner from first duct. Splitter bodies are arranged such that they oblige fluid in the fluid flow to follow a convoluted path if it is to pass from first duct to second duct via the flow passages.

Claims

1. A fluid intake comprising: a first duct; a second duct; and a particle separation spinner defining an interface between the first duct and the second duct, the spinner being hollow, the first duct being on an outer side of the spinner, and the second duct being on an inner side of the spinner, the spinner comprising: flow passages passing from the outer side of the spinner to the inner side of the spinner; and splitter bodies separating the flow passages, the flow passages and the splitter bodies being arranged in a thread-like screw manner about the spinner, wherein: when the fluid intake is in use, the spinner is spun about an axis of rotation; a longitudinal dimension of each splitter body corresponds to a chord extending between a respective leading edge and a respective trailing edge of each splitter body, and is canted out of a parallel alignment with a generator line of a hypothetical surface of revolution of the spinner; an extent of the longitudinal dimension of each splitter body is sufficient such that the trailing edge of each splitter body conceals a part of an adjacent splitter body with respect to a main travel direction of a fluid flow incident towards the spinner from the first duct when the fluid intake is in use; the generator line for the surface of revolution passes through the leading edge of each splitter body and is included in a plane that includes the axis of rotation of the spinner; and the splitter bodies oblige fluid in the fluid flow to follow a convoluted path if the fluid is to pass from the first duct to the second duct via the flow passages.

2. The fluid intake according to claim 1, wherein the splitter bodies are arranged to conceal the flow passages from the main travel direction of the fluid flow incident towards the spinner from the first duct when the fluid intake is in use.

3. The fluid intake according to claim 1, further comprising a scavenge duct having an inlet from the first duct.

4. The fluid intake according to claim 3, wherein when the fluid intake is in use, the fluid flow is drawn into the scavenge duct via the inlet using a rotor powered by the rotation of the spinner.

5. The fluid intake according to claim 1, wherein the spinner is substantially conical.

6. The fluid intake according to claim 1, wherein the leading edges of the splitter bodies are angled so as to be substantially perpendicular to a resultant gas flow vector resulting from a particular incident gas velocity and circumferential velocity of the spinner.

7. The fluid intake according to claim 1, wherein an outer surface of each splitter body facing the first duct and the first duct itself are angled such that at least one particle in the fluid following a ballistic trajectory incident towards the spinner parallel to the main travel direction of the fluid flow and bouncing at one of the outer surfaces of the splitter bodies will pass into a scavenge duct.

8. The fluid intake according to claim 7, wherein the ballistic trajectory includes a bounce on an outer wall of the first duct subsequent to the bouncing at one of the outer surfaces of the splitter bodies, such that the at least one particle following the ballistic trajectory passes into the scavenge duct.

9. The fluid intake according to claim 1, wherein the spinner is passively driven in use by the fluid flow.

10. The fluid intake according to claim 1, wherein one or more vanes are provided on an inner side of one or more of the splitter bodies facing the second duct.

11. The fluid intake according to claim 1, wherein: a filter mesh is provided downstream of the spinner across the second duct, the filter mesh being attached to a rotating spinner support structure such that the filter mesh rotates with the spinner.

12. The fluid intake according to claim 1, wherein the fluid intake uses ambient air as a working fluid.

Description

(1) Embodiments of the invention will now be described by way of example only, with reference to the Figures, in which:

(2) FIG. 1 is a sectional side view of a gas turbine engine;

(3) FIG. 2 is a cross-sectional view showing a gas intake in accordance with an embodiment of the invention;

(4) FIG. 3 is a top view showing a disassembled particle separation spinner in accordance with an embodiment of the invention;

(5) FIG. 4 is a cross-sectional view showing part of a particle separation spinner in accordance with an embodiment of the invention;

(6) FIG. 5 is a cross-sectional view showing a gas intake in accordance with an embodiment of the invention;

(7) FIG. 6 is a cut-away view showing a gas intake in accordance with an embodiment of the invention.

(8) 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, and 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.

(9) 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.

(10) 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.

(11) Referring now to FIG. 2 a fluid intake, in this case a gas turbine engine gas intake, is generally shown at 30. The gas intake 30 has a first duct, in this case an intake duct 32, upstream of a second duct, in this case a core duct 34. Both the intake duct 32 and core duct 34 are annular, being disposed about a main rotational axis 36 of an associated gas turbine engine (not shown). The intake duct 32 follows a substantially straight path from an inlet (not shown) of the intake duct 32 to a particle separation spinner 38 provided at an interface between the intake duct 32 and core duct 34.

(12) The spinner 38 has a substantially conical shape with an apex 40 of the cone upstream in the gas intake 30 and having a diameter that increases in a downstream direction. The substantially conical shape of the spinner 38 makes the interface between the intake duct 32 and core duct 34 oblique with respect to a main axis of both ducts 32, 34 and with respect to a main gas flow direction incident towards the spinner 38 from the intake duct 32 when the gas intake is in use. The spinner 38 is supported by the core duct 34 by an upstream bearing 42 and a downstream bearing 44.

(13) An outer wall 46 of the intake duct 32 increases in radius in a uniform manner throughout an area of axial alignment with the spinner 38. Throughout the same region the cross-sectional area of the intake duct 32 decreases in view of the greater gradient of the spinner 38 conical surface by comparison with the increase in the intake duct 32 radius. At a downstream end of the spinner 38 the intake duct 32 has a greater radius than the core duct 34, creating an annular inlet 48 to a scavenge duct 50 of the gas intake 30 at a radially outer periphery of the intake duct 32. The outer wall 46 of the intake duct 32 transitions into an outer wall 52 of the scavenge duct 50. An outer wall 54 of the core duct 34 transitions into an inner wall 56 of the scavenge duct 50 via a knuckle 58 housing the downstream bearing 44. In the region of axial alignment with the spinner 38, the intake duct 32 defines a channel 60 towards the scavenge duct 50, there being an alternative exit from the intake duct 32 to the core duct 34 via the spinner 38 as described further below.

(14) Referring now to FIGS. 2 and 3 the spinner 38 is described in more detail. It should be noted that FIG. 3 shows a top view of the spinner 38 unwound and thus not in a configuration in which it would be used.

(15) The spinner 38 has a plurality of flow passages 62 and a plurality of splitter bodies 64 separating the flow passages 62. Both the flow passages 62 and splitter bodies 64 are arranged in a thread like screw manner about the spinner 38. The flow passages 62 pass from an intake duct side 66 of the spinner 38 to a core duct side 68 of the spinner 38 providing a route for gas flow from the intake duct 32 to the core duct 34.

(16) Separate flow passages 62 may be thought of as flow passages 62 divided by a splitter body 64 when the spinner 38 is viewed from any particular circumferential position. Similarly separate splitter bodies 64 may be thought of as splitter bodies 64 divided by a flow passage 62 when the spinner 38 is viewed from any particular circumferential position.

(17) In the case of the spinner 38 of FIGS. 2 and 3 both the flow passages 62 and splitter bodies 64 are multi-start, in the sense that both the flow passages 62 and splitter bodies 64 are distributed among multiple threads. The threads of the splitter bodies 64 meet and are supported at the apex 40 of the spinner 38. As will be appreciated the multi-start arrangement might be replaced in alternative embodiments with a single start arrangement. Specifically all flow passages 62 may be provided in a single thread and similarly all splitter bodies 64 may be provided in a single thread.

(18) Referring now to FIG. 4 a close-up cross-section of three adjacent splitter bodies 64 and two adjacent flow passages 62 is shown. Each splitter body 64 has a leading edge 70, a trailing edge 72 and an outer surface 74. A longitudinal dimension of each splitter body 64 corresponding to a chord extending between the leading 70 and trailing edges 72 is canted out of parallel alignment with a surface of revolution, a generator 75 line for the surface of revolution passing through the leading edges 70 of each of the adjacent splitter bodies 64 and being included in a plane (not shown) also including an axis of rotation 76 of the spinner 38. In other words the splitter bodies 64 extend in an off perpendicular direction away from the conical surface. Because in the embodiment of FIG. 4 the cant of each splitter body 64 is uniform, projections of circumferentially aligned chords of each splitter body 64 are parallel but do not intersect. In the embodiment of FIG. 4 the cant is such that the radius of the leading edge 70 is reduced and the radius of the trailing edge 72 is increased. Specifically The longitudinal dimension of the splitter bodies 64 is sufficient such that the trailing edge 72 of each body 64 conceals (e.g. overlaps) part of an adjacent body 64 with respect to a main travel direction 78 of gas flow incident towards the spinner 38 from the intake duct 32. The angular offset of the splitter bodies 64 with respect to an underlying conical surface therefore allows for the provision of the flow passages 62.

(19) Referring again to FIG. 2, the spinner 38 is provided with a flow moving device, in this case a plurality of rotors 80. The rotors 80 extend radially outwards from the intake duct side 66 of the spinner 38 into the intake duct 32. The rotors 80 are located adjacent the scavenge duct inlet 48 and are circumferentially distributed about its annulus. Further the rotors 80 span the radial extent of the inlet 48.

(20) FIG. 2 also shows a plurality of vanes 82 provided on an inner side 84 of splitter bodies 64 facing the core duct 34. Each vane 82 extends substantially radially from a respective splitter body 64 into the core duct 34 from a point adjacent the leading edge 70 of the splitter body 64. Each vane 82 is rotatable about a respective radial axis 84.

(21) Referring now to FIGS. 1 to 5 operation of the gas intake 30 is described. In use a gas flow 86 laden with particles is ingested by an inlet to the intake duct 32. The main travel direction 78 of the gas flow 80 is incident in a downstream direction towards the spinner 38 parallel to walls of the intake duct 30. The majority of the gas flow 86 passes through the flow passages 62 and into the core duct 34 and onwards to a core of an associated gas turbine engine. A proportion of the gas flow 86 also travels via channel 60 into the scavenge duct 50 via the inlet 48 to the scavenge duct 50 as depicted by arrow 88.

(22) As gas passes through the flow passages 62, drag created by the splitter bodies 64 causes rotation of the spinner 38 on the bearings 42, 44. Aerodynamic drag on the splitter bodies 64 will cause the rotation of the spinner 38 to accelerate until a resultant gas flow vector of the incident gas velocity and circumferential velocity of the spinner 38 is substantially perpendicular to the leading edges 70 of the splitter bodies 64. Then a circumferential force on the spinner 38 will be in equilibrium and spinning will be at a constant speed. Additional drag and therefore power extraction from the gas flow 86 is created by the vanes 82. The additional power extraction is valuable in view of the power required to rotate rotors 80, which rotate with the spinner 38 and drive particle laden gas flow into the scavenge duct 50. The vanes 82 may nonetheless be selectively feathered about respective axes 84 in order to vary the degree of additional power extracted depending on particle extraction and engine efficiency requirements.

(23) The rotation direction of the spinner 38 is such that the flow passages 62 and splitter bodies 64 move towards the apex 40 of the spinner 38 from a static frame of reference with respect to the intake duct 32 as depicted by arrow 90. Consequently the flow passages 62 and splitter bodies 64 also have a component of movement towards the main travel direction 78 of the gas flow incident towards the spinner 38 from the intake duct 32. This component of movement increases the relative velocity between the gas flow 86 and the splitter bodies 64 and consequently the relative momentum of particles within the gas flow 86.

(24) As gas passes through the flow passages 62, it is obliged to follow a convoluted path 92 between the trailing edge 72 and leading edge 70 of adjacent splitter bodies 64 as they travel towards the apex 40. Smaller particles, substantially entrained with the gas flow 86, with their relative momentum increased, tend to leave the gas flow as it follows the convoluted path 92, joining gas incident towards the scavenge inlet 48 along channel 60. The gas flow passing through the flow passages 62, stripped of smaller particles, then continues along the core duct 34.

(25) Larger particles incident towards the spinner 38 are not strongly entrained in the gas flow 86, but instead tend to follow ballistic trajectories (example 94 shown), bouncing at any surfaces they intersect. In view of the overlap and consequent concealment of the flow passages 62 by their adjacent upstream splitter body 64 from the main flow direction of the gas flow 86, larger particles entering the intake duct 32 are blocked from entering the core duct 34 by the outer surfaces 74 of the splitter bodies 64. Specifically there is no clear line of sight for a ballistic trajectory from the inlet to the intake duct 32 to the core duct 34. Further the angle presented by the outer surfaces 74 of the splitter bodies 64 tends to cause larger particles incident on them to bounce towards a secondary impact zone 96 of an outer wall of the intake duct 32. The secondary impact zone 96 in turn is angled so as the larger particles then tend to bounce and travel along a trajectory taking them into the scavenge duct 50 via scavenge inlet 48.

(26) Small and large particles in the scavenge duct 50 alike are forced out by the rotors 80 and vented to atmosphere. The rotors also control the rate of extraction via the scavenge duct 50. Referring now to FIG. 6 a fluid intake, in this case a gas turbine engine gas intake, is generally shown at 100. The intake 100 is substantially similar to the intake 30, but the spinner is cylindrical rather than conical. Differences are highlighted via further explanation of intake 100 below.

(27) The gas intake 100 has a first duct, in this case an intake duct 102, upstream of a second duct, in this case a core duct 104. The intake duct 102 has an upstream circular portion 106 and a downstream annular portion 108. The core duct 104 is circular and has a smaller diameter than the inlet duct 102, it partially axially overlapping and being provided within the downstream annular portion 108.

(28) A spinner 110 has a substantially cylindrical shape. An outer wall 112 of the intake duct 102 decreases in radius in a uniform manner throughout an area of axial alignment with the spinner 110. Throughout the same region the cross-sectional area of the intake duct 102 decreases, defined between the outer wall 112 and the spinner 110.

(29) Upstream of the spinner is a substantially cylindrical buffer body 114. The buffer body 114 is coaxial with and has a similar radius to the spinner 110. The buffer body 114 supports the spinner 110 at its upstream end via a bearing (not shown). An annular opening 116 to the downstream annular portion 108 of the intake duct 102 is defined between the buffer body 114 and the outer wall 112 of the intake duct 102.

(30) At a downstream end of the spinner 110 the intake duct 102 transitions into a scavenge duct 118. The outer wall 112 of the intake duct 102 transitions into an outer wall 120 of the scavenge duct 118 and the scavenge duct 118 is provided between the outer wall 120 and a wall 124 of the core duct 104.

(31) In the region of axial alignment with the spinner 110, the intake duct 102 defines a channel 126 towards the scavenge duct 118 there being an alternative exit from the intake duct 102 to the core duct 104 via the spinner 110 as described further below.

(32) Aside from its different shape the spinner 110 is similar to the spinner 38, having a plurality of flow passages 128 and a plurality of splitter bodies 130 separating the flow passages 128. As before both the flow passages 128 and splitter bodies 130 are arranged in a thread like screw manner about the spinner 110. The flow passages 128 pass from an intake duct side 132 of the spinner 110 to a core duct side (not shown) of the spinner 110 providing a route for gas flow from the intake duct 102 to the core duct 104. An interior of the spinner 110 forms part of the core duct 104.

(33) The intake 100 functions in a similar manner to intake 30. A gas flow entering the intake 100 is obliged to follow a convoluted path if it is to enter the core duct 104 from the intake duct 102 via the passages 128. Rotation of the spinner 110 gives the flow passages 128 and splitter bodies 130 a component of movement towards a main travel direction of the gas flow incident towards the spinner 110 from the intake duct 102. This component of movement increases the relative velocity between the gas flow and the splitter bodies 130 and consequently the relative momentum of particles within the gas flow. Smaller particles, substantially entrained with the gas flow, with their relative momentum increased, tend to leave the gas flow as it follows the convoluted path into and through the flow passages 128, joining gas incident towards the scavenge duct 118. The gas flow passing through the flow passages 128, stripped of smaller particles, then continues along the core duct 104.

(34) The arrangement of intake 100 gives less control over scavenge of larger particles than the intake 30. The intake 100 nonetheless may present a viable option (at least where removal of smaller particles is the priority).

(35) 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.