Hot air anti-icing system and air entraining pipeline thereof

Abstract

The air entraining pipeline can transmit hot air in a heat insulation mode and can release thermal deformation of the pipeline, and internal stress of the structure is reduced. A hot air anti-icing system can reduce heat loss of hot air flow passing through an air inlet cabin. The gas guiding pipe comprises an inner-layer pipe wall and an outer-layer pipe wall, a heat insulation structure is arranged between the inner-layer pipe wall and the outer-layer pipe wall, the inner-layer pipe wall comprises a floating section, and the floating section comprises a first pipe end and a second pipe end which are in lap joint with each other and are in sliding fit. One end of the corrugated pipe is connected with the first pipe end, the other end of the corrugated pipe is connected with the second pipe end, and the corrugated pipe covers the lap joint position between the first pipe end and the second pipe end.

Description

Technical Field

[0001] The invention relates to a hot gas anti-icing system and an air bleed pipeline thereof, in particular to a hot gas anti-icing system and an air bleed pipeline thereof for an air inlet of an aircraft engine. Background Art

[0002] The leading edge of the aircraft engine's air inlet is prone to ice accumulation, mainly due to supercooled water droplets in the clouds, supercooled rain in precipitation hitting the surface of the air inlet lip and freezing, or water vapor in the air condensing directly on the lip surface. When flying under continuous maximum icing conditions and intermittent maximum icing conditions, the leading edge of the engine nacelle is prone to ice due to the collection of water in the atmosphere.

[0003] Icing may cause airflow separation and unstable engine operation. In severe cases, the detached ice may be sucked into the engine, causing damage to engine components and possibly causing flight accidents. When ice forms on the leading edge of the inlet duct, the inlet area is reduced, the intake flow rate is reduced, and the engine thrust is reduced. In order to maintain the engine thrust, it is necessary to increase the fuel supply, thereby increasing the temperature before the turbine and shortening the service life of the engine. In addition, the ice detached from the inlet lip may also be sucked into the engine and hit and damage the fan blades, causing serious consequences. Therefore, the anti-icing device of the inlet duct has become an indispensable system to protect the inlet duct lip from ice during the flight of the aircraft.

[0004] At present, the air inlet anti-icing and de-icing systems of civil aviation engines mostly use hot air anti-icing, that is, the high-pressure compressor of the engine draws high-temperature and high-pressure gas to heat the ice area of ​​the engine air inlet to achieve hot air de-icing. In order to prevent ice by bleed hot air from the engine high-pressure compressor, a special anti-icing bleed air pipeline system is designed, that is, starting from the engine core cabin, passing through the fan cabin and the air inlet cavity, and finally introducing the hot air into the air inlet anti-icing cavity, and ejecting hot air from the jet hole for anti-icing. In order to calibrate the hot gas pressure and hot gas interception, pressure calibration and switch valves are usually arranged in the engine core cabin or fan cabin. Under non-icing conditions, the valve is in a closed state, that is, hot air is not bleed from the engine.

[0005] When the anti-icing hot air pipeline passes through the fan compartment at the cold end of the engine, the heat radiation along the way heats the electronic accessories in the fan compartment and affects normal operation. The engine fan compartment is relatively spacious, and the hot air pipeline is generally insulated by wrapping a thermal insulation blanket. However, the space of the air inlet compartment is relatively small and the openness is far less than that of the fan compartment. The space for arranging the thermal insulation blanket is limited and the maintenance is poor. Summary of the invention

[0006] An object of the present invention is to provide an air bleed pipe which can be heat-insulated and can release thermal deformation of the pipe and reduce internal stress of the structure.

[0007] Another object of the present invention is to provide a hot gas anti-icing system that can reduce heat loss when hot gas flows through an air inlet compartment.

[0008] According to one aspect of the present invention, the air duct includes an inner tube wall and an outer tube wall, a heat insulation structure is arranged between the inner tube wall and the outer tube wall, the inner tube wall includes a floating section, the floating section includes a first tube end and a second tube end which overlap each other and can slide together, and a corrugated tube which has one end connected to the first tube end and the other end connected to the second tube end and covers the overlapping position between the first tube end and the second tube end.

[0009] In one embodiment, the thermal insulation structure comprises a cylindrical thermal insulation layer arranged in a gap between the inner tube wall and the outer tube wall.

[0010] In one embodiment, the cylindrical heat insulation layer is ceramic fiber paper.

[0011] In one embodiment, the ceramic fiber paper is pasted on the inner wall surface of the outer tube wall.

[0012] In one embodiment, the bleed air duct is an air duct installed in an air intake compartment of an aircraft engine.

[0013] According to another aspect of the present invention, a hot gas anti-icing system comprises an air bleed line, wherein the air bleed line comprises a portion located in an air inlet compartment, and the portion located in the air inlet compartment comprises any one of the air bleed pipes described above.

[0014] In one embodiment, the hot gas anti-icing system also includes a hot gas distribution pipe for being arranged in the air inlet anti-icing cavity, the hot gas distribution pipe includes a front mounting flange, the air duct includes a front joint, the front joint and the front mounting flange are connected by a clamp, and the butt surfaces of the front mounting flange and the front joint are sealed by clamping a sealing ring.

[0015] In one embodiment, the sealing ring is a ceramic fiber sealing ring.

[0016] In one embodiment, the inner tube wall has an adjustment section, and the adjustment section is a Venturi tube.

[0017] In one embodiment, the hot gas anti-icing system also includes a first sensor, a second sensor and a third sensor, wherein the first sensor and the second sensor are arranged at the front end and the rear end of the venturi tube, and are used to detect changes in the pressure difference of the anti-icing hot gas passing through the venturi tube; the third sensor is arranged at one end of the part of the air bleed line located in the inlet cabin, close to the inlet anti-icing chamber, and is used to detect the temperature pressure signal before the hot gas is introduced into the inlet anti-icing chamber.

[0018] The heat radiation and heat conduction of the engine inlet anti-icing air bleed pipe cause the temperature of the structure inside the inlet cabin to rise. In order to insulate and block the heat radiation conduction medium, an insulation structure is adopted in the interlayer. At the same time, the floating section maximizes the freedom of thermal expansion of the anti-icing flute tube along the axial and radial deformation of the engine, and has the function of a flexible universal joint, while improving the vibration problem in the working environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0020] Figure 1 is a schematic diagram of the hot gas anti-icing system;

[0021] Figure 2 is a schematic diagram of the installation space of the hot gas anti-icing system;

[0022] Figure 3 It is a partial schematic diagram of the hot gas anti-icing system corresponding to the air inlet compartment;

[0023] Figure 4 yes Figure 3 Schematic diagram of the middle floating section. DETAILED DESCRIPTION

[0024] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the present invention, not to limit the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the scope or spirit of the present invention. For example, a feature illustrated or described as part of one embodiment may be used together with another embodiment to produce yet another embodiment. Therefore, the present invention is intended to cover these modifications and variations within the scope of the appended claims and their equivalents.

[0025] Figure 1 and Figure 2 The hot gas anti-icing system is shown, which leads hot gas through the engine high pressure compressor (not shown in the figure), and the hot gas is led out from the core cabin through the EBU pipeline, such as Figure 2 As shown, it passes through the fan compartment P3, passes through the rear partition of the air inlet into the air inlet compartment P2, and then passes through Figure 3 The bleed air line 20 shown is introduced into the hot air distribution pipe 14 in the inlet anti-icing chamber P1. An example of the hot air distribution pipe 14 is a flute. The hot air 11 is sprayed from the jet holes of the hot air distribution pipe 14 to the inner wall surface 12a of the lip skin 12 of the leading edge of the inlet to achieve heating and deicing. The hot air distribution pipe 14 sprays hot air to heat the lip, and the hot exhaust gas 15 after the anti-icing hot air is used is discharged to the atmosphere from the exhaust grille 12b arranged on the lip skin 12 at the lowest point of the inlet.

[0026] like Figure 3 As shown, a hot gas anti-icing system 10 includes an air bleed duct 20, which includes a portion located in the air inlet compartment P2, which is roughly the portion between the front joint 25 and the rear flange 28. In the following description, the portion of the air bleed duct 20 located in the air inlet compartment P2 is called the bleed duct.

[0027] The air duct includes an inner tube wall 22 and an outer tube wall 23, and a heat insulation structure is arranged between the inner tube wall 22 and the outer tube wall 23. One embodiment of the heat insulation structure is a gap, and another embodiment is a cylindrical heat insulation layer 23a described later. The inner tube wall 22 includes a floating section, and the floating section includes a first tube end 22a and a second tube end 22b that overlap each other and can slide together, and also includes a corrugated tube 221d whose one end is connected to the first tube end 22a and the other end is connected to the second tube end 22b and covers the overlapping position between the first tube end 22a and the second tube end 22b. As used herein, the terms "first", "second" and "third" can be used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of each component.

[0028] Specifically, the first pipe end 22a has a first pipe interface 222d at the overlapping position, and the second pipe end 22b has a second pipe interface 223d at the overlapping position, and one of the first pipe interface 222d and the second pipe interface 223d is sleeved on the outer peripheral side of the other and slidably matched. The arrangement of the first pipe interface 222d on the first pipe end 22a includes but is not limited to integral molding or welding. The arrangement of the second pipe interface 223d on the second pipe end 22b includes but is not limited to integral molding or welding. One end of the bellows 221d is welded to the first pipe end 22a, and the other end is welded to the second pipe end 22b. The first pipe interface 222d and the second pipe interface 223d act as sliding compensators. The first pipe interface 222d, the second pipe interface 223d, and the bellows 221d can be referred to as a bellows universal joint 22d with a sliding function.

[0029] When the anti-icing system is working, after the hot air is introduced into the inlet anti-icing chamber P2, the air bleed pipe expands radially after being heated. The first pipe end 22a and the second pipe end 22b located on the inner pipe wall 22 of the air bleed pipe, combined with the characteristics of the bellows 221d that can rotate angularly and can be fine-tuned in the axial direction to achieve expansion and contraction, and the axial sliding compensation function provided by the first pipe end 22a and the second pipe end 22b themselves, thereby realizing the function of compensating for the thermal deformation displacement of the air bleed pipe. At the same time, when the hot gas distribution pipe 14 thermally expands, it drives the air bleed pipe to slide axially and swing radially, thereby maximizing the freedom of the hot gas distribution pipe to deform axially and radially along the engine, and improving the vibration problem of the hot gas distribution pipe.

[0030] In one embodiment, the thermal insulation structure includes a cylindrical thermal insulation layer 23a arranged in the gap between the outer tube wall 23 and the inner tube wall 22. The anti-icing air duct in the air intake cabin adopts an anti-icing air duct structure with two layers of inner and outer insurance. When the inner air duct has a pipeline explosion condition, the outer casing still assumes the function of introducing the anti-icing hot air into the air intake anti-icing cavity. An insulation layer is arranged between the inner tube for introducing hot air and the outer protective casing for insulation, which greatly compresses the space volume of the heat radiation conduction medium of the inner tube.

[0031] Preferably, the cylindrical heat insulation layer 23a is ceramic fiber paper, which allows the gap between the outer tube wall 23 and the inner tube wall 22 to be very small, thus minimizing the diameter of the outer tube wall 23 and reducing the weight of the anti-icing system. Optionally, the ceramic fiber paper is pasted on the inner wall surface of the outer tube wall 23. The ceramic fiber paper pasted on the inner wall of the outer tube wall 23 for heat insulation uses its good heat insulation performance of blocking heat transfer at high temperatures to reduce the heat radiation of the hot air of the inner tube wall 22 to the outer tube wall 23, so that the temperature in the inlet cavity P2 is lower than 120 degrees Celsius, ensuring the normal operation of the thermosetting composite skin, and there is no need to add the traditional quartz wool stainless steel insulation blanket to protect the composite structure due to the temperature exceeding 120 degrees Celsius, which increases the weight and is not conducive to maintenance. The material ceramic paper has good heat conduction blocking properties and slowing heat transfer properties, and has extremely low thermal conductivity at high temperatures. The thermal conductivity coefficient is as low as 0.12w / (mk) at a high temperature of 800℃. In the manufacturing process, the thickness of traditional sandwich insulation blankets is poorly controlled due to the inherent characteristics of the sandwich structure, which is not conducive to the use of small space areas and their fixed installation, especially for areas where the thickness of the insulation blanket needs to be accurately controlled, such as the insulation blanket is located in the middle of the clamped part, which affects the size selection of fasteners. Ceramic fiber can be precisely controlled in thickness, and the installation process is much better than traditional insulation blanket materials. Ceramic fiber paper is laid in the gap of the double-layer pipe wall cavity, and the space occupied by the anti-icing system pipeline is not increased due to the laying of the insulation blanket, and the structure is light in weight. The traditional insulation blanket needs to be wrapped around the outer casing, occupying the tight space in the air intake cabin, increasing the overall outline size of the anti-icing air bleed pipeline system, and the structure is heavy. The maintenance of the fire blanket is poor. Compared with stainless steel quartz wool insulation materials, ceramic insulation blankets have good toughness and good deformation coordination and follow-up when the anti-icing pipeline is thermally expanded and deformed, that is, the thermal fatigue performance is good in a hot and humid environment. The ceramic fiber paper insulation blanket also has a certain elasticity, and has a certain energy absorption and vibration reduction effect on the structure of the flute anti-icing configuration.

[0032] Combination Figures 1 to 3The hot gas distribution pipe 14 includes a front mounting flange 24, and the air duct includes a front joint 25. The front joint 25 and the front mounting flange 24 are connected by a clamp 26, and the butting surfaces of the front mounting flange 24 and the front joint 25 are sealed by clamping a sealing ring 27. The air duct in the air inlet cavity P2 is provided with a quick-release clamp 26 near the front baffle 16, so that quick installation and removal can be achieved. The inner tube wall 22 and the outer casing wall 23 are welded or integrally formed at both ends, and are respectively welded or integrally formed with the front joint 25 and the rear flange 28 to form a detachable air duct.

[0033] The sealing ring is a 27 ceramic fiber sealing ring. Compared with the traditional high-temperature alloy sealing ring, it also uses the good sealing and elasticity of ceramic fiber at high temperature. The buckle adopts a flexible sealing form to improve the sealing performance while increasing the product life and reliability. Compared with the traditional sealing ring, it has obvious advantages.

[0034] like Figure 3 As shown, the inner tube wall 22 has an adjustment section 22c, which is a venturi tube. The venturi tube can change the flow rate of the hot air flow, shorten the control process, and quickly meet the hot air anti-icing requirements.

[0035] The hot gas anti-icing system 10 also includes a first sensor S1, a second sensor S2 and a third sensor PT1. The sensors S1 and S2 are respectively arranged at the front end and the rear end of the regulating section 22c, and are respectively used to detect the pressure difference change of the anti-icing hot gas introduced into the air intake through the regulating section 22c, and to feed back the electronic controller EEC to control the hot gas flow rate. Before the hot gas of the bleed air pipeline 20 is about to be introduced into the anti-icing chamber P1, the third sensor PT1 is arranged to detect and feed back the temperature and pressure signal to the electronic controller EEC, and by adjusting the anti-icing hot gas pressure at the front and rear ends of the regulating section 22c, the hot gas flow rate and flow velocity are controlled to ensure that the hot gas pressure and temperature detected by the third sensor PT1 after the heat loss of the high-pressure hot gas of the engine along the way are constant and continuous, and the anti-icing performance parameters such as the temperature, flow and hot air pressure of the hot gas required for deicing are achieved, and the hot gas anti-icing requirements are met.

[0036] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. An air duct, comprising an inner tube wall and an outer tube wall, wherein a heat insulation structure is arranged between the inner tube wall and the outer tube wall, and characterized in that: The inner tube wall includes a floating section, and the floating section includes: a first pipe end and a second pipe end that overlap and slidably fit each other, and A corrugated tube having one end connected to the first tube end and the other end connected to the second tube end and covering the overlapping position between the first tube end and the second tube end.

2. The air duct according to claim 1, characterized in that: The heat insulation structure includes a cylindrical heat insulation layer arranged in a gap between the inner tube wall and the outer tube wall.

3. The air duct according to claim 2, characterized in that: The cylindrical heat insulation layer is ceramic fiber paper.

4. The air duct according to claim 3, characterized in that: The ceramic fiber paper is pasted on the inner wall surface of the outer tube wall.

5. The air duct according to claim 1, characterized in that: The air bleed pipe is an air bleed pipe used for being installed in an air intake compartment of an aircraft engine.

6. A hot gas anti-icing system, comprising a bleed air line, the bleed air line including a portion located in an air inlet compartment, characterized in that: The portion located in the air inlet compartment comprises the bleed air duct according to any one of claims 1 to 4.

7. The hot gas anti-icing system according to claim 6, characterized in that: The hot gas anti-icing system further comprises a hot gas distribution pipe arranged in the air inlet anti-icing cavity. The hot gas distribution pipe includes a front mounting flange, The air duct comprises a front joint, The front joint and the front mounting flange are connected by a clamp. The butt surfaces of the front mounting flange and the front joint are sealed by clamping a sealing ring.

8. The hot gas anti-icing system according to claim 7, characterized in that: The sealing ring is a ceramic fiber sealing ring.

9. The hot gas anti-icing system according to claim 6, characterized in that: The inner tube wall has an adjustment section, and the adjustment section is a Venturi tube.

10. The hot gas anti-icing system according to claim 9, characterized in that: The hot gas anti-icing system also includes a first sensor, a second sensor and a third sensor. The first sensor and the second sensor are arranged at the front end and the rear end of the venturi tube, and are used to detect the change in the pressure difference of the anti-icing hot gas passing through the venturi tube; the third sensor is arranged at one end of the part of the air bleed line located in the air inlet cabin close to the air inlet anti-icing cavity, and is used to detect the temperature pressure signal before the hot gas is about to be introduced into the air inlet anti-icing cavity.

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