Apparatus for suppressing temperature distortion of short takeoff and landing aircraft inlet

Abstract

The application relates to a short-distance vertical take-off and landing aircraft air inlet temperature distortion suppression device, relates to the technical field of short-distance vertical take-off and landing aircraft air inlet temperature distortion prevention, and comprises an engine cabin, a first jet device, a second jet device and a third jet device, a compressor is arranged in the engine cabin, the first jet device and the second jet device are arranged on the two sides of the engine cabin and connected with the engine cabin, and the third jet device is arranged at the bottom of the engine cabin and connected with the engine cabin. The application changes the flow direction of high-temperature gas to make the high-temperature gas far away from the air inlet, so that the effect of suppressing near-field suction is achieved. The jet nozzle which is symmetrical to the central axis of the aircraft is arranged on the belly to form a barrier, which can prevent the high-temperature gas from flowing to the air inlet and change the flow direction of the high-temperature gas, and on the other hand, the cold air blown out of the jet nozzle is fully mixed with the high-temperature gas, so that the high-temperature gas is cooled.

Description

Technical Field

[0001] This invention relates to the field of air intake temperature distortion prevention technology for short takeoff and vertical landing (STOVL) aircraft, and particularly to a device for suppressing air intake temperature distortion for STOVL aircraft. Background Technology

[0002] Beginning in the 1950s, short takeoff and vertical landing (STOVL) fighter jets gained favor among major military powers. After decades of development, the Harrier, Yak-38, Yak-141, and F-35B successively entered the scene. Among them, the F-35B is the most advanced STOVL fighter jet of its time, employing a combined thrust system of lift fan and cruise engine. This thrust system will guide the development direction of STOVL fighter jets for a long time to come.

[0003] Currently, although the development of short takeoff and vertical landing (STOVL) aircraft has been successful, problems such as heat inhalation and ground erosion have not yet been effectively solved. Heat inhalation poses safety hazards to STOVL aircraft, including reduced engine thrust, engine surge, and in severe cases, engine shutdown. The main reason for this is that as the aircraft approaches the ground, multiple jets impact the ground, creating a very complex flow field. High-temperature exhaust gases in this flow field, under the interference of the fuselage and the entrainment effect of the airflow, flow to the vicinity of the air intake and are drawn in. Heat inhalation causes an increase in the average temperature of the air intake and temperature distortion.

[0004] High-temperature exhaust gases in the airflow field are drawn into the engine intake in two ways: far-field intake and near-field intake. Far-field intake occurs when the nozzle strikes the ground, forming a wall jet. This wall jet flows on the ground, and its flow rate gradually decreases. Under buoyancy, it separates from the ground. If affected by a headwind or when the aircraft is moving forward at a low speed, it will be drawn into the intake. In other cases, the wall jet encounters a low-speed boundary layer flow from the headwind, causing it to separate from the ground and form a horseshoe vortex. This vortex is then drawn into the aircraft intake by the entrainment effect of the far-field flow. The impact of far-field intake on the intake's heat flow is related to the speed of the headwind. There is a separation point between the wall jet and the ground, and its distance from the aircraft intake changes with wind speed. The closer to the aircraft, the more significant the impact of far-field intake on heat flow intake. Near-field intake is caused by the "heat fountain" washout. Two or more nozzle jets impact the ground and diffuse in all directions, forming radial wall jets. These wall jets from different impact points collide and compress, forming an upward "heat fountain" that impacts the fuselage. This creates a recirculation zone between the nozzle jets, wall jets, and the "heat fountain." The high-temperature exhaust gases are drawn into the air intake near the intake due to the entrainment effect in this recirculation zone. Near-field intake is related to the aircraft's altitude. The higher the altitude, the smaller the airflow of the wall jets formed after the nozzle jets impact the ground, and consequently, the smaller the airflow of the "heat fountain." As a result, the "heat fountain" not only lacks sufficient energy to reach the fuselage but also gradually dissipates during ascent.

[0005] Although there are two ways of heat flow intake, far-field intake is less harmful than near-field intake because the outward-spreading wall jet travels a longer distance and its temperature drops significantly after being fully mixed with the air. In contrast, the "heat fountain" has a small diffusion range and is sucked into the intake duct before it can mix with the air. Therefore, near-field intake is the main source of temperature distortion in the intake duct.

[0006] To address the issue of hot air intake ingress, a 1997 paper published in the American Institute of Aeronautics and Astronautics (AIAA), titled "Inlet Hot Gas Ingestion (HGI) and Its Control in V / STOL Aircraft," proposed installing baffles on the AV-8B's fuselage to block and redirect the flow of high-temperature airflow. This measure effectively suppressed hot air intake ingress. However, these baffles were fixed to the fuselage bottom and could not be retracted, increasing the aircraft's weight and failing to meet modern stealth requirements for fighter jets. Boeing also installed baffles at the intake lip. This method blocked high-temperature airflow from entering the intake, as the airflow had already developed sufficiently in the flow field and its temperature had decreased. This method was more effective at suppressing hot air intake, but it also increased the aircraft's weight and affected its stealth performance. A 2002 AIAA paper, "The JSF STOVL Performance Process from Small-Scale Database to Flight Test Demonstration," demonstrated the X-32B's jet screen system for suppressing hot air intake. The jet shield system consists of two nozzles located in front of the lift nozzle. One nozzle is on the aircraft's centerline, and the other is perpendicular to the centerline, arranged in a "T" shape. The jet shield on the X-32B primarily blocks the forward-flowing "heat fountain," but is ineffective against "heat fountains" flowing to the sides of the aircraft. A 2017 article in *Fan Turbine Technology*, titled "Research Prospects for the F-35B Contra-rotating Lift Fan," points out that the downward-flowing cool air from the lift fan mitigates ground erosion and also prevents the intake of gases from the axial-flow engine. However, the lift fan only blocks the forward-flowing hot airflow; it is powerless against the hot airflow flowing to the sides of the aircraft. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a device for suppressing temperature distortion in the air intake of short takeoff and vertical landing (STOVL) aircraft. By changing the flow direction of high-temperature gas away from the air intake, the device suppresses near-field inhalation. A barrier is formed by installing jet nozzles symmetrical to the aircraft's centerline on the fuselage. This not only prevents high-temperature gas from flowing into the air intake and changes its flow direction, but also allows the cold air blown out from the jet nozzles to mix thoroughly with the high-temperature gas, thus cooling the high-temperature gas.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows:

[0009] A device for suppressing temperature distortion in the air intake of a short takeoff and vertical landing (STOVL) aircraft includes an engine compartment, a first jet device, a second jet device, and a third jet device. An air compressor is installed inside the engine compartment. The first and second jet devices are located on both sides of the engine compartment and connected to it. The third jet device is located at the bottom of the engine compartment and connected to it.

[0010] Furthermore, the No. 1, No. 2, and No. 3 jet devices include a circular-to-square barrel body, a two-dimensional transition section, and a two-dimensional expanding nozzle. The circular-to-square barrel body includes a horizontal section. The circular-to-square barrel bodies of the No. 1 and No. 2 jet devices also include a curved section. The horizontal section of the circular-to-square barrel body of the No. 3 jet device is placed vertically, with its upper end connected to the compressor installed inside the engine compartment and its lower end connected to the two-dimensional transition section. The horizontal section of the circular-to-square barrel body of the No. 1 and No. 2 jet devices is placed horizontally, with one end connected to the compressor installed inside the engine compartment and the other end connected to the curved section. The lower end of the curved section is connected to the two-dimensional transition section. The two-dimensional transition section includes a vertical expanding section and a vertical section. The upper end of the vertical expanding section is connected to the circular-to-square barrel body, and the lower end of the vertical expanding section is connected to the vertical section. The bottom of the vertical section is connected to the inlet of the two-dimensional expanding nozzle.

[0011] Furthermore, a flow controller is installed inside the circular-to-square barrel.

[0012] Furthermore, the bending angle of the curved section of the circular-to-square barrel of the No. 1 and No. 2 jet devices is between 60 and 90 degrees.

[0013] Furthermore, the horizontal section of the cylindrical square tube is a hollow cylinder.

[0014] Furthermore, the internal structure of the binary transition section is hollow, the vertical expansion section of the binary transition section is slotted, the internal structure of the binary expansion nozzle is also hollow, and the outlet of the binary expansion nozzle is slotted.

[0015] The beneficial effects of this invention are:

[0016] This invention suppresses near-field inhalation by altering the flow direction of high-temperature gas, directing it away from the air intake. A barrier is formed by installing jet nozzles symmetrical to the aircraft's centerline on the fuselage. This not only prevents high-temperature gas from flowing into the air intake and changes its flow direction, but also allows the cool air blown from the jet nozzles to fully mix with the high-temperature gas, thus cooling it. Attached Figure Description

[0017] Figure 1 This invention describes the formation process of a near-ground thermal flow fountain for a short takeoff and landing aircraft.

[0018] Figure 2 This invention describes the flow process of high-temperature gas under the aircraft after the hot flow fountain washes the fuselage.

[0019] Figure 3 This is a schematic diagram of the internal structure of an aircraft with an added jet screen device, provided by the present invention.

[0020] Figure 4 This invention describes the flow process of high-temperature gas under the fuselage after the addition of a jet screen device.

[0021] Figure 5 This is a schematic diagram of the structure of the No. 1 jet device and the No. 2 jet device provided by the present invention;

[0022] Figure 6 This is the working principle of the heat flow suction jet screen device provided by the present invention;

[0023] Figure 7 This is the shape of the heat flow fountain provided by the present invention;

[0024] Figure 8 This is the principle of heat flow absorption suppression of the No. 1 and No. 2 jet devices in Embodiment 2 provided by the present invention;

[0025] Figure 9 This is a schematic diagram of the internal structure of an aircraft according to Embodiment 2 of the present invention.

[0026] The reference numerals in the accompanying drawings include:

[0027] 1-Intake, 2-Lift fan, 3-Engine compartment, 4-Tail nozzle, 5-Jet device 1, 6-Jet device 2, 7-Jet device 3, 8-Circular to square barrel body, 9-Two-dimensional transition section, 10-Two-dimensional expanding nozzle. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0029] Example 1

[0030] like Figures 1 to 6As shown, a device for suppressing temperature distortion in the air intake of a short takeoff and vertical landing (STOVL) aircraft includes an engine compartment 3, a primary jet device 5, a secondary jet device 6, and a tertiary jet device 7. A compressor is installed inside the engine compartment 3. The primary jet devices 5 and 6 are located on either side of the engine compartment 3 and connected to it. The tertiary jet device 7 is located at the bottom of the engine compartment 3 and connected to it. The device is located inside the aircraft, with the engine compartment 3 centered on the aircraft's central axis. The primary jet devices 5 and 6 are symmetrically arranged with the central axis as a reference. The tertiary jet device 7 is located near the nose of the aircraft and perpendicular to the central axis. The two-dimensional expanding nozzles 10 of the primary jet devices 5, 6, and 7 open at their contact points with the aircraft. The engine compartment 3 is located between the lift fan 2 and the tail nozzle 4.

[0031] The first jet device 5, the second jet device 6, and the third jet device 7 each include a circular-to-square barrel body 8, a two-dimensional transition section 9, and a two-dimensional expansion nozzle 10. The circular-to-square barrel body 8 includes a horizontal section and a flow controller is installed within it. The circular-to-square barrel bodies 8 of the first and second jet devices 5 and 6 also include a curved section. The horizontal section of the circular-to-square barrel body 8 of the third jet device 7 is placed vertically, with its upper end connected to the compressor installed inside the engine compartment 3, and its lower end connected to... The two-dimensional transition section 9 is connected; the horizontal sections of the round-to-square barrel 8 of the first jet device 5 and the second jet device 6 are placed horizontally, one end of the horizontal section is connected to the compressor installed inside the engine compartment 3, and the other end is connected to the curved section. The lower end of the curved section is connected to the two-dimensional transition section 9; the two-dimensional transition section 9 includes a vertical expansion section and a vertical section. The upper end of the vertical expansion section is connected to the round-to-square barrel 8, the lower end of the vertical expansion section is connected to the vertical section, and the bottom of the vertical section is connected to the inlet of the two-dimensional expansion nozzle 10.

[0032] In this embodiment, the diameter of the circular-to-square barrel 8 is 200mm. The horizontal section length of the circular-to-square barrel 8 of the first jet device 5 and the second jet device 6 is 500mm. The bending radius of the curved section of the circular-to-square barrel 8 of the first jet device 5 and the second jet device 6 is 160mm, and the bending angle is 90 degrees. The binary transition section 9 of the first jet device 5, the second jet device 6, and the third jet device 7 is slotted, with a slot width of 190mm and a distance of 150mm between the two centers at both ends of the slot. The outlet of the binary expansion nozzle 10 of the first jet device 5, the second jet device 6, and the third jet device 7 is also slotted, with a slot width of 100mm and a distance of 900mm between the two centers at both ends of the slot. The vertical expansion section of the binary transition section 9 of the first jet device 5 and the second jet device 6 is 200mm long, and the vertical section is 100mm long. The two-dimensional expanding nozzle 10 of jet device 5 and jet device 6 is 380mm long; the circular-to-square barrel 8 of jet device 7 has a diameter of 200mm and a horizontal section length of 100mm; the two-dimensional transition section 9 of jet device 7 has a vertical expanding section length of 100mm and a vertical section length of 80mm. The two-dimensional expanding nozzle 10 of jet device 7 is 190mm long.

[0033] Figure 1 It demonstrates the formation process of a thermal fountain. For example... Figure 1 As shown, the cold airflow from lift fan 2 and the hot airflow from tail nozzle 4 collide and compress near the ground, forming a heat jet fountain. This heat jet fountain then directly impacts the fuselage, and the hot gas flows outwards along the fuselage. The flow direction of the heat jet fountain on the fuselage is as follows: Figure 2 As shown, a portion flows to both sides of the aircraft, roughly symmetrical to the aircraft's central axis. Then, under the entrainment effect of the airflow around the fuselage, it approaches the area near intake 1 and is drawn into intake 1. The other portion flows along the fuselage towards the nose and gradually approaches the area below intake 1 before being drawn in. The idea behind suppressing the intake of hot air is to take certain measures to block the flow of high-temperature gas in the fuselage.

[0034] Figure 3 This is a schematic diagram of the structure inside the aircraft in this embodiment. The circular-to-square barrel 8 is connected to the aero-engine compressor, and the two-dimensional transition section 9 connects the circular-to-square barrel 8 and the two-dimensional expanding nozzle 10. The two-dimensional expanding nozzle 10 is designed for two main purposes: first, the expanding nozzle can increase the jet velocity, improve the airflow, and form a stable jet barrier; second, the two-dimensional expanding nozzle 10 can form a fan-shaped jet barrier, increasing the area of ​​the jet barrier.

[0035] Figure 4This diagram illustrates the flow of high-temperature gas under the fuselage after a jet screen device has been installed. The airflow decreases after the hot jet impacts the fuselage, resulting in a relatively low velocity for the high-temperature gas flowing along the fuselage. Meanwhile, the high velocity of the low-temperature airflow completely impedes further flow of the high-temperature gas, confining it to a limited area where it is deflected and cooled by the low-temperature airflow.

[0036] Figure 6 This is a schematic diagram of the jet screen device. The jet screen device introduces cryogenic gas from the aircraft engine compressor, which is then ejected from the jet nozzle after passing through a flow controller. It blocks the high-temperature gas flowing along the fuselage and changes its flow direction. During this process, the cryogenic and high-temperature gases mix, thus lowering the temperature of the high-temperature gas. The mixed gas flows towards the ground under the action of the jet, and after being deflected by the ground, diffuses to both sides of the aircraft, gradually moving away from the aircraft. Jet devices 5 and 6 block the high-temperature gas flowing to both sides after the hot jet fountain impacts the fuselage, while jet device 7 blocks the high-temperature gas flowing towards the nose after the hot jet fountain impacts the fuselage. This portion of high-temperature gas is confined within a limited area, preventing it from approaching the air intake 1. After being deflected by the jet, it mixes with the jet from the front nozzle, thus reducing its temperature.

[0037] 1. Move the jet nozzle, which is perpendicular to the aircraft's centerline, to the rear of the lift fan 2, close to the position where the heat fountain impacts the fuselage, to block the high-temperature airflow that moves forward after impacting the fuselage.

[0038] 2. Jet nozzles parallel to the centerline are opened on both sides of the aircraft's centerline to block the high-temperature airflow moving to the sides of the aircraft.

[0039] 3. The design of the two-dimensional expanding nozzle 10 can accelerate the airflow and increase the surface area of ​​the jet screen.

[0040] Example 2

[0041] like Figures 8 to 9As shown, a device for suppressing temperature distortion in the air intake of a short takeoff and vertical landing (STOVL) aircraft includes an engine compartment 3, a primary jet device 5, a secondary jet device 6, and a tertiary jet device 7. A compressor is installed inside the engine compartment 3. The primary jet devices 5 and 6 are located on either side of the engine compartment 3 and connected to it. The tertiary jet device 7 is located at the bottom of the engine compartment 3 and connected to it. The device is located inside the aircraft, with the engine compartment 3 centered on the aircraft's central axis. The primary jet devices 5 and 6 are symmetrically arranged with the central axis as a reference. The tertiary jet device 7 is located near the nose of the aircraft and perpendicular to the central axis. The two-dimensional expanding nozzles 10 of the primary jet devices 5, 6, and 7 open at their contact points with the aircraft. The engine compartment 3 is located between the lift fan 2 and the tail nozzle 4.

[0042] The first jet device 5, the second jet device 6, and the third jet device 7 each include a circular-to-square barrel body 8, a two-dimensional transition section 9, and a two-dimensional expansion nozzle 10. The circular-to-square barrel body 8 includes a horizontal section and a flow controller is installed within it. The circular-to-square barrel bodies 8 of the first and second jet devices 5 and 6 also include a curved section. The horizontal section of the circular-to-square barrel body 8 of the third jet device 7 is placed vertically, with its upper end connected to the compressor installed inside the engine compartment 3, and its lower end connected to... The two-dimensional transition section 9 is connected; the horizontal sections of the round-to-square barrel 8 of the first jet device 5 and the second jet device 6 are placed horizontally, one end of the horizontal section is connected to the compressor installed inside the engine compartment 3, and the other end is connected to the curved section. The lower end of the curved section is connected to the two-dimensional transition section 9; the two-dimensional transition section 9 includes a vertical expansion section and a vertical section. The upper end of the vertical expansion section is connected to the round-to-square barrel 8, the lower end of the vertical expansion section is connected to the vertical section, and the bottom of the vertical section is connected to the inlet of the two-dimensional expansion nozzle 10.

[0043] In this embodiment, the diameter of the circular-to-square barrel 8 is 200mm. The horizontal section length of the circular-to-square barrel 8 of the first jet device 5 and the second jet device 6 is 100mm. The bending radius of the curved section of the circular-to-square barrel 8 of the first jet device 5 and the second jet device 6 is 160mm, and the bending angle is 60 degrees. The binary transition section 9 of the first jet device 5, the second jet device 6, and the third jet device 7 is slotted, with a slot width of 190mm and a distance of 150mm between the two centers at both ends of the slot. The outlet of the binary expansion nozzle 10 of the first jet device 5, the second jet device 6, and the third jet device 7 is also slotted, with a slot width of 100mm and a distance of 900mm between the two centers at both ends of the slot. The vertical expansion section of the binary transition section 9 of the first jet device 5 and the second jet device 6 is 200mm long, and the vertical section is 100mm long. The two-dimensional expanding nozzle 10 of jet device 5 and jet device 6 is 380mm long; the circular-to-square barrel 8 of jet device 7 has a diameter of 200mm and a horizontal section length of 100mm; the two-dimensional transition section 9 of jet device 7 has a vertical expanding section length of 100mm and a vertical section length of 80mm. The two-dimensional expanding nozzle 10 of jet device 7 is 190mm long.

[0044] The airflow ejected by the jet device is perpendicular to the ground; however, viewed from the nose to the tail, the heat fountain appears as an arc perpendicular to the ground, such as... Figure 7 As shown. At this time, the airflow direction of the hot flow fountain is opposite to the low-temperature airflow, which will affect the effect of the jet device in forming a jet screen and is not conducive to the deflection of the high-temperature gas in the belly of the machine. If the high-temperature gas can be successfully deflected to the ground by the low-temperature airflow, but considering that its flow direction is perpendicular to the ground, it will form a new wall jet flow towards the position of the hot flow fountain after directly impacting the ground. In view of this situation, it is necessary to adjust the two-dimensional expansion nozzle 10 of the first jet device 5 and the second jet device 6. The two-dimensional expansion nozzle 10 of the second jet device 6 is not considered except for the influence of the airflow rushing on the "hot flow fountain". The principle of the jet screen device in Example 2 is as follows. Figure 7 As shown, the two-dimensional expanding nozzle 10 is tilted at a certain angle, so the upward-rushing "heat fountain" will no longer directly impact the jet nozzle, reducing its impact on the formation of a jet barrier. In Example 2, the jet nozzles on both sides of the central axis of the aircraft are tilted outward at a certain angle, which not only blocks the high-temperature airflow but also deflects it. Under the entrainment effect of the jet, the airflow moves away from the aircraft. The tilted nozzle ejects a tilted jet, which will have a better effect on deflecting the high-temperature gas. Moreover, under the entrainment effect of the tilted jet and the wall jet, the high-temperature gas will move further away from the aircraft. The tilted nozzle can better suppress the temperature distortion of the intake duct 1 caused by the intake of heat flow.

Claims

1. A device for suppressing temperature distortion in the air intake of a short takeoff and vertical landing aircraft, characterized in that, It includes an engine compartment, a first jet device, a second jet device, and a third jet device. A compressor is installed inside the engine compartment. The first and second jet devices are located on both sides of the engine compartment and connected to it. The third jet device is located at the bottom of the engine compartment and connected to it. The No. 1, No. 2, and No. 3 jet devices include a circular-to-square barrel body, a two-dimensional transition section, and a two-dimensional expanding nozzle. The circular-to-square barrel body includes a horizontal section. The circular-to-square barrel bodies of the No. 1 and No. 2 jet devices also include a curved section. The horizontal section of the circular-to-square barrel body of the No. 3 jet device is placed vertically, with its upper end connected to the compressor installed inside the engine compartment and its lower end connected to the two-dimensional transition section. The horizontal section of the circular-to-square barrel body of the No. 1 and No. 2 jet devices is placed horizontally, with one end connected to the compressor installed inside the engine compartment and the other end connected to the curved section. The lower end of the curved section is connected to the two-dimensional transition section. The two-dimensional transition section includes a vertical expanding section and a vertical section. The upper end of the vertical expanding section is connected to the circular-to-square barrel body, and the lower end of the vertical expanding section is connected to the vertical section. The bottom of the vertical section is connected to the inlet of the two-dimensional expanding nozzle. The bending angle of the curved section of the circular-to-square barrel of the No. 1 and No. 2 jet devices is between 60 and 90 degrees.

2. The device for suppressing temperature distortion in the air intake of a short takeoff and landing aircraft according to claim 1, characterized in that, A flow controller is installed inside the circular-to-square barrel.

3. The device for suppressing temperature distortion in the air intake of a short takeoff and landing aircraft according to claim 1, characterized in that, The horizontal section of the circular-to-square barrel is a hollow cylinder.

4. The device for suppressing temperature distortion in the air intake of a short takeoff and landing aircraft according to claim 1, characterized in that, The internal structure of the binary transition section is hollow, the vertical expansion section of the binary transition section is slotted, the internal structure of the binary expansion nozzle is also hollow, and the outlet of the binary expansion nozzle is slotted.

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