A plug nozzle air film cooling enhancement device based on Coanda effect

Abstract

The present invention belongs to the technical field of aircraft engine exhaust systems, and in particular, is a plug-type nozzle air film cooling enhancement device based on the Coanda effect. The plug cone of the binary plug-type nozzle is located in the nozzle, which makes the plug cone temperature very high. In order to protect the plug cone and improve the stealth capability, the plug cone must be cooled. The traditional air film cooling structure cannot avoid the separation of the cooling airflow downstream of the air film groove and the wall surface, resulting in low air film cooling efficiency. The following scheme is proposed, including a binary nozzle, the front section of the binary nozzle is a circular square section, the rear section is a binary section, a plug cone is arranged in the binary section, and the upper and lower sides of the plug cone are both provided with air film grooves and bosses, and the bosses are located downstream of the outlet of the air film groove. The present invention discloses a plug-type nozzle air film cooling enhancement device based on the Coanda effect, which suppresses the separation of the cooling airflow through the Coanda effect generated when the airflow flows through the boss, and can improve the air film cooling efficiency under the same cooling air flow rate.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft engine exhaust systems, and in particular to a plug-type nozzle air film cooling enhancement device based on the Coanda effect. Background Art

[0002] As a typical supersonic exhaust system structure, the two-dimensional plug nozzle has advantages in meeting the requirements of flight-engine integrated design, infrared stealth and reducing flow resistance. It is one of the preferred configurations of the exhaust system of supersonic fighters. The two-dimensional vector nozzle is an aircraft tail nozzle that can deflect in the pitch and yaw directions, so that the aircraft can generate additional torque perpendicular to the aircraft axis in the pitch and yaw directions, thus enabling the aircraft to have thrust vector control capabilities. The aircraft's vector engine is an engine whose nozzle can be deflected in different directions to generate thrust in different directions. In short, thrust vector technology is a technology that obtains additional control torque by deflecting the direction of the engine jet. We know that the thrust acting on the aircraft is a quantity with size and direction, which is called a vector. However, on general aircraft, the thrust is forward along the aircraft axis and the direction cannot be changed, so we call the characteristic of the aircraft's variable thrust direction thrust vector technology.

[0003] The plug cone of the binary plug nozzle is located in the nozzle, which makes the plug cone temperature very high. In order to protect the plug cone and improve the stealth capability, the plug cone must be cooled. The traditional air film cooling structure cannot avoid the separation of the cooling airflow and the wall surface downstream of the air film groove, resulting in low air film cooling efficiency. Therefore, the present invention provides a binary plug nozzle air film cooling enhancement device based on the Coanda effect to solve the above problem. Summary of the invention

[0004] The present invention discloses a plug nozzle air film cooling enhancement device based on Coanda effect, which aims to solve the technical problem that the plug cone of the binary plug nozzle in the background technology is located in the nozzle, which makes the plug cone temperature very high. In order to protect the plug cone and improve the stealth capability, the plug cone must be cooled. The traditional air film cooling structure cannot avoid the separation of the cooling airflow downstream of the air film groove and the wall surface, resulting in low air film cooling efficiency.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A plug-type nozzle air film cooling enhancement device based on the Coanda effect comprises a binary nozzle, wherein the front section of the binary nozzle is a circular-to-square section, and the rear section is a binary section. A plug cone is arranged in the binary section, and air film grooves and bosses are arranged on the upper and lower sides of the plug cone, and the boss is located downstream of the outlet of the air film groove.

[0007] Furthermore, the plug cone comprises a plug cone front section, a plug cone rear section and a transition section, and the transition section is arranged between the plug cone front section and the plug cone rear section.

[0008] Furthermore, the cross-sectional area of ​​the channel between the binary section and the plug cone is of a pure convergent type or a convergent-divergent type.

[0009] Furthermore, the air film groove is arranged in the front section, transition section or rear section of the plug cone.

[0010] Furthermore, the boss is arranged downstream of the air film groove outlet, and the boss profile is arc-shaped.

[0011] Furthermore, an adjustment module is provided on the outside of the binary section, and the adjustment module includes an L-support plate, circular holes are opened on both sides of the binary section, and the interiors of the two circular holes are connected with rotating adjustment circular tubes through bearings, and the interiors of the two rotating adjustment circular tubes are fixedly connected with the same mounting circular tube, and the mounting circular tube is located inside the plug cone, and air holes are opened on the outside of the mounting circular tube at equal distances, and the interiors of the multiple air holes are fixedly connected with metal telescopic tubes, and the metal telescopic tubes are located inside the plug cone.

[0012] Furthermore, one side of the binary section is connected with two tooling limit blocks by bolts, and one side of the two tooling limit blocks is provided with a mounting circular hole, the interior of the two mounting circular holes is fixedly connected with the same transmission pipe, one end of the transmission pipe is movably connected to the interior of the mounting circular pipe, an air inlet is provided on the outside of the transmission pipe, and the interior of the air inlet is fixedly connected with an air intake pipe.

[0013] Furthermore, one of the rotating adjustment circular tubes is fixedly connected to the outside with a linkage gear, which is located on the outside of the binary section. A second circular hole is opened on one side of the binary section, and a rotating cylinder is connected to the inside of the second circular hole through a bearing. A T-shaped tooth plate is fixedly connected to the outside of the rotating cylinder, and a sliding groove is opened on the side of the T-shaped tooth plate. The T-shaped tooth plate is located on the outside of the binary section, and the tooth block end of the T-shaped tooth plate is meshed with the linkage gear.

[0014] Furthermore, the side of the L-support plate is connected to a fixed seat by bolts, and one side of the fixed seat is fixedly connected to a driving motor, the driving end of the driving motor is fixedly connected to a rotating push rod, a circular hole three is opened on the side of the rotating push rod, the inside of the circular hole three is connected to a rotating shaft through a bearing, the outside of the rotating shaft is fixedly connected to a pushing wheel, and the pushing wheel is movably connected to the inside of a sliding groove opened in the T-shaped tooth plate.

[0015] Furthermore, two installation ports are opened on the outside of the binary section, and hollow installation preheating frames are fixedly connected to the inside of the two installation ports, oil pipes are arranged inside the two hollow installation preheating frames, and one side of the two hollow installation preheating frames is fixedly connected to oil tanks, which are located on the upper and lower sides of the binary section, and the inlet and outlet ends of the two oil tanks are fixedly connected to circulation pipes, and the other end of the circulation pipe is fixedly connected to one end of the oil pipe.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The left end of the circular rotating square section is connected to the turbine outlet of the aircraft engine. When the engine is working, the mainstream high-temperature combustion gas enters the circular rotating square section of the nozzle and passes through the air flow channel between the binary section and the plug cone. The cooling airflow is injected into the mainstream through the air film groove and flows through the boss. The cooling airflow produces a Coanda effect under the action of the boss, thereby suppressing the separation of the cooling airflow. The cooling airflow flows along the surface of the boss and the rear section of the plug cone. The present invention suppresses the separation of the cooling airflow through the Coanda effect generated when the airflow flows through the boss, and can improve the air film cooling efficiency under the same cooling air flow rate.

[0018] When the plug cone is cooled by the cooling air flow, the air intake pipe transmits the cooling air flow to the installation circular tube through the transmission pipe, and then disperses the air flow to the inside of the plug cone through the multiple metal telescopic tubes on the installation circular tube, so that the cooling air flow contacts the boss evenly, avoiding the cooling air flow gathering at a certain place inside the plug cone. At the same time, the driving motor is started, and the driving motor drives the rotating push rod to rotate, so that the pushing wheel on the rotating push rod moves in the slide groove on the T-shaped tooth plate, so that the pushing wheel drives the tooth block end of the T-shaped tooth plate to move back and forth in an arc shape, so that the T-shaped tooth plate drives the linkage gear to rotate in both directions, and the tail end of the plug cone is driven to swing back and forth by the rotating adjustment tube, thereby extending the stay of the cooling air flow and improving the cooling effect on the plug cone.

[0019] When the device is in use, the fuel tank circulates unused fuel through the oil pipe, so that the oil pipe in the hollow preheating frame absorbs heat to preheat the fuel, thereby improving the energy saving of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural schematic diagram of a plug nozzle air film cooling enhancement device based on the Coanda effect proposed by the present invention;

[0021] Figure 2 A schematic diagram of the symmetrical cross-sectional structure of a plug-type nozzle air film cooling enhancement device based on the Coanda effect proposed by the present invention;

[0022] Figure 3A schematic diagram of the local structure near the upper boss of the plug cone of a plug-type nozzle air film cooling enhancement device based on the Coanda effect proposed by the present invention;

[0023] Figure 4 This is a schematic diagram of the overall structure of a plug nozzle air film cooling enhancement device based on the Coanda effect proposed by the present invention;

[0024] Figure 5 A schematic diagram of the internal structure of a two-element section of a plug-type nozzle air film cooling enhancement device based on the Coanda effect proposed by the present invention;

[0025] Figure 6 This is a schematic diagram of the structure of an adjustment module of a plug-type nozzle air film cooling enhancement device based on the Coanda effect proposed by the present invention;

[0026] Figure 7 This is a schematic diagram of the structure of a hollow installation preheating frame of a plug-type nozzle air film cooling enhancement device based on the Coanda effect proposed by the present invention;

[0027] Figure 8 for Figure 6 Schematic diagram of the enlarged structure of part A.

[0028] In the figure: 1. circular rotating square section; 2. binary section; 3. plug cone; 4. air film groove; 5. boss; 6. front section of plug cone; 7. rear section of plug cone; 8. transition section; 9. adjustment module; 901. rotating adjustment round tube; 902. installation round tube; 903. metal telescopic tube; 904. L support plate; 905. tooling limit block; 906. air intake pipe; 907. transmission pipe; 908. linkage gear; 909. fixed seat; 910. driving motor; 911. rotating cylinder; 912. T-shaped tooth plate; 913. rotating push rod; 914. rotating shaft; 915. pushing wheel; 10. hollow installation preheating frame; 11. oil pipe; 12. installation port; 13. circulation pipe; 14. oil tank. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0030] The invention discloses a plug nozzle air film cooling enhancement device based on Coanda effect, which is mainly used in a binary plug nozzle where the plug cone is located in the nozzle, which makes the plug cone temperature very high. In order to protect the plug cone and improve the stealth capability, the plug cone must be cooled. The traditional air film cooling structure cannot avoid the separation of the cooling airflow and the wall surface downstream of the air film groove, resulting in a low air film cooling efficiency.

[0031] like Figure 1-3 As shown, the present invention provides a two-dimensional plug nozzle air film cooling enhancement device based on Coanda effect, including a two-dimensional nozzle, the two-dimensional nozzle including a circular square section 1 and a two-dimensional section 2, a plug cone 3 is arranged in the two-dimensional section 2, the plug cone 3 includes a plug cone front section 6, a plug cone rear section 7 and a transition section 8, the transition section 8 is between the plug cone front section 6 and the plug cone rear section 7, air film grooves 4 are arranged on the upper and lower sides of the transition section 8, a boss 5 is arranged downstream of the outlet of the air film groove 4, and the boss 5 has an arc-shaped surface.

[0032] Specifically, the cooling airflow is injected into the mainstream through the air film groove 4 and flows through the boss 5. Under the action of the boss 5, the cooling airflow generates a Coanda effect.

[0033] In a more specific application scenario, the left end of the circular rotating square section 1 is connected to the turbine outlet of the aircraft engine. When the engine is working, the mainstream high-temperature combustion gas enters the circular rotating square section 1 of the nozzle and passes through the air flow channel between the binary section 2 and the plug cone 3. The cooling airflow is injected into the mainstream through the air film groove 4 and flows through the boss 5. The cooling airflow produces a Coanda effect under the action of the boss 5, thereby suppressing the separation of the cooling airflow. The cooling airflow flows along the surface of the boss 5 and the rear section 7 of the plug cone.

[0034] It should be noted that a plug cone 3 is provided in the binary section 2 . The plug cone 3 includes a plug cone front section 6 , a plug cone rear section 7 and a transition section 8 . The transition section 8 is between the plug cone front section 6 and the plug cone rear section 7 .

[0035] like Figure 1-8 As shown, an adjustment module 9 is provided on the outside of the binary section 2, and the adjustment module 9 includes an L support plate 904, circular holes are opened on both sides of the binary section 2, and the interiors of the two circular holes are connected with rotating adjustment circular tubes 901 through bearings, and the interiors of the two rotating adjustment circular tubes 901 are fixedly connected with the same mounting circular tube 902, and the mounting circular tube 902 is located inside the plug cone 3. Air holes are opened on the outside of the mounting circular tube 902 at equal distances, and the interiors of the multiple air holes are fixedly connected with metal telescopic tubes 903, and the metal telescopic tubes 903 are located inside the plug cone 3.

[0036] like Figure 1-8 As shown, one side of the binary section 2 is connected with two tooling limit blocks 905 by bolts, and one side of the two tooling limit blocks 905 is provided with a mounting circular hole, the interior of the two mounting circular holes is fixedly connected with the same transmission tube 907, one end of the transmission tube 907 is movably connected to the interior of the mounting circular tube 902, an air inlet is provided on the outside of the transmission tube 907, and the interior of the air inlet is fixedly connected with an air inlet pipe 906.

[0037] Specifically, the cooling airflow flows along the surface of the boss 5 and the rear section 7 of the plug cone, thereby improving the air film cooling efficiency. When the plug cone 3 is cooled by the cooling airflow, the air inlet pipe 906 transports the cooling airflow to the mounting circular tube 902 through the transmission pipe 907, and then disperses the airflow to the interior of the plug cone 3 through the multiple metal telescopic tubes 903 on the mounting circular tube 902, so that the cooling airflow is evenly in contact with the boss 5.

[0038] like Figure 1-8 As shown, one of the rotating adjustment circular tubes 901 is fixedly connected to the outside with a linkage gear 908, which is located on the outside of the binary section 2. A circular hole 2 is provided on one side of the binary section 2, and a rotating cylinder 911 is connected to the inside of the circular hole 2 through a bearing. A T-shaped tooth plate 912 is fixedly connected to the outside of the rotating cylinder 911, and a sliding groove is provided on the side of the T-shaped tooth plate 912. The T-shaped tooth plate 912 is located on the outside of the binary section 2, and the tooth block end of the T-shaped tooth plate 912 is meshed with the linkage gear 908.

[0039] like Figure 1-8 As shown, the side of the L support plate 904 is connected to a fixed seat 909 by bolts, and one side of the fixed seat 909 is fixedly connected to a driving motor 910, and the driving end of the driving motor 910 is fixedly connected to a rotating push rod 913, and a circular hole three is opened on the side of the rotating push rod 913, and the interior of the circular hole three is connected to a rotating shaft 914 through a bearing, and the outside of the rotating shaft 914 is fixedly connected to a pushing wheel 915, and the pushing wheel 915 is movably connected to the inside of the sliding groove opened by the T-shaped tooth plate 912.

[0040] Specifically, the air intake pipe 906 transports the cooling airflow to the installation circular tube 902 through the transmission pipe 907, and then disperses the airflow to the interior of the plug cone 3 through the multiple metal telescopic tubes 903 on the installation circular tube 902, so that the cooling airflow is evenly in contact with the boss 5, and the driving wheel 915 drives the tooth block end of the T-shaped tooth plate 912 to move back and forth in an arc shape, so that the T-shaped tooth plate 912 drives the linkage gear 908 to rotate in both directions, and the rotation of the adjustment circular tube 901 drives the tail end of the plug cone 3 to swing back and forth.

[0041] In another specific application scenario, the cooling airflow flows along the surface of the boss 5 and the rear section 7 of the plug cone, thereby improving the air film cooling efficiency. When the plug cone 3 is cooled by the cooling airflow, the air inlet pipe 906 conveys the cooling airflow to the installation circular tube 902 through the transmission pipe 907, and then disperses the airflow to the inside of the plug cone 3 through the multiple metal telescopic tubes 903 on the installation circular tube 902, so that the cooling airflow is evenly in contact with the boss 5, and the cooling airflow is prevented from gathering and flowing at a certain place inside the plug cone 3. At the same time, the driving motor 910 is started, and the driving motor 910 drives the rotating push rod 913 to rotate, so that the pushing wheel 915 on the rotating push rod 913 moves in the slide groove on the T-shaped tooth plate 912, so that the pushing wheel 915 drives the tooth block end of the T-shaped tooth plate 912 to move back and forth in an arc shape, so that the T-shaped tooth plate 912 drives the linkage gear 908 to rotate in both directions, and the tail end of the plug cone 3 is driven to swing back and forth by the rotating adjustment tube 901, thereby extending the stay of the cooling airflow.

[0042] It should be noted that one end of the transmission tube 907 is movably connected to the inside of the mounting circular tube 902, a slide groove is provided on the side of the T-shaped tooth plate 912, the pushing wheel 915 is movably connected to the inside of the slide groove provided in the T-shaped tooth plate 912, and the tooth block end of the T-shaped tooth plate 912 is meshed with the linkage gear 908.

[0043] like Figure 1-7 As shown, two installation openings 12 are opened on the outside of the binary section 2, and the insides of the two installation openings 12 are fixedly connected with hollow installation preheating frames 10, and the insides of the two hollow installation preheating frames 10 are provided with oil circuit pipes 11. One side of the two hollow installation preheating frames 10 is fixedly connected with oil tanks 14, and the oil tanks 14 are located on the upper and lower sides of the binary section 2. The inlet and outlet ends of the two oil tanks 14 are fixedly connected with circulation pipes 13, and the other end of the circulation pipe 13 is fixedly connected to one end of the oil circuit pipe 11.

[0044] Specifically, the oil pipe 11 performs a circulation preheating operation on the fuel.

[0045] In another specific application scenario, the fuel tank 14 circulates unused fuel through the oil pipe 11, so that the oil pipe 11 in the hollow preheating frame 10 absorbs heat to preheat the fuel, thereby improving the energy saving of the device.

[0046] Working principle: The left end of the rotating square section 1 is connected to the turbine outlet of the aircraft engine. When the engine is working, the mainstream high-temperature combustion gas enters the rotating square section 1 of the nozzle and passes through the air flow channel between the binary section 2 and the plug cone 3. The cooling airflow is ejected into the mainstream through the air film groove 4 and flows through the boss 5. The cooling airflow produces a Coanda effect under the action of the boss 5, thereby suppressing the separation of the cooling airflow. The cooling airflow flows along the surface of the boss 5 and the rear section 7 of the plug cone, thereby improving the air film cooling efficiency. When the plug cone 3 is cooled by the cooling airflow, the air intake pipe 906 conveys the cooling airflow to the installation circular tube 902 through the transmission pipe 907, and then disperses the airflow to the inside of the plug cone 3 through the multiple metal telescopic tubes 903 on the installation circular tube 902, so that the cooling airflow is evenly in contact with the boss 5, avoiding the cooling airflow from gathering at a certain place inside the plug cone 3. At the same time, the drive motor 910 is started, and the rotating push rod 913 is driven to rotate by the drive motor 910, so that the rotating push rod 913 is rotated. The push wheel 915 moves in the slide groove on the T-shaped tooth plate 912, so that the push wheel 915 drives the tooth block end of the T-shaped tooth plate 912 to move back and forth in an arc shape, so that the T-shaped tooth plate 912 drives the linkage gear 908 to rotate in both directions, and the tail end of the plug cone 3 is driven to swing back and forth by rotating the adjustment tube 901, thereby extending the stay of the cooling airflow and improving the cooling effect on the plug cone. When the device is in use, the oil tank 14 circulates unused fuel through the oil pipe 11, so that the oil pipe 11 in the hollow preheating frame 10 absorbs heat to preheat the fuel, thereby improving the energy saving of the device.

[0047] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A plug nozzle air film cooling enhancement device based on Coanda effect, comprising a binary nozzle, characterized in that: The front section of the binary nozzle is a circular rotating square section (1), and the rear section is a binary section (2). A plug cone (3) is arranged in the binary section (2). The upper and lower sides of the plug cone (3) are both provided with an air film groove (4) and a boss (5). The boss (5) is located downstream of the outlet of the air film groove (4). An adjustment module (9) is arranged outside the binary section (2), and the adjustment module (9) comprises an L-support plate (904). Round holes (1) are provided on both sides of the binary section (2). Rotational adjustment round tubes (901) are connected to the inside of the two round holes (1) via bearings. The insides of the two rotational adjustment round tubes (901) are fixedly connected to the same mounting round tube (902). The mounting round tube (902) is located inside the plug cone (3). Air holes are provided outside the mounting round tube (902) at equal distances. Metal telescopic tubes (903) are fixedly connected to the insides of the multiple air holes. The metal telescopic tubes (903) are located inside the plug cone (3). One side of the binary section (2) is connected to two tooling limit blocks (905) by bolts, and one side of the two tooling limit blocks (905) is provided with a mounting circular hole, the interior of the two mounting circular holes is fixedly connected to a same transmission tube (907), one end of the transmission tube (907) is movably connected to the interior of the mounting circular tube (902), an air inlet is provided on the outside of the transmission tube (907), and the interior of the air inlet is fixedly connected to an air inlet pipe (906); The outside of one of the rotating adjustment circular tubes (901) is fixedly connected to a linkage gear (908), the linkage gear (908) is located outside the binary section (2), a second circular hole is opened on one side of the binary section (2), the inside of the second circular hole is connected to a rotating cylinder (911) via a bearing, the outside of the rotating cylinder (911) is fixedly connected to a T-shaped toothed plate (912), a sliding groove is opened on the side of the T-shaped toothed plate (912), the T-shaped toothed plate (912) is located outside the binary section (2), and the tooth block end of the T-shaped toothed plate (912) is meshed with the linkage gear (908).

2. The device for enhancing plug nozzle film cooling based on Coanda effect according to claim 1, characterized in that: The plug cone (3) comprises a plug cone front section (6), a plug cone rear section (7) and a transition section (8), wherein the transition section (8) is arranged between the plug cone front section (6) and the plug cone rear section (7).

3. The plug nozzle air film cooling enhancement device based on Coanda effect according to claim 1, characterized in that: The cross-sectional area of ​​the channel between the binary section (2) and the plug cone (3) is of a purely convergent type or a convergent-divergent type.

4. The plug nozzle air film cooling enhancement device based on Coanda effect according to claim 2 is characterized in that: The air film groove (4) is arranged in the front section (6), transition section (8) or rear section (7) of the plug cone.

5. The plug nozzle air film cooling enhancement device based on Coanda effect according to claim 1, characterized in that: The boss (5) is arranged downstream of the outlet of the air film groove (4), and the boss (5) has an arc-shaped profile.

6. The device for enhancing plug nozzle film cooling based on Coanda effect according to claim 1, characterized in that: The side of the L-shaped support plate (904) is connected to a fixing seat (909) via bolts, and a driving motor (910) is fixedly connected to one side of the fixing seat (909), and a rotating push rod (913) is fixedly connected to the driving end of the driving motor (910), and a circular hole three is opened on the side of the rotating push rod (913), and a rotating shaft (914) is connected to the inside of the circular hole three via a bearing, and a driving wheel (915) is fixedly connected to the outside of the rotating shaft (914), and the driving wheel (915) is movably connected to the inside of a slide groove opened in the T-shaped tooth plate (912).

7. The device for enhancing the air film cooling of a plug nozzle based on the Coanda effect according to claim 6, characterized in that: The binary section (2) is provided with two mounting openings (12) on the outside, and the insides of the two mounting openings (12) are fixedly connected to a hollow mounting preheating frame (10), the insides of the two hollow mounting preheating frames (10) are provided with an oil pipe (11), one side of the two hollow mounting preheating frames (10) is fixedly connected to an oil tank (14), the oil tank (14) is located on the upper and lower sides of the binary section (2), the inlet and outlet ends of the two oil tanks (14) are fixedly connected to a circulation pipe (13), and the other end of the circulation pipe (13) is fixedly connected to one end of the oil pipe (11).

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