A rudder shaft protection structure integrating round trapezoidal transition variable curved surface drag reduction and heat protection

Abstract

The present invention provides a rudder shaft protection structure with integrated drag reduction and heat protection by means of a circular trapezoidal transition variable curved surface, belonging to the technical field of heat protection structure design. It includes a cabin heat protection sleeve structure, a variable curved surface integrated drag reduction and heat protection structure, heat protection screws, and a rudder shaft heat protection structure. The outer shape of the cabin heat protection sleeve structure is cylindrical. The variable curved surface integrated drag reduction and heat protection structure includes a variable curved surface transition section and an equal cross-section trapezoidal section, which are fixed by heat protection screws. The upper surface of the equal cross-section trapezoidal section is perpendicular to the axis of the rudder shaft, and a fillet is provided at the junction of the inclined surface and the upper surface. The rear end cross-section of the variable curved surface transition section is the same as that of the equal cross-section trapezoidal section, and the front end is a circle consistent with the outer surface of the cabin heat protection sleeve structure, with the overall structure having a smooth transition of the variable curved surface. The heat protection screws include a screw rod and a nut, and the top outer shape of the nut is the same as the outer shape of the variable curved surface integrated drag reduction and heat protection structure. The present invention solves the problems of large local protrusion height, large aerodynamic drag, and high manufacturing and installation difficulty of the fairing structure of existing high-speed aircraft.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat protection structure design, and particularly relates to a rudder shaft protection structure with integrated drag reduction and heat protection of a circular trapezoidal transition variable curved surface, which is applicable to local heat protection and drag reduction of the actuator rudder system of high-speed aircraft. Background Art

[0002] The thermal environment where the relevant actuators of the rudder system of high-speed aircraft are located is extremely harsh. In order to optimize the aerodynamic flow field and thermal environment conditions and achieve thermal protection of the rudder shaft structure of the air rudder, in the prior art, the rectification and heat protection design is generally carried out by installing a local rectification structure on the outer surface of the projectile body.

[0003] At present, the local protrusion height of the rectification structure of most large aircraft is relatively large. Although the heat protection function is achieved, the aerodynamic drag is increased, which affects the optimization of performance indicators such as range and speed. At the same time, the rectification structure is a separate structural part, which increases the number of product types and the complexity of the general assembly process, and it is necessary to make improvements. Summary of the Invention

[0004] The present invention provides a rudder shaft protection structure with integrated drag reduction and heat protection of a circular trapezoidal transition variable curved surface, aiming to solve the problems in the prior art that the local protrusion height of the rectification structure of high-speed aircraft is large, the aerodynamic drag is large, and the manufacturing and installation are difficult.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] A rudder shaft protection structure with integrated drag reduction and heat protection of a circular trapezoidal transition variable curved surface includes a cabin heat protection sleeve structure, a variable curved surface drag reduction and heat protection integrated structure, heat protection screws, and a rudder shaft heat protection structure;

[0007] The outer shape of the cabin heat protection sleeve structure is cylindrical, which is formed by winding and installed on the shell structure of the cabin through a sleeving process, covering a large area of the cylindrical surface of the cabin;

[0008] The variable curved surface drag reduction and heat protection integrated structure includes a variable curved surface transition section and an equal cross-section trapezoidal section; the variable curved surface transition section and the equal cross-section trapezoidal section are symmetric integrated structures, and are respectively detachably fixed on the outer surface of the cabin heat protection sleeve structure vertically through heat protection screws; installation holes are provided on the cabin heat protection sleeve structure and the variable curved surface drag reduction and heat protection integrated structure for installing heat protection screws, wherein the installation holes provided on the cabin heat protection sleeve structure are threaded blind holes, and the installation holes provided on the variable curved surface drag reduction and heat protection integrated structure are conical through holes;

[0009] The heat shield structure of the cabin body and the equal cross-section trapezoidal section are provided with rudder shaft installation holes. The heat shield structure of the rudder shaft is sleeved on the rudder shaft. After the heat shield structure of the rudder shaft and the rudder shaft penetrate through the rudder shaft installation holes of the equal cross-section trapezoidal section and the heat shield structure of the cabin body, they are connected to the steering gear. The distance between the airfoil root chord plane of the rudder shaft and the outer surface of the equal cross-section trapezoidal section is 3.5 mm to 4 mm;

[0010] The upper surface of the equal cross-section trapezoidal section is perpendicular to the axis of the rudder shaft. The intersection of the inclined plane and the upper surface is rounded. The minimum distance between the upper surface and the outer surface of the heat shield structure of the cabin body is 7 mm; The rear end section of the variable-curved surface transition section is the same as the cross-section of the equal cross-section trapezoidal section, and the front end is a circle consistent with the outer surface of the heat shield structure of the cabin body. The overall structure is a smooth transition of variable-curved surfaces;

[0011] The heat shield screw includes a screw rod and a nut. The part where the nut is connected to the screw rod is conical, and the conical angle is the same as that of the conical through hole of the variable-curved surface drag-reducing and heat shield integrated structure. The outer shape of the top of the nut is the same as the outer shape of the variable-curved surface drag-reducing and heat shield integrated structure at the installation position.

[0012] As a preferred solution, the upper surface of the equal cross-section trapezoidal section is perpendicular to the axis of the rudder shaft, and the included angle between the inclined plane and the upper surface is 27°.

[0013] As a preferred solution, the rudder shaft installation hole on the equal cross-section trapezoidal section is opened at a distance of 75 mm from the front end face.

[0014] As a preferred solution, an adhesive is evenly applied to the contact surface between the variable-curved surface drag-reducing and heat shield integrated structure and the heat shield structure of the cabin body and the thread of the heat shield screw.

[0015] As a preferred solution, the material of the adhesive is SG200.

[0016] As a preferred solution, the material of the heat shield structure of the cabin body is SPQ / phenolic winding, and the material of the cabin body structure is magnesium alloy.

[0017] As a preferred solution, the materials of the variable-curved surface drag-reducing and heat shield integrated structure and the heat shield screw are both high silica / phenolic molding.

[0018] As a preferred solution, the material of the heat shield structure of the rudder shaft is quartz / phenolic braiding.

[0019] As a preferred solution, the material of the rudder shaft is titanium alloy.

[0020] The beneficial technical effects achieved by the present invention are:

[0021] It can meet the heat insulation and protection functions for the rudder shaft and the surrounding projectile body. Compared with the prior art, it also effectively optimizes the aerodynamic fairing form of the protrusions on the aircraft surface, optimizes the aerodynamic flow field of the air rudder, thereby reducing the harsh thermal environment in the area around the rudder shaft and the projectile body. It is installed on the surface of the large-area heat protection structure of the projectile body through a split connection, reducing the processing and installation difficulty, improving the general assembly operability, and solving the problems of large local protrusion height, large aerodynamic resistance, and large manufacturing and installation difficulty of the fairing structure of existing high-speed aircraft, having prominent substantial features and remarkable progress. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the structural composition of one specific embodiment of the present invention;

[0023] Figure 2 is Figure 1 the internal structure schematic diagram of

[0024] Figure 3 is an external view of the cabin heat protection sleeve structure and the variable-curved surface drag reduction and heat protection integrated structure of one specific embodiment of the present invention;

[0025] Figure 4 is Figure 3 the left view of

[0026] Figure 5 is an external view of the heat protection screw of one specific embodiment of the present invention;

[0027] Figure 6 is the heat flux distribution diagram of the variable-curved surface integrated heat protection structure of one specific embodiment of the present invention, Dp = 1.5°;

[0028] Figure 7 is the heat flux distribution diagram of the variable-curved surface integrated heat protection structure of one specific embodiment of the present invention, Dp = 10°;

[0029] Figure 8 is the heat flux distribution diagram of the rudder shaft area of one specific embodiment of the present invention, Dp = 1.5°;

[0030] Figure 9 is the heat flux distribution diagram of the rudder shaft area of one specific embodiment of the present invention, Dp = 10°;

[0031] Figure 10 is the comparison curve graph of the heat flux peak value before and after optimization of one specific embodiment of the present invention;

[0032] Figure 11 is the surface temperature heat protection analysis result graph of the variable-curved surface heat protection structure of one specific embodiment of the present invention;

[0033] Figure 12It is the result diagram of the heat protection analysis of the inner wall temperature of the corresponding bulkhead structure in one specific embodiment of the present invention;

[0034] Figure 13 It is the result diagram of the surface temperature heat protection analysis of the rudder shaft heat protection structure in one specific embodiment of the present invention;

[0035] Figure 14 It is the result diagram of the wall temperature heat protection analysis of the rudder shaft in one specific embodiment of the present invention;

[0036] Reference numerals: 1. Cabin heat protection sleeve structure; 2. Variable-curved surface drag reduction and heat protection integrated structure; 3. Heat protection screw; 4. Rudder shaft heat protection structure; 5. Rudder shaft; 6. Adhesive; 21. Variable-curved surface transition section; 22. Equal-section trapezoidal section; 31. Screw rod; 32. Nut. Specific embodiments

[0037] The technical solution of the present invention will be further described in detail below in conjunction with the drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present invention.

[0038] As Figures 1 to 5 shown, a specific embodiment of a rudder shaft protection structure with a circular trapezoidal transition variable-curved surface drag reduction and heat protection integration includes a cabin heat protection sleeve structure 1, a variable-curved surface drag reduction and heat protection integrated structure 2, a heat protection screw 3, a rudder shaft heat protection structure 4, a rudder shaft 5 and an adhesive 6.

[0039] In this specific embodiment, the materials of the variable-curved surface drag reduction and heat protection integrated structure 2 and the heat protection screw 3 are high silica / phenolic molding. The high silica / phenolic molding material can meet the use requirements with an ablation temperature of 1600 °C and below.

[0040] In this specific embodiment, the material of the rudder shaft heat protection structure 4 is quartz / phenolic braiding. The quartz / phenolic braiding material can meet the use requirements with an ablation temperature of 2000 °C and below.

[0041] In this specific embodiment, the material of the rudder shaft 5 is titanium alloy, and the use temperature of the titanium alloy material is 600 °C and below.

[0042] In this specific embodiment, the material of the adhesive 6 is SG200.

[0043] For the convenience of description, in this specific embodiment, the windward side is regarded as the front and the leeward side is regarded as the rear. In this specific embodiment, the outer shape of the cabin heat protection sleeve structure 1 is cylindrical, with an outer diameter of 754 mm. It is formed by winding and installed on the shell structure of the cabin through a sleeving process, covering the large-area cylindrical surface of the cabin. In this specific embodiment, the material of the cabin heat protection sleeve structure 1 is SPQ / phenolic winding. The cabin structure material is magnesium alloy, and the service temperature of the magnesium alloy material is 200 °C and below.

[0044] In this specific embodiment, the variable-curved surface drag reduction and heat protection integrated structure 2 includes a variable-curved surface transition section 21 and an equal-section trapezoidal section 22. The variable-curved surface transition section 21 and the equal-section trapezoidal section 22 are symmetric integral structures, and are detachably fixed on the outer surface of the cabin heat protection sleeve structure 1 along the vertical direction. The variable-curved surface drag reduction and heat protection integrated structure 2 and the cabin heat protection sleeve structure 1 are detachably fixed through heat protection screws 3. Adhesive 6 is evenly applied on the contact surface between the variable-curved surface drag reduction and heat protection integrated structure 2 and the cabin heat protection sleeve structure 1 and on the threads of the heat protection screws 3 to enhance the connection force. Installation holes are opened at the same positions on the cabin heat protection sleeve structure 1 and the variable-curved surface drag reduction and heat protection integrated structure 2 for installing the heat protection screws 3. Among them, the installation holes opened on the cabin heat protection sleeve structure 1 are threaded blind holes, and the installation holes opened on the variable-curved surface drag reduction and heat protection integrated structure 2 are conical through holes. In this specific embodiment, the axial length of the variable-curved surface transition section 21 is 309 mm, and it can be adjusted adaptively according to the structural requirements such as the root chord surface length of the air rudder and the outer diameter of the cabin heat protection sleeve structure 1.

[0045] Rudder shaft installation holes are opened at the same positions on the cabin heat protection sleeve structure 1 and the equal-section trapezoidal section 22. The rudder shaft heat protection structure 4 is sleeved on the rudder shaft 5. The rudder shaft heat protection structure 4 and the rudder shaft 5 pass through the rudder shaft installation holes of the equal-section trapezoidal section 22 and the cabin heat protection sleeve structure 1 and then connect to the steering gear. The distance between the root chord surface of the air rudder of the rudder shaft 5 and the outer surface of the equal-section trapezoidal section 22 is 3.5 mm to 4 mm. In this specific embodiment, the rudder shaft installation holes are opened 75 mm from the front end face of the equal-section trapezoidal section 22, and can be adjusted adaptively according to needs.

[0046] In this specific embodiment, the upper surface of the equal-section trapezoidal section 22 is perpendicular to the axis of the rudder shaft 5, with a width of 150 mm. The included angle between the inclined surface and the upper surface is 27°. The intersection is rounded with a fillet radius of 40 mm. The distance between the upper surface and the axis of the cabin is 384 mm. The minimum distance between the upper surface and the outer surface of the cabin heat protection sleeve structure 1, that is, the protrusion height, is 7 mm. It should be noted that Figure 4 The 153° marked is the supplementary angle, the actual planar width after rounding is 132 mm, and the overall chord length width of 338.5 mm is a reference dimension. The rear end section of the variable-curved surface transition section 21 is the same as the section of the equal-section trapezoidal section 22, and the front end is a circle consistent with the outer surface of the cabin heat protection sleeve structure 1, and the overall structure has a smooth variable-curved surface transition.

[0047] In this specific embodiment, the heat-resistant screw 3 includes a screw rod 31 and a nut 32. The screw rod 31 has a full-thread external thread, which is consistent with the specification of the threaded blind hole of the cabin heat-resistant sleeve structure 1. The part of the nut 32 connected to the screw rod 31 is conical, which is consistent with the conical angle of the conical through hole of the variable-curved surface drag reduction and heat-resistant integrated structure 2. The top shape of the nut 32 is consistent with the shape of the variable-curved surface drag reduction and heat-resistant integrated structure 2 at the installation position, and it can be made to fit or polished after installation.

[0048] Design and analysis are carried out on the rudder shaft protection structure of the circular trapezoidal transition variable-curved surface drag reduction and heat insulation integration in this specific embodiment, including aerodynamic drag reduction, thermal environment analysis and heat-resistant analysis. The specific situations are as follows:

[0049] ①. Aerodynamic drag reduction and thermal environment analysis

[0050] Through aerodynamic analysis, compared with the existing scheme with a fairing structure around the rudder shaft, the height of the variable-curved surface drag reduction and heat-resistant integrated structure 2 is reduced by about 15 mm. After the shape at this place is optimized, under the condition of Ma = 5, the axial force of the whole missile during flight is reduced by about 3%, and the range can be increased by about 30 km. Since it does not affect other external shapes of the air rudder, the control force of the aircraft remains basically unchanged. The comparison of the axial force coefficient CA before and after optimization is shown in Table 1:

[0051] Table 1 Comparison of the axial force coefficient CA before and after optimization

[0052]

[0053]

[0054] As Figures 6 to 10 shown, according to the results of multiple-flight tests, heat measurement tests, the selection of flight attitude deviations, and the results of thermal environment simulations, corrections were made. The thermal environment and heat-resistant results completed accordingly show that the heat flux environment of the variable-curved surface drag reduction and heat-resistant integrated structure 2 in this specific embodiment has also been optimized to a certain extent compared with the original structure.

[0055] ②. Heat-resistant analysis

[0056] With an initial temperature of 15 °C and considering the ablation factor, heat insulation analysis is carried out on the variable-curved surface drag reduction and heat-resistant integrated structure 2 and the rudder shaft to obtain data such as the surface temperature of the top surface of the structure, the inner wall temperature of the corresponding cabin wall structure, and the heat-resistant temperature of the rudder shaft.

[0057] As Figures 11 to 14As shown in the figure, the highest surface temperature of the structure's top surface is 1482.8 °C, which occurs under the thermal environment with the maximum heat flux integral for heat protection, meeting the usage requirement of the high-silica / furan molded ablation temperature of 1600 °C. The highest inner wall temperature of the corresponding bulkhead structure is 142.3 °C, which occurs under the thermal environment with the maximum heat protection time and is lower than the usage temperature of the magnesium alloy material by 200 °C. The highest surface temperature of the heat protection structure of the rudder shaft is 1993.3 °C, which occurs under the thermal environment with the maximum heat flux integral for heat protection, meeting the quartz / furan woven ablation temperature of 2000 °C. The highest temperature of the corresponding rudder shaft wall is 236.2 °C, which occurs under the thermal environment with the maximum heat flux integral for heat protection and is lower than the usage temperature of the titanium alloy by 600 °C.

[0058] In summary, the heat protection design of the variable-curved surface heat protection structure and the rudder shaft part meets the overall usage requirements.

[0059] The beneficial technical effects obtained from this specific embodiment are as follows:

[0060] A fusion transition design from a circular surface to a trapezoidal surface is carried out for the local fairing structure of the rudder shaft and the outer shape of the large-area heat protection structure of the projectile body, reducing the height of the local fairing convex structure of the rudder shaft, more effectively optimizing the aerodynamic shape and the surrounding thermal environment, and achieving multi-functional effects such as drag reduction, fairing, and heat protection.

[0061] A heat protection structure design for the rudder shaft of the air rudder that integrates drag reduction, fairing, and heat protection is adopted. The variable-curved surface drag reduction and heat protection structure can play a role in heat protection for the actuator of the air rudder shaft.

[0062] A split connection and installation design for the variable-curved surface drag reduction and heat protection structure is adopted. The variable-curved surface drag reduction and heat protection structure is connected and installed on the surface of the large-area heat protection structure of the projectile body through a split connection, reducing the processing and installation difficulty, improving the general assembly operability, and can be applied to the heat protection design of the projectile body and the rudder shaft of various high-speed aircraft.

Claims

1. A rudder shaft protection structure with integrated drag reduction and heat protection for a circular trapezoidal transition variable curved surface, characterized in that, It includes a cabin heat protection sleeve structure (1), a variable-curved surface drag reduction and heat protection integrated structure (2), heat protection screws (3), and a rudder shaft heat protection structure (4); The outer shape of the cabin heat protection sleeve structure (1) is cylindrical. It is formed by winding and installed on the shell structure of the cabin through a sleeving process, covering the large-area cylindrical surface of the cabin; The variable-curved surface drag reduction and heat protection integrated structure (2) includes a variable-curved surface transition section (21) and an equal-section trapezoidal section (22); the variable-curved surface transition section (21) and the equal-section trapezoidal section (22) are symmetric integrated structures, and are respectively detachably fixed on the outer surface of the cabin heat protection sleeve structure (1) vertically through heat protection screws (3); Installation holes are provided on the cabin heat protection sleeve structure (1) and the variable-curved surface drag reduction and heat protection integrated structure (2) for installing heat protection screws (3). Among them, the installation hole provided on the cabin heat protection sleeve structure (1) is a threaded blind hole, and the installation hole provided on the variable-curved surface drag reduction and heat protection integrated structure (2) is a conical through hole; Rudder shaft installation holes are provided on the cabin heat protection sleeve structure (1) and the equal-section trapezoidal section (22). The rudder shaft heat protection structure (4) is sleeved on the rudder shaft. The rudder shaft heat protection structure (4) and the rudder shaft (5) pass through the rudder shaft installation holes of the equal-section trapezoidal section (22) and the cabin heat protection sleeve structure (1) and then connect to the steering gear. The distance between the airfoil root chord surface of the rudder shaft and the outer surface of the equal-section trapezoidal section (22) is 3.5 mm to 4 mm; The upper surface of the equal-section trapezoidal section (22) is perpendicular to the axis of the rudder shaft. The intersection of the inclined surface and the upper surface is rounded. The minimum distance between the upper surface and the outer surface of the cabin heat protection sleeve structure (1) is 7 mm; the rear end section of the variable-curved surface transition section (21) is consistent with the section of the equal-section trapezoidal section (22), and the front end is a circle consistent with the outer surface of the cabin heat protection sleeve structure (1). The overall structure is a smooth transition of variable-curved surfaces; The heat protection screw (3) includes a screw rod (31) and a nut (32). The part where the nut (32) is connected to the screw rod (31) is conical, with the same conical angle as the conical through hole of the variable-curved surface drag reduction and heat protection integrated structure (2). The outer shape of the top of the nut (32) is the same as the outer shape of the variable-curved surface drag reduction and heat protection integrated structure (2) at the installation position; 2. The rudder shaft protection structure according to claim 1, characterized in that, The upper surface of the equal-section trapezoidal section (22) is perpendicular to the axis of the rudder shaft, and the included angle between the inclined surface and the upper surface is 27°; 3. The rudder shaft protection structure according to claim 1, characterized in that, The rudder shaft installation hole on the equal-section trapezoidal section (22) is provided 75 mm from the front end face; 4. The rudder shaft protection structure according to claim 1, wherein Adhesive (6) is evenly applied on the contact surface between the variable-curved surface drag reduction and heat protection integrated structure (2) and the cabin heat protection sleeve structure (1) and on the threads of the heat protection screws (3); 5. The rudder shaft protection structure according to claim 4, characterized in that, The material of the adhesive (6) is SG200; 6. The rudder shaft protection structure according to any one of claims 1 to 5, characterized in that, The material of the cabin heat protection sleeve structure (1) is SPQ / phenolic winding, and the material of the cabin structure is magnesium alloy; 7. The rudder shaft protection structure according to any one of claims 1 to 5, characterized in that, The materials of the variable-curved surface drag reduction and heat protection integrated structure (2) and the heat protection screws (3) are both high-silica / phenolic molding; 8. The rudder shaft protection structure according to any one of claims 1 to 5, characterized in that, The material of the rudder shaft heat protection structure (4) is quartz / phenolic weaving; 9. The rudder shaft protection structure according to any one of claims 1 to 5, characterized in that The material of the rudder shaft is titanium alloy.

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