Discharge pressure and heat reduction structure for rudder shaft interference area of high-speed aircraft

Abstract

The invention provides a high-speed aircraft rudder shaft interference area drainage pressure and heat reduction structure which comprises two drainage pressure reduction grooves, the first drainage pressure reduction groove is located in the bottom face of an air rudder, and the second drainage pressure reduction groove is located in the surface of an aircraft body. The first drainage pressure reducing groove is a first annular groove or a semi-annular groove; under the condition that the difference value between the width of the bottom surface of the aerial rudder and the diameter of the rudder shaft is larger than or equal to a preset value, the first drainage pressure reduction groove is a first annular groove; under the condition that the difference value between the width of the bottom surface of the aerial rudder and the diameter of the rudder shaft is smaller than a preset value, the first drainage pressure reduction groove is a semi-annular groove, and the semi-annular groove is located on the windward front side of the rudder shaft; and the second drainage pressure reducing groove is a second annular groove. Separation reattachment vortexes between an air rudder and an airframe can be eliminated, and therefore peak heat flow, pressure and shearing force of the airframe and the rudder bottom in a rudder shaft interference area are greatly reduced; the drop amplitude of peak heat flow, pressure and shear force of the missile body and the rudder bottom can reach 30%-90%.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, and in particular to a flow relief, decompression and heat reduction structure in a rudder shaft interference zone of a high-speed aircraft. Background Art

[0002] High-speed aircraft, with their high maneuverability and strong penetration and defense capabilities, are a key research area for major military powers. The air rudder is a key component of high-speed aircraft, playing a role in maintaining stable attitude and flexible maneuverability during flight. During high-speed flight, complex shock wave / boundary layer interference, shock wave / shock wave interference, and boundary layer separation and reattachment occur near the air rudder, which are key and difficult points in the thermal protection design of high-speed aircraft. The flow in the gap between the air rudder and the fuselage is complex. When the high-speed airflow impacts the surface of the rudder shaft, the airflow separates and reattaches, and the separation and reattachment vortex severely scours the rudder shaft and the nearby fuselage and rudder bottom, forming a rudder shaft interference zone. The rudder shaft interference zone is an area of ​​high heat flux, high pressure, and high shear force, and is a key area in the thermal protection design of high-speed aircraft.

[0003] At present, the thermal protection design schemes for the rudder shaft interference area mainly include passive thermal protection and active thermal protection. The passive thermal protection scheme mainly includes rudder front block, high-temperature resistant shaft sleeve, heat protection ring, etc.; the active thermal protection scheme is mainly convection cooling, that is, using kerosene or water and other working fluids to cool the rudder shaft interference area through pipes.

[0004] The rudder front block solution features a wedge-shaped block positioned a certain distance in front of the rudder tip. When high-speed airflow passes through the block, it generates a shock wave deceleration, thereby reducing its impact on the rudder shaft interference zone. However, the block introduces a backstep flow, increasing the complexity of the flow in the rudder interference zone. Consequently, the heat flux reduction in the rudder shaft interference zone varies with block height, rudder deflection angle, and angle of attack.

[0005] The high temperature resistant sleeve is a layer of high temperature resistant material wrapped around the outer surface of the rudder shaft interference area, such as C f / SiC composite materials, ultra-high temperature ceramics, etc. This solution does not change the flow field near the rudder shaft, nor does it eliminate the separation and reattachment vortices in the interference zone. There is still an extreme peak thermal environment, so it has high requirements for the sleeve material.

[0006] A heat shield ring, a ring of high-temperature-resistant material installed around the rudder, reduces the aerodynamic heat load on the rudder shaft and decouples the rudder bearing forces from the heat shield ring's heat-bearing function. The main difference between a heat shield ring and a sleeve is the gap between the heat shield ring and the rudder shaft, making it easier to manufacture. However, the larger radius of the heat shield ring complicates the flow field in the rudder shaft interference zone, resulting in greater aerodynamic heating loads on the heat shield ring surface than on a rudder shaft without a heat shield ring.

[0007] Convection cooling offers flexible flow control and controllable cooling temperatures. However, the extreme peak thermal environment at the fuselage and rudder base, in the rudder shaft interference zone, is relatively small and close to the rudder shaft, making it difficult to arrange cooling pipes. Furthermore, its low convection heat transfer coefficient makes it less effective at cooling peak heat fluxes in small areas. Therefore, it is primarily used for thermal protection of large areas, such as the rudder surface, rudder shaft, and fuselage.

[0008] The rudder front block, bushing, heat protection ring and convection cooling technology are all unable to eliminate the separation and reattachment vortex in front of the rudder shaft. The rudder shaft interference zone still has high peak heat flux, pressure and shear force. The rudder front block changes the shape of the fuselage, affecting the aerodynamic performance, and the heat reduction effect in the rudder shaft interference zone is weak. The bushing structure uses high-temperature resistant materials, which is expensive. As the flight speed increases, the requirements for the temperature resistance of the material are getting higher and higher. New materials and new processes are not mature. The heat protection ring structure is larger than the rudder shaft diameter, so it needs to bear a larger heat load, and there is also the problem of material temperature resistance limit. The convection cooling solution requires the arrangement of cooling pipes in the rudder shaft interference zone, which has a complex structure. In addition, it is not easy to arrange pipes in the interference zone between the fuselage and the rudder bottom, and the cooling effect is weak. Summary of the Invention

[0009] The present invention provides a flow discharge, pressure reduction and heat reduction structure for a rudder shaft interference zone of a high-speed aircraft, which can eliminate the separation and reattachment flow field structure of the rudder shaft interference zone, thereby reducing the peak thermal environment at the rudder shaft interference zone of the high-speed aircraft and avoiding damage to the body and rudder bottom position of the rudder shaft interference zone.

[0010] The present invention provides a flow relief, decompression and heat reduction structure for a rudder shaft interference zone of a high-speed aircraft. The aircraft comprises an aircraft body, a rudder shaft and an air rudder. The air rudder is connected to the aircraft body via the rudder shaft, with a gap between the air rudder and the aircraft body. The rudder shaft is cylindrical, and the diameter of the rudder shaft is less than or equal to the width of the bottom surface of the air rudder. The structure comprises two flow relief and decompression grooves, a first flow relief and decompression groove being located on the bottom surface of the air rudder, and a second flow relief and decompression groove being located on the surface of the aircraft body.

[0011] The first flow relief and decompression groove is a first annular groove or a semi-annular groove, and the groove widths of the first annular groove and the semi-annular groove are equal; when the difference between the bottom surface width of the air rudder and the diameter of the rudder shaft is greater than or equal to a preset value, the first flow relief and decompression groove is a first annular groove, the inner cylindrical surface of the first annular groove is seamlessly connected to the outer cylindrical surface of the rudder shaft and are coaxial and have the same radius, and the outer cylindrical surface and the bottom surface of the air rudder have a chamfer at the intersection; when the difference between the bottom surface width of the air rudder and the diameter of the rudder shaft is less than a preset value, the first flow relief and decompression groove is a semi-annular groove, the semi-annular groove is located on the windward front side of the rudder shaft, the inner cylindrical surface of the semi-annular groove is seamlessly connected to the outer cylindrical surface of the rudder shaft and are coaxial and have the same radius, and the outer cylindrical surface and the bottom surface of the air rudder have a chamfer at the intersection; wherein the preset value is 2 to 6 times the groove width;

[0012] The second flow relief and pressure relief groove is a second annular groove, the inner cylindrical surface of the second annular groove is seamlessly connected to the outer cylindrical surface of the rudder shaft and is coaxial and has the same radius, and the outer cylindrical surface has a chamfer at the intersection with the body surface.

[0013] Preferably, the first flow relief and pressure relief groove and the second flow relief and pressure relief groove have the same groove width.

[0014] Preferably, the chamfer is a rounded corner, and the radius of the rounded corner is in the range of 1 to 10 mm.

[0015] Preferably, the rudder axis is perpendicular to the bottom surface of the air rudder, and the rudder axis is parallel to the normal vector of the body surface at the contact position.

[0016] The application of the technical solution of the present invention has the following beneficial effects:

[0017] 1. The present invention eliminates the separation and reattachment vortex between the air rudder and the airframe by providing the first and second relief and pressure relief grooves, thereby significantly reducing the peak heat flux, pressure, and shear force at the airframe and rudder base in the rudder shaft interference area. The peak heat flux, pressure, and shear force at the airframe and rudder base are reduced by 30%-90%.

[0018] 2. The present invention can simplify the structure of the rudder shaft interference zone of a high-speed aircraft, achieve the effect of using conventional materials in the rudder shaft interference zone body and the rudder bottom without damage, and avoid quality problems caused by the splicing structure of conventional materials and high-temperature resistant materials;

[0019] 3. The present invention can reduce the use of new high-temperature resistant materials, which can shorten the aircraft processing cycle and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are included to provide a further understanding of the embodiments of the present invention, constitute a part of the specification, illustrate the embodiments of the present invention, and together with the description, explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0021] Figure 1 A schematic diagram of the three-dimensional structure of a high-speed aircraft rudder shaft interference area flow relief, decompression and heat reduction structure according to an embodiment of the present invention is shown;

[0022] Figure 2 Shown Figure 1 A cross-sectional view of the flow relief, pressure reduction and heat reduction structure in the interference area of ​​the middle rudder shaft;

[0023] Figure 3 A flow chart showing the design and verification of a discharge, pressure reduction and heat reduction solution according to an embodiment of the present invention is shown.

[0024] The above drawings include the following reference numerals:

[0025] 1. First relief groove; 2. Gap; 3. Chamfer; 4. Second relief groove; 5. Airframe; 6. Rudder shaft; 7. Air rudder. DETAILED DESCRIPTION

[0026] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described 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, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0028] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values ​​set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0029] like Figure 1 and Figure 2 As shown, the present invention provides a flow relief, decompression and heat reduction structure for a rudder shaft interference area of ​​a high-speed aircraft. The aircraft includes an aircraft body 5, a rudder shaft 6 and an air rudder 7. The air rudder 7 is connected to the aircraft body 5 via the rudder shaft 6. A gap 2 is defined between the air rudder 7 and the aircraft body 5. The rudder shaft 6 is cylindrical, and the diameter of the rudder shaft 6 is less than or equal to the width of the bottom surface of the air rudder 7. The structure includes two flow relief and decompression grooves, a first flow relief and decompression groove 1 located on the bottom surface of the air rudder 7, and a second flow relief and decompression groove 4 located on the surface of the aircraft body 5.

[0030] The first flow relief groove 1 is a first annular groove or a semi-annular groove, and the first annular groove and the semi-annular groove have the same groove width;

[0031] When the difference between the bottom width of the air rudder 7 and the diameter of the rudder shaft 6 is greater than or equal to a preset value, the first flow relief and pressure relief groove 1 is a first annular groove, the inner cylindrical surface of the first annular groove is seamlessly connected to the outer cylindrical surface of the rudder shaft 6 and is coaxial and has the same radius, and the outer cylindrical surface and the bottom surface of the air rudder 7 have a chamfer 3 at the intersection. In this case, the separated and reattached vortex at the rudder bottom position in the rudder shaft interference area is channeled and dispersed through the first annular groove, thereby eliminating the peak thermal environment at the rudder bottom position.

[0032] When the difference between the bottom width of the air rudder 7 and the diameter of the rudder shaft 6 is less than a preset value, there is not enough space between the rudder bottom and the rudder shaft 6 on both sides of the rudder surface to open annular grooves. Therefore, the first flow relief and pressure relief groove 1 is a semi-annular groove, which is located on the windward front side of the rudder shaft 6, and no groove is required on the leeward rear side of the rudder shaft 6. The inner cylindrical surface of the semi-annular groove is seamlessly connected to the outer cylindrical surface of the rudder shaft 6 and is coaxial and has the same radius. The outer cylindrical surface has a chamfer 3 at the intersection with the bottom surface of the air rudder 7. In other words, the inner cylindrical surface of the semi-annular groove at an angle of 180° in the middle is seamlessly connected to the outer cylindrical surface of the rudder shaft 6, and is coaxial and has the same radius. The cylindrical surface outside the angle of 180° needs to smoothly transition to the rudder surface. At this time, the semi-annular groove runs through the entire rudder bottom, and the gas in the groove is discharged from the openings at the left and right ends, thereby eliminating the peak thermal environment at the rudder bottom position in the rudder shaft interference area.

[0033] The second relief groove 4 is a second annular groove. The inner cylindrical surface of the second annular groove seamlessly connects to the outer cylindrical surface of the rudder shaft 6, sharing the same axis and radius. The outer cylindrical surface has a chamfer 3 at the intersection with the surface of the body 5. The vortex that separates and reattaches in the rudder shaft interference area at the body 5 is channeled and dispersed through the second annular groove, thereby eliminating the peak thermal environment at the body 5.

[0034] The present invention has the following beneficial effects:

[0035] 1. The present invention eliminates the separation and reattachment vortex between the air rudder 7 and the body 5 by providing the first and second relief and pressure relief grooves 1 and 4, thereby significantly reducing the peak heat flow, pressure, and shear force at the body 5 and the rudder base in the rudder shaft interference area. The peak heat flow, pressure, and shear force at the body and the rudder base are reduced by 30%-90%.

[0036] 2. The present invention can simplify the structure of the rudder shaft interference zone of a high-speed aircraft, achieve the effect of using conventional materials to prevent the rudder shaft interference zone body 5 and the rudder bottom from being damaged, and avoid the quality problems caused by the splicing structure of conventional materials and high-temperature resistant materials;

[0037] 3. The present invention can reduce the use of new high-temperature resistant materials, which can shorten the aircraft processing cycle and reduce costs.

[0038] According to an embodiment of the present invention, the first flow relief and pressure relief groove 1 and the second flow relief and pressure relief groove 4 have the same groove width.

[0039] In addition, in order to further reduce the peak thermal environment of the local interference area, the chamfer 3 is a rounded corner, and the radius of the rounded corner is in the range of 1 to 10 mm.

[0040] According to an embodiment of the present invention, the rudder shaft 6 is perpendicular to the bottom surface of the air rudder 7 , and the rudder shaft 6 is parallel to the normal vector of the surface of the body 5 at the contact position.

[0041] In order to have a further understanding of the present invention, the following Figure 1-Figure 3 The flow relief, decompression and heat reduction structure of the high-speed aircraft rudder shaft interference area of ​​the present invention is described in detail.

[0042] like Figure 1 and Figure 2 As shown, in this embodiment, the diameter of the rudder shaft 6 is set to 5 mm, significantly smaller than the 10 mm width of the rudder base of the air rudder 7. That is, there is sufficient space between the rudder base and the rudder shaft 6 to form a groove. In this case, the first flow relief groove 1 is an annular groove with a shape similar to the second flow relief groove 4. The inner cylindrical surface of the first flow relief groove 1 is seamlessly connected to the outer cylindrical surface of the rudder shaft 6, and they are coaxial and have the same radius. The intersection of the outer cylindrical surface of the first flow relief groove 1 and the rudder base requires rounding. The separated and reattached vortices at the rudder base in the rudder shaft interference zone are channeled and dispersed through the first flow relief groove 1, thereby eliminating the peak thermal environment at the rudder base. The second flow relief groove 4 is an annular groove with an inner cylindrical surface seamlessly connected to the outer cylindrical surface of the rudder shaft 6, and they are coaxial and have the same radius. The intersection of the outer cylindrical surface and the surface of the body 5 requires rounding. The separated and reattached vortices at the body 5 in the rudder shaft interference zone are channeled and dispersed through the second flow relief groove 4, thereby eliminating the peak thermal environment at the body 5.

[0043] Taking into account the size of the separation and reattachment vortex in the rudder shaft interference area, the gas flow law and geometric structure in the concave cavity, in order to achieve better drainage and decompression effect in the rudder shaft interference area, the depth of the first drainage and decompression groove is 5mm, and the depth of the second drainage and decompression groove is 5mm; the groove width is 1mm, and the radius of the outer boundary corner of the groove is 1mm.

[0044] The heat reduction effect of the rudder shaft interference zone discharge and pressure relief structure is verified by numerical method, specifically as follows: Figure 3 As shown. Numerical simulation software was used to calculate the original shape and the shape with the discharge pressure reduction and heat reduction structure, and the peak heat flux at the rudder shaft interference area, the pressure and shear force at the peak heat flux location, and the flow pattern in the rudder gap were compared to obtain the heat reduction conclusion. The peak thermal environment at the rudder shaft interference area (body 5) is shown in Table 1. It can be seen from Table 1 that the peak heat flux of the cold wall at body 5 without the heat reduction structure is 54.4kW / m 2 After the design of the discharge pressure reduction and heat reduction structure, the heat flux of the cold wall at this location is 10.3kW / m 2, a decrease of 81%, and the corresponding pressure and shear force decreases of 46% and 68% respectively. The peak thermal environment of the rudder shaft interference area (rudder bottom) is shown in Table 2. By comparison, it can be found that the discharge pressure reduction and heat reduction structure reduces the peak heat flow, pressure and shear force of the rudder bottom cold wall by 84%, 61% and 69% respectively. Analysis shows that the rudder shaft interference area discharge pressure reduction and heat reduction structure proposed by the present invention can evacuate the separation and reattachment vortex on the windward front side of the rudder shaft 6, thereby eliminating the peak thermal environment at the rudder bottom and the body 5, and achieving the purpose of pressure reduction and heat reduction.

[0045] Table 1 Comparison of thermal environment in the rudder interference area (aircraft body)

[0046] <![CDATA[Cold wall heat flux (kW / m 2 )]]> Pressure (kPa) Shear force (Pa) No heat reduction structure 54.4 5.88 138 Discharge pressure and heat reduction 10.3 3.17 44

[0047] Table 2 Comparison of thermal environment in the rudder interference area (rudder bottom)

[0048] <![CDATA[Cold wall heat flux (kW / m 2 )]]> Pressure (kPa) Shear force (Pa) No heat reduction structure 73.2 7.68 106 Discharge pressure and heat reduction 11.4 3.00 33

[0049] In summary, the present invention provides a flow relief, pressure reduction and heat reduction structure for the interference zone of the rudder shaft of a high-speed aircraft, which has the following beneficial effects:

[0050] 1. The present invention eliminates the separation and reattachment vortex between the air rudder 7 and the body 5 by providing the first and second relief and pressure relief grooves 1 and 4, thereby significantly reducing the peak heat flow, pressure, and shear force at the body 5 and the rudder base in the rudder shaft interference area. The peak heat flow, pressure, and shear force at the body and the rudder base are reduced by 30%-90%.

[0051] 2. The present invention can simplify the structure of the rudder shaft interference zone of a high-speed aircraft, achieve the effect of using conventional materials to prevent the rudder shaft interference zone body 5 and the rudder bottom from being damaged, and avoid the quality problems caused by the splicing structure of conventional materials and high-temperature resistant materials;

[0052] 3. The present invention can reduce the use of new high-temperature resistant materials, which can shorten the aircraft processing cycle and reduce costs;

[0053] 4. The present invention provides a design specification for flow relief, pressure reduction and heat reduction in the rudder shaft interference area, and provides a recommended size range and verification method for the heat reduction structure.

[0054] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0055] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0056] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A high-speed aircraft rudder shaft interference area flow relief, decompression and heat reduction structure, characterized in that: The aircraft includes an airframe, a rudder shaft, and an air rudder. The air rudder is connected to the airframe via the rudder shaft, with a gap between the air rudder and the airframe. The rudder shaft is cylindrical, and the diameter of the rudder shaft is less than or equal to the width of the bottom surface of the air rudder. The structure includes two flow relief and pressure relief grooves, a first flow relief and pressure relief groove is located on the bottom surface of the air rudder, and a second flow relief and pressure relief groove is located on the surface of the airframe. The first flow relief and decompression groove is a first annular groove or a semi-annular groove, and the groove widths of the first annular groove and the semi-annular groove are equal; when the difference between the bottom surface width of the air rudder and the diameter of the rudder shaft is greater than or equal to a preset value, the first flow relief and decompression groove is a first annular groove, the inner cylindrical surface of the first annular groove is seamlessly connected to the outer cylindrical surface of the rudder shaft and are coaxial and have the same radius, and the outer cylindrical surface and the bottom surface of the air rudder have a chamfer at the intersection; when the difference between the bottom surface width of the air rudder and the diameter of the rudder shaft is less than a preset value, the first flow relief and decompression groove is a semi-annular groove, the semi-annular groove is located on the windward front side of the rudder shaft, the inner cylindrical surface of the semi-annular groove is seamlessly connected to the outer cylindrical surface of the rudder shaft and are coaxial and have the same radius, and the outer cylindrical surface and the bottom surface of the air rudder have a chamfer at the intersection; wherein the preset value is 2 to 6 times the groove width; The second flow relief and pressure relief groove is a second annular groove, the inner cylindrical surface of the second annular groove is seamlessly connected to the outer cylindrical surface of the rudder shaft and is coaxial and has the same radius, and the outer cylindrical surface has a chamfer at the intersection with the body surface.

2. The structure according to claim 1, characterized in that The first flow relief and pressure relief groove and the second flow relief and pressure relief groove have the same groove width.

3. The structure according to claim 1, characterized in that The chamfer is a rounded corner, and the radius of the rounded corner ranges from 1 to 10 mm.

4. The structure according to any one of claims 1 to 3, characterized in that: The rudder shaft is perpendicular to the bottom surface of the air rudder, and the rudder shaft is parallel to the normal vector of the body surface at the contact position.

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