Low-cost micro-ablation heat-resistant load-bearing wave-transmitting integrated antenna and design method

Abstract

The present invention discloses a low-cost micro-ablation anti-heat bearing wave-transmitting integrated combined antenna and design method, wherein the combined antenna comprises a terminal cap assembly, a terminal cap connector, a cover body and an antenna device; the terminal cap assembly adopts a high-silicon / phenolic composite material, the front end of the terminal cap connector is buried inside the rear end of the terminal cap assembly, and the terminal cap assembly and the terminal cap connector are integrally molded; the cover body is processed and formed by polytetrafluoroethylene material, a cavity is formed inside the cover body, and the front end face of the cover body is docked with the terminal cap assembly; the antenna device is installed in the cavity inside the cover body, and there is an angle between the antenna device and the axis of the cover body; wherein the angle should be able to ensure that the terminal cap assembly and the terminal cap connector are outside the effective detection area of ​​the antenna device. The present invention realizes the low-cost and large-scale preparation of the combined antenna structure, thereby improving the overall performance of the aircraft.

Description

Technical Field

[0001] The present invention relates to the field of aircraft design, and in particular to a low-cost micro-ablation heat-resistant load-bearing wave-transmitting integrated combined antenna and a design method thereof. Background Art

[0002] The radome is a necessary structure to protect the normal operation of the antenna equipment of long-range aircraft in the natural environment and the flight force and heat environment. For antennas such as altitude detection devices installed at the end of the aircraft, commonly used radome materials include fused quartz ceramics, quartz fiber reinforced quartz ceramics, polytetrafluoroethylene, etc. Among them, fused quartz ceramics and quartz fiber reinforced quartz ceramics are suitable for high Mach number aircraft, which can achieve near-zero ablation throughout the flight and help reduce the resistance of the aircraft. However, their production processes are many, the cycle is long, and the cost is high. For medium and low Mach number aircraft, they often have excess performance, which is not conducive to the low-cost design and large-scale preparation of aircraft. Polytetrafluoroethylene materials have good and stable dielectric properties, excellent processing and thermal insulation properties, low cost, and will not carbonize under thermal loads. Under high temperature loads exceeding 400°C, they will sublimate and take away heat. They are very suitable for use as wave-transmitting radomes for medium and low Mach number aircraft. However, when polytetrafluoroethylene is used as the radome at the end of Ma4 to Ma6 low Mach number aircraft, the amount of ablation caused by sublimation in the aerodynamic thermal environment is too large, resulting in a significant increase in the radius of the aircraft head, greatly increasing the aerodynamic drag characteristics of the aircraft, and seriously affecting the overall performance of the aircraft. Summary of the invention

[0003] The purpose of the present invention is to provide a low-cost micro-ablation heat-resistant load-bearing wave-transmitting integrated combined antenna and design method, so as to achieve low-cost and large-scale preparation of the combined antenna structure and improve the overall performance of the aircraft.

[0004] In order to achieve the above tasks, the present invention adopts the following technical solutions:

[0005] A low-cost micro-ablation heat-resistant load-bearing wave-transmitting integrated antenna, including a terminal cap assembly, a terminal cap connector, a cover body, and an antenna device;

[0006] The end cap assembly is made of a high-silicon / phenolic composite material, the front end of the end cap connector is buried inside the rear end of the end cap assembly, and the end cap assembly and the end cap connector are integrally molded;

[0007] The cover body is formed by processing polytetrafluoroethylene material, a cavity is formed inside the cover body, and the front end surface of the cover body is connected to the end cap assembly;

[0008] The antenna device is installed in a cavity inside the cover body, and there is an angle between the antenna device and the axis of the cover body; wherein, the angle should be able to ensure that the end cap assembly and the end cap connector are outside the effective detection area of ​​the antenna device.

[0009] Furthermore, a through hole cooperating with the end cap connector is provided on the front end surface; and the rear end of the end cap connector is fastened after passing through the through hole.

[0010] Furthermore, the end cap assembly is a solid conical structure, and its front end is a blunt circle; after the end cap assembly is connected to the cover body, the connection between the two has a smooth transition.

[0011] Furthermore, the front end surface of the cover body is a plane, and a flange is provided at the front end of the cavity inside the cover body. After the rear end of the end cap connector passes through the through hole and the flange, it is fastened using an end cap nut.

[0012] A design method for a low-cost micro-ablation heat-resistant load-bearing wave-transmitting integrated antenna, comprising:

[0013] Step 1: first, according to the aerodynamic shape constraint of the combined antenna, determine the design space of the antenna device in the combined antenna;

[0014] Step 2, calculating the aerodynamic thermal environment of the combined antenna according to the flight trajectory parameters and aerodynamic shape of the aircraft carrying the combined antenna, and determining the position of the turning point on the combined antenna;

[0015] Step 3, designing the axial length of the end cap assembly according to the determined position of the turning point;

[0016] Step 4: Calculate the pyrolysis and ablation amount and inner wall temperature of the cover during the entire flight of the aircraft based on the calculated aerodynamic thermal environment of the combined antenna and the thermophysical performance parameters of the polytetrafluoroethylene material used in the cover; adjust the thickness of the cover so that the inner wall temperature of the cover is lower than the maximum operating temperature of the antenna device;

[0017] Step 5, deducting the pyrolysis ablation amount from the cover body, and applying an aerodynamic load to the cover body after the deduction, and judging whether the cover body after the deduction of the pyrolysis ablation amount can meet the structural bearing requirements through the stress and deformation data of the cover body, and if so, taking the cover body thickness when the inner wall temperature of the cover body is lower than the maximum operating temperature of the antenna device as the minimum value of the cover body thickness;

[0018] Step six, given the angle between the antenna device and the axis of the cover body, calculate the radiation pattern of the antenna device;

[0019] Step seven, simulate the electrical performance of the antenna device to determine whether the radiation pattern of the antenna device meets the requirements that the end cap assembly and the end cap connector are outside the effective detection area of ​​the antenna device. If the requirements are met, the design of the combined antenna is completed.

[0020] Further, according to the aerodynamic shape constraint of the combined antenna, determining the design space of the antenna device in the combined antenna includes:

[0021] The position and circumferential space of the antenna device inside the cover are determined according to the outer shape structure of the cover, which serves as the design input of the antenna device.

[0022] Further, the calculation of the aerodynamic thermal environment of the combined antenna according to the flight trajectory parameters and aerodynamic shape of the aircraft equipped with the combined antenna, and the determination of the position of the turning point on the combined antenna include:

[0023] The method of solving NS equations based on computational fluid dynamics is adopted to obtain the aerodynamic thermal environment of the combined antenna, including the aerodynamic pressure distribution and the heat flux density distribution on the outer wall of the combined antenna; the method of solving NS equations based on computational fluid dynamics is adopted to determine the position of the turning point on the combined antenna.

[0024] Furthermore, the judgment criteria of the turning point are:

[0025] ;

[0026] In the formula, is the Reynolds number corresponding to the transition point, is the flight Mach number of the aircraft.

[0027] Further, the step of designing the axial length of the end cap assembly according to the determined position of the turning point comprises:

[0028] The axial length of the end cap assembly is greater than the axial distance between the position of the turning point and the front end of the combined antenna.

[0029] Furthermore, the pyrolysis and ablation amount and the inner wall temperature of the cover during the entire flight of the aircraft are calculated by constructing a pyrolysis and ablation calculation model for the cover made of polytetrafluoroethylene.

[0030] Furthermore, in step five, if the structural bearing requirements are not met, the thickness of the cover is further increased, the pyrolysis ablation amount and the inner wall temperature of the cover are recalculated, and step five is repeated;

[0031] In step seven, if the requirement outside the effective detection area is not met, the angle between the antenna device and the axis of the cover body is optimized and step seven is repeated.

[0032] An aircraft is provided, on which the low-cost micro-ablation heat-resistant load-bearing and wave-transmitting integrated combined antenna is carried.

[0033] The present invention makes full use of the characteristics of heat insulation and wave transmission performance of different materials, adopts a high-silicon phenolic composite material with low cost, good ablation resistance and poor wave transmission performance at the end of the combined antenna where the aerodynamic thermal environment is harsh, to achieve micro-ablation during flight and maintain good aerodynamic characteristics; and adopts a polytetrafluoroethylene material with low cost, poor ablation resistance and excellent wave transmission performance at the cover part of the combined antenna where the wave transmission performance requirement is high. Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. Compared with the traditional fused quartz ceramic and quartz fiber reinforced quartz ceramic antenna cover structures, the combined antenna structure provided by the present invention has a short production cycle and low cost, which is conducive to the large-scale preparation of aircraft such as long-range aircraft.

[0035] 2. Compared with the traditional polytetrafluoroethylene antenna cover, the combined antenna structure provided by the present invention has a small amount of ablation, which effectively avoids the problem that the large amount of ablation displacement of the polytetrafluoroethylene antenna cover leads to a significant increase in the radius of the aircraft head and a significant increase in the aerodynamic drag characteristics of the aircraft.

[0036] 3. The combined antenna structure provided by the present invention can better exert the detection performance of the antenna device through a collaborative design process through analysis of the heat insulation performance of the antenna cover body, analysis of the load-bearing performance, and analysis of the electrical performance matching between the antenna device and the antenna cover body. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic structural diagram of a low-cost micro-ablation heat-resistant, load-bearing and wave-transmitting integrated antenna provided by the present invention;

[0038] Figure 2 Schematic diagram of the design method flow of low-cost micro-ablation heat-resistant load-bearing and wave-transmitting integrated combination antenna.

[0039] Explanation of the numbers in the figure: 1 end cap assembly, 2 end cap connector, 3 end cap nut, 4 cover body, 5 antenna device. DETAILED DESCRIPTION

[0040] The present invention provides a low-cost micro-ablation heat-resistant, load-bearing and wave-transmitting integrated combined antenna and design method. By making full use of the heat-resistant insulation and wave-transmitting properties of different materials, it is easy to realize low-cost and large-scale preparation of the combined antenna structure and improve the overall performance of the aircraft.

[0041] See attached Figure 1 The present invention provides a low-cost micro-ablation heat-resistant load-bearing wave-transmitting integrated combined antenna, including an end cap assembly 1, an end cap connector 2, a cover body 4 and an antenna device 5;

[0042] The end cap assembly 1 is made of a high-silicon / phenolic composite material, the front end of the end cap connector 2 is buried inside the rear end of the end cap assembly 1, and the end cap assembly 1 and the end cap connector 2 are integrally molded;

[0043] The cover body 4 is formed by processing with polytetrafluoroethylene material, a cavity is formed inside the cover body 4, the front end face of the cover body 4 is butted with the end cap assembly 1, a through hole matching with the end cap connector 2 is provided on the front end face; the rear end of the end cap connector 2 is fastened after passing through the through hole;

[0044] The antenna device 5 is installed in a cavity inside the cover body 4, and there is an angle θ between the antenna device 5 and the axis of the cover body 4, ensuring that the electromagnetic wave signal can pass through the cover body 4 to detect the external environment; wherein, the angle should be able to ensure that the end cap assembly 1 and the end cap connector 2 are outside the effective detection area of ​​the antenna device 5.

[0045] The end cap assembly 1 is a solid cone structure, and its front end is a blunt circle; after the end cap assembly 1 is connected to the cover body 4, the connection between the two has a smooth transition.

[0046] The front end face of the cover body 4 is a plane, and a flange is provided at the front end of the cavity inside the cover body 4. After the rear end of the end cap connector 2 passes through the through hole and the flange, it is fastened using the end cap nut 3 to achieve the connection between the cover body 4 and the end cap assembly 1.

[0047] See also Figure 2 The present invention further provides a design method for a low-cost micro-ablation heat-resistant load-bearing wave-transmitting integrated antenna, comprising:

[0048] Step one, first determine the design space of the antenna device 5 in the combined antenna according to the aerodynamic shape constraints of the combined antenna; that is, first determine the position and circumferential space of the antenna device 5 inside the cover body 4 according to the shape structure of the cover body 4 as the design input of the antenna device 5.

[0049] Step 2: According to the flight trajectory parameters and aerodynamic shape of the aircraft equipped with the combined antenna, a method for solving the NS equation based on computational fluid dynamics is used to obtain the aerodynamic thermal environment of the combined antenna, including the aerodynamic pressure distribution and heat flux density distribution of the outer wall surface of the combined antenna (the outer wall surface of the end cap assembly 1 and the cover body 4); the position of the turning point on the combined antenna is determined by using a method for solving the NS equation based on computational fluid dynamics; in the combined antenna of this scheme, the judgment criterion of the turning point is:

[0050] ;

[0051] In the formula, is the Reynolds number corresponding to the transition point, is the flight Mach number of the aircraft.

[0052] Step three, design the axial length L1 of the end cap assembly 1 according to the determined turning point position, and ensure that L1 is greater than the axial distance between the turning point position and the front end of the combined antenna, thereby ensuring that the turning point is on the outer wall of the end cap assembly 1 and not on the cover body 4 of the polytetrafluoroethylene material, avoiding drastic changes in heat flow near the turning point causing excessive ablation of the cover body 4.

[0053] Step four, firstly, according to the calculated aerodynamic thermal environment of the combined antenna and the thermal physical performance parameters of the polytetrafluoroethylene material used in the cover 4, a pyrolysis and ablation calculation model of the polytetrafluoroethylene material cover 4 is constructed, and the pyrolysis and ablation amount and the inner wall temperature of the cover 4 during the entire flight of the aircraft are calculated; by adjusting the thickness of the cover 4, the inner wall temperature of the cover 4 is made lower than the maximum operating temperature of the antenna device 5.

[0054] Step five, deduct the pyrolysis and ablation amount from the cover body 4, and apply aerodynamic load to the cover body 4 after the deduction, and determine whether the cover body 4 after the pyrolysis and ablation amount is deducted can meet the structural bearing requirements through the stress and deformation data of the cover body 4. If so, the thickness of the cover body 4 when the inner wall temperature of the cover body 4 is lower than the maximum operating temperature of the antenna device 5 is taken as the minimum value t of the thickness of the cover body 4; if not, further increase the thickness of the cover body 4, recalculate the pyrolysis and ablation amount and the inner wall temperature of the cover body 4, and repeat step five.

[0055] The method for establishing the pyrolysis and ablation calculation model is a conventional technology in the field of aircraft design, that is, a model for studying the time-dependent changes of polytetrafluoroethylene materials under pyrolysis conditions.

[0056] Step six, given the angle θ between the antenna device 5 and the axis of the cover body 4, calculate the radiation pattern of the antenna device 5.

[0057] Step seven, simulate the electrical performance of the antenna device 5 to determine whether the radiation pattern of the antenna device 5 meets the requirements that the end cap assembly 1 and the end cap connector 2 are outside the effective detection area of ​​the antenna device 5. If the requirements are met, the design of the combined antenna is completed; if the requirements are not met, optimize the angle θ between the antenna device 5 and the axis of the cover body 4 and repeat step seven.

[0058] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. Low-cost micro-ablation heat-resistant load-bearing wave-transmitting integrated antenna, characterized in that: It comprises a terminal cap assembly (1), a terminal cap connector (2), a cover body (4) and an antenna device (5); The end cap assembly (1) is made of a high-silicon / phenolic composite material, the front end of the end cap connector (2) is buried inside the rear end of the end cap assembly (1), and the end cap assembly (1) and the end cap connector (2) are integrally molded; The cover body (4) is formed by processing with polytetrafluoroethylene material, a cavity is formed inside the cover body (4), and the front end surface of the cover body (4) is butted with the end cap assembly (1); The antenna device (5) is installed in a cavity inside the cover body (4), and there is an angle between the antenna device (5) and the axis of the cover body (4); wherein the angle should be able to ensure that the end cap assembly (1) and the end cap connector (2) are outside the effective detection area of ​​the antenna device (5).

2. The low-cost micro-ablation heat-resistant load-bearing wave-transmitting integrated antenna according to claim 1 is characterized in that: The end cap assembly (1) is a solid cone structure, and its front end is a blunt circle; after the end cap assembly (1) is connected to the cover body (4), the connection between the two has a smooth transition.

3. The low-cost micro-ablation heat-resistant load-bearing wave-transmitting integrated antenna according to claim 1 is characterized in that: The front end face of the cover body (4) is a plane, and a flange is provided at the front end of the cavity inside the cover body (4). After the rear end of the end cap connector (2) passes through the through hole and the flange, it is fastened using an end cap nut (3).

4. A design method for a low-cost micro-ablation heat-resistant, load-bearing and wave-transmitting integrated antenna according to any one of claims 1 to 3, characterized in that: include: Step 1: first, according to the aerodynamic shape constraints of the combined antenna, determine the design space of the antenna device (5) in the combined antenna; Step 2, calculating the aerodynamic thermal environment of the combined antenna according to the flight trajectory parameters and aerodynamic shape of the aircraft carrying the combined antenna, and determining the position of the turning point on the combined antenna; Step 3, designing the axial length of the end cap assembly (1) according to the determined position of the turning point; Step 4: Calculate the pyrolysis and ablation amount and the inner wall temperature of the cover (4) during the entire flight of the aircraft based on the calculated aerodynamic thermal environment of the combined antenna and the thermophysical performance parameters of the polytetrafluoroethylene material used in the cover (4); and adjust the thickness of the cover (4) so ​​that the inner wall temperature of the cover (4) is lower than the maximum operating temperature of the antenna device (5); Step 5, deducting the pyrolysis ablation amount from the cover body (4), and applying an aerodynamic load to the cover body (4) after the deduction, and judging whether the cover body (4) after the deduction of the pyrolysis ablation amount can meet the structural load-bearing requirements through the stress and deformation data of the cover body (4); if so, the thickness of the cover body (4) when the inner wall temperature of the cover body (4) is lower than the maximum operating temperature of the antenna device (5) is taken as the minimum value of the thickness of the cover body (4); Step six, given the angle between the antenna device (5) and the axis of the cover body (4), calculate the radiation pattern of the antenna device (5); Step seven, perform electrical performance simulation of the antenna device (5) to determine whether the radiation pattern of the antenna device (5) meets the requirements that the end cap assembly (1) and the end cap connector (2) are outside the effective detection area of ​​the antenna device (5). If the requirements are met, the design of the combined antenna is completed.

5. The design method according to claim 4, characterized in that: Determining the design space of the antenna device (5) in the combined antenna according to the aerodynamic shape constraints of the combined antenna includes: The position and circumferential space of the antenna device (5) inside the cover body (4) are determined according to the external structure of the cover body (4) and serve as design input for the antenna device (5).

6. The design method according to claim 4, characterized in that: The step of calculating the aerodynamic thermal environment of the combined antenna according to the flight trajectory parameters and aerodynamic shape of the aircraft carrying the combined antenna, and determining the position of the turning point on the combined antenna, comprises: The method of solving NS equations based on computational fluid dynamics is adopted to obtain the aerodynamic thermal environment of the combined antenna, including the aerodynamic pressure distribution and the heat flux density distribution on the outer wall of the combined antenna; the method of solving NS equations based on computational fluid dynamics is adopted to determine the position of the turning point on the combined antenna.

7. The design method according to claim 4, characterized in that: The judgment criteria of the turning point are: ； In the formula, is the Reynolds number corresponding to the transition point, is the flight Mach number of the aircraft.

8. The design method according to claim 4, characterized in that: The step of designing the axial length of the end cap assembly (1) according to the determined position of the turning point comprises: The axial length of the end cap assembly (1) is greater than the axial distance between the position of the turning point and the front end of the combined antenna.

9. The design method according to claim 4, characterized in that: In step 5, if the structural bearing requirements are not met, the thickness of the cover body (4) is further increased, the pyrolysis ablation amount and the inner wall temperature of the cover body (4) are recalculated, and step 5 is repeated; In step seven, if the requirement outside the effective detection area is not met, the angle between the antenna device (5) and the axis of the cover body (4) is optimized and step seven is repeated.

10. An aircraft, characterized in that: The aircraft is equipped with a low-cost micro-ablation, heat-resistant, load-bearing and wave-transmitting integrated combined antenna according to any one of claims 1 to 3.

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