CN216052163U - Axisymmetric double-emission low-scattering carrier for RCS test - Google Patents
Axisymmetric double-emission low-scattering carrier for RCS test Download PDFInfo
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- CN216052163U CN216052163U CN202121269480.3U CN202121269480U CN216052163U CN 216052163 U CN216052163 U CN 216052163U CN 202121269480 U CN202121269480 U CN 202121269480U CN 216052163 U CN216052163 U CN 216052163U
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Abstract
The invention relates to an axisymmetric double-emission low-scattering carrier for RCS (Radar Cross section) test, belonging to the field of RCS test of aeroengines; the device comprises a carrier body with a smooth curved surface, wherein the carrier body is axially divided into a carrier front half section and a carrier rear half section; the carrier is in the shape of a flat cone; the tail end of the rear half section of the carrier is symmetrically provided with two ports by using a central axis and is used for installing a double-nozzle pipe during electromagnetic testing; a caudal vertebra is arranged between the two ports, and the outer sides of the two ports are symmetrically provided with horizontal tails. The aircraft afterbody layout is simulated by introducing the horizontal tails at the two sides and the middle tail cone, the shielding of radar waves in the nozzle cavity is realized when the radar waves are incident from the side direction, and radar echo is reduced. In addition, the invention can research the relation between single-shot and double-shot backward RCS through testing the scattering characteristics of the dual-nozzle backward radar.
Description
Technical Field
The invention belongs to the field of RCS testing of aircraft engines, and particularly relates to an axisymmetric dual-emission low-scattering carrier for RCS testing.
Background
Aircraft radar stealth is currently an important research direction in the design of a new generation of warplanes. The jet pipe is used as an important part of an exhaust system, and due to the cavity structure of the jet pipe, electromagnetic waves are easy to generate large echoes along the incident direction after being reflected for multiple times after being incident, and the jet pipe is a main scattering source behind an aircraft at present. Therefore, the stealth design of the aircraft nozzle is very important for improving the radar stealth characteristic of the aircraft.
The design of the spray pipe stealth mainly comprises a numerical simulation method and an experimental test method, wherein the experimental test method is mainly used for testing scattering from the interior of a spray pipe cavity in a microwave dark chamber by connecting the spray pipe with a low-scattering carrier at present, and meanwhile, in order to further reduce the contribution of the carrier to the whole echo, a wave-absorbing coating can be coated on the exterior of the carrier.
Application number 201811503774.0, application date 2018, 12/10 entitled "Low Scattering housing for assembling binary nozzle Engine", discloses a low Scattering Carrier with a binary nozzle, which realizes an average RCS lower than-20 dBsm within a backward + -45 DEG detection angle, and can be integrally designed with the binary nozzle to simulate the layout of an airplane afterbody, but has the disadvantage that the backward RCS test cannot be carried out on double-engine.
Disclosure of Invention
The technical problem to be solved is as follows:
in order to avoid the defects of the prior art, the invention provides an axisymmetric double-emission low-scattering carrier for RCS test, and the low-scattering carrier capable of being used for testing double spray pipes is designed by simulating the layout of the rear body of a stealth fighter. This carrier and axisymmetric spray tube carry out the integrated design, have solved behind the two spray tubes RCS experiment test difficult to reach the not accurate problem inadequately.
The technical scheme of the invention is as follows: an axisymmetric double-emitting low-scattering carrier for RCS test comprises a carrier body with a smooth curved surface, wherein the carrier body is axially divided into a carrier front half section and a carrier rear half section; the method is characterized in that: the carrier is in the shape of a flat cone; the tail end of the rear half section of the carrier is symmetrically provided with two ports by using a central axis and is used for installing a double-nozzle pipe during electromagnetic testing; a caudal vertebra is arranged between the two ports, and the outer sides of the two ports are symmetrically provided with horizontal tails.
The further technical scheme of the invention is as follows: the front half section of the carrier body is symmetrical relative to a vertical plane passing through the central axis and is symmetrical relative to a transverse plane passing through the central axis; the projection of the front half section of the carrier on a vertical plane passing through the central axis is close to an isosceles triangle, and the two waists are curves; the rear half section of the carrier is symmetrical relative to a vertical plane passing through the central axis and is smoothly connected with the front half section of the carrier.
The further technical scheme of the invention is as follows: the lower wall surface of the front half section of the carrier is close to a plane, so that stable placement on a test platform can be ensured during experimental testing.
The further technical scheme of the invention is as follows: the ratio of the length of the front half section of the carrier to the length of the rear half section of the carrier is 1-3; the height of the rear half section of the carrier is 1-2 times of the center offset distance of the inlet and outlet of the spray pipe, so that the spray pipe is convenient to mount; at the same time, the maximum height of the carrier should be less than 1/5 of the total length of the carrier, so that the carrier is flat when viewed from the back or side, which is beneficial to RCS reduction.
The further technical scheme of the invention is as follows: the tail end of the horizontal tail is conical, and the cone angle is an acute angle; the inner side wall surface of the optical fiber connector close to the port is formed by splicing a plurality of inclined planes, so that the generation of mirror reflection when radar waves are incident from the front to the back or from the side is avoided.
The further technical scheme of the invention is as follows: the ratio of the axial length of the horizontal tail to the axial length of the rear half section of the carrier is 0.7-1.
The further technical scheme of the invention is as follows: the radial sections of the two ports are circular, and are integrally designed with the circular outlets of the axisymmetric double-nozzle.
The further technical scheme of the invention is as follows: the arbitrary radial cross-section of caudal vertebra is circular, and its radial sectional area reduces gradually along the axial to be smooth connection with the carrier fuselage, this junction is smooth curved surface, avoids producing specular reflection when radar wave from the backward incidence.
The further technical scheme of the invention is as follows: the axial length of the caudal vertebra is less than or equal to that of the flat tail.
Advantageous effects
The invention has the beneficial effects that:
the invention designs an axisymmetric double-emission low-scattering carrier for RCS test by simulating the back body layout of the stealth fighter. The aircraft afterbody layout is simulated by introducing the horizontal tails at the two sides and the middle tail cone, the shielding of radar waves in the nozzle cavity is realized when the radar waves are incident from the side direction, and radar echo is reduced. In addition, the invention can research the relation between single-shot and double-shot backward RCS through testing the scattering characteristics of the dual-nozzle backward radar.
The height of the carrier is less than 1/5 of the length of the carrier, so that the carrier is flat when viewed from the front or side, which is beneficial for RCS reduction. In addition, the horizontal tail is formed by splicing a plurality of inclined planes close to the side wall surface of the spray pipe, and the tail cone is smoothly connected with the carrier, so that the generation of mirror reflection when electromagnetic waves are incident from the front to the back or from the side direction is avoided, and the radar echo is reduced.
To verify the effectiveness of the present invention, the two circular ports of the carrier were sealed with conical surfaces, and the RCS was numerically simulated after the axisymmetric dual-launch carrier, the results of which are shown in fig. 1. As can be seen, RCS of the carrier is-15 dBsm under most of the receiving detection angles within the range of +/-45 degrees, so that the dual-wave carrier has a small backward radar scattering cross section and can be used as an engine backward RCS test carrier.
Drawings
Fig. 1 is an overall schematic view of a double hair carrier according to the present invention.
Fig. 2 is a front view of a double hair carrier according to the present invention.
Fig. 3 is a rear view of a double hair carrier according to the present invention.
Fig. 4 is a top view of a dual hair carrier according to the present invention.
Fig. 5 is a side view of a dual hair carrier according to the present invention.
FIG. 6 is a rear sectional view of the symmetrical nozzle for the double hair carrier mounting shaft according to the present invention.
Fig. 7 is a curve distribution of an axially symmetric dual-transmit carrier RCS in the vertical polarization horizontal detection plane.
Description of reference numerals: 1. the carrier body, 11, the front half section of the carrier body, 12, the rear half section of the carrier body, 2, a horizontal tail, 3, a circular port, 4, a tail cone, 5, an axisymmetric spray pipe, 51, a spray pipe outlet and 52, a spray pipe outlet and carrier port connecting section.
Detailed Description
The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.
Referring to fig. 1-6, the axisymmetric dual-emission low-scattering carrier for RCS test of the present invention includes a carrier body 1 with a smooth curved surface, wherein the carrier body 1 includes a carrier front half-section 11 and a carrier rear half-section 12; the carrier is a flat cone, and the front half section 11 of the carrier is symmetrical relative to a vertical plane passing through the central axis and is symmetrical relative to a transverse plane passing through the central axis; the projection of the front half section 11 of the carrier on a vertical plane passing through the central axis is close to an isosceles triangle, and the two waists are curves; the rear carrier half 12 is symmetrical with respect to a vertical plane passing through the central axis and is smoothly connected with the front carrier half 11. And the lower wall surface of the front half section 11 of the carrier is close to a plane, so that the stable placement on a test platform can be ensured during experimental testing.
The tail end of the rear half section 12 of the carrier is symmetrically provided with two circular ports 3 by a central axis, and is integrally designed with the circular outlet of the axisymmetric spray pipe and used for installing the double-emission spray pipe during electromagnetic testing; a tail cone 4 is arranged between the two circular ports 3, any radial section of the tail cone 4 is circular, the radial sectional area of the tail cone 4 is gradually reduced along the axial direction, the tail cone is smoothly connected with the carrier body 1, and the joint is a smooth curved surface, so that the mirror reflection generated when radar waves are incident from the back is avoided. Meanwhile, the axial length of the caudal vertebra is less than or equal to that of the horizontal tail.
The outer sides of the two circular ports 3 are symmetrically provided with horizontal tails, the tail ends of the horizontal tails 2 are conical, and the cone angles are acute angles; the inner side wall surface of the jet pipe is formed by splicing a plurality of inclined planes, so that the generation of mirror reflection when radar waves are incident from the front to the back or from the side direction is avoided. In addition, in the horizontal detection plane, when radar waves are incident from the lateral direction of the carrier, the horizontal tail can shield the inside of the cavity to a certain extent, the area of the radar waves directly irradiating the inside of the cavity is reduced, and the generation of strong radar echoes is avoided.
The ratio of the axial length of the horizontal tail 4 to the axial length of the rear half section of the carrier is 0.7-1.
An axisymmetric double-emission low-scattering carrier design and application method for RCS test comprises the following steps:
the method comprises the following steps: determining axisymmetric dual hair carrier dimensions
The size of the nozzle to be tested is measured, and mainly comprises the length of the nozzle, the diameter of an outlet and the center offset distance of an inlet and an outlet, and the length of the carrier is generally selected to be 3-4 times of the length of the nozzle. In this embodiment, the length of the axisymmetric nozzle is 2.5m, the diameter of the outlet is 0.8m, and the center offset distance is 0. Therefore, the total length of the double-hair carrier is designed to be 7.7m, wherein the length of the front half section is 5.2m, the length of the rear half section is 2.5m, the lengths of the flat tails at the two sides of the caudal vertebra are 2.4m, the length of the middle caudal vertebra is 1.8m, the diameter of the circular port is 1.2m, and the whole width of the carrier is 4.97 m. And finally, determining the height of the carrier according to the offset distance of the centers of the inlet and the outlet of the spray pipe, wherein the height of the carrier is required to ensure that the spray pipe can be completely positioned in the carrier, and a certain installation operation space is reserved between the spray pipe and the upper wall surface and the lower wall surface of the carrier, the diameter of the spray pipe is 1m in the embodiment, and the height of the designed carrier is 1.44 m.
Step two: determining nozzle installation location
And determining the axial installation position of the spray pipe according to the size of the spray pipe. The axisymmetric nozzle outlet is coaxial with the circular port and ensures that more than half of the nozzle is positioned in the carrier. The axial distance between the circular port and the nozzle outlet in this embodiment is 0.75m, the axial length of the member 52 in fig. 7. Note that to ensure that the tail cone acts as a shield, the nozzle mounting location should not exceed the tail cone in the axial position.
Step three: determining the connection surface between the nozzle outlet and the circular carrier port
The nozzle outlet is designed integrally with the circular port of the carrier, depending on the position of the nozzle outlet, to ensure that the connector is smooth over the carrier at the port, as shown at 52 in fig. 7.
Step four: axisymmetric double hair carrier processing
And processing the carrier model according to the size of the axisymmetric nozzle carrier. In order to facilitate the installation of the spray pipe, the upper wall surface and the lower wall surface of the front section and the rear section of the carrier are respectively divided into a plurality of sections for processing, and finally, the carrier is assembled and spliced. In the assembling process, the lower wall surface of the carrier is firstly placed on the ground, then the two axisymmetric spray pipes and the connecting surface are respectively installed on the lower wall surface of the carrier, and the spray pipes are connected with the lower wall surface of the carrier through a bracket installed in the carrier. Finally, the upper wall surface of the carrier is installed, and a bracket is also installed inside the upper wall surface of the carrier and is used for being connected with the spray pipe part and fixing the position of the spray pipe, as shown in figure 6, the bracket connection between the inside of the carrier and the spray pipe is omitted.
Step five: RCS test
And finally, hoisting the carrier to a test platform, and placing the rear half section of the lower wall surface on the test platform to ensure the stability of the carrier in the test process. Therefore, a set of axisymmetric dual-emission low-scattering carrier for RCS test and experimental test thereof are completely designed.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.
Claims (9)
1. An axisymmetric double-emitting low-scattering carrier for RCS test comprises a carrier body with a smooth curved surface, wherein the carrier body is axially divided into a carrier front half section and a carrier rear half section; the method is characterized in that: the carrier is in the shape of a flat cone; the tail end of the rear half section of the carrier is symmetrically provided with two ports by using a central axis and is used for installing a double-nozzle pipe during electromagnetic testing; a caudal vertebra is arranged between the two ports, and the outer sides of the two ports are symmetrically provided with horizontal tails.
2. The axisymmetric dual-emission low-scattering carrier for RCS testing of claim 1, wherein: the front half section of the carrier body is symmetrical relative to a vertical plane passing through the central axis and is symmetrical relative to a transverse plane passing through the central axis; the projection of the front half section of the carrier on a vertical plane passing through the central axis is close to an isosceles triangle, and the two waists are curves; the rear half section of the carrier is symmetrical relative to a vertical plane passing through the central axis and is smoothly connected with the front half section of the carrier.
3. The axisymmetric dual-emission low-scattering carrier for RCS testing of claim 1, wherein: the lower wall surface of the front half section of the carrier is close to a plane, so that stable placement on a test platform can be ensured during experimental testing.
4. The axisymmetric dual-emission low-scattering carrier for RCS testing of claim 1, wherein: the ratio of the length of the front half section of the carrier to the length of the rear half section of the carrier is 1-3; the height of the rear half section of the carrier is 1-2 times of the center offset distance of the inlet and outlet of the spray pipe, so that the spray pipe is convenient to mount; at the same time, the maximum height of the carrier should be less than 1/5 of the total length of the carrier, so that the carrier is flat when viewed from the back or side, which is beneficial to RCS reduction.
5. The axisymmetric dual-emission low-scattering carrier for RCS testing of claim 1, wherein: the tail end of the horizontal tail is conical, and the cone angle is an acute angle; the inner side wall surface of the optical fiber connector close to the port is formed by splicing a plurality of inclined planes, so that the generation of mirror reflection when radar waves are incident from the front to the back or from the side is avoided.
6. The axisymmetric dual-emission low-scattering carrier for RCS testing of claim 1, wherein: the ratio of the axial length of the horizontal tail to the axial length of the rear half section of the carrier is 0.7-1.
7. The axisymmetric dual-emission low-scattering carrier for RCS testing of claim 1, wherein: the radial sections of the two ports are circular, and are integrally designed with the circular outlets of the axisymmetric double-nozzle.
8. The axisymmetric dual-emission low-scattering carrier for RCS testing of claim 1, wherein: the arbitrary radial cross-section of caudal vertebra is circular, and its radial sectional area reduces gradually along the axial to be smooth connection with the carrier fuselage, this junction is smooth curved surface, avoids producing specular reflection when radar wave from the backward incidence.
9. The axisymmetric dual-emission low-scattering carrier for RCS testing of claim 1, wherein: the axial length of the caudal vertebra is less than or equal to that of the flat tail.
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| CN202121269480.3U CN216052163U (en) | 2021-06-07 | 2021-06-07 | Axisymmetric double-emission low-scattering carrier for RCS test |
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| CN202121269480.3U CN216052163U (en) | 2021-06-07 | 2021-06-07 | Axisymmetric double-emission low-scattering carrier for RCS test |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113219212A (en) * | 2021-06-07 | 2021-08-06 | 西北工业大学 | Low-scattering carrier for dual-engine binary nozzle |
| CN113419224A (en) * | 2021-06-07 | 2021-09-21 | 西北工业大学 | Axisymmetric double-emission low-scattering carrier for RCS test and application method thereof |
| CN115267687A (en) * | 2022-09-29 | 2022-11-01 | 中国航发四川燃气涡轮研究院 | Low-cost modularized multi-posture engine low-scattering carrier |
-
2021
- 2021-06-07 CN CN202121269480.3U patent/CN216052163U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113219212A (en) * | 2021-06-07 | 2021-08-06 | 西北工业大学 | Low-scattering carrier for dual-engine binary nozzle |
| CN113419224A (en) * | 2021-06-07 | 2021-09-21 | 西北工业大学 | Axisymmetric double-emission low-scattering carrier for RCS test and application method thereof |
| CN113219212B (en) * | 2021-06-07 | 2024-03-19 | 西北工业大学 | Low-scattering carrier for double-emission binary spray pipe |
| CN115267687A (en) * | 2022-09-29 | 2022-11-01 | 中国航发四川燃气涡轮研究院 | Low-cost modularized multi-posture engine low-scattering carrier |
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