A double-rail rocket sled aerodynamic shape structure applicable to hypersonic speed

Abstract

The present invention discloses a pneumatic shape structure of a double-rail rocket sled applicable to hypersonic speeds, which includes a large inclined surface wedge-shaped fairing structure, a fairing cap, a column, a circular snap ring, and skids; the longitudinal section of the large inclined surface wedge-shaped fairing structure, i.e., the section in the YZ plane direction, is a trapezoid + 1 / 4 ellipse, and the top view is a trapezoid; four skids are installed on the lower surface, two in the front and two in the back, for the rocket sled to slide along the track; the fairing cap is installed on the upper surface of the wedge-shaped fairing structure to rectify the uncovered engine head; a column is designed in the middle of the large inclined surface wedge-shaped fairing structure, the column has a pointed wedge shape at the front and a cuboid shape at the back, and the pointed wedge shape and the cuboid shape are integrally installed with the test article; the test article is clamped inside the column by a circular snap ring. The present invention greatly reduces the aerodynamic drag of the wedge-shaped fairing shape and can achieve an operating speed of 5Ma for the double-rail rocket sled under the existing power conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of range testing, and particularly relates to a double-rail rocket sled aerodynamic configuration suitable for hypersonic speeds. Background Art

[0002] A rocket sled is a ground test system that uses a rocket engine as power and slides at high speed along a specially constructed rail. It mainly simulates the speed and acceleration conditions during the development process of weapon systems and is used for functional assessment of aircraft, missiles, aerospace vehicles, and their components.

[0003] Ground tests can achieve good measurement accuracy while simulating real environmental conditions according to different test purposes, but the range of simulated parameters is restricted by test equipment. For example, hypersonic wind tunnel tests are limited by equipment scale and usually cannot conduct 1:1 sample tests. At the same time, since the dynamic pressure can only reach about 100,000 Pa at most, it is impossible to simulate the mechanical environment with dynamic pressures of several hundred thousand Pa or even more than one million Pa. Therefore, technical solutions related to control in high-speed environments cannot be evaluated through wind tunnel equipment; the balancing gun has limited acceleration ability and cannot meet the hypersonic assessment requirements; the light gas gun is restricted by its multi-stage caliber acceleration launch principle, and the size and mass of the warhead (projectile) that can be loaded are quite limited. Rocket sled tests can simulate the main characteristics of flight states and have become a relatively effective special test method among current advanced weapon ground test equipment, especially with more prominent advantages in simulating the supersonic high Reynolds number aerodynamic environment with dynamic assessment events.

[0004] As hypersonic weapon systems have become one of the key technologies actively developed by aerospace powers in the world today, simulating hypersonic test and measurement environments has become an important research direction for the continuous development of ground rocket sled test technology. Due to the high speed of hypersonic rocket sleds during operation, large influence of ground effects, and simultaneous exposure to harsh aerodynamic environments and rail impact vibration environments, the movement stability of rocket sleds is greatly reduced. A reasonable aerodynamic environment, especially an appropriate aerodynamic pressure environment, can effectively generate aerodynamic damping and suppress the vibration of rocket sleds. Therefore, designing a reasonable aerodynamic pressure environment is of great significance for hypersonic movement stability.

[0005] China has successfully carried out hypersonic single-rail rocket sled tests and has certain experience in aerodynamic design. However, a single-rail rocket sled slides at high speed along a single rail and is extremely prone to roll effects, and the vibration mechanical environment is also more severe. A double-rail rocket sled slides across two rails and can carry a much larger load than a single-rail rocket sled, and can adapt to hypersonic rocket sled tests of large-load warheads that China is vigorously developing at present. However, the maximum speed of the double-rail rocket sled successfully implemented in China currently is 3.5 Ma, and there is no aerodynamic design experience and relevant data for 5 Ma double-rail rocket sleds.

[0006] In the aerodynamic design of a medium-supersonic two-rail rocket sled at 3.5 Ma, the negative-lift low-drag large-inclination aerodynamic structure applicable to medium-supersonic speeds can provide a good aerodynamic environment below the speed of 3.5 Ma, meeting the requirements of motion stability. However, when it is pushed to a speed of 5 Ma, the aerodynamic pressure increases from less than 20 tons to more than 50 tons. The excessive aerodynamic pressure makes it difficult for the skids to bear, deteriorating the skid-rail mechanical environment. At the same time, the existing structural drag coefficient is too large, and it is difficult to achieve hypersonic speed with the existing power configuration. Therefore, it is necessary to develop an aerodynamic shape structure applicable to hypersonic two-rail rocket sleds to meet the requirements of ballistic design and motion stability. At present, no effective measures have been taken to reduce the aerodynamic drag of hypersonic two-rail rocket sleds and simultaneously provide reasonable downward pressure to suppress the vibration environment, and there is no public report on relevant aerodynamic structures. Summary of the Invention

[0007] To overcome the deficiencies of the prior art, the present invention provides an aerodynamic shape structure for a hypersonic two-rail rocket sled, which includes a large-inclination wedge-shaped fairing structure, a fairing cap, a column, a circular snap ring, and skids; the longitudinal section of the large-inclination wedge-shaped fairing structure, i.e., the section in the YZ plane direction, is a trapezoid + 1 / 4 ellipse, and the top view is a trapezoid; four skids are installed on the lower surface, two in the front and two in the back, for the rocket sled to slide along the track; the fairing cap is installed on the upper surface of the wedge-shaped fairing structure to fair the uncovered engine head; a column is designed in the middle of the large-inclination wedge-shaped fairing structure, with a pointed wedge shape at the front and a cuboid shape at the back, and the pointed wedge shape and the cuboid shape are integrally installed with the test article; the test article is clamped inside the column by a circular snap ring. The present invention greatly reduces the aerodynamic drag of the wedge-shaped fairing shape, and can achieve a running speed of 5 Ma for the two-rail rocket sled under the existing power conditions.

[0008] The technical solution adopted by the present invention to solve its technical problems includes the following steps:

[0009] An aerodynamic shape structure for a hypersonic two-rail rocket sled, which includes a large-inclination wedge-shaped fairing structure, a fairing cap, a column, a circular snap ring, and skids;

[0010] Define the running direction of the rocket sled as the negative direction of the Y axis; perpendicular to the Y axis, and the vertical direction pointing upward is the positive direction of the Z axis; perpendicular to the YZ plane, and the direction pointing to the left side of the rocket sled running direction is the positive direction of the X axis;

[0011] The longitudinal section of the large-inclination wedge-shaped fairing structure, i.e., the section in the YZ plane direction, is a trapezoid + 1 / 4 ellipse, and the top view is a trapezoid;

[0012] Four skids are installed on the lower surface of the wedge-shaped fairing structure, two in the front and two in the back, for the rocket sled to slide along the track;

[0013] The fairing cap is installed on the upper surface of the wedge-shaped fairing structure to fair the uncovered engine head. The fairing cap is formed by the fusion of the conical surface of the conical structure and the upper surface of the large inclined surface wedge-shaped fairing structure. The intersection line extends forward to the front end face of the cross beam of the two front skids at the farthest. The rear end face of the fairing cap fits with the front end face of the engine to play a role in covering and fairing the engine.

[0014] A column is designed in the middle of the large inclined surface wedge-shaped fairing structure. The column has a pointed wedge shape at the front and a cuboid shape at the rear. The pointed wedge shape and the cuboid shape are integrally installed with the test article. The test article is clamped inside the column by a circular snap ring.

[0015] Preferably, the trapezoidal structure of the longitudinal section of the large inclined surface wedge-shaped fairing structure is a right trapezoid. The right-angled side forms the bottom surface of the aerodynamic shape structure. The upper side length of the right trapezoid is determined by the height of the cross beam supported by the front skids. The lower side of the right trapezoid is used to cover the engine. The waist line of the right trapezoid forms the wedge-shaped large inclined surface of the aerodynamic shape structure.

[0016] The upper side length of the right trapezoid is the same as the height of the cross beam of the two front skids in front, which is 70 mm.

[0017] The lower side length of the right trapezoid is the vertical distance from the upper top surface of the two front skids to the center of the engine.

[0018] The length of the right-angled side of the right trapezoid is between 1.2 m and 1.6 m.

[0019] Preferably, the short side of the 1 / 4 ellipse of the longitudinal section of the large inclined surface wedge-shaped fairing structure is the vertical side, and its length is the same as the height of the cross beam of the two front skids in front, which is 70 mm. The long side length of the ellipse is 240 mm.

[0020] The upper surface of the ellipse structure is an inclined surface from the rear to the front, and the inclination angle is the same as the wedge surface of the wedge-shaped fairing aerodynamic shape, that is, this inclined surface is coplanar with the wedge surface.

[0021] Preferably, the rear end face of the fairing cap coincides with the front end face of the engine and the surface formed by the part of the installation snap ring above the wedge surface, so as to completely cover the engine and achieve the purpose of fairing and reducing drag for the engine of the thrust sled part.

[0022] Preferably, the front width of the wedge-shaped fairing structure is equal to the distance between the outer sides of the two front skids, which is 1745 mm. The side surface of the wedge surface and the outermost engine fairing cap longitudinally cut out the side surface of the fairing structure based on this front and rear width.

[0023] The beneficial effects of the present invention are as follows:

[0024] (1) The aerodynamic shape of the hypersonic double-rail rocket sled of the present invention covers half of the engine and adopts the form of an engine fairing to reduce drag. Compared with the conventional wedge-shaped fairing that completely covers the engine in the past, the aerodynamic drag is significantly reduced. Under the existing power conditions, a running speed of 5 Ma for the double-rail rocket sled can be achieved.

[0025] (2) The aerodynamic shape of the hypersonic double-rail rocket sled of the present invention can adjust the longitudinal length of the aerodynamic shape of the rocket sled within a certain range, and then adjust the angle of the wedge surface to adjust the aerodynamic pressure within a reasonable range, avoiding the problem that the aerodynamic pressure of the wedge-shaped structural surface within 3.5 Ma in the past is too large at a speed of 5 Ma, resulting in an excessive vibration level of the entire sled.

[0026] (3) The present invention designs a 1 / 4 elliptical front crossbeam fairing method at the front of the wedge-shaped fairing, which not only reasonably adjusts the aerodynamic pressure at the front of the structure, but also avoids the problem of excessive aerodynamic pressure at the position of the skids when the traditional triangular cross-section design is a pure downward pressure surface. At the same time, it weakens the shock wave intensity at the bottom of the rocket sled when using a simple wedge structure, avoiding the vibration induction caused by the high-frequency impact of the high-intensity shock wave on the track fasteners. Brief Description of the Drawings

[0027] Figure 1 is a schematic diagram of the overall structure of the aerodynamic shape of the hypersonic double-rail rocket sled of the present invention.

[0028] Figure 2 is a trapezoidal longitudinal cross-sectional view of the wedge-shaped fairing structure of the hypersonic double-rail rocket sled of the present invention.

[0029] Figure 3 is a top view of the aerodynamic shape of the hypersonic double-rail rocket sled of the present invention, with the upward direction being the course.

[0030] Figure 4 is a cross-sectional view of the installation column of the test article of the hypersonic double-rail rocket sled of the present invention. Detailed Description of the Invention

[0031] The present invention will be further described below in conjunction with the drawings and embodiments.

[0032] The purpose of the present invention is to develop an aerodynamic structure with a lower drag coefficient and an appropriate aerodynamic pressure level for the large inclined surface aerodynamic structure of the existing double-rail rocket sled suitable for medium hypersonic speeds, which is difficult to adapt to the pressure environment under hypersonic conditions and has a large aerodynamic drag. The existing engine thrust capacity is difficult to achieve hypersonic conditions, so that while further reducing drag, it can provide an appropriate aerodynamic downward pressure to suppress the vibration mechanical environment at the position of the first pair of skids with aerodynamic damping.

[0033] The present invention will be described in detail below:

[0034] As Figures 1 to 4, the present invention is an aerodynamic shape structure applicable to a hypersonic dual-rail rocket sled, which is developed to ensure that the front structure of the rocket sled can provide an aerodynamic downward pressure suitable for the requirements of stability and vibration suppression in dynamics during a 5Ma speed rocket sled test, while ensuring that the aerodynamic drag meets the thrust requirements of the existing engine.

[0035] Here, the running direction of the rocket sled is defined as the negative direction of the Y-axis. Perpendicular to the Y-axis, and the vertical direction pointing upward is the positive direction of the Z-axis. Perpendicular to the YZ plane, and the direction pointing to the left of the running direction of the rocket sled is the positive direction of the X-axis.

[0036] The main body of this structure is a large inclined plane wedge-shaped fairing structure with a trapezoid + 1 / 4 ellipse in the longitudinal section (section in the YZ plane direction). Looking from the top view (looking from the positive direction of the Z-axis to the negative direction of the Z-axis), this wedge-shaped fairing is a trapezoid. On the upper surface of the wedge-shaped fairing structure, a fairing cap for the engine is designed to fair the uncovered engine head. The fairing cap is the conical surface of a conical structure that is integrally intersected with the upper surface of the wedge-shaped fairing structure. The intersection line extends forward to the front end face position of the first pair of slider crossbeams at the front at the farthest. At this time, the aerodynamic drag of the fairing cap structure is the lowest, and the aerodynamic downward pressure is the lowest. The rear end face of the fairing cap is completely fitted with the front end face of the engine to play a role in covering and fairing the engine. According to the shape of the test article, mounting columns are designed and installed in the middle of the wedge-shaped fairing. The mounting columns have a pointed wedge shape at the front and a cuboid shape at the rear. The pointed wedge shape and the cuboid shape are integrally installed with the test article. The test article is installed inside the column by using a circular snap ring. Four sliders are installed on the lower surface of the wedge-shaped fairing structure for the rocket sled to slide along the track.

[0037] The realization of the present invention also lies in that: the trapezoid structure in the longitudinal section is a horizontally placed right trapezoid, and the right-angled side forms the bottom surface of the aerodynamic shape of the present invention. The length of the upper side of the right trapezoid is determined by the height of the front slider support crossbeam. The lower side is used to cover the engine, and the waistline of the trapezoid forms the large inclined plane of the wedge shape of the aerodynamic shape of the present invention.

[0038] The realization of the present invention also lies in that: the value of the length L1 of the upper side of the right trapezoid is taken as the height of the commonly used front slider crossbeam, which is 70mm, that is, L1 = 70mm.

[0039] The realization of the present invention also lies in that: the length L2 of the lower side of the right trapezoid is used to cover the engine. In order to minimize the resistance to the greatest extent and be able to cover the engine and structures such as the engine mounting snap ring, and play a role in fairing the engine, in the present invention, the height of L2 needs to cover half of the engine, and the length is the vertical distance from the upper surface of the slider to the center of the engine.

[0040] The implementation of the present invention also lies in that: the length h of the right-angled side of the trapezoid of the cross-section ranges from 1.2 m to 1.6 m. The mass of the hypersonic test article is generally below 600 kg. The product sled selects two pairs of skids. According to the experience of the dynamic stability of the rocket sled, the safe distance between the two pairs of skids in the course direction is 1.2 m to 1.6 m. The specific value is determined according to the length a of the installation position of the test article and the required aerodynamic pressure. First, it is necessary to ensure that the length h of the right-angled side is greater than the length a of the installation position of the test article, that is, h > a, to ensure that there is enough space for the test article to be installed on the product sled. Then, according to the aerodynamic pressure required for dynamic stability, after carrying out aerodynamic simulation, the length h is determined to meet the required aerodynamic pressure.

[0041] The implementation of the present invention also lies in that: the 1 / 4 elliptical fairing structure is a structural design carried out to fair the front crossbeam. The traditional double-rail rocket sled front crossbeam fairing uses a wedge structure. In the hypersonic stage, the shock wave intensity formed along the lower surface of the wedge is too strong. In order to avoid the high-frequency impact of the high-intensity shock wave on the track fasteners and induce vibration of the rocket sled, an elliptical fairing structure is adopted on the lower surface to weaken the shock wave intensity hitting the fasteners.

[0042] The implementation of the present invention also lies in that: the short side of the elliptical fairing structure is the vertical side, with a length equal to the height of the crossbeam, that is, 70 mm, and the length of the long side is determined by the coupled aerodynamic and dynamic analysis. The optimal value at a speed of 5 Ma is 240 mm.

[0043] The implementation of the present invention also lies in that: the upper surface of the elliptical fairing structure is an inclined plane from the rear to the front, and the inclination angle is the same as the wedge surface of the wedge-shaped fairing aerodynamic shape, that is, this inclined plane is coplanar with the wedge surface.

[0044] The implementation of the present invention also lies in that: the rear end face of the engine fairing cap coincides with the plane formed by the front end face of the engine and the part above the installation clamping ring on the wedge surface, so as to completely cover the engine and achieve the purpose of reducing drag for the engine fairing of the thrust sled part.

[0045] The implementation of the present invention also lies in that: taking the plane formed by the outer circle of the engine and the installation clamping ring surface as the bottom surface, and taking the sum of the height h of the longitudinal cross-section right-angled trapezoid and the length of the long side of the ellipse, 240 mm, as the height of the cone, a cone is formed. The cone slopes downward, and its conical surface is tangent to the large inclined surface of the wedge-shaped fairing surface to form the engine fairing cap. The length of the intersection line after tangency is farthest to the front end face of the front skid crossbeam. At this time, the aerodynamic pressure and resistance of the engine fairing are both the smallest. The nearest is to make the inclination angle of the inclined plane not exceed 45 degrees, otherwise the resistance is too large at a speed of 5 Ma.

[0046] The implementation of the present invention also lies in that: the front width W1 of the wedge-shaped rectifying structure is equal to the distance between the outer sides of the first pair of sliding shoes, that is, W1 = 1745 mm, and the rear width W2 is determined according to the engine installation situation, with the main engine installation clamp ring being covered as the criterion. The side surface of the wedge-shaped surface and the outermost engine fairing are longitudinally cut to form the side surface of the rectifying structure based on the front and rear widths.

[0047] The implementation of the present invention also lies in that: mounting columns are designed and installed in the middle of the wedge-shaped rectification according to the shape of the test article. The mounting columns have a sharp wedge shape at the front and a cuboid shape at the rear. The sharp wedge shape and the cuboid shape are designed and installed in combination with the test article according to the shape of the test article, and the rear part and the engine are transitioned with an inclined surface.

[0048] The implementation of the present invention also lies in that: four sliding shoes are installed on the lower surface of the wedge-shaped rectifying structure, and the standard sliding shoes in use are selected for the rocket sled to slide along the track. The transverse span of the four sliding shoes is the same as that of the two tracks, which is 1530 mm. The first pair of sliding shoes in the longitudinal direction is installed at the sliding shoe installation position of the front cross beam, and the second pair of sliding shoes is installed at the sliding shoe installation position of the second cross beam. Specific embodiments:

[0050] A certain type of missile weapon system needs to conduct a rocket sled test at a speed of 5 Ma. The mass of the test article is 550 kg, the main body length is 1450 mm (excluding rectification and accessories), and the installation position radius is 160 mm.

[0051] Analyzing the mass and size of the test article and combining with the evaluation of the bearing capacity of the single-rail rocket sled, it is difficult to conduct a rocket sled test under the condition of 5 Ma speed. It is necessary to conduct a double-rail rocket sled aerodynamic design to achieve the functional assessment of the test article under the condition of 5 Ma speed.

[0052] According to the above input conditions of the test item entrusted, a dual-rail rocket sled aerodynamic shape design is carried out. The wedge-shaped structure of the hypersonic dual-rail rocket sled aerodynamic shape is a large inclined plane wedge-shaped fairing structure of trapezoid + 1 / 4 ellipse. The longitudinal section of this wedge-shaped fairing is a right trapezoid placed horizontally, and the right-angled side forms the bottom surface of the aerodynamic shape in this example. The upper side length L1 of the right trapezoid is determined by the standard part height of the front crossbeam, and L1 = 70 mm. The lower side length L2 of the right trapezoid is used to cover the engine. In order to minimize drag and at the same time can rectify the windward engine and the retaining ring on the thrust sled, L2 is taken as half of the engine. In this example, the vertical distance from the top surface of the slider to the center of the engine is 234 mm, so L2 = 234 mm. The right-angled side length h of the right trapezoid is taken between 1.2 m and 1.6 m. This range is determined by the shoe-rail mating and motion stability. The specific value needs to be determined according to the length of the test item and the aerodynamic downforce. First, it is necessary to ensure that the right-angled side length h is greater than the length a of the installation position of the test item, that is, h > a. In this example, a = 1450 mm to ensure that the test item can have enough space to be installed on the product sled. After that, according to the aerodynamic pressure required for dynamic stability, aerodynamic simulation is carried out, and the length h is determined based on the required aerodynamic pressure. In this example, h is temporarily taken as 1570 mm according to experience. After establishing the model later, dynamic and aerodynamic simulation analyses are carried out for verification to ensure that the provided aerodynamic downforce is within the range that meets the dynamic stability requirements.

[0053] The front part of the wedge-shaped fairing structure is the front sled shoe crossbeam. It is necessary to design a fairing structure to fair the front end face of the crossbeam. The front fairing structure of the crossbeam is located at the front windward position of the hypersonic flow, and the aerodynamic force it receives is very large. Even a slight change in the structure will bring about a change in the aerodynamic force direction of several tons or even dozens of tons. Therefore, it must be carefully designed. For traditional double-rail rocket sleds with a speed of 3.5 Ma, a staggered-tooth structure is generally adopted. A lower triangular structure is selected near the sled shoe position and at the position where there are track clip fasteners, so that the airflow is pressed on it to avoid the shock wave formed from hitting the track clip fastener plate. An upper triangular structure is selected at the position far from the track fastener, so that the airflow is pressed below to form lift and relieve the excessive aerodynamic pressure on the front sled shoe, resulting in a poor vibration environment for the sled shoe. At a speed of 5 Ma, the aerodynamic downward pressure formed by the staggered-tooth structure is still too large to be relieved. Selecting a wedge-shaped structure with an isosceles triangular cross-section results in the lower shock wave hitting the track fastener frequently, inducing vibration. Therefore, in this example, a front fairing structure with a 1 / 4 ellipse is designed, so that the shock wave is pressed on the head. While weakening the lower shock wave from hitting the track fastener, it can also make both the upper and lower surfaces pressure surfaces, weakening the aerodynamic downward pressure at the front sled shoe position and keeping its downward pressure within a reasonable range. In this example, the short side of the elliptical fairing structure is the vertical side, and the short side length is the crossbeam height, which is 70 mm. The long side length is determined by the coupled aerodynamic and dynamic analysis, and the optimal value at a speed of 5 Ma is 240 mm. The upper surface of the elliptical fairing structure is an inclined plane from the rear to the front, and the inclination angle is the same as the wedge surface of the wedge-shaped fairing aerodynamic shape, that is, this inclined plane is coplanar with the wedge surface.

[0054] The lower half of the rear thrust engine is covered by the wedge-shaped fairing structure, and the upper half is fairing in the form of an engine fairing cap, avoiding the problem of excessive aerodynamic pressure under hypersonic conditions in the structure form where the traditional double-rail rocket sled uses a wedge-shaped structure to completely cover the engine. The rear end face of the engine fairing cap coincides with the plane formed by the front end face of the engine and the part above the installation snap ring on the wedge surface. Taking the plane formed by the outer circle of the engine installation snap ring surface as the bottom surface and the sum of the height h of the longitudinal section right trapezoid and the long side length 240 mm of the ellipse as the cone height, a cone is formed. This cone slopes downward, and its conical surface is tangent to the large inclined plane of the wedge-shaped fairing surface to form the engine fairing cap. In this example, it is necessary to minimize the aerodynamic downward pressure of the double-rail rocket sled. Therefore, the length of the intersection line after tangency is up to the front end face of the front sled shoe crossbeam. At this time, both the aerodynamic pressure and resistance of the engine fairing are the smallest. The fairing cap of the middle engine needs to be integrally designed with the test article installation column. The front intersection point of the fairing cap and the wedge surface is taken at the splicing position of the front triangular tip and the rear cuboid of the column.

[0055] The front width W1 of the wedge-shaped fairing structure is equal to the distance from the outer side of the first pair of skids, i.e., W1 = 1745 mm. The rear width W2 is based on the engine installation situation and is designed to cover the main engine installation clamp ring. In this example, 6 engines are required to reach a speed of 5 Ma. Adding the width of the installation clamp ring, W2 is taken as 2067 mm. The side surface of the wedge-shaped surface and the outermost engine fairing cap are longitudinally cut to form the side surface of the fairing aerodynamic structure based on the front and rear widths.

[0056] In the middle of the wedge-shaped fairing, installation columns are designed according to the shape of the test article. The installation columns have a pointed wedge shape at the front and a cuboid shape at the rear. The pointed wedge shape and the cuboid shape are designed to be integrated with the test article according to the shape of the test article. In this example, the leading-edge wedge angle is designed to be 40°, and the longitudinal length of the wedge is 286 mm. After the size design meets the installation strength requirements of the test article, in order to reduce drag, the slope angle of the second wedge surface is reduced to 20°, and the longitudinal length is 495 mm. Then, the cuboid is extended backward with the width of the wedge column as the width of the cuboid to the front end face of the engine. The height is based on the installation height requirements of the special commission of the test article. In this example, the height of the cuboid is 230 mm, and the rear part and the engine are connected by an inclined surface.

[0057] Four skids are installed on the lower surface of the wedge-shaped fairing structure. Standard skids in use are selected for the rocket sled to slide along the track. The transverse span of the four skids is the same as that of the two rails, which is 1530 mm. The first pair of skids is installed at the skid installation position of the front crossbeam, and the second pair of skids is installed at the skid installation position of the second crossbeam.

[0058] The dynamic stability of the designed double-rail rocket sled aerodynamic shape is calculated. The aerodynamic downward pressure required to meet the stable movement at a speed of 5 Ma is 34.6 tons to 39 tons. The aerodynamic characteristics are simulated. In this example, the aerodynamic pressure at a speed of 5 Ma is 37.4 t, which meets the requirement of the aerodynamic downward pressure, and the aerodynamic shape design of the double-rail rocket sled is completed.

Claims

1. A double-rail rocket sled aerodynamic shape structure applicable to hypersonic speeds, characterized in that, It includes a large inclined-plane wedge-shaped fairing structure, a fairing cap, a column, a circular snap ring and a sliding shoe; Define the running direction of the rocket sled as the negative Y-axis; perpendicular to the Y-axis, and the vertical direction pointing upward as the positive Z-axis; perpendicular to the YZ plane, and the direction pointing to the left of the running direction of the rocket sled as the positive X-axis; The longitudinal section of the large inclined-plane wedge-shaped fairing structure, i.e., the section in the YZ plane direction, is a trapezoid + 1 / 4 ellipse, and the top view is a trapezoid; Four sliding shoes are installed on the lower surface of the wedge-shaped fairing structure, two in the front and two in the back, for the rocket sled to slide along the track; The fairing cap is installed on the upper surface of the wedge-shaped fairing structure to fair the uncovered engine head; the fairing cap is the conical surface of a conical structure that is integrally intersected with the upper surface of the large inclined-plane wedge-shaped fairing structure, and the intersection line extends forward to the front end face position of the cross beam of the two front sliding shoes at the farthest; the rear end face of the fairing cap is in contact with the front end face of the engine to play a role in covering and fairing the engine; A column is designed in the middle of the large inclined-plane wedge-shaped fairing structure. The column has a pointed wedge shape at the front and a cuboid shape at the rear. The pointed wedge shape and the cuboid shape are integrally installed with the test article; the test article is clamped inside the column by a circular snap ring.

2. The aerodynamic shape structure of a double-rail rocket sled applicable to hypersonic speed according to claim 1, characterized in that, The trapezoidal structure in the longitudinal section of the large inclined-plane wedge-shaped fairing structure is a right trapezoid. The right side forms the bottom surface of the aerodynamic shape structure. The length of the upper side of the right trapezoid is determined by the height of the cross beam supported by the front sliding shoes. The lower side of the right trapezoid is used to cover the engine. The waist line of the right trapezoid forms the wedge-shaped large inclined plane of the aerodynamic shape structure.

3. The aerodynamic shape structure of a dual-rail rocket sled applicable to hypersonic speed according to claim 2, characterized in that, The length of the upper side of the right trapezoid is the same as the height of the cross beam of the two front sliding shoes, which is 70 mm; the length of the lower side of the right trapezoid is the vertical distance from the upper top surface of the two front sliding shoes to the center of the engine; the length of the right side of the right trapezoid ranges from 1.2 m to 1.6 m.

4. A double-rail rocket sled aerodynamic shape structure applicable to hypersonic, characterized in that, The short side of the 1 / 4 ellipse in the longitudinal section of the large inclined-plane wedge-shaped fairing structure is the vertical side, and its length is the same as the height of the cross beam of the two front sliding shoes, which is 70 mm; the length of the long side of the ellipse is 240 mm; The upper surface of the ellipse structure is an inclined plane from the rear to the front, and the inclination angle is the same as the wedge-shaped surface of the wedge-shaped fairing aerodynamic shape, that is, this inclined plane is coplanar with the wedge-shaped surface.

5. A double-rail rocket sled aerodynamic shape structure applicable to hypersonic speed according to claim 1, characterized in that The rear end face of the fairing cap coincides with the front end face of the engine and the surface formed by the part of the installation snap ring above the wedge-shaped surface, so as to completely cover the engine and achieve the purpose of fairing and reducing drag for the engine of the thrust sled part.

6. The aerodynamic shape structure of a double-rail rocket sled applicable to hypersonic speed according to claim 1, characterized in that, The width of the front part of the wedge-shaped fairing structure is equal to the distance between the outer sides of the two front sliding shoes, which is 1745 mm; the side surface of the wedge-shaped surface and the outermost engine fairing cap longitudinally cut out the side surface of the fairing structure based on this front-back width.

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