A channel-type angle-of-attack design device and method

Abstract

This invention discloses a channel-type angle-of-attack design device and method, including a skin, a venting channel, a directional rectangular tube, an upper triangular rectifier structure, a front crossbeam, a middle crossbeam, a rear crossbeam, a wedge-shaped rectifier, and a rectifier cap. The channel-type angle-of-attack design device is symmetrical about the spanwise midsection of the rocket sled system, extending from the front end to the rear end of the product sled. The front, middle, and rear crossbeams are installed on the product sled chassis, located at the front, middle, and rear ends of the product sled, respectively. The front side is on the same plane as the inner support surface of the front column of the rocket sled, and the rear side is on the same plane as the inner support surface of the rear column of the rocket sled. A steel plate connects the inner support surfaces of the front and rear columns to form the middle side. The spanwise position of the inner support surface of the rear column of the rocket sled is outside the spanwise position of the inner support surface of the front column. The steel plate is bent during installation to form a flow-expanding channel, which decelerates the gas and reduces the aerodynamic lift force on the tail of the test sample. The device of this invention has a simple structure and is easy to process and install.

Description

Technical Field

[0001] This invention belongs to the field of target range testing technology, and specifically relates to a channel-type angle of attack design device and method. Background Technology

[0002] Rocket sled tests are simulation tests that utilize a dedicated ground-based rail, powered by a rocket engine, and using a rocket sled as a carrier to run at high speed on the rail. These tests can simulate the real-world operating conditions of weapon systems or key components, including speed, overload, separation, wing deployment, and terminal effects, and obtain valuable test data, providing strong support for weapon development.

[0003] Traditional dual-track rocket sleds have a truss structure, capable of conducting rocket sled tests on large-mass test subjects at a maximum speed of 950 m / s, and have nearly reached the thrust-to-drag ratio limit based on current propulsion systems. To meet the testing requirements of weapon models with increased speeds, a negative lift, low drag, large-slope aerodynamic rectification structure was designed at the front of the dual-track rocket sled to significantly reduce aerodynamic drag. However, the presence of this large-slope structure creates a constricted channel between the test subject and the large slope, with the tail of the test subject embedded inside the large-slope rectification. During the operation of the rocket sled, the supersonic airflow decreases in velocity and increases in density when passing through this constricted channel, resulting in a large internal support force within the channel. This causes the middle and rear parts of the test subject to experience significant aerodynamic lift, generating an aerodynamic overturning moment in the nose-down direction.

[0004] In rocket sled tests involving the terminal effect of missile launch systems, the test subject separates from the rocket sled on a track and flies freely for a certain distance before penetrating the target. The limiting attitude angle of the test subject upon penetrating the target is one of the important indicators for test evaluation. However, the designed large-slope shape causes the test subject to generate angular acceleration in the nose-down direction under the action of aerodynamic rollover torque after separation from the sled, resulting in a large negative angle of attack when landing on the target, making it impossible to evaluate the terminal effect of the test subject under extreme conditions. Therefore, in dual-track rocket sleds of Mach 3 to Mach 5, it is necessary to design a device based on this large-slope drag reduction concept to change the aerodynamic rollover torque of the test subject on the sled, so as to ensure that the angle of attack of the test subject when landing on the target is within the required range of the test. The internal support force of the contraction channel between the test specimen and the large inclined plane is the main reason for the aerodynamic rollover force rectangle in the nose-down direction. Therefore, the direction of the angle of attack design device is to remove the skin and internal ribs of the large inclined plane rectification part located directly below the test specimen to greatly reduce the contraction effect. The venting channel in the middle of the heading further reduces the pressure of the channel between the test specimen and the rocket skid. The rocket engine is designed with a slanted rectification structure in front. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a channel-type angle-of-attack design device and method, including a skin, a venting channel, a directional rectangular tube, an upper triangular rectifying structure, a front crossbeam, a middle crossbeam, a rear crossbeam, a wedge-shaped rectifyer, and a rectifying cap. The channel-type angle-of-attack design device is symmetrical about the spanwise midsection of the rocket sled system, extending from the front end to the rear end of the product sled. The front, middle, and rear crossbeams are mounted on the product sled chassis, located at the front, middle, and rear ends of the product sled, respectively. The front side is on the same plane as the inner support surface of the front column of the rocket sled, and the rear side is on the same plane as the inner support surface of the rear column of the rocket sled. A steel plate connects the inner support surfaces of the front and rear columns to form the middle side. The spanwise position of the inner support surface of the rear column of the rocket sled is outside the spanwise position of the inner support surface of the front column. The steel plate is bent during installation to form a flow-expanding channel, which decelerates the gas and reduces the aerodynamic lift force on the tail of the test sample. This invention has a simple structure and is easy to process and install.

[0006] The technical solution adopted by this invention to solve its technical problem is as follows:

[0007] A channel-type angle-of-attack design device includes a skin, a bleed channel, a yaw tube, an upper triangular rectifier structure, a front crossbeam, a middle crossbeam, a rear crossbeam, a wedge-shaped rectifier, and a rectifier cap;

[0008] The direction of the rocket sled's movement is defined as the heading; the direction perpendicular to the heading and with the plumb bob pointing upwards is the longitudinal direction; the direction perpendicular to the plane formed by the heading and the longitudinal direction and pointing to the left of the heading is the span.

[0009] The channel-type angle-of-attack design device is symmetrical about the spanwise midsection of the rocket skid system, extending from the front end of the product skid to the rear end of the product skid; a front crossbeam, a middle crossbeam, and a rear crossbeam are provided on the product skid chassis, located at the front, middle, and rear ends of the product skid, respectively; the middle crossbeam is used to share the support reaction force of the sliding shoes of the front and rear crossbeams;

[0010] The drainage channel is located between the front crossbeam and the middle crossbeam;

[0011] The skin is located behind the front crossbeam and is used to smooth the airflow after passing the front crossbeam of the rocket skid. The end of the skin is welded to the inner support surface of the front column of the rocket skid and the yaw rectangular tube below the front column. The outer height of the skin is the same as the height of the front crossbeam.

[0012] The upper triangular rectifier structure is located in front of the middle crossbeam, and the height of the upper triangular rectifier structure is the same as the height of the middle crossbeam.

[0013] The yaw tube is located in the middle of the spanwise direction of the airflow channel to ensure the rigidity of the rocket skid;

[0014] A wedge-shaped rectifier and rectifier cap are built in front of the rocket engine to completely cover the mounting ring of the rocket engine. The rectifier heading starts from the rear column of the rocket skid and is welded to the inner support surface of the rear column and the spanwise rectangular tube below the rear column.

[0015] The front side of the channel-type angle-of-attack design device is on the same plane as the inner support surface of the front column of the rocket sled, and the rear side is on the same plane as the inner support surface of the rear column of the rocket sled. The inner support surfaces of the front and rear columns are connected by steel plates to form the middle side. The spanwise position of the inner support surface of the rear column of the rocket sled is outside the spanwise position of the inner support surface of the front column. The steel plate is bent during installation to form a flow-expanding channel, which slows down the gas and reduces the aerodynamic lift force on the tail of the test sample.

[0016] Preferably, the azimuth length and longitudinal height of the front crossbeam and the rear crossbeam are 0.12m and 0.086m respectively, the azimuth length and longitudinal height of the middle crossbeam are 0.1m and 0.086m respectively, the front end face of the middle crossbeam is 1m from the rear end face of the front crossbeam, and the front end face of the rear crossbeam is 2.06m from the rear end face of the front crossbeam.

[0017] Preferably, the yaw distance between the rear end face of the skin and the rear end face of the front crossbeam is between 0.2m and 0.3m.

[0018] Preferably, the angle of the triangular rectifier structure ranges from 20° to 70°.

[0019] Preferably, the wedge-shaped rectifier distance from the rear end face of the front crossbeam is between 1.65m and 1.735m.

[0020] Preferably, the front side of the channel-type angle of attack design device is on the same plane as the inner support surface of the front column of the rocket skid, with a flow channel width of 0.46m, and the rear side is on the same plane as the inner support surface of the rear column of the rocket skid, with a flow channel width of 0.7m.

[0021] Preferably, the bending position is set at a 0.67m directional distance from the rear end face of the front crossbeam.

[0022] A channel-type angle-of-attack design method includes the following steps:

[0023] Step 1: Define S1 as the directional distance between the rear skin of the front crossbeam and the rear face of the front crossbeam, α as the angle of the upper triangular rectifier structure in front of the middle crossbeam, and S2 as the directional distance between the front end of the rocket engine wedge rectifier and the rear face of the front crossbeam. The design variables and value ranges of the channel-type angle of attack design device are shown in Table 1.

[0024] Table 1. Design variables and value ranges of the channel-type angle-of-attack design device.

[0025]

[0026] Step 2: Based on the test sample's mass, center of mass position, moment of inertia in the pitch direction relative to the center of mass, impact velocity, impact angle of attack requirements, and test facility conditions provided by the test client, determine the skid separation scheme;

[0027] Step 3: Based on the kinematic and dynamic equations of the rigid body, estimate the design range parameters of the test specimen's preset angle of attack, heading velocity at the moment of skid separation, and aerodynamic overturning moment to meet the test requirements.

[0028] Step 4: Based on the estimated aerodynamic overturning torque required for the test sample at the moment of separation of the rocket skid, select values ​​for the three parameters S1, α, and S2, and design the initial rocket skid channel-type angle of attack design device.

[0029] Step 5: Establish an aerodynamic simulation model of the rocket skid, simulate the aerodynamic characteristics of the rocket skid system at the moment of skid separation, and obtain the aerodynamic drag, aerodynamic lift, aerodynamic overturning torque of the test object and the aerodynamic drag and aerodynamic lift of the rocket skid.

[0030] Step 6: Assuming that the aerodynamic characteristics of the test specimen and the rocket sled are the same at each moment after the separation of the missile and the rocket sled, based on the kinematic and dynamic equations of the rigid body and considering the constraint of the slide rail on the rocket sled, the position, velocity and attitude of the test specimen and the rocket sled at different moments from the separation of the missile and the landing of the test specimen are calculated by interpolation.

[0031] Step 7: Divide the azimuth distance from the separation of the missile skid to the landing point of the test specimen into equal segments. Calculate the simulation model of the second position of the segment. Read the aerodynamic drag, aerodynamic lift, and aerodynamic rollover moment of the test specimen and the aerodynamic drag and aerodynamic lift of the rocket skid. Perform interpolation calculations between the separation position of the missile skid and the second position of the segment, and extrapolate the position, velocity, and attitude of the test specimen and the rocket skid at the third segment point. Continue in this manner until the landing point of the test specimen to obtain the angle of attack of the test specimen.

[0032] Step 8: Determine whether the target angle of attack calculated in Step 7 is within the test requirements. If it is not within the range, re-estimate the aerodynamic overturning torque of the test specimen at the moment of separation of the skid based on the trend of the angle of attack change. According to the law that the aerodynamic overturning torque of the test specimen increases with the increase of S1, increases with the increase of α, and decreases and then increases with the increase of S2, select the values ​​of the three parameters S1, α, and S2 to obtain a new angle of attack design device, and return to Step 5; if it is within the range, determine the values ​​of the three parameters S1, α, and S2 as the final design values.

[0033] The beneficial effects of this invention are as follows:

[0034] 1. The advantage of this invention is that it establishes for the first time a test specimen angle of attack design device and method for a 3Ma~5Ma dual-track rocket sled test platform, which makes the aerodynamic lift and aerodynamic overturning torque of the test specimen more reasonable and solves the problem of test specimen angle of attack control in 3Ma~5Ma dual-track rocket sled tests.

[0035] 2. Another advantage of this invention is that, for dual-rail rocket skids with different shapes and higher operating speeds than traditional truss-type dual-rail rocket skids, a pressure relief channel is designed on the skid for the first time. By changing the parameters of the pressure relief channel, the airflow and pressure between the test sample and the rocket skid can be effectively adjusted, thereby alleviating the degree of airflow obstruction.

[0036] 3. The advantages of this invention also lie in the fact that the designed channel-type angle of attack design device can achieve different angle of attack requirements for test specimens with different parameters by adjusting only three design variable parameters. Moreover, the changing trend of the aerodynamic overturning torque of the test specimen under the influence of these three design variables is known, and the design values ​​of the variables are easy to determine.

[0037] 4. Another advantage of this invention is that the device has a simple structure and is easy to process and install. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a 3Ma to 5Ma dual-rail rocket skid using the angle-of-attack design device of the present invention.

[0039] Figure 2 This is a schematic diagram of the aerodynamic shape of the device of the present invention.

[0040] Figure 3 This is a diagram illustrating the design variables of this invention.

[0041] Figure 4 This is an example of a rocket sled according to an embodiment of the present invention.

[0042] Wherein: 1-Front crossbeam; 2-Rear skin of front crossbeam; 3-Front column; 4-Yaw tube; 5-Upper triangular rectifier; 6-Middle crossbeam; 7-Large inclined plane rectifier; 8-Airflow channel side plate; 9-Rear skin of middle crossbeam; 10-Rear column; 11-Rocket engine rectifier cap; 12-Rocket engine oblique rectifier; 13-Exhaust channel; 14-Test warhead; 15-Rocket skid; 16-Rocket engine. Detailed Implementation

[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0044] The purpose of this invention is to address the problem that the large-slope drag-reduction structure in the design of dual-rail rocket sleds operating at speeds of 3 to 5 Mach results in excessive aerodynamic rollover torque in the nose-down direction, making it difficult to achieve the required angle of attack for target landing in end-effect rocket sled tests. This invention provides an angle of attack design device and method that reduces the contraction channel effect between the test subject and the rocket sled, effectively ensuring the test subject's flight attitude after sled separation and meeting the required angle of attack for target landing. Specifically, it is a channel-type angle of attack design device and method for mesonic dual-rail rocket sleds.

[0045] This invention is a channel-type device and method designed to achieve the required angle of attack of the test subject by designing a large inclined plane rectification structure between the front crossbeam of a dual-rail rocket skid suitable for 3Ma to 5Ma rocket skid tests and the front end face of the rocket engine to reduce the aerodynamic drag of the rocket skid.

[0046] Here, the direction of the rocket sled's movement is defined as the heading, the direction perpendicular to the heading and with the plumb bob pointing upwards is the longitudinal direction, and the direction perpendicular to the plane formed by the heading and the longitudinal direction and pointing to the left of the heading is the span.

[0047] like Figure 1 and Figure 2 As shown, the design method of this device is to remove the skin and inner stiffener plate of the large inclined plane rectifier structure located directly below the test object, and install skin on the exposed internal structure of the rocket skid chassis and the inner side of the large inclined plane rectifier after the plates are removed to smooth the airflow. A certain length of venting channel is opened in the middle of the flight path so that some airflow flows through it to the bottom of the rocket skid chassis, further reducing the degree of airflow obstruction in the channel formed between the test object and the rocket skid. A rectifier structure is designed in front of the rocket engine to reduce the aerodynamic drag on the rocket engine.

[0048] The invention is achieved by the following: the device is symmetrical about the spanwise midsection of the rocket sled system, extending from the front end of the product sled to the rear end of the product sled. There are three crossbeams on the product sled chassis: front, middle, and rear. The front and rear crossbeams are located at the front and rear ends of the product sled, respectively, and are the main load-bearing components. Their azimuth length and longitudinal height are 0.12m and 0.086m, respectively. The middle crossbeam is used to share the support reaction force of the sliding shoes of the front and rear crossbeams. Its azimuth length and longitudinal height are 0.1m and 0.086m, respectively. The front end of the middle crossbeam is 1m away from the rear end of the front crossbeam, and the front end of the rear crossbeam is 2.06m away from the rear end of the front crossbeam.

[0049] The invention further comprises the following: the venting channel is located between the front crossbeam and the middle crossbeam. A skin is designed behind the front crossbeam to smooth the airflow after passing through the front crossbeam of the rocket sled. Its end is welded to the inner support surface of the front column of the rocket sled and the directional rectangular tube below the front column. The directional distance S1 from the rear end face of the front crossbeam is between 0.2m and 0.3m to ensure structural strength. The outer height of the skin is the same as the height of the front crossbeam. An upper triangular rectifier structure is designed in front of the middle crossbeam. The height of the rectifier structure is the same as the height of the middle crossbeam. To ensure effective venting, α is set between 20° and 70°.

[0050] The invention is further realized by the fact that a directional rectangular tube is designed in the middle of the airflow channel to ensure the rigidity of the rocket skid.

[0051] The invention is further realized by the following: the airflow channel between the middle crossbeam and the rear crossbeam is constructed by establishing a wedge-shaped rectifier and a rectifier cap in front of the exposed front end face of the rocket engine, which is required to completely cover the mounting ring of the rocket engine. The rectifier direction starts from the rear column of the rocket skid and is welded to the inner support surface of the rear column and the spanwise rectangular tube below the rear column, which can ensure the structural strength. Therefore, the directional distance of the wedge-shaped rectifier from the rear end face of the front crossbeam is between 1.65m and 1.735m.

[0052] The invention is further realized in that: the front side of the device is on the same plane as the inner support surface of the front column of the rocket sled, with a flow channel width of 0.46m; the rear side is on the same plane as the inner support surface of the rear column of the rocket sled, with a flow channel width of 0.7m; the inner support surfaces of the front and rear columns are connected by a steel plate to form the middle side; the spanwise position of the inner support surface of the rear column of the rocket sled is outside the spanwise position of the inner support surface of the front column; the steel plate is bent during installation to form a flow expansion channel, which slows down the gas and reduces the aerodynamic lift force on the tail of the test sample; the change in the bending position affects the upper surface area of ​​the large inclined plane rectification, thereby affecting the aerodynamic lift force on the rocket sled and the vibration and wear of the skid; in order to ensure the operational safety of the rocket sled, the bending position is set at a directional distance of 0.67m from the rear end face of the front crossbeam.

[0053] like Figure 3 As shown in Table 1, the design variables and value ranges of the channel-type angle-of-attack design device formed by the present invention are as follows: S1 is the directional distance between the rear end face of the skin behind the front crossbeam and the rear end face of the front crossbeam; α is the angle of the upper triangular rectifying structure in front of the middle crossbeam; and S2 is the directional distance between the front end of the rocket engine wedge-shaped rectifying structure and the rear end face of the front crossbeam. The design method includes the following steps:

[0054] 1. Based on the requirements provided by the client regarding the mass of the test specimen, the position of its center of mass, the moment of inertia in the pitch direction relative to the center of mass, the impact velocity, the angle of attack, and other requirements, as well as the conditions of the test facilities, determine the skid separation scheme.

[0055] 2. Based on the kinematic and dynamic equations of rigid bodies and with sufficient safety margin, preliminarily estimate parameters such as the pre-set angle of attack of the test specimen, the heading velocity at the moment of separation of the skid and the design range of the aerodynamic overturning moment of the test specimen to meet the test requirements.

[0056] 3. Based on the estimated aerodynamic overturning torque required for the test sample at the moment of separation of the rocket skid, the values ​​of three parameters, namely S1, α, and S2, are selected, and the initial rocket skid channel-type angle of attack design device is designed.

[0057] 4. Establish an aerodynamic simulation model of the rocket skid to simulate the aerodynamic characteristics of the rocket skid system at the moment of skid separation, and obtain the aerodynamic drag, aerodynamic lift, aerodynamic overturning torque of the test object and the aerodynamic drag and aerodynamic lift of the rocket skid.

[0058] 5. Assuming that the aerodynamic characteristics of the test specimen and the rocket sled are the same at each moment after the separation of the missile and the sled, based on the kinematic and dynamic equations of the rigid body and considering the constraint of the slide rail on the rocket sled, the position, velocity and attitude of the test specimen and the rocket sled at different moments from the separation of the missile and the landing of the test specimen are calculated by interpolation.

[0059] 6. Divide the azimuth distance from the separation of the missile skid to the impact point of the test specimen into equal segments. Calculate the simulation model of the second position of each segment. The simulation model must reflect the attitude and relative position of the test specimen and the rocket skid. Read the aerodynamic drag, aerodynamic lift, and aerodynamic rollover moment of the test specimen, and the aerodynamic drag and aerodynamic lift of the rocket skid. Perform interpolation calculations between the separation position of the missile skid and the second position of the segment, and extrapolate the position, velocity, and attitude of the test specimen and the rocket skid at the third segment point. Continue in this manner until the impact point of the test specimen, and obtain the angle of attack of the test specimen.

[0060] 7. Determine whether the target angle of attack calculated in step 6 is within the test requirements. If it is not within the range, re-estimate the aerodynamic overturning torque of the test specimen at the moment of separation of the skid based on the trend of the angle of attack. According to the law that the aerodynamic overturning torque of the test specimen increases with the increase of S1, increases with the increase of α, and decreases and then increases with the increase of S2, select the values ​​of the three parameters S1, α, and S2 to obtain a new angle of attack design device, and return to step 4. If it is within the range, determine the values ​​of the three parameters S1, α, and S2 as the final design values.

[0061] The realization of this invention also lies in the fact that the range of values ​​for the design variables is determined by the effectiveness of the venting channel, the structural strength of the rocket skid, and the operational safety of the rocket skid.

[0062] The invention is further realized in that the shape and position relationship between the test sample and the rocket skid is also a factor affecting the aerodynamic overturning torque of the test sample. Therefore, the stepwise segmented interpolation method in step 6 takes into account this influencing factor and can more accurately predict the target attack angle of the test sample. Specific implementation examples:

[0064] This invention relates to a device and method for designing the target angle of attack of a test subject in a dual-track rocket sled with a large inclined plane rectifying structure operating at speeds of 3Ma to 5Ma, further achieving the experimental objective of the terminal effect test of a mesonic dual-track rocket sled.

[0065] A certain warhead has a mass of 1210 kg and a moment of inertia of 460 kg·m about its center of mass in the pitch direction. 2 It is necessary to conduct rocket skid tests with a target velocity of 1200m / s±30m / s and a target attack angle of -3° to +3°.

[0066] To prevent interference between the rocket skid and the warhead after separation, the separation mechanism was designed with a separation speed of 1200 m / s. Upon passing the electric grid, the fixed constraints on the warhead and rocket skid are released, allowing the warhead to fly freely under aerodynamic forces. The rocket skid, constrained by the rails and under aerodynamic forces, moves along a 2-meter straight rail followed by a 15-meter curved rail (radius 1200 m). The skid then slides off the curved track, and the warhead travels 6.5 meters before impacting the target. During the test, the atmospheric pressure was 0.86 atm, the temperature was 15℃, and the air density was 1.08 kg / m³. 3 .

[0067] Simulation calculations show that without this channel-type angle-of-attack design device, the aerodynamic overturning torque of the warhead can reach -180,000 N·m when the rocket skid is running at a speed of 1200 m / s. After the skid separates and flies for 23.5 m, the warhead's angle of attack will diverge to 4.95°, which does not meet the test requirements.

[0068] Therefore, it is necessary to design the channel-type angle of attack design device of this invention to achieve the target angle of attack required for testing. In this example, the design steps of the angle of attack design device are as follows:

[0069] Step 1: Based on the requirements of warhead mass, center of gravity position, moment of inertia in the pitch direction about the center of gravity, impact velocity, and angle of attack, determine the directional distance between the warhead at the skid separation point and the impact point to be 23.5m.

[0070] Step 2: Based on the kinematic and dynamic equations of rigid bodies, and with sufficient safety margins for the target impact velocity and angle of attack, the warhead's pre-set angle of attack of 0° and the heading speed at the moment of skid separation are initially estimated to be 1200 m / s, and the aerodynamic rollover torque design range is -8000 N·m to +8000 N·m.

[0071] Step 3: Based on the estimated aerodynamic overturning torque required by the warhead at the moment of missile separation, S1 is set to 0.3m, α to 30°, and S2 to 1.68m, design the initial rocket skid channel angle of attack design device.

[0072] Step 4: Establish an aerodynamic simulation model of the rocket skid to simulate the aerodynamic characteristics of the rocket skid system at the moment of separation of the missile and skid, and obtain the aerodynamic drag, aerodynamic lift, and aerodynamic overturning torque of the warhead, as well as the aerodynamic drag and aerodynamic lift of the rocket skid, as shown in Table 2.

[0073] Table 2 Aerodynamic characteristics of the rocket skid system at the moment of skid separation.

[0074] Step 5: Assuming that the aerodynamic characteristics of the warhead and rocket skid are the same at each moment after the separation of the warhead and the rocket skid, based on the kinematic and dynamic equations of rigid bodies and considering the constraint of the slide rail on the rocket skid, the position, velocity and attitude of the warhead and rocket skid at different moments from the separation of the warhead and the impact of the warhead are calculated by interpolation. Among them, considering the factor of equidistant segmentation, the calculation is up to the position 25m after the separation of the warhead and the rocket skid, as shown in Table 3.

[0075] Table 3 shows the preliminary calculations of changes in warhead and skid flight parameters at various time points.

[0076]

[0077] Step 6: Divide the azimuth distance from the separation of the missile skid to the impact of the warhead into 5 equal segments, each 5m apart. Calculate the simulation model of the second position in each segment, and read the aerodynamic drag, aerodynamic lift, and aerodynamic rollover moment of the warhead, as well as the aerodynamic drag and aerodynamic lift of the rocket skid. Perform interpolation calculations between the separation position of the missile skid and the second position in each segment, and extrapolate the position, velocity, and attitude of the warhead and rocket skid at the third segment point. Continue this process until the warhead impact point. The calculation results are shown in Tables 4 and 5, where Table 4 shows the aerodynamic characteristic parameters of the rocket skid system at each position, and Table 5 shows the changes in the flight parameters of the warhead and skid at each moment during the interpolation calculation for the entire segment.

[0078] Step 7: The warhead's target attack angle calculated in Step 6 is -0.20°, which is within the range of -3° to +3° required by the test, and has a large safety margin. Therefore, the values ​​of the three parameters S1, α, and S2 are determined to be S1 = 0.3m, α = 30°, and S2 = 1.68m.

[0079] Table 4 Aerodynamic characteristic parameters of rocket skid system at various locations

[0080]

[0081] Table 5 shows the changes in warhead and skid flight parameters at each moment based on the interpolation calculations for the entire segment.

[0082]

[0083] The angle-of-attack design device and rocket sled test platform in this embodiment are as follows: Figure 4 As shown, the test results show that the warhead landed on the target at a speed of 1209.23 m / s and an angle of attack of 0°, which meets the requirements for landing speed and angle of attack.

Claims

1. A channel-type angle-of-attack design device, characterized in that, This includes the skin, bleed channel, yaw tube, upper triangular rectifier structure, front crossbeam, middle crossbeam, rear crossbeam, wedge rectifier, and rectifier cap; Define the direction of the rocket sled's movement as the heading; The direction perpendicular to the heading and with the plumb line pointing upwards is the longitudinal direction; the direction perpendicular to the plane formed by the heading and the longitudinal direction and pointing to the left of the heading is the span. The channel-type angle-of-attack design device is symmetrical about the spanwise midsection of the rocket skid system, extending from the front end of the product skid to the rear end of the product skid; a front crossbeam, a middle crossbeam, and a rear crossbeam are provided on the product skid chassis, located at the front, middle, and rear ends of the product skid, respectively; the middle crossbeam is used to share the support reaction force of the sliding shoes of the front and rear crossbeams; The drainage channel is located between the front crossbeam and the middle crossbeam; The skin is located behind the front crossbeam and is used to smooth the airflow after passing the front crossbeam of the rocket skid. The end of the skin is welded to the inner support surface of the front column of the rocket skid and the yaw rectangular tube below the front column. The outer height of the skin is the same as the height of the front crossbeam. The upper triangular rectifier structure is located in front of the middle crossbeam, and the height of the upper triangular rectifier structure is the same as the height of the middle crossbeam. The yaw tube is located in the middle of the spanwise direction of the airflow channel to ensure the rigidity of the rocket skid; A wedge-shaped rectifier and rectifier cap are built in front of the rocket engine to completely cover the mounting ring of the rocket engine. The rectifier heading starts from the rear column of the rocket skid and is welded to the inner support surface of the rear column and the spanwise rectangular tube below the rear column. The front side of the channel-type angle-of-attack design device is on the same plane as the inner support surface of the front column of the rocket sled, and the rear side is on the same plane as the inner support surface of the rear column of the rocket sled. The inner support surfaces of the front and rear columns are connected by steel plates to form the middle side. The spanwise position of the inner support surface of the rear column of the rocket sled is outside the spanwise position of the inner support surface of the front column. The steel plate is bent during installation to form a flow-expanding channel, which slows down the gas and reduces the aerodynamic lift force on the tail of the test sample.

2. The channel-type angle-of-attack design device according to claim 1, characterized in that, The azimuth length and longitudinal height of the front and rear crossbeams are 0.12m and 0.086m respectively, and the azimuth length and longitudinal height of the middle crossbeam are 0.1m and 0.086m respectively. The front end face of the middle crossbeam is 1m away from the rear end face of the front crossbeam, and the front end face of the rear crossbeam is 2.06m away from the rear end face of the front crossbeam.

3. The channel-type angle-of-attack design device according to claim 1, characterized in that, The directional distance between the rear end face of the skin and the rear end face of the front crossbeam is between 0.2m and 0.3m.

4. The channel-type angle-of-attack design device according to claim 1, characterized in that, The angle of the triangular rectifier structure ranges from 20° to 70°.

5. The channel-type angle-of-attack design device according to claim 1, characterized in that, The distance between the wedge-shaped rectifier and the rear end face of the front crossbeam is between 1.65m and 1.735m.

6. The channel-type angle-of-attack design device according to claim 1, characterized in that, The front side of the channel-type angle of attack design device is on the same plane as the inner support surface of the front column of the rocket skid, with a flow channel width of 0.46m. The rear side is on the same plane as the inner support surface of the rear column of the rocket skid, with a flow channel width of 0.7m.

7. The channel-type angle-of-attack design device according to claim 1, characterized in that, The bending position is defined as a 0.67m directional distance from the rear end face of the front crossbeam.

8. The design method of the angle-of-attack design device as described in claim 1, characterized in that, Includes the following steps: Step 1: Define S1 as the directional distance between the rear skin of the front crossbeam and the rear face of the front crossbeam, α as the angle of the upper triangular rectifier structure in front of the middle crossbeam, and S2 as the directional distance between the front end of the rocket engine wedge rectifier and the rear face of the front crossbeam. The design variables and value ranges of the channel-type angle of attack design device are shown in Table 1. Table 1. Design variables and value ranges of the channel-type angle-of-attack design device. Step 2: Based on the test sample's mass, center of mass position, moment of inertia in the pitch direction relative to the center of mass, impact velocity, impact angle of attack requirements, and test facility conditions provided by the test client, determine the skid separation scheme; Step 3: Based on the kinematic and dynamic equations of the rigid body, estimate the design range parameters of the test specimen's preset angle of attack, heading velocity at the moment of skid separation, and aerodynamic overturning moment to meet the test requirements. Step 4: Based on the estimated aerodynamic overturning torque required for the test sample at the moment of separation of the rocket skid, select values ​​for the three parameters S1, α, and S2, and design the initial rocket skid channel angle of attack design device. Step 5: Establish an aerodynamic simulation model of the rocket skid, simulate the aerodynamic characteristics of the rocket skid system at the moment of skid separation, and obtain the aerodynamic drag, aerodynamic lift, aerodynamic overturning torque of the test object and the aerodynamic drag and aerodynamic lift of the rocket skid. Step 6: Assuming that the aerodynamic characteristics of the test specimen and the rocket sled are the same at each moment after the separation of the missile and the rocket sled, based on the kinematic and dynamic equations of the rigid body and considering the constraint of the slide rail on the rocket sled, the position, velocity and attitude of the test specimen and the rocket sled at different moments from the separation of the missile and the landing of the test specimen are calculated by interpolation. Step 7: Divide the azimuth distance from the separation of the missile skid to the landing point of the test specimen into equal segments. Calculate the simulation model of the second position of the segment. Read the aerodynamic drag, aerodynamic lift, and aerodynamic rollover moment of the test specimen and the aerodynamic drag and aerodynamic lift of the rocket skid. Perform interpolation calculations between the separation position of the missile skid and the second position of the segment, and extrapolate the position, velocity, and attitude of the test specimen and the rocket skid at the third segment point. Continue in this manner until the landing point of the test specimen to obtain the angle of attack of the test specimen. Step 8: Determine whether the target angle of attack calculated in Step 7 is within the test requirements. If it is not within the range, re-estimate the aerodynamic overturning torque of the test specimen at the moment of separation of the skid based on the trend of the angle of attack change. According to the law that the aerodynamic overturning torque of the test specimen increases with the increase of S1, increases with the increase of α, and decreases and then increases with the increase of S2, select the values ​​of the three parameters S1, α, and S2 to obtain a new angle of attack design device, and return to Step 5; if it is within the range, determine the values ​​of the three parameters S1, α, and S2 as the final design values.

Images