Pre-tightening force loading method for ground static firing test of large-thrust solid rocket engine

Abstract

The application provides a pre-tightening force loading method for ground static ignition test of a large-thrust solid rocket engine, adopts a pre-tightening force loading device with a double ball head and a ball socket matching structure form, and ensures that the loading force direction is coaxial with the engine combustion chamber. When in use, two pre-tightening force loading devices are required, which are symmetrically arranged on the two sides of a force bearing assembly and a force measuring assembly relative to the engine combustion chamber axis, and are installed between a force bearing wall and a transition frame to implement the pre-tightening force loading scheme. The axial length of the pre-tightening force loading device can be adjusted within a certain range, the sensor is subjected to the expected force value by adjusting the force bearing assembly, and the pre-tightening force loading device bears the axial direction tension force at this time. The application solves the pre-tightening force loading problem of the large-thrust engine, and the rationality of the scheme is verified through the engine ignition test verification. The force loading method is reliable, the force value loading is stable, and the requirements of the pre-tightening force loading of the ground ignition test of the large-thrust solid rocket engine are met.

Description

Technical Field

[0001] This invention belongs to the field of thrust measurement technology for ground static ignition tests of solid rocket engines, specifically relating to a preload loading method for ground static ignition tests of high-thrust solid rocket engines, which can be widely applied to preload loading in ground ignition tests of solid rocket engines. Background Technology

[0002] Thrust, as a crucial performance parameter of solid rocket engines, is the most important test parameter in ground ignition tests. Due to factors such as test frame installation and assembly clearances between load-bearing and thrust components (connection clearances, thread clearances, machining errors, installation and debugging errors), preload loading is typically implemented during ground ignition tests of high-thrust solid rocket engines to eliminate thrust measurement errors caused by these factors, thereby ensuring the accuracy and safety of thrust measurements.

[0003] Currently, commonly used pre-tightening devices are made of steel wire ropes and springs. These methods can help eliminate errors to some extent during ground ignition tests of small-thrust solid rocket engines. However, they cannot eliminate the influence of assembly gaps before ignition for China's largest, heaviest, and most powerful solid rocket engine (3.5 meters in diameter, 160 tons in weight, and up to 500 tons in thrust).

[0004] Therefore, it is necessary to design a new preload loading method to ensure the accurate and reliable conduct of solid rocket engine thrust experiments, and to provide more effective test data and technical support for engine development. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that existing preload loading devices cannot eliminate the influence of assembly gaps before ignition of high-thrust solid rocket engines, which easily leads to problems with the accuracy and safety of thrust measurement. This invention provides a preload loading method for ground static ignition tests of high-thrust solid rocket engines.

[0006] To achieve the above objectives, the technical solution provided by this invention is:

[0007] The preload loading method for ground static ignition tests of high-thrust solid rocket engines is characterized by the following steps:

[0008] 1) The two preload loading devices are respectively set on both sides of the load-bearing component and the force measuring component, and the two preload loading devices are symmetrically set with respect to the engine axis;

[0009] The installation height of the preload loading device at the end furthest from the engine is higher than that at the end closest to the engine.

[0010] 2) Adjust the length of the preload loading device, make sure the two preload loading devices are adjusted to the same length, and ensure that the preload loading devices are in a straight state before ignition to apply the preload.

[0011] Furthermore, the preload loading device includes a first ball socket, a first ball head, an adjusting rod, a second ball head, and a second ball socket;

[0012] The first ball head and the second ball head are respectively installed at both ends of the adjusting rod;

[0013] The first ball head and the second ball head are respectively fitted into the first ball socket and the second ball socket, and can rotate omnidirectionally within them.

[0014] Furthermore, the first ball head and the second ball head are respectively threaded to both ends of the adjusting rod, and their positions on the adjusting rod are adjustable.

[0015] The beneficial effects of this invention are:

[0016] 1. The pre-tightening device used in the pre-tightening method of this invention has a novel and ingenious structure with axial length adjustment function. It is not only convenient to install and debug, but also combines rigidity and flexibility in use, and the force value is controllable (that is, the magnitude of the loading force value can be adjusted according to the actual needs of thrust measurement). When the pre-tightening device is tightened, it can eliminate the influence of the gap between the load-bearing component and the ball head of the force sensor, prevent the impact on the force sensor at the moment of engine ignition, reduce the impact on engine thrust measurement, and improve the thrust measurement accuracy. When it is loosened, it can be controlled within a certain range so as to protect the test components (such as: precision parts of the sensor) in case of unexpected situations, thus improving safety.

[0017] 2. This invention proposes a novel preload loading device, and for the first time designs a preload loading device with a double ball-and-socket structure, which solves the problem of preload loading and meets the thrust preload loading requirements for ground ignition tests of high-thrust engines.

[0018] 3. The preload loading method of the present invention takes into account the thermal expansion of the housing during engine ignition. When installing the preload loading device, the end away from the engine is installed at a height higher than the engine axis, while the other end is directly installed on the engine axis. Generally, the height is controlled at about the amount of engine expansion to ensure that the preload loading device is in a relaxed state during the test. Attached Figure Description

[0019] Figure 1 This is a structural diagram of the preload loading device of the present invention;

[0020] Figure 2 This is a three-dimensional view of the preload loading device of the present invention;

[0021] Figure 3This is a structural diagram of the adjusting rod in the preload loading device of the present invention;

[0022] Figure 4 This is a structural diagram of the adjusting base in the preload loading device of the present invention;

[0023] Figure 5 This is a structural diagram of the ball head in the preload loading device of the present invention;

[0024] Figure 6 This is a structural diagram of the ball socket in the preload loading device of the present invention;

[0025] Figure 7 This is a structural diagram of the force measurement assembly used in a ground ignition test of a high-thrust solid rocket engine.

[0026] Figure 8 This is a structural diagram of the load-bearing components used in the ground ignition test of a high-thrust solid rocket engine.

[0027] Figure 9 for Figure 8 3D diagram of the load-bearing component;

[0028] Figure 10 This is a schematic diagram showing the assembly relationship between the load-bearing components and the force-measuring components during a ground ignition test of a high-thrust solid rocket engine.

[0029] Figure 11 This is a schematic diagram of the actual installation of the preload loading device of the present invention. Figure 1 ;

[0030] Figure 12 This is a schematic diagram of the actual installation of the preload loading device of the present invention. Figure 2 ;

[0031] Figure 13 These are physical images of the various components of the preload loading device of the present invention;

[0032] Figure 14 This is a schematic diagram of the installation state of the preload loading device of the present invention.

[0033] The attached figures are labeled as follows:

[0034] 1-Adjusting base, 2-First ball socket, 3-First ball head, 4-Adjusting rod, 5-Second ball head, 6-Second ball socket, 7-Bearing wall, 8-Bearing plate, 9-Bearing component, 10-Force measuring component, 11-Thrust sensor ball cap, 12-Thrust sensor, 13-Flange, 14-Transition frame top plate.

[0035] The dimensions in the diagram are in mm. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0037] To eliminate the influence of internal thread clearance in the load-bearing component and the gaps between the load-bearing component and the sensor ball joint, and between the sensor ball joint and the sensor, and to prevent the impact on the sensor at the moment of engine ignition, a preload loading device with a double ball joint and ball-and-socket fit was designed. For example... Figure 1-6 As shown, the preload loading device (part 13) adopts a combination structure with a double ball head and ball socket structure, mainly including an adjusting base, a first ball socket, a first ball head, an adjusting rod, a second ball head, and a second ball socket.

[0038] The adjusting rod has a reference part in the middle and external threads at both ends.

[0039] Both the first and second ball heads include a head and a tail connected coaxially. The head is a hemispherical shape with its bottom cut off (its cross-sectional outline along the axis resembles an isosceles trapezoid with outwardly convex arcs on its sides, i.e., the two sides are outwardly convex arcs, and the entire outer circumference of the head is an arc surface). The tail is a cylindrical shape (which can be cylindrical or nut-shaped) with internal threads, one end of which is connected to the small end of the head and communicates with the inside of the head. The inside of the head is provided with a stepped through hole, including a first stepped hole and a second stepped hole. The first stepped hole is located near the tail and its diameter is equal to the diameter of the through hole in the tail. The diameter of the second stepped hole is larger than the diameter of the first stepped hole, and the step of the stepped hole is chamfered.

[0040] Both the first and second ball sockets include a coaxially connected and interconnected main body and base. The main body, from the end closest to the base to the end furthest from the base, consists of a first segment, a second segment, a third segment, and a fourth segment. The diameter of the through-hole in the first segment is equal to the diameter of the through-hole in the base. The through-hole in the second segment fits the outer circumferential surface of the ball head, and the larger end diameter of this through-hole is smaller than the diameter of the first segment through-hole, facilitating the installation and removal of the ball head. The diameter of the through-hole in the third segment is equal to the smaller end diameter of the second segment through-hole. The through-hole in the fourth segment is outwardly flared, meaning its diameter gradually increases from the inside out, facilitating the omnidirectional rotation of the ball head within the socket. The base is square, with mounting holes at each of its four corners.

[0041] The adjusting base is a cuboid or cube with two square faces. Stepped through holes are formed inside the adjusting base along the direction of the square faces. One square face has a strip-shaped hole, and the other square face has a circular hole. The diameter of each sub-through hole of the stepped through hole increases sequentially from the strip-shaped hole to the circular hole. Mounting holes are also provided on the adjusting base at positions corresponding to the mounting holes of the first ball-and-socket base.

[0042] The first ball head and the second ball head of each preload loading device are threadedly connected to both ends of the adjusting rod, and the first ball head and the second ball head are respectively fitted into the first ball socket and the second ball socket, and can rotate omnidirectionally therein; wherein, the first ball socket is installed on the adjusting base.

[0043] Function and usage of preload loading device:

[0044] An installation diagram of the preload loading device of the present invention is shown below. Figure 11 and 12 In use, a preload loading device is installed on each side of the load-bearing component and the force-measuring component, with the two preload loading devices symmetrically arranged relative to the engine axis. The structure and assembly relationship of the load-bearing component and the force-measuring component are as follows: Figures 7-10 as well as Figure 13 As shown, the installation status of the preload loading device is as follows: Figure 14 As shown:

[0045] The loading method using a preload loading device specifically includes the following steps:

[0046] 1) Two preload loading devices are respectively set on both sides of the load-bearing component and the force-measuring component, and the two preload loading devices are symmetrical components with respect to the engine axis.

[0047] The adjusting base of each preload loading device is installed on the load-bearing plate (which is installed on the load-bearing wall) of the load-bearing assembly for the ground static ignition test of the high-thrust solid rocket engine, and the second ball socket is installed on the top plate of the transition frame for the ground static ignition test of the high-thrust solid rocket engine.

[0048] 2) Before the test (i.e. before ignition), adjust the length of the preload loading device, use the reference part on the adjusting rod to ensure that the adjusted lengths of the two preload loading devices are consistent, and use the operator to rotate the top plate of the load-bearing component with a calibrating rod to apply a predetermined force value to the sensor in the direction of the engine axis. Both preload loading devices are in a tensioned state (i.e., the ball head cannot rotate relative to the ball socket) to perform preload loading.

[0049] Considering the thermal expansion of the housing during engine ignition, the installation position of the preload loading device adjustment base needs to be adjusted so that its installation position is slightly higher than the engine axis (slightly higher than the horizontal position, i.e., slightly higher than the installation position of the second ball socket, which is installed on the engine axis). Figure 14As shown, for example, the maximum radial deformation of the engine cylinder section is 20mm. Since the housing will expand during the engine ignition process, the expansion is estimated at 20mm. The axis of the transition frame will move upward as the housing expands. Before the test, the front end of the preload adjustment device (i.e. the end closest to the load-bearing wall) is about 20mm higher than the rear end to ensure that the preload loading device is in a relaxed state during the test (i.e., whether the ball head can rotate in the ball socket).

[0050] 3) When the engine is ignited, the sensor is subjected to the thrust of the engine, and the preload loading device is in a relaxed state. At this time, within a certain range, the preload loading device still has a certain protective function for the test object and the parts used. If a deviation occurs, it can be pulled back.

[0051] After the ignition test is finally completed, the engine thrust drops to zero, the thrust sensor returns to zero, and the preload loading device is in a relaxed state.

[0052] This invention relates to a preload loading device employing a double-ball-head and ball-and-socket joint structure. Its axial length is adjustable within a certain range, ensuring the loading force direction is coaxial with the engine combustion chamber. In use, two preload loading devices are required, symmetrically positioned on either side of the load-bearing component and the force-measuring component relative to the engine combustion chamber axis. They are installed between the load-bearing wall and the transition frame to implement the preload loading scheme, subjecting the force sensor to a preset force value. At this point, the preload loading device bears tensile force in the axial direction. The axial length of this preload loading device is adjustable within a certain range. By adjusting the load-bearing component, the sensor receives the expected force value, and the preload loading device bears tensile force in the axial direction. This invention solves the preload loading problem for high-thrust engines. Engine ignition tests have verified the rationality of this scheme, demonstrating reliable loading methods, stable force loading, and meeting the preload loading requirements for ground ignition tests of high-thrust solid rocket engines.

[0053] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A preload loading method for ground static ignition tests of high-thrust solid rocket engines, characterized in that, The preload loading device includes a first ball socket, a first ball head, an adjusting rod, a second ball head, and a second ball socket; The first ball head and the second ball head are respectively installed at both ends of the adjusting rod; The first ball head and the second ball head are respectively fitted into the first ball socket and the second ball socket, and can rotate omnidirectionally therein; The preload method includes the following steps: 1) The two preload loading devices are respectively set on both sides of the load-bearing component and the force measuring component, and the two preload loading devices are symmetrically set with respect to the engine axis; The installation height of the preload loading device at the end furthest from the engine is higher than that at the end closest to the engine. 2) Adjust the length of the preload loading device, make sure the two preload loading devices are adjusted to the same length, and ensure that the preload loading devices are in a straight state before ignition to apply the preload.

2. The preload loading method for ground static ignition tests of high-thrust solid rocket engines according to claim 1, characterized in that: The first ball head and the second ball head are respectively threaded to both ends of the adjusting rod, and their positions on the adjusting rod are adjustable.

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