A scaled-down model ground test device and method for simulating rocket stage separation

Abstract

A scaled-down model ground test device for simulating rocket stage separation, comprising: a test bench foundation for bearing the inter-stage section and the cylinder; an inter-stage section with a scaled-down engine installed at one end, a front head installed at the other end, and a detonating cord installed in the middle for splitting the inter-stage section; a thrust measuring device for resisting the scaled-down engine to measure the ignition thrust and transmitting it to the data acquisition system; a thrust ejector rod installed between the cylinder and the front head, and when the thrust ejector rod receives the thrust from the front head, it moves to pierce the pressure relief diaphragm on the cylinder, causing the cylinder to relieve pressure; an ignition device for igniting the detonating cord; a synchronization device for synchronizing the ignition signal and the data acquisition signal; and a data acquisition system for measuring and collecting temperature and pressure data.

Description

Technical Field

[0001] The present invention relates to a ground test device and method for a scaled-down model of simulating rocket stage separation, and particularly to a study of the influence of the tail flame and the residual thrust of the first stage on the trajectory and flight ballistic generated under the combined action of the second stage after the ignition of the second stage engine during the rocket stage separation process. Background Art

[0002] During the development of rockets, in order to be able to send payloads to higher altitudes, it is necessary to adopt multi-stage rocket connection technology, so rockets need to be designed into multi-stage structures. Using multi-stage rockets is like a relay race, accelerating stage by stage to send spacecraft into Earth orbit. The connection of multi-stage rockets has three forms: series, parallel, and hybrid. If the stages of the rocket are connected end to end, it is a series connection; if the bodies of each stage are connected around the core body, it is a parallel connection; and the hybrid connection is a combination of series and parallel. For the convenience of connection and separation, some rockets also have inter-stage sections. The connection of each stage generally uses connection components such as explosive bolts, explosive cords, and positioning pins. During the rocket flight process, each stage starts and shuts down the engine according to program instructions, and then discards them in turn, thus reducing the energy consumption required for continued acceleration. The separation of multi-stage rockets can neither be too early nor too late, and it is not allowed to fail to separate when it should. This requires its separation to be timely, accurate, reliable, and safe. There are usually two methods: thermal separation and cold separation.

[0003] The basic procedure of thermal separation is: start the second stage engine, shut down the first stage engine, and detonate and break the connection components. Obviously, this separation mainly relies on the gas flow of the second stage rocket engine to decelerate the first stage after disconnecting the joint, and at the same time, the second stage is subjected to an axial overload before starting to ensure the reliability of starting, so it is very simple. However, during separation, the second stage will undoubtedly be subjected to greater disturbances and consume more propellants.

[0004] Cold separation is also called deceleration separation. Its separation instruction program is generally: the inter-stage connection components are detonated and disconnected, start the braking rocket or other braking devices of the first stage, and start the rocket engine of the second stage. In this case, the components of the inter-stage separation mechanism are few and light, and the working process will not be affected by large axial, lateral, vibration and other forces, so the separation appears stable. However, this separation method requires a higher precision for the control system.

[0005] When the inter-stage connection components are unlocked, the second stage engine ignites to generate acceleration, and the first stage is decelerated by the braking force, so a "safety distance" is formed between these two stages. The braking force of the first stage can be generated by installing devices such as braking rockets or reflecting nozzles. After they are put into work in a timely manner, it can avoid the collision caused by the first stage catching up with the second stage under the action of the after-effect thrust of the engine, and ensure the flight stability of the second stage after separation.

[0006] Typical inter-stage separation tests include: rocket sled separation, scaled model flight separation test, wind tunnel model inter-stage separation, and simulated loading separation test. The wind tunnel model inter-stage separation mainly examines the aerodynamic interaction during the separation process and belongs to a cold separation test with external flow. The simulated loading separation test, also known as the static test, mainly simulates the force conditions of each component during the separation process, and then a rocket sled or model flight separation test is carried out. The above test processes are all decoupled tests and cannot perform comprehensive data measurement. Summary of the Invention

[0007] The technical problem to be solved by the present invention is: to overcome the deficiencies of the prior art and solve the parameter measurement problem of rocket inter-stage separation.

[0008] The object of the present invention is achieved through the following technical solutions:

[0009] A scaled model ground test device for simulating rocket inter-stage separation, comprising:

[0010] A test bench foundation for bearing the inter-stage section and the cylinder;

[0011] An inter-stage section, with a scaled engine installed at one end, a front head installed at the other end, and a detonating cord installed in the middle for splitting the inter-stage section;

[0012] A thrust measurement device for resisting the scaled engine to measure the ignition thrust and transmitting it to the data acquisition system;

[0013] A thrust ejector rod installed between the cylinder and the front head, and when the thrust ejector rod receives the thrust from the front head, it moves to pierce the pressure relief diaphragm on the cylinder, causing the cylinder to relieve pressure;

[0014] An ignition device for igniting the detonating cord;

[0015] A synchronization device for synchronizing the ignition signal and the data acquisition signal;

[0016] A data acquisition system for measuring and collecting temperature and pressure data.

[0017] Preferably, the scaled engine is connected to the inter-stage section through a flange; the front head is connected to the inter-stage section through a flange.

[0018] Preferably, the temperature data at least includes the temperature inside the inter-stage section cavity and the temperature on the back of the front head.

[0019] Preferably, the pressure data at least includes the combustion chamber pressure of the scaled engine, the pressure inside the inter-stage section cavity, the pressure on the back of the front head, and the cylinder pressure.

[0020] Preferably, different residual thrusts are simulated by adjusting the pressure of the cylinder.

[0021] Preferably, it further includes a vacuum chamber for accommodating all other components and providing different degrees of vacuum environment.

[0022] Preferably, the vacuum chamber adjusts the vacuum degree inside the vacuum chamber according to the altitude to be simulated in the test.

[0023] Preferably, an absolute pressure sensor is selected when collecting pressure data.

[0024] A ground test method for a scaled-down model of simulating rocket stage separation, using the above test device, includes:

[0025] The data acquisition system starts to collect; the scaled-down engine; the detonating cord is ignited; the inter-stage section is separated; the thrust push rod breaks through the pressure relief diaphragm; the cylinder deflates; the test system finishes collecting; the test is completed.

[0026] A ground test method for a scaled-down model of simulating rocket stage separation, using the above test device, includes:

[0027] Adjust the vacuum degree inside the vacuum chamber according to the altitude to be simulated in the test;

[0028] The data acquisition system starts to collect; the scaled-down engine; the detonating cord is ignited; the inter-stage section is separated; the thrust push rod breaks through the pressure relief diaphragm; the cylinder deflates; the test system finishes collecting; the test is completed.

[0029] The present invention has the following beneficial effects compared with the prior art:

[0030] (1) The present invention uses a scaled-down inter-stage section model to simulate the ignition separation process and a scaled-down engine model to simulate the ignition of the second-stage engine, thereby measuring parameters such as the engine thrust, the reaction force of the first stage on the second stage, and the pressure and temperature during the inter-stage section separation process. It is a new ground test device for simulating rocket separation.

[0031] (2) The present invention uses the scaled-down inter-stage section and detonating cord, and uses a time control program to simulate the engine thrust and the ignition performance of the engine under high-altitude conditions during the engine ignition, inter-stage section blasting, and separation of the first and second stages.

[0032] (3) The present invention uses the simulation principle of the thrust push rod and simulates the remaining thrust of the first stage of the rocket by using different cylinder pressures, and provides a new method for simulating the remaining thrust of the first stage of the rocket.

[0033] (4) The present invention can be used as a general inter-stage separation assessment platform for dynamically assessing the verification of different engines and different separation schemes, and is a new engine ignition test performance assessment platform.

[0034] (5) Temperature and pressure sensors are arranged in both the separation device and the main components of the present invention, which can effectively collect environmental parameters during the dynamic separation process and provide effective data support for the overall design;

[0035] (6) The present invention uses the method of reverse film breaking by the thrust ejector rod to effectively simulate the separation effect after the thrust of the second-stage engine offsets the remaining thrust of the first-stage engine;

[0036] (7) The present invention belongs to a scaled-down design. If it is necessary to evaluate the separation process at high altitude, this device can be placed in a vacuum tank, and the altitude can be simulated by adjusting the pressure of the vacuum tank, and different altitude separation schemes can be simulated. Description of the Drawings

[0037] Figure 1 It is a schematic diagram before and after the separation of the ground simulation device of the present invention. Detailed Embodiment

[0038] To make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the drawings.

[0039] A ground simulation device for simulating rocket stage separation on the ground, as Figure 1 shown, includes: test bench foundation 1, thrust measurement device 2, scaled-down engine 3, interstage section 4, detonating cord 5, front head 6, thrust ejector rod 7, cylinder 8, pressure relief diaphragm 9, ignition device 10, synchronization device 11, data acquisition system 12. This device mainly tests the thrust superposition or interference phenomenon that occurs during the ignition process of the second-stage engine of the scaled-down rocket engine under the influence of the remaining thrust of the first-stage engine. The main simulation methods of the device include: the scaled-down engine simulates engine ignition, and after the interstage section explodes, it is separated into front and rear ends. One end is connected to one side of the second-stage engine, and the other end is connected to one side of the first-stage front head. After being separated into two sections, the first-stage front head is affected by the coupling of the first-stage thrust simulation device and the tail flame of the second-stage engine, and a reaction force on the second-stage rocket will occur. By measuring information such as the reaction force and temperature, the influence of the coupling effect can be obtained, providing effective and accurate test data for the safe separation of the rocket interstage section.

[0040] A ground simulation method for simulating rocket stage separation on the ground, first, the installation of the simulation device is carried out, including:

[0041] Step 1, install the second-stage engine. Install the second-stage engine on the engine bracket, fasten the front section to the pressure sensor on the test bench, which can be used to measure the ignition thrust of the engine. The tail end of the second-stage engine is designed with a connecting flange for connecting to the flange of the interstage section. A special pressure sensor is set to measure the pressure in the engine combustion chamber and is connected to the acquisition system. The ignition lead is introduced into the ignition timing controller.

[0042] Step 2: Install the interstage section. One end of the interstage section is connected to the flange of the second-stage engine through a flange, and the other end is connected to the flange of the front head of the first-stage engine (only the outer shape of the front head). A detonating cord is designed on the interstage section, and the lead wire of the detonation is led out from the interstage section through a small hole and connected to the timing controller. During the test, when the second-stage engine is ignited, the detonating cord is ignited, and the interstage section is blown into two sections. Under the combined action of the detonating cord and the second-stage engine, the internal cavity pressure and temperature of the interstage section suddenly increase, resulting in unsteady local stress. Therefore, pressure and temperature sensors can be installed at different positions of the interstage section.

[0043] Step 3: Connect the front head model of the first-stage engine. The front head of the first-stage engine is designed with an installation flange, which can be connected to the flange at the other end of the interstage section. In order to compare the measurement results of the pressure and temperature of the interstage section, pressure and temperature sensors can be installed on the back of the front head of the first-stage engine. A push rod is connected to the back of the front head model. The thrust push rod is inserted into the cylinder at the back, and a sealing ring is used for sealing between them. Different pressures in the cylinder simulate different residual thrusts. A diaphragm is installed at the rear of the cylinder and compacted and sealed with a compression ring. As the simulated residual pressure changes, the type of the pressure relief diaphragm is also different.

[0044] Step 4: Inflate the cylinder. This cylinder is used to simulate the residual thrust of the first-stage engine. Before inflating the cylinder, calculate the required residual thrust in advance and fill the cylinder pressure to the required pressure. A diaphragm is installed at the rear section of the cylinder, which can withstand the cylinder pressure. When the push rod is pushed backward by the force of the front head, the head of the push rod can easily pierce the diaphragm, so as to achieve the purpose of pressure relief.

[0045] Step 5: Connect the test system. The test system of the whole device includes: a thrust sensor, an engine chamber pressure sensor, sensors for measuring temperature and pressure of the interstage section, and a cylinder pressure sensor. All of them are connected to the measurement system. The ignition signal is connected to the measurement system through a tee.

[0046] Then conduct the test, including:

[0047] 1) The test system starts to collect data; 2) The second-stage engine is ignited; 3) The detonating cord is ignited; 4) The interstage section is separated; 5) The push rod breaks through the diaphragm; 6) The cylinder deflates; 7) The test system finishes collecting data; 8) The test is completed.

[0048] The test device and method described in the present invention are for scaled models. Therefore, when conditions permit, high-altitude stage separation simulation can also be carried out. For high-altitude simulation, a large vacuum chamber can be used. Place the above test device in the vacuum chamber and change the vacuum degree of the vacuum chamber to simulate altitude. Since it is in a negative pressure state, an absolute pressure sensor should be used to collect data from the pressure sensor at this time. After the above improvements, by performing the operations of the above five steps, a high-altitude separation simulation test can be carried out, further improving the authenticity and reliability of test data.

[0049] The present invention is a test device that combines ground static tests and flight separation tests. It can not only meet the simulation and measurement of the force on components in static tests, but also satisfy the parameter acquisition during the dynamic separation process after the ignition of pyrotechnics. It can effectively simulate different thrust engines and different stage separation structural characteristics, obtain effective ground simulation data, and provide support for the overall design.

[0050] The content not described in detail in the specification of the present invention belongs to the well-known technology in the art.

[0051] Although the present invention has been disclosed above with preferred embodiments, it is not used to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the methods and technical content disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention all belong to the protection scope of the technical solution of the present invention.

Claims

1. A scaled-down model ground test device for simulating rocket stage separation, characterized in that, Comprising: A test bench foundation for bearing the interstage section and the cylinder; An interstage section, with a scaled-down engine installed at one end, a front head installed at the other end, and a detonating cord installed in the middle for separating the interstage section; A thrust measurement device for resisting the scaled-down engine to measure the ignition thrust and transmitting it to the data acquisition system; A thrust ejector rod installed between the cylinder and the front head, and when the thrust ejector rod is subjected to the thrust of the front head, it moves to pierce the pressure relief diaphragm on the cylinder, causing the cylinder to relieve pressure; An ignition device for igniting the detonating cord; A synchronization device for synchronizing the ignition signal and the data acquisition signal; A data acquisition system for measuring and collecting temperature and pressure data.

2. The test device according to claim 1, characterized in that, The scaled-down engine is connected to the interstage section through a flange; the front head is connected to the interstage section through a flange.

3. The test device according to claim 1, characterized in that, The temperature data at least includes the temperature inside the interstage section cavity and the temperature on the back of the front head.

4. The test device according to claim 1, wherein The pressure data at least includes the combustion chamber pressure of the scaled-down engine, the pressure inside the interstage section cavity, the pressure on the back of the front head, and the cylinder pressure.

5. The test device according to claim 1, characterized in that, By adjusting the pressure of the cylinder, different residual thrusts are simulated.

6. The test device according to any one of claims 1 to 5, characterized in that, It further includes a vacuum chamber for accommodating all other components and providing different degrees of vacuum environment.

7. The test device according to claim 6, wherein, The vacuum chamber adjusts the vacuum degree inside the vacuum chamber according to the altitude to be simulated in the test.

8. The test device according to claim 6, characterized in that, When collecting pressure data, an absolute pressure sensor is selected.

9. A ground test method for a scaled model to simulate the separation between rocket stages, characterized in that Using the test device according to any one of claims 1 to 5, comprising: 1) The data acquisition system starts to collect; 2) The scaled-down engine ignites; 3) The detonating cord ignites; 4) The interstage section separates; 5) The thrust ejector rod breaks through the pressure relief diaphragm; 6) The cylinder deflates; 7) The data acquisition system finishes collecting; 8) The test is completed.

10. A ground test method for a scaled-down model to simulate the separation between rocket stages, characterized in that, Using the test device according to claim 6, comprising: 1) According to the altitude to be simulated in the test, adjust the vacuum degree inside the vacuum chamber; 2) The data acquisition system starts to collect; 3) The scaled-down engine ignites; 4) The detonating cord ignites; 5) The interstage section separates; 6) The thrust ejector rod breaks through the pressure relief diaphragm; 7) The cylinder deflates; 8) The data acquisition system finishes collecting; 9) The test is completed.

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