Method for testing burning rate by target line method

Abstract

The invention relates to a target line method burning rate testing method. The method comprises the following steps: an I / O control card circuit sends a control signal to a valve control drive circuit, so that the valve control drive circuit generates water required by a test temperature; the I / O control card circuit sends a control signal to the valve control drive circuit, and a buffer gas valve is opened to communicate the combustion chamber with the nitrogen buffer bottle; when the system recognizes the temperature and pressure meeting the test conditions, an ignition command is sent out, at the moment, an I / O control card circuit sends a control signal to an ignition circuit to enable the ignition circuit to apply ignition current to an electrode of a top cover of a combustion chamber through a cable, and an ignition wire is heated to ignite a solid propellant sample; along with continuous combustion, different disconnection signals can be recognized, and then generated data can be sent to a data acquisition card in a computer. In addition, by introducing an automatic operating system, the influence on the accuracy of burning rate test data due to fluctuation change of temperature and pressure caused by human factors is reduced as much as possible.

Description

Technical Field

[0001] The invention relates to the technical field of material testing, and in particular to a target line method burning rate testing method. Background Art

[0002] In recent years, with the rapid development of aerospace technology, higher requirements have been put forward for the research and production of solid rocket propellant formulas. The energy of solid propellant determines the take-off, endurance and combat capability of solid rocket engines. After the energy of solid propellant is determined, the engine energy release rate is controlled to achieve the design goal of the engine. The energy release rate depends on the solid propellant combustion rate and the charging method. Therefore, the combustion performance of solid propellant is an important performance parameter required by weapons. The combustion process can not only release energy and affect the injection speed of combustion products, but also generate working fluid and determine the injection quality. The two effects together directly affect the thrust of the engine and play a decisive role in the main performance of the engine. The combustion of solid propellant is characterized by the retreat of its surface after the start of combustion. The speed of the retreat of the combustion surface is generally expressed by the burning rate. With the continuous development of test methods, the most widely used and applicable methods are still the target line method and static underwater acoustic emission method.

[0003] The target line method burn rate test is to coat the fully solidified propellant strip, drill holes at both ends of the known length and insert the target line. Ignite the propellant strip under nitrogen pressurization and constant temperature conditions, and then measure the time taken between the two target points to get the specific value of the burn rate. With the continuous development of solid propellants, the workload of burn rate testing has increased dramatically. Under the conditions of ensuring both data accuracy and test safety, and ensuring the timely delivery of the test, higher requirements are put forward for the speed and efficiency of the target line method burn rate test.

[0004] During the target line method burning rate test, the burning rate value changes with the changes in the pressure and initial temperature conditions in the combustion chamber. For most propellants, the burning rate increases significantly with the increase in pressure, while the burning rate of some propellants increases less or remains unchanged with the increase in pressure. From the common double-base propellant combustion process, we know that under low pressure, a certain pressure is required to enable the initial stage of the propellant nitrogen dioxide to continue to exothermically react in the solid phase surface layer, maintain the heat required for the decomposition of the solid phase, and play a role in stabilizing combustion. As the pressure increases, the concentration of reactants in the gas phase increases proportionally, the reaction rate increases, the thickness of the reaction zone becomes thinner, and the temperature gradient increases, which accelerates the thermal feedback of the gas phase to the solid phase, ultimately leading to an increase in the burning rate. From the perspective of the combustion process of the propellant, the initial temperature increases, the original heat in the solid phase increases, and under the same thermal feedback, the temperature in the surface reaction zone is higher, which accelerates the decomposition rate of the solid phase, ultimately leading to an increase in the burning rate. It can be seen that the changes in temperature and pressure have an impact on the burning rate test.

[0005] At present, the daily burning rate test of solid propellant target line method has the characteristics of high risk, large number of tests, and long time for sub-sample testing. In order to ensure the data quality, work efficiency and personnel safety of the test process, it is necessary to automate and intelligently control the workflow of the existing burning rate test process of the target line method, so that the test personnel can understand the test progress and the accuracy analysis of the test data at any time during the burning rate test process, and take corresponding countermeasures immediately in the event of an emergency. Summary of the invention

[0006] The present invention proposes a target line method burning rate test method to solve the problems of high risk and long sub-sample test time in the current target line method burning rate test.

[0007] In order to solve the above technical problems, one of the purposes of the present invention is to provide a target line burning rate test method, the specific steps are as follows:

[0008] 1) Through the software control module, the I / O control card circuit sends a control signal to the valve control drive circuit, and the valve control drive circuit box temperature control system sends a control signal to produce water that meets the test temperature;

[0009] 2) The I / O control card circuit sends a control signal to the valve control drive circuit, opens the buffer gas valve to connect the combustion chamber and the nitrogen buffer bottle, and the pressure sensor senses the combustion chamber pressure and transmits it to the computer through the signal data acquisition card. The I / O control card circuit in the industrial computer sends a control signal to control the high-pressure intake valve and exhaust valve to open and close the test pressure in the combustion chamber to meet the test pressure, and closes the buffer gas valve before the test;

[0010] 3) When the system recognizes that the temperature and pressure meet the test conditions, it will issue an ignition command. At this time, the I / O control card circuit sends a control signal to the ignition circuit, so that the ignition circuit applies an ignition current to the electrode on the combustion chamber top cover through the cable, so that the ignition wire heats up and ignites the solid propellant sample;

[0011] 4) As the combustion continues, different disconnection signals will be identified, and the AD sampling interface circuit will realize automatic analysis and timely storage of the data, and then the generated data will be sent to the data acquisition card in the computer.

[0012] Furthermore, in the case of 2) when the pressure in the combustion chamber is greater than the pressure required for the test, the I / O control card circuit sends a control signal to the valve control drive circuit to open the exhaust valve for a short time to reduce the pressure in the combustion chamber until the pressure in the combustion chamber meets the test requirements. The exhaust valve opening time is determined by a special algorithm based on the difference between the required pressure and the actual pressure.

[0013] Furthermore, if 2) the pressure in the combustion chamber is less than the pressure required for the test, the I / O control card circuit sends a control signal to the valve control drive circuit to open the high-pressure intake valve for a short time to pressurize the combustion chamber and the nitrogen buffer bottle.

[0014] Furthermore, the I / O control port circuit shown completes the detection of various switch parameters of the combustion chamber, including the status of the target line and the ignition line.

[0015] Furthermore, to determine whether the combustion chamber temperature is equal to the target temperature in 1), it is necessary to determine whether the combustion chamber temperature is greater than the target temperature, and to control the temperature by a temperature control unit until the combustion chamber temperature is equal to the target temperature.

[0016] Furthermore, if the temperature of the combustion chamber is greater than the target temperature, the temperature of the combustion chamber is adjusted by cooling through the temperature control unit; if the temperature of the combustion chamber is lower than the target temperature, the temperature is increased through the temperature control unit.

[0017] Furthermore, the I / O control card circuit adopts an 8255A parallel chip interface. In this circuit, mode 0 is adopted, which is the basic I / O mode (unconditional I / O mode), wherein port A, port B, and port C (upper and lower halves) can be used as input or output to realize unconditional transmission, and the CPU can use IN / OUT instructions to realize data transmission.

[0018] Furthermore, the buffer D7-D0 of the 8255A bus is connected to the ISA bus DB0-DB7 of the CPU, the RD and WR of the 8255A are directly connected to the RD and WR of the CPU, the reset signal RESET is connected to the reset signal RESET of the CPU, the port address A2-A9 of the 8255 generates a chip select signal through a logic gate circuit, the address lines A1 and A0 of the CPU respectively constitute 4 port addresses, the 4 port addresses of the 8255 are 280H-283H, port C is used as the input port, ports A and B are used as output ports, all work in mode 0, and the control suffix of the mode selection is 10001001B.

[0019] Furthermore, the AD sampling interface circuit adopts a complete 12-bit parallel analog / digital conversion monolithic integrated circuit-AD1674, and uses 89C51 microcontroller as the lower computer program, and sends the temperature signal, pressure signal and timing signal collected by AD1674 to the computer for processing through 89C51.

[0020] The above one or more technical solutions of the present invention have at least one or more of the following technical effects:

[0021] The present invention also introduces an automated operating system to minimize fluctuations in temperature and pressure caused by human factors, thereby reducing the accuracy of the burning rate test data.

[0022] The present invention specifically relates to a technical application that can simultaneously achieve simplification and intelligence of the operation of the entire process of solid propellant target line method burning rate test, as well as precision and intelligence of data analysis. The technical application proposed by the present invention can collect each state parameter in the test process to the front-end operation platform in a timely manner when the operator leaves the operation room. Then the operator only needs to start the entire burning rate test process with one button to realize automated testing and timely calculation and feedback of the data. At the same time, automatic control can be realized at all key nodes, which greatly increases the stability of variable factors and fundamentally solves the impact of environmental and human influences on data changes. It is expected to achieve further improvement in efficiency in burning rate testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : Target line method test flow chart;

[0024] Figure 2 : I / O control port circuit diagram;

[0025] Figure 3 : 8255 working timing diagram;

[0026] Figure 4 : Computer operation control interface;

[0027] Figure 5 : AD sampling interface circuit. Specific implementation plan

[0028] A technical application that can simultaneously achieve simplification and intelligence of the operation of the entire process of solid propellant target line method burning rate test, as well as precision and intelligence of data analysis, with the ability to switch between two control modes at any time: fully automatic computer control and manual control; the ability to visualize the real-time test of temperature, pressure and propellant burning process; the ability to perform closed-loop control of pressure and temperature and automatically adjust pressure and temperature changes; and the ability to automatically analyze and store test data.

[0029] The two control modes can be switched at any time, and the I / O control card circuit is used to complete the detection and setting of each switch and parameter of the combustion chamber.

[0030] Visualization capabilities are presented by presenting dynamic data acquisition in the test software display to simulate the propellant combustion process.

[0031] In order to realize the ability of automatic analysis and timely preservation of data, a complete 12-bit parallel analog / digital conversion single-chip integrated circuit - AD1674 is adopted, and the 89C51 single-chip microcomputer is used as the lower computer program. The temperature signal, pressure signal and timing signal collected by AD1674 are sent to the computer for processing through 89C51.

[0032] The whole process operation is simplified and intelligent, and the technical application for data analysis is precise and intelligent, by connecting the I / O control card and the A / D card in parallel.

[0033] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in combination with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the obtained embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0034] The whole process of solid propellant burning rate test is simplified and intelligent. Figure 1 This is the target line method burning rate test flow chart. The process is mainly started by one button, and different situations are automatically identified and adjusted during the whole process. Through the software control module, the I / O control card circuit first sends a control signal to the valve control drive circuit, and the valve control drive circuit box temperature control system sends a control signal to produce water that meets the test temperature. The I / O control card circuit sends a control signal to the valve control drive circuit to open the buffer gas valve to connect the combustion chamber and the nitrogen buffer bottle. At this time, the pressure sensor senses the pressure in the combustion chamber and transmits it to the computer through the signal data acquisition card. If the pressure in the combustion chamber is greater than the pressure required for the test, the I / O control card circuit sends a control signal to the valve control drive circuit to open the exhaust valve for a short time to reduce the pressure in the combustion chamber until the pressure in the combustion chamber meets the test requirements. The exhaust valve opening time is determined by a special algorithm based on the difference between the required pressure and the actual pressure. If the pressure in the combustion chamber is less than the pressure required for the test, the I / O control card circuit sends a control signal to the valve control drive circuit to open the high-pressure intake valve for a short time to pressurize the combustion chamber and the nitrogen buffer bottle. The I / O control card circuit in the industrial computer sends a control signal to control the high-pressure intake valve and exhaust valve to open and close. The test pressure in the combustion chamber meets the test pressure. Close the buffer gas valve before testing.

[0035] When the system recognizes that the temperature and pressure meet the test conditions, it will issue an ignition command. At this time, the I / O control card circuit sends a control signal to the ignition circuit, which causes the ignition circuit to send an ignition current to the electrode on the combustion chamber cover through the cable, thereby heating the ignition wire and igniting the solid propellant sample. As the combustion continues, different disconnection signals will be recognized, and the generated data will then be sent to the data acquisition card in the computer.

[0036] I / O control card circuit diagram Figure 2 As shown, the I / O control card circuit mainly completes the detection of various switch parameters of the combustion chamber, such as the status of the target line and the ignition line, and can manually or automatically adjust the working pressure and temperature conditions of the combustion chamber, as well as the control of the pipeline valve to improve the degree of automation of the test.

[0037] In the I / O control card circuit, the most critical part is the 8255A working mode. In this circuit, mode 0 is used, which is the basic I / O mode (unconditional I / O mode). Port A, port B, and port C (upper and lower parts) can all be used as input or output to achieve unconditional transmission. The CPU can use IN / OUT instructions to achieve data transmission.

[0038] 8255 working timing diagram is as follows Figure 3 As shown. The buffer D7-D0 of the 8255 bus is connected to the ISA bus DB0-DB7 of the CPU, the RD and WR of the 8255 are directly connected to the RD and WR of the CPU, and the reset signal RESET is connected to the reset signal RESET of the CPU. The port address A2-A9 of the 8255 generates a chip select signal through a logic gate circuit, and the address lines A1 and A0 of the CPU form 4 port addresses respectively. In this way, the 4 port addresses of the 8255 are 280H-283H. Use port C as the input port, and ports A and B as the output ports, all working in mode 0, and the control word suffix of the mode selection is 10001001B.

[0039] Intelligentization of solid propellant burning rate test data

[0040] Computer operation control interface such as Figure 4 The target line method computer test control interface can be roughly divided into the main menu, shortcut buttons, tables, system diagrams and animations, and sampling diagrams. In order to realize intelligent data collection, during the test, you only need to manually set the corresponding data parameters, and then the system will automatically display the data on the control interface according to the attached Figure 1 The test process and real-time data will be updated in real time on the operation interface. The tester only needs to prepare the next batch of samples after the test.

[0041] Solid propellant burning rate test data precision

[0042] In order to achieve data accuracy, in the signal sampling process, we use a complete 12-bit parallel analog / digital conversion single-chip integrated circuit-AD1674, and use 89C51 microcontroller as the lower computer program to send the temperature signal, pressure signal and timing signal collected by AD1674 to the computer for processing through 89C51. The software further ensures the accuracy of the data. The AD sampling interface circuit is as follows Figure 5 shown.

[0043] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A target line burning rate test method, characterized in that: The specific steps are as follows: 1) Through the software control module, the I / O control card circuit sends a control signal to the valve control drive circuit, and the valve control drive circuit box temperature control system sends a control signal to produce water that meets the test temperature; 2) The I / O control card circuit sends a control signal to the valve control drive circuit, opens the buffer gas valve to connect the combustion chamber and the nitrogen buffer bottle, and the pressure sensor senses the combustion chamber pressure and transmits it to the computer through the signal data acquisition card. The I / O control card circuit in the industrial computer sends a control signal to control the high-pressure intake valve and exhaust valve to open and close the test pressure in the combustion chamber to meet the test pressure, and closes the buffer gas valve before the test; 3) When the system recognizes that the temperature and pressure meet the test conditions, it will issue an ignition command. At this time, the I / O control card circuit sends a control signal to the ignition circuit, so that the ignition circuit applies an ignition current to the electrode on the combustion chamber top cover through the cable, so that the ignition wire heats up and ignites the solid propellant sample; 4) As the combustion continues, different disconnection signals will be identified, and the AD sampling interface circuit will realize automatic analysis and timely storage of the data, and then the generated data will be sent to the data acquisition card in the computer.

2. The target line burning rate test method according to claim 1, characterized in that: 2) If the pressure in the combustion chamber is greater than the pressure required for the test, the I / O control card circuit sends a control signal to the valve control drive circuit to open the exhaust valve for a short time to reduce the pressure in the combustion chamber until the pressure in the combustion chamber meets the test requirements. The exhaust valve opening time is determined by a special algorithm based on the difference between the required pressure and the actual pressure.

3. The target line burning rate test method according to claim 1, characterized in that: If 2) the pressure in the combustion chamber is less than the pressure required for the test, the I / O control card circuit sends a control signal to the valve control drive circuit to open the high-pressure intake valve for a short time to pressurize the combustion chamber and the nitrogen buffer bottle.

4. The target line burning rate test method according to claim 1, characterized in that: The I / O control port circuit shown completes the detection of various switch parameters of the combustion chamber, including the status of the target line and the ignition line.

5. The target line burning rate test method according to claim 1, characterized in that: To judge whether the combustion chamber temperature is equal to the target temperature in 1), it is necessary to determine whether the combustion chamber temperature is greater than the target temperature, and control the temperature through the temperature control unit until the combustion chamber temperature is equal to the target temperature.

6. The target line burning rate test method according to claim 5, characterized in that: If the combustion chamber temperature is greater than the target temperature, the temperature of the combustion chamber is adjusted by cooling through the temperature control unit; if the combustion chamber temperature is lower than the target temperature, the temperature is increased through the temperature control unit.

7. The target line burning rate test method according to claim 1, characterized in that: The I / O control card circuit adopts 8255A parallel chip interface. In this circuit, mode 0 is adopted, which is the basic I / O mode (unconditional I / O mode), among which port A, port B, and port C (upper and lower halves) can be used as input or output to realize unconditional transmission, and the CPU can use IN / OUT instructions to realize data transmission.

8. The target line burning rate test method according to claim 7, characterized in that: The buffer D7-D0 of the 8255A bus is connected to the ISA bus DB0-DB7 of the CPU. The RD and WR of the 8255A are directly connected to the RD and WR of the CPU. The reset signal RESET is connected to the reset signal RESET of the CPU. The port address A2-A9 of the 8255 generates a chip select signal through a logic gate circuit. The address lines A1 and A0 of the CPU respectively form 4 port addresses. The 4 port addresses of the 8255 are 280H-283H. Port C is used as the input port, and ports A and B are used as output ports. They all work in mode 0, and the control suffix of the mode selection is 10001001B.

9. The target line burning rate test method according to claim 1, characterized in that: The AD sampling interface circuit uses a complete 12-bit parallel analog / digital conversion monolithic integrated circuit-AD1674, and uses the 89C51 microcontroller as the lower computer program. The temperature signal, pressure signal and timing signal collected by AD1674 are sent to the computer for processing through 89C51.

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