Device for measuring high-temperature constant-pressure friction ignition threshold value of solid propellant

Abstract

The invention discloses a device for measuring a high-temperature constant-pressure friction ignition threshold value of a solid propellant, and relates to the technical field of solid power. The solid propellant friction ignition test under the high-temperature condition can be carried out by means of an integrated heating system, the device structurally comprises a test loading part, a data measuring part and an anti-explosion-constraint part, friction force is regulated and controlled by replacing friction plates with different surface roughness, changing air bag pressure and the like, and the friction ignition test of the solid propellant under the high-temperature condition can be carried out. The friction speed is regulated and controlled by changing the speed of the impact rod, and the friction force and the friction speed in the high-temperature friction ignition test of the solid propellant can be synchronously collected at high frequency. Compared with a previous friction test device, the device can keep the loading pressure of the sample constant, can carry out a high-temperature friction ignition test and characterize an ignition threshold measurement result in the form of an initial temperature-friction power two-dimensional ignition probability cloud picture, is safe and reliable, is small in size, and is easy to detach and clean after parts are stained and damaged.

Description

Technical Field

[0001] The invention relates to the field of solid power technology, in particular to a test device for measuring the friction ignition threshold of solid propellant under high temperature and constant pressure loading conditions. Background Art

[0002] Solid propellant is an energetic composite material with specific properties. It is the power source for strategic missiles, tactical missiles, various solid engines of space vehicles, kinetic interceptor missiles and other weapons. Solid propellant technology is a common technology, supporting technology, and also a restrictive technology for weapons and equipment. Its performance directly affects the survivability and combat effectiveness of strategic and tactical weapons. However, during the production, storage and use of solid propellants, they may be stimulated by various loads such as high temperature and friction, which may cause ignition. Subsequent explosion accidents often cause significant casualties and economic losses. Therefore, designing a test device to study the ignition mechanism of solid propellants under high temperature and friction loads is of great significance to improving the production safety and battlefield survivability of weapons and equipment.

[0003] In order to study the response law of solid propellants under high-temperature load stimulation, researchers have designed various fast and slow baking equipment and gradually improved them into standard tests; the commonly used test equipment for studying the friction stimulus response of solid propellants includes Kozlov friction pendulum, BAM tribometer, etc. These instruments have been continuously improved and their technical level has also become mature. However, most of the existing friction testers are aimed at tests under normal temperature conditions, or lack modules for conducting high-temperature friction tests, or cannot perform high-frame-rate synchronous measurements of friction force and friction speed. In addition, the existing friction testers use metal clamps to clamp the sample or use a push rod to press the sample on the friction surface. The sample will wear and become thinner in the early stage of friction loading, resulting in a serious drop in loading pressure. It is difficult to keep the loading pressure constant during the test. This loading characteristic is quite different from the real physical scene of friction ignition of solid propellants.

[0004] In order to solve the above problems, the present invention proposes a device for determining a high-temperature constant-pressure friction ignition threshold of a solid propellant. Summary of the invention

[0005] The purpose of the present invention is to provide a solid propellant high temperature constant pressure friction ignition threshold determination device to solve the problems raised in the background technology:

[0006] Most existing friction testers are designed for tests under normal temperature conditions, or lack modules for conducting high-temperature friction tests, or are unable to perform high-frame-rate synchronous measurements of friction force and friction speed. In addition, existing friction testers use metal fixtures to clamp the sample or use a push rod to press the sample on the friction surface. The sample will wear and become thinner at the beginning of friction loading, resulting in a serious drop in loading pressure. It is difficult to keep the loading pressure constant during the test. This loading characteristic is quite different from the real physical scene of friction ignition of solid propellants.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A solid propellant high temperature constant pressure friction ignition threshold determination device, comprising an explosion-proof-restraint module, a test loading module, and a data acquisition module;

[0009] The explosion-proof-restraint module includes an upper cover, a support bar, an observation window, a bracket, an aluminum alloy guide rail and a base; the aluminum alloy guide rail is arranged at the bottom, the base is slidably connected to the aluminum alloy guide rail, the bracket is fixedly installed on the base, the support bar is fixedly connected to one side and the top of the bracket, the support bar adopts a detachable structure, and the detachable restraint structure formed makes the installation of other components more convenient; the test loading module is arranged between the support bar and the vertical section of the bracket, the upper cover is fixedly installed on the support bar and the top of the bracket, and the front and rear edges of the upper cover are provided with through grooves, the observation window is inserted into the through groove, and is made of sapphire glass with high light transmittance and high hardness, which has a strong protective effect against the possible combustion and powder splashing hazards in the test;

[0010] The test loading module includes an airbag, a heat insulation plate, a force transmission plate, an impact cylinder, a bullet rod, a gun barrel, a collision rod, a friction plate, a sample, a heating rod, and a slide; the slide is fixedly connected to the bracket by bolts, the friction plate is slidably connected to the slide, the force transmission plate is arranged above the friction plate, the sample is arranged between the force transmission plate and the friction plate, the sample is adhered to the lower surface of the force transmission plate, the heat insulation plate is fixedly connected to the upper surface of the force transmission plate, the airbag is placed above the heat insulation plate and is restricted by the upper cover plate on the top; the airbag The impact rod is fixedly connected to the side wall of the friction plate, the impact cylinder is also connected to the external high-pressure gas source, the gun barrel is fixedly connected to the impact cylinder and placed opposite to the impact rod, the bullet rod is arranged inside the gun barrel, the impact cylinder is controlled by the external high-pressure gas source, the valve is opened to release air during the test, the impact bullet rod is accelerated in the gun barrel and then drives the impact rod to move; the friction plate can slide to the right along the slideway under the drive of the impact rod; a through hole is opened on one side of the friction plate, and the heating rod is inserted into the through hole;

[0011] The data acquisition part includes a force sensor, a thermocouple sensor, a displacement sensor, a data acquisition device, a temperature controller, a high-speed camera, an LED point light source and a sensor pad; the force sensor is installed on one side of the force transmission plate through the sensor pad to measure the horizontal friction force loaded on the sample; a deep fine hole is also arranged above the through hole of the friction plate, and the thermocouple sensor is installed in the deep fine hole to monitor the initial heating temperature of the sample; the displacement sensor is installed on the side of the friction plate close to the vertical section of the bracket, and the displacement of the friction plate is measured during the test, and the time-varying curve of the friction speed can be calculated; several data acquisition cards and charge amplifiers are integrated in the data acquisition device to synchronously collect data from the force sensor and the displacement sensor; the temperature controller is connected to the heating rod and the thermocouple sensor, and the heating temperature and duration can be set, and the heating temperature can be controlled by the built-in PID control module; the LED point light source is used to fill the field of view, and the high-speed camera records the friction ignition response process of the sample at an ultra-high frame rate of 200,000fps.

[0012] Preferably, a triangular truss is provided on the side of the bracket away from the test loading module, and the bracket can form an impact-resistant supporting structure through the triangular truss and the base bracket.

[0013] Preferably, the airbag pressurizes the sample by inflation, which is different from the rigid pressurization method in which the sample is pressed on the friction surface by a push rod to wear and the pressure drops significantly. After the sample is worn and thinned, the airbag can compensate for the displacement of the sample by volume expansion and continue to pressurize the sample, thereby keeping the loading pressure constant during the friction of the sample.

[0014] Preferably, the temperature controller adjusts the temperature of the heating rod through input thermocouple temperature measurement data and a built-in PID control module.

[0015] Preferably, the upper surface of the force transmission plate and the slideway are both equipped with straight-row needle rollers; wherein, the straight-row needle rollers on the upper surface of the force transmission plate can reduce the friction coefficient of relative sliding with the heat insulation plate, and the straight-row needle rollers installed on the slideway can ensure that the friction plate will not slide freely on the slideway. The surface of the friction plate is rough, and the friction force can be controlled by replacing friction plates with different surface roughness, changing the airbag pressure, etc., and the friction speed can be controlled by changing the speed of the impact rod. The ignition threshold measurement result is characterized in the form of a two-dimensional ignition probability cloud diagram of initial temperature-friction power.

[0016] Preferably, the force sensor is a piezoelectric force sensor with a resonant frequency of >70kHz, which is used to measure high-frequency impact loads; the displacement sensor is a laser displacement sensor with a response time of ≤0.5μs and an accuracy of ±3μm, which is used to measure the displacement of the friction plate and is installed in the through hole on the side wall of the bracket; the laser displacement sensor cannot protrude out of the through hole to prevent the friction plate from hitting the displacement sensor.

[0017] Preferably, the test loading part is visualized, and supports shooting through an observation window using optical equipment such as a high-speed camera.

[0018] A method for determining the high-temperature constant-pressure friction ignition threshold of solid propellant based on the above device comprises the following steps:

[0019] S1: Glue the sample to the lower surface of the force transfer plate, and place the friction plate, sample, force transfer plate, heat insulation plate, and airbag in order from bottom to top;

[0020] S2: Inflate the airbag to stabilize the air pressure at the test loading pressure;

[0021] S3: Debug the force sensor, displacement sensor, heating control system, high-speed camera and other data acquisition equipment, and put them in the trigger state after debugging;

[0022] S4: First trigger the data acquisition system, then open the air valve of the impact cylinder, so that the bullet rod accelerates in the barrel and collides with the impact rod, causing the friction plate to slide horizontally to the right and rub the sample;

[0023] S5: After the sample has responded, check and save the test data, and clean the reaction residues and stains in the device.

[0024] Compared with the prior art, the present invention provides a solid propellant high temperature constant pressure friction ignition threshold determination device, which has the following beneficial effects:

[0025] The present invention improves and optimizes the structure of the existing solid propellant friction test device, and proposes a solid propellant high-temperature constant-pressure friction ignition threshold determination device. The test device uses airbag inflation to pressurize the sample and can maintain a constant loading pressure during the friction process. In addition, with the help of an integrated heating system, a solid propellant friction ignition test under high temperature conditions can be carried out. The present invention controls the friction force by replacing friction plates with different surface roughness, changing the airbag pressure, and controlling the friction speed by changing the impact rod speed. The friction force and friction speed in the solid propellant high-temperature friction ignition test can be collected synchronously at high frequency, and the ignition threshold determination results are characterized in the form of an initial temperature-friction power two-dimensional ignition probability cloud map. The device is safe and reliable, small in size, and easy to disassemble and clean after the components are contaminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a front cross-sectional view of the test loading portion of the device mentioned in Example 1 of the present invention;

[0027] Figure 2 This is a schematic diagram of the three-dimensional effect of the device mentioned in Example 1 of the present invention;

[0028] Figure 3 This is a schematic diagram of the macroscopic arrangement of the device mentioned in Example 1 of the present invention;

[0029] Description of the markings in the figure:

[0030] 1. Upper cover; 2. Support bar; 3. Airbag; 4. Observation window; 5. Heat insulation board; 6. Force transmission plate; 7. Impact cylinder; 8. Bullet rod; 9. Gun barrel; 10. Impact rod; 11. Friction plate; 12. Test specimen; 13. Force sensor; 14. Thermocouple sensor; 15. Heating rod; 16. Displacement sensor; 17. Bracket; 18. Aluminum alloy guide rail; 19. Data acquisition device; 20. Temperature controller; 21. High-speed camera; 22. LED point light source; 23. Sensor pad; 24. Slide; 25. Base. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0032] The present invention improves the solid propellant friction test device. By using an airbag to inflate the test device to pressurize the sample and keep the loading pressure constant during the friction process, the solid propellant friction ignition test under high temperature conditions can be carried out with the help of an integrated heating system. The present invention controls the friction force by replacing friction plates with different surface roughness, changing the airbag pressure, etc., and controls the friction speed by changing the impact rod speed. The friction force and friction speed in the solid propellant high-temperature friction ignition test can be collected synchronously at high frequency, and the ignition threshold measurement results are characterized in the form of an initial temperature-friction power two-dimensional ignition probability cloud map. The device is safe and reliable, with a small overall size of about 15cm×10cm×5cm, low processing cost, and easy to disassemble and clean after the components are contaminated. The test device of the present invention can be installed on the SHPB equipment with relatively mature technology as a high-temperature constant-pressure friction function expansion module. Specifically include the following contents.

[0033] Embodiment 1:

[0034] See also Figure 1-2 , the present invention is a solid propellant high temperature constant pressure friction ignition threshold determination device, the device is arranged on an aluminum alloy guide rail 18, and is composed of a test loading module, a data acquisition module, and an explosion-proof-restraint module;

[0035] The test loading module includes an airbag 3, a heat insulation plate 5, a force transmission plate 6, an impact cylinder 7, a bullet rod 8, a gun barrel 9, an impact rod 10, a friction plate 11, a sample 12, a heating rod 15, and a slide 24; the airbag 3 is located on the upper side of the device, connected to an external high-pressure gas source, and pressurizes the lower structure through the heat insulation plate 5 made of aluminum silicate ceramic; a straight row of rollers is arranged on the upper surface of the force transmission plate 6 to reduce the friction coefficient of relative sliding with the heat insulation plate 5, and the sample 12 is glued to the lower surface of the force transmission plate 6; the impact cylinder 7 is inflated and controlled by an external high-pressure gas source, and the valve is opened to release air during the test, and the bullet rod 8 is impacted to accelerate it in the gun barrel 9 and then drive the impact rod 10 to move; the friction plate 11 can slide to the right along the slide under the drive of the impact rod 10, and a through hole is opened on its front side for inserting the heating rod 15 and the thermocouple sensor 14;

[0036] The data acquisition part includes a force sensor 13, a thermocouple sensor 14, a displacement sensor 16, a data acquisition device 19, a temperature controller 20, a high-speed camera 21, an LED point light source 22, and a sensor pad 23; the force sensor 11 is placed on the right side of the force transmission plate 6 to measure the horizontal friction force loaded on the sample; the thermocouple sensor 14 is installed in the deep fine hole on the front side of the friction plate 11 to monitor the initial heating temperature of the sample; the displacement sensor 16 is installed on the right side of the friction plate 11 to measure the displacement of the friction plate 11 during the test and calculate the time-varying curve of the friction speed; the data acquisition device 19 integrates several data acquisition cards and charge amplifiers, which can synchronously collect data from the force sensor 11 and the displacement sensor 16; the temperature controller 20 is connected to the heating rod 15 and the thermocouple sensor 14, and the temperature controller 20 can set the heating temperature and duration, and realize the heating temperature control through the built-in PID control module; the high-speed camera 21 uses the LED point light source 22 to fill the field of view, and records the friction ignition response process of the sample at an ultra-high frame rate of 200,000fps;

[0037] The explosion-proof-restraint part includes an upper cover plate 1, a support bar 2, an observation window 4, a bracket 17, an aluminum alloy guide rail 18, and a base 25; the upper cover plate 1 and the support bar 2 are respectively located on the upper side and the left side of the device, and the detachable restraint structure makes the installation of other components more convenient; the observation window 4 is arranged on the front and rear sides of the sample loading part, and is made of sapphire glass with high light transmittance and high hardness, which has a strong protective effect against the possible combustion and powder splashing hazards in the test; the bracket 17 is installed on the aluminum alloy guide rail 18 of the SHPB equipment, the left half of the bracket 17 is the test loading part, and the triangular truss on the right is the impact-resistant supporting structure of the entire device.

[0038] During the test, the sample 12 is first glued to the lower surface of the force transmission plate 6, and the friction plate 11, sample 12, force transmission plate 6, heat insulation plate 5, and airbag 3 are placed from bottom to top; then the airbag 3 is inflated to stabilize the air pressure at the test loading air pressure; the force sensor 13, displacement sensor 16, heating control system, high-speed camera 21 and other data acquisition equipment are debugged, and after debugging, they are placed in a triggering state; first trigger the data acquisition system, then open the air valve of the impact cylinder 7, so that the bullet rod 8 accelerates in the barrel 9 and collides with the impact rod 10, so that the friction plate 11 slides horizontally to the right and rubs the sample 12; after the sample 12 responds, check and save the test data, and clean the reaction residues and stains in the device; after the test, the test measured data is processed into the time-varying curves of friction force and friction power, and the two-dimensional ignition probability cloud map of initial temperature-friction power, and the high-temperature constant-pressure friction ignition threshold of solid propellant is comprehensively characterized. .

[0039] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A solid propellant high temperature constant pressure friction ignition threshold determination device, characterized in that: It includes explosion-proof-restraint module, test loading module, and data acquisition module; The explosion-proof-restraint module comprises an upper cover plate (1), a support bar (2), an observation window (4), a bracket (17), an aluminum alloy guide rail (18) and a base (25); the aluminum alloy guide rail (18) is arranged at the bottom, the base (25) is slidably connected to the aluminum alloy guide rail (18), the bracket (17) is fixedly installed on the base (25), the support bar (2) is fixedly connected to one side and the top of the bracket (17), the test loading module is arranged between the support bar (2) and the vertical section of the bracket (17), the upper cover plate (1) is fixedly installed on the support bar (2) and the top of the bracket (17), and the upper cover plate (1) is provided with through grooves at the front and rear edges of the upper cover plate (1), and the observation window (4) is inserted into the through grooves; The test loading module comprises an air bag (3), a heat insulation plate (5), a force transmission plate (6), an impact cylinder (7), a bullet rod (8), a gun barrel (9), an impact rod (10), a friction plate (11), a sample (12), a heating rod (15), and a slideway (24); the slideway (24) is fixedly connected to the bracket (17) by bolts, the friction plate (11) is slidably connected to the slideway (24), the force transmission plate (6) is arranged above the friction plate (11), the sample (12) is arranged between the force transmission plate (6) and the friction plate (11), and the sample (12) is adhered to the lower surface of the force transmission plate (6). The heat insulation plate (5) is fixedly connected to the upper surface of the force transmission plate (6), the air bag (3) is placed above the heat insulation plate (5) and is restricted by the upper cover plate (1) on the top; the air bag (3) is connected to an external high-pressure gas source; the impact rod (10) is fixedly connected to the side wall of the friction plate (11), the impact cylinder (7) is also connected to the external high-pressure gas source, the gun barrel (9) is fixedly connected to the impact cylinder (7) and is placed opposite to the impact rod (10), and the bullet rod (8) is arranged inside the gun barrel (9); a through hole is opened on one side of the friction plate (11), and the heating rod (15) is inserted into the through hole; The data acquisition part comprises a force sensor (13), a thermocouple sensor (14), a displacement sensor (16), a data acquisition device (19), a temperature controller (20), a high-speed camera (21), an LED point light source (22) and a sensor pad (23); the force sensor (11) is installed on one side of the force transmission plate (6) through the sensor pad (23); a deep fine hole is also arranged above the through hole of the friction plate (11), and the thermocouple sensor (14) is installed in the deep fine hole; the displacement sensor (16) is installed on one side of the friction plate (11) close to the vertical section of the bracket (17); a plurality of data acquisition cards and charge amplifiers are integrated in the data acquisition device (19) to synchronously acquire data from the force sensor (11) and the displacement sensor (16); the temperature controller (20) is connected to the heating rod (15) and the thermocouple sensor (14); the LED point light source (22) is used to fill in the field of view, and the high-speed camera (21) is used to record the friction ignition response process of the sample (12).

2. A solid propellant high temperature constant pressure friction ignition threshold determination device according to claim 1, characterized in that: The airbag (3) pressurizes the sample (12) by means of inflation and keeps the loading pressure of the sample (12) constant during the friction process.

3. A solid propellant high temperature constant pressure friction ignition threshold determination device according to claim 1, characterized in that: The temperature controller (20) controls the temperature of the heating rod (15) through input thermocouple temperature measurement data and a built-in PID control module.

4. A solid propellant high temperature constant pressure friction ignition threshold determination device according to claim 1, characterized in that: Inline needle rollers are installed on the upper surface of the force transmission plate (6) and the slideway (24), and the surface of the friction plate (11) is rough.

5. The solid propellant high temperature constant pressure friction ignition threshold determination device according to claim 1, characterized in that: The force sensor (13) is a piezoelectric force sensor with a resonance frequency of >70 kHz, and is used to measure high-frequency impact loads; the displacement sensor (16) is a laser displacement sensor with a response time of ≤0.5 μs and an accuracy of ±3 μm, and is used to measure the displacement of the friction plate, and is installed in a through hole on the side wall of the bracket (17).

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