1. The non-contact type explosive burning speed measurement experiment device based on terahertz waves is characterized by comprising a high-pressure sealed burning experiment device, a speed measurement unit, an ignition unit and a gas product pressure real-time measurement unit, wherein the speed measurement unit, the ignition unit and the gas product pressure real-time measurement unit are respectively connected with the high-pressure sealed burning experiment device,

the high-pressure airtight combustion experimental device is internally fixed with a test explosive column (8), and the test explosive column (8) performs a high-pressure airtight combustion experiment in the high-pressure airtight combustion experimental device;

the ignition unit is used for carrying out non-contact ignition on a test explosive column (8) in the high-pressure closed combustion experimental device by utilizing laser irradiation;

the speed measurement unit is used for carrying out combustion speed measurement on a test explosive column (8) in the high-pressure sealed combustion experimental device by utilizing the Doppler effect of the terahertz waves;

and the gas product pressure real-time measuring unit is used for measuring and recording pressure data changes generated by the high-pressure closed combustion experimental device.

2. The non-contact type explosive burning rate measurement experimental device based on the terahertz waves as claimed in claim 1, wherein the high-pressure sealed combustion experimental device comprises a sealing device main body, a device cavity (12) is arranged in the sealing device main body, a positioning assembly is arranged in the device cavity (12), the positioning assembly is sleeved outside the test explosive column (8), an ignition agent (11) is arranged outside the positioning assembly, a laser ignition window (6) is arranged above the device cavity (12), a speed measurement window (7) is arranged below the device cavity (12), the position of the laser ignition window (6) corresponds to the position of an ignition unit, the speed measurement window (7) corresponds to the position of the speed measurement unit, and a pressure sensor mounting hole (5) is arranged on the side surface of the sealing device main body.

3. The non-contact type explosive burning rate measurement experiment device based on the terahertz waves as claimed in claim 2, wherein the sealing device main body comprises a cylinder (2), a cover plate (1) is arranged above the cylinder (2), the cover plate (1) is fixedly connected with the cylinder (2) in a detachable mode, a bottom plate (3) is arranged below the cylinder (2), the bottom plate (3) is fixedly connected with the cylinder (2) in a detachable mode, the laser ignition window (6) is located at the top of the cylinder (2), a laser hole is formed in the cover plate (1), the laser can reach the laser ignition window (6) through the laser hole, a terahertz wave hole is formed in the bottom plate (3), and the terahertz waves can reach the speed measurement window (7) through the terahertz wave hole.

4. The non-contact type explosive burning rate measurement experiment device based on the terahertz waves as claimed in claim 3, wherein a cover plate sealing ring (14) is arranged between the cover plate (1) and the barrel body (2), and an ignition window gasket (13) is arranged between the laser ignition window (6) and the cover plate (1) or the barrel body (2); a bottom plate sealing ring (16) is arranged between the bottom plate (3) and the cylinder body (2), and speed measuring window gaskets (15) are arranged between the speed measuring window (7) and the bottom plate (3) or the cylinder body (2).

5. The non-contact type explosive burning rate measurement experiment device based on the terahertz waves as claimed in claim 2, wherein the positioning assembly comprises epoxy resin (9), the epoxy resin (9) is sleeved outside the test explosive column (8), a sleeve (10) is sleeved outside the epoxy resin (9), and the sleeve (10), the epoxy resin (9) and the test explosive column (8) are all fixed with the speed measurement window (7).

6. The non-contact type explosive burning rate measurement experiment device based on the terahertz waves as claimed in claim 1, wherein the speed measurement unit comprises a terahertz wave source, a transmission collection optical path and an orthogonal probe, wherein,

the terahertz wave source is used for emitting terahertz waves, focusing the terahertz waves and irradiating the terahertz waves into the high-pressure sealed combustion experimental device;

the transmission and collection optical path is used for transmitting the terahertz waves emitted by the terahertz wave source to the high-pressure sealed combustion experimental device, collecting the terahertz waves transmitted back by a combustion interface in the high-pressure sealed combustion experimental device and transmitting the terahertz waves to the orthogonal probe;

and the orthogonal probe is used for receiving the terahertz waves transmitted back from the high-pressure closed combustion experimental device, generating and outputting orthogonal IQ interference signals, and recording the orthogonal IQ interference signals by an oscilloscope.

7. The non-contact type explosive burning rate measurement experimental device based on the terahertz waves as claimed in claim 1, further comprising a synchronizer, wherein the speed measurement unit, the ignition unit and the real-time gas product pressure measurement unit are respectively connected with the synchronizer, the ignition unit comprises a laser, and the laser can emit laser radiation into the high-pressure closed combustion experimental device; the real-time measuring unit for the pressure of the gas product comprises a pressure sensor and an oscilloscope, wherein the pressure sensor can measure the pressure change in the high-pressure closed combustion experimental device, and the oscilloscope can receive the signal of the pressure sensor and display the pressure fluctuation in the high-pressure closed combustion experimental device.

8. An experiment method adopting the terahertz wave-based explosive burning rate non-contact measurement experiment device according to any one of claims 1 to 7 is characterized by comprising the following steps of:

s1: preparing a grain and packaging and fixing the grain into the high-pressure closed combustion experimental device;

s2: assembling a high-pressure closed combustion experimental device, and checking the sealing property;

s3: installing a pressure sensor; the ignition laser and the ignition unit are aligned; the speed measuring terahertz wave and the speed measuring unit are aligned;

s4: arranging an oscilloscope and a synchronizer;

s5: and sending an ignition instruction and recording test data of each system.

9. The non-contact measurement experiment method for the burning rate of the terahertz-wave-based explosive is characterized in that when an ignition agent (11) is arranged, the ignition agent (11) is laid on the ignition end face of the test explosive column (8).

10. The non-contact measurement experiment method for the burning rate of the terahertz-wave-based explosive is characterized in that in step S3, the indicating light of the ignition laser is vertically and downwards incident into the ignition window from the ignition window through the reflector, and the light spot of the indicating light is adjusted to be located at the center of the window; the indicating light of the speed measuring terahertz wave is vertically and upwards injected into the speed measuring window (7) from the speed measuring window (7) through the reflector, and the light spot of the indicating light is adjusted to be positioned in the center of the window.

Background

Under the action of mechanical or thermal stimulation, the explosive under the constrained condition can generate continuous combustion reaction, and the energy transfer mechanism of the explosive is mainly based on layer-by-layer propagation of a heat conduction surface, namely, the so-called heat conduction combustion or laminar flow combustion. For PBX explosives formed by a press-fitting process, the pores in the material can be ignored, and high-temperature gas products generated by combustion are difficult to permeate into the pores to preheat unreacted explosives. Thus, it is believed that the combustion reaction is maintained only at the surface of the explosive. In this process, there is a well-defined gas-solid reaction front, and energy is transferred between the reactants and the unreacted reactants primarily by heat conduction. The burn rate of the explosive increases with increasing pressure. In the confined space, the pressure of the gas product generated by the combustion of the explosive is rapidly increased, the combustion rate of the explosive is greatly increased, and even finally, high-intensity reaction is caused, and disastrous results are caused. Therefore, researching the law that the combustion rate of the explosive changes along with the pressure of the gas product is an important basis for deeply knowing the reaction evolution behavior of the PBX explosive under the constraint condition.

However, the current research on the combustion rate of the explosive faces a lot of difficulties, and particularly, on the collection of relevant combustion data, the relevant data of a relatively proper combustion rate of the explosive cannot be completely collected, and the obtained experimental result is usually an average result and cannot accurately reflect the combustion process.

Disclosure of Invention

The invention aims to overcome the defects of low test precision, small data amount obtained in a single experiment and high experiment operation difficulty in the non-contact speed measurement of the combustion speed in the prior art, and provides an explosive combustion speed non-contact measurement experiment device and method based on terahertz waves.

The purpose of the invention is mainly realized by the following technical scheme:

the non-contact type explosive burning speed measurement experiment device based on terahertz waves comprises a high-pressure closed combustion experiment device, a speed measurement unit, an ignition unit and a gas product pressure real-time measurement unit, wherein the speed measurement unit, the ignition unit and the gas product pressure real-time measurement unit are respectively connected with the high-pressure closed combustion experiment device,

the high-pressure airtight combustion experimental device is internally fixed with a test explosive column, and the test explosive column is used for carrying out a high-pressure airtight combustion experiment in the high-pressure airtight combustion experimental device;

the ignition unit is used for carrying out non-contact ignition on a test explosive column in the high-pressure closed combustion experimental device by utilizing laser irradiation;

the speed measurement unit is used for carrying out combustion speed measurement on a test explosive column in the high-pressure sealed combustion experimental device by utilizing the Doppler effect of terahertz waves;

and the gas product pressure real-time measuring unit is used for measuring and recording pressure data changes generated by the high-pressure closed combustion experimental device.

At present, in the experiment for measuring the combustion rate of the solid explosive under high pressure, the combustion rate is mostly measured by adopting a wire breaking method in a closed combustion container. Firstly, the data volume obtained by the wire breaking method is limited, and the obtained speed is actually the average speed in the combustion process of a small section of explosive sample, so that the instantaneous and continuous change of the combustion speed along with the gas phase pressure in the actual combustion process cannot be reflected; secondly, the method belongs to invasive measurement, in order to arrange a test element, an explosive interface needs to be artificially manufactured on a tested explosive column, and the propagation of combustion is necessarily interfered to a certain extent; thirdly, the metal wire implanted into the grain needs to be subjected to certain melting time before being fused, and cannot give out signals immediately, so that the signals are delayed; finally, the ignition head, the test wire and the like of the explosive need to penetrate through the closed combustion from the outsideThe container wall reaches the tested explosive column, which brings certain challenge to the sealing design at the threading hole; the wire is thinner in the disconnected silk method, very easily is destroyed, and this has also brought certain difficulty to the installation before the experiment, has seriously influenced experimental efficiency, has just so led to have had that measuring accuracy is on the low side, single experiment acquisition data volume is on the low side less, the experiment operation degree of difficulty is on the big side not enough in the experiment, leads to the leading cause of this kind of not enough production to lie in: firstly, the burning temperature of the explosive is high and strong light is emitted in the experimental process, and the common visible light testing technology cannot accurately distinguish the moving position of a burning surface; secondly, the pressure of the explosive combustion gas product is high and needs to reach the level of hundreds of MPa even GPa, so that the requirements on the high pressure resistance and the sealing performance of the closed combustion container are high; third, the variation of the explosive burning rate with the product pressure is large, usually from 0.1mm/s to 10⁴mm/s magnitude change, and most of burning rate measurement technologies are difficult to realize multi-magnitude high-precision diagnosis; therefore, in the invention, the commonly adopted combustion speed measurement method is abandoned, the combination of a high-pressure closed combustion experimental device, a speed measurement unit, an ignition unit and a gas product pressure real-time measurement unit is adopted to realize the non-contact high-precision measurement of the combustion rate of the explosive under high pressure, and the development relation of the combustion rate of the explosive under high pressure changing with the product pressure is obtained, in the invention, the speed measurement unit utilizes the Doppler effect of the terahertz wave to measure the combustion speed by an interference method, because the terahertz wave is an electromagnetic wave with the frequency ranging from 0.1 terahertz to 10 terahertz, the wavelength ranges from 0.03mm to 3mm approximately, and is between microwave and infrared, the terahertz wave belongs to invisible wave, the typical pulse width of the pulse of the terahertz wave is in picosecond magnitude, not only can the research of time resolution be conveniently carried out, but also through the sampling measurement technology, the high-pressure sealed combustion device can effectively inhibit the interference of far infrared background noise, and meanwhile, the transmission time of the terahertz waves on the optical path is nanosecond level, so that the speed measurement method is considered as instant response, the problem of response lag is solved, and therefore, the terahertz waves can effectively resist clutter interference when the combustion speed is measured, so that more accurate measurement speed is obtainedAnd the non-contact laser ignition can be effectively adapted to the pressure of the combustion gas product of the test explosive column, and the real-time gas product pressure measuring unit can collect and record real-time pressure change, so that the invention can obtain accurate combustion speed by utilizing the Doppler effect of terahertz waves and in a wave interference measuring mode, and the specific speed measuring principle is an interference measuring principle.

Further, the airtight burning experimental apparatus of high pressure includes the sealing device main part, be equipped with the device cavity in the sealing device main part, be equipped with locating component in the device cavity, locating component establishes outside the test grain locating component is equipped with the ignition agent outward, the top of device cavity is equipped with laser ignition window, the below of device cavity is equipped with the window that tests the speed, the position and the ignition unit position of laser ignition window correspond, the window that tests the speed with the unit position that tests the speed corresponds, is equipped with the pressure sensor mounting hole in the side of sealing device main part. In the invention, in order to improve the sealing performance of the high-pressure sealed combustion experimental device, a cavity is directly arranged in the middle of the sealing device main body, an ignition agent outside a positioning component in the cavity of the device is ignited through a laser ignition window in a non-contact laser irradiation mode, so that a test explosive column is ignited, terahertz waves are emitted and collected through a speed measurement window, and the combustion speed is measured by utilizing the interference of the terahertz waves.

Further, the sealing device main part includes the barrel, is equipped with the apron in the top of barrel, apron and barrel detachable fixed connection, is equipped with the bottom plate in the below of barrel, bottom plate and barrel detachable fixed connection, laser ignition window is located the top of barrel, be equipped with the laser hole on the apron, laser can reach the laser ignition window through the laser hole, be equipped with the terahertz wave hole on the bottom plate, terahertz wave can reach the window that tests the speed through the terahertz wave hole. In order to facilitate the installation of the positioning assembly, the sealing device main body is divided into a cover plate, a cylinder body and a bottom plate which are fixedly connected in a detachable mode, the top and the bottom of the cylinder body are not in a fully-open mode, and only the position enough for accommodating the installation of the positioning assembly and the position where laser and terahertz waves pass are reserved, so that the sealing performance of the device is enhanced, the laser ignition window corresponds to the laser hole in position, and the terahertz wave hole corresponds to the speed measurement window in position, so that the optimal ignition effect and the optimal speed measurement effect are achieved.

Further, a cover plate sealing ring is arranged between the cover plate and the cylinder body, and ignition window gaskets are arranged between the laser ignition window and the cover plate or the cylinder body; and a bottom plate sealing ring is arranged between the bottom plate and the cylinder body, and speed measuring window gaskets are arranged between the speed measuring window and the bottom plate or the cylinder body. The sealing ring is arranged at all the joints, the cover plate sealing ring is arranged between the cover plate and the cylinder body, the bottom plate sealing ring is arranged between the bottom plate and the cylinder body, the connection between the cover plate and the cylinder body and the connection between the bottom plate and the cylinder body are tighter through the limitation of the sealing rings, the sealing performance is more excellent, and the speed measurement window gasket and the ignition window gasket can effectively prevent high pressure from directly acting on the speed measurement window and the ignition window, so that the speed measurement window and the ignition window are prevented from being damaged by pressure, and the pressure resistance of the whole device is improved.

Further, locating component includes epoxy, the epoxy cover is located outside the test explosive column the epoxy overcoat is equipped with the sleeve, epoxy and test explosive column all with the window that tests the speed is fixed. In order to prevent the end face flame of the test explosive column from igniting the side face of the test explosive column and ensure that a combustion face is downward propagated along the axis of the test explosive column, the test explosive column needs to be packaged, the test explosive column is placed in a sleeve in the packaging treatment, the sleeve can be made of polytetrafluoroethylene so as to avoid influencing the test explosive column in the combustion process, and the epoxy resin is adopted to fill the gap in the sleeve in the invention, so that the epoxy resin in the sleeve can be normally used after being cured.

Further, the speed measuring unit comprises a terahertz wave source, a transmission and collection optical path and an orthogonal probe, wherein,

the terahertz wave source is used for emitting terahertz waves, focusing the terahertz waves and irradiating the terahertz waves into the high-pressure sealed combustion experimental device;

the transmission and collection optical path is used for transmitting the terahertz waves emitted by the terahertz wave source to the high-pressure sealed combustion experimental device, collecting the terahertz waves transmitted back by a combustion interface in the high-pressure sealed combustion experimental device and transmitting the terahertz waves to the orthogonal probe;

and the orthogonal probe is used for receiving the terahertz waves transmitted back from the high-pressure closed combustion experimental device, generating and outputting orthogonal IQ interference signals, and recording the orthogonal IQ interference signals by an oscilloscope.

In the speed measuring unit, terahertz waves emitted by a terahertz wave source are focused by a terahertz wave lens and then enter a target (namely a high-pressure sealed combustion experimental device), are reflected by an internal combustion interface and then return along an original path, and enter an orthogonal probe. According to the method, the reflected terahertz waves are subjected to phase change along with the movement of a combustion interface, orthogonal IQ interference signals are generated and output on an orthogonal probe after the reflected terahertz waves are interfered with a reference wall, and finally the orthogonal IQ interference signals are recorded by an oscilloscope. Therefore, the interface advancing speed in this time Δ t can be obtained. The refractive index of the general terahertz waveband explosive is 1.7-2.2, and high-precision (+/-1%) measurement can be carried out by methods such as terahertz-TDS and the like.

The device comprises a high-pressure closed combustion experimental device, a speed measuring unit, an ignition unit and a gas product pressure real-time measuring unit, wherein the speed measuring unit, the ignition unit and the gas product pressure real-time measuring unit are respectively connected with the synchronous machine; the real-time measuring unit for the pressure of the gas product comprises a pressure sensor and an oscilloscope, wherein the pressure sensor can measure the pressure change in the high-pressure closed combustion experimental device, and the oscilloscope can receive the signal of the pressure sensor and display the pressure fluctuation in the high-pressure closed combustion experimental device.

The non-contact type explosive burning rate measurement experiment method based on the terahertz waves comprises the following steps:

s1: preparing a grain and packaging and fixing the grain into the high-pressure closed combustion experimental device;

s2: assembling a high-pressure closed combustion experimental device, and checking the sealing property;

s3: installing a pressure sensor; the ignition laser and the ignition unit are aligned; the speed measuring terahertz wave and the speed measuring unit are aligned;

s4: arranging an oscilloscope and a synchronizer;

s5: and sending an ignition instruction and recording test data of each system.

The experiment method is adopted for carrying out the experiment, the tested sample is not interfered, because the method adopts a laser irradiation mode to ignite the tested explosive, the terahertz wave Doppler interference which can penetrate the explosive is utilized to measure the combustion rate of the explosive, the explosive does not need to be manually divided and spliced, any component is not needed to be placed in a combustion cavity, and the propagation of the combustion surface of the explosive and the pressurization process of the product gas cannot be interfered; the method can continuously measure the measured object based on the terahertz wave Doppler interference speed measurement, and compared with a method similar to a wire breaking method, which can only obtain 5-7 pieces of speed measurement data at most in each experiment, the method can obtain at least dozens of hundreds of data, so that the test efficiency is improved.

Further, when the ignition agent is arranged, the ignition agent is laid on the ignition end face of the test explosive column. The ignition agent is laid on the ignition end face of the explosive column, so that the explosive column can be effectively ignited, and the explosive column can start to burn from the end face, and therefore the burning face is guaranteed to be downward propagated along the axial line of the explosive column.

Further, in step S3, the indication light of the ignition laser is vertically incident downwards from the ignition window into the ignition window through the reflector, and the adjustment indication light spot is located at the center of the window. By means of the pre-adjustment under the combined action of the reflector and the indicating light, the ignition laser can be adjusted to an accurate position so as to achieve the optimal ignition effect.

Further, in step S3, the indicator light of the speed measurement terahertz wave is vertically incident into the speed measurement window from the speed measurement window upwards through the reflector, and the light spot of the indicator light is adjusted to be located at the center of the window. Through the preconditioning under the combined action of the reflector and the indicating light, the transmitting path of the terahertz wave can be adjusted to an accurate position, so that the best measuring effect is achieved, and the human error is reduced.

In conclusion, compared with the prior art, the invention has the following beneficial effects:

(1) the high-pressure sealed combustion device and the non-contact laser ignition in the invention can effectively adapt to the pressure of explosive combustion gas products, and the real-time gas product pressure measuring unit can collect and record real-time pressure changes, so that the invention can obtain accurate combustion speed by utilizing the Doppler effect of terahertz waves and in a mode of measuring wave interference.

(2) In the invention, in order to prevent the flame on the end face of the explosive column from igniting the side face of the explosive column and ensure that the combustion face is transmitted downwards along the axis of the explosive column, the test explosive column needs to be packaged.

(3) The method has the advantages that the terahertz wave Doppler interference speed measurement adopted by the method can be used for continuously measuring the measured object, compared with a wire breaking method which can only obtain 5-7 pieces of speed measurement data at most in each experiment, the data quantity obtained by the method can reach at least dozens of hundreds, so that the test efficiency is improved; the invention can be used for testing the combustion speed of the explosive column and measuring the relation of the combustion rate of fixed energetic materials such as solid propellant and the like along with the change of reaction pressure.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a structural layout diagram of an experimental apparatus according to the present invention;

FIG. 2 is a schematic structural diagram of a high-pressure closed combustion experimental facility according to the present invention;

FIG. 3 is a flow chart of an experimental method of the present invention;

FIG. 4 is a graph of pressure signal amplitude for an embodiment of the present invention;

FIG. 5 is a graph of magnitude of combustion velocity for an embodiment of the present invention;

FIG. 6 is a graph of combustion speed versus pressure for an embodiment of the present invention;

the reference numerals referred to in the present invention denote: 1. a cover plate; 2. a barrel; 3. a base plate; 4. fastening a bolt; 5. a pressure sensor mounting hole; 6. a laser ignition window; 7. a speed measuring window; 8. testing the explosive column; 9. an epoxy resin; 10. a sleeve; 11. an ignition agent; 12. a device cavity; 13. a firing window gasket; 14. a cover plate sealing ring; 15. a speed measuring window gasket; 16. and the bottom plate is provided with a sealing ring.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

Example 1:

as shown in FIGS. 1-2, the terahertz wave-based explosive burning rate non-contact measurement experimental device comprises a high-pressure closed combustion experimental device, a speed measurement unit, an ignition unit and a gas product pressure real-time measurement unit, wherein the speed measurement unit, the ignition unit and the gas product pressure real-time measurement unit are respectively connected with the high-pressure closed combustion experimental device,

the high-pressure airtight combustion experimental device is internally fixed with a test explosive column 8, and the test explosive column 8 is used for carrying out a high-pressure airtight combustion experiment in the high-pressure airtight combustion experimental device;

the ignition unit is used for carrying out non-contact ignition on the test explosive column 8 in the high-pressure closed combustion experimental device by utilizing laser irradiation;

the speed measurement unit is used for carrying out combustion speed measurement on the test explosive column 8 in the high-pressure sealed combustion experimental device by utilizing the Doppler effect of the terahertz waves;

and the gas product pressure real-time measuring unit is used for measuring and recording pressure data changes generated by the high-pressure closed combustion experimental device.

In the embodiment, the ignition unit is a non-contact laser irradiation ignition unit; the speed measuring unit is a terahertz wave Doppler interference speed measuring unit.

The device comprises a high-pressure closed combustion experimental device and is characterized by further comprising a synchronizer, wherein the speed measuring unit, the ignition unit and the real-time gas product pressure measuring unit are respectively connected with the synchronizer, the ignition unit comprises a laser, and the laser can emit laser irradiation into the high-pressure closed combustion experimental device; the real-time measuring unit for the pressure of the gas product comprises a pressure sensor and an oscilloscope, wherein the pressure sensor can measure the pressure change in the high-pressure closed combustion experimental device, and the oscilloscope can receive the signal of the pressure sensor and display the pressure fluctuation in the high-pressure closed combustion experimental device. The pressure sensor mounting hole can be communicated with the pressure sensor and the device cavity, so that the pressure sensor can achieve the purpose of detecting the change of the internal pressure on the basis of not damaging the sealing performance of the sealing device main body.

The high-pressure airtight combustion experimental device comprises a sealing device main body, a device cavity 12 is arranged in the sealing device main body, a positioning assembly is arranged in the device cavity 12, the positioning assembly is sleeved outside a test explosive column 8, an ignition agent 11 is arranged outside the positioning assembly, a laser ignition window 6 is arranged above the device cavity 12, a speed measurement window 7 is arranged below the device cavity 12, the position of the laser ignition window 6 corresponds to the position of an ignition unit, the speed measurement window 7 corresponds to the position of the speed measurement unit, and a pressure sensor mounting hole 5 is formed in the side face of the sealing device main body.

The sealing device main part includes barrel 2, is equipped with apron 1 in the top of barrel 2, apron 1 and barrel 2 detachable fixed connection, is equipped with bottom plate 3 in the below of barrel 2, bottom plate 3 and barrel 2 detachable fixed connection, laser ignition window 6 is located the top of barrel 2, be equipped with the laser hole on the apron 1, laser can reach laser ignition window 6 through the laser hole, be equipped with terahertz wave hole on the bottom plate 3, terahertz wave can reach speed measuring window 7 through terahertz wave hole.

A cover plate sealing ring 14 is arranged between the cover plate 1 and the cylinder body 2, and ignition window gaskets 13 are arranged between the laser ignition window 6 and the cover plate 1 or the cylinder body 2; a bottom plate sealing ring 16 is arranged between the bottom plate 3 and the cylinder body 2, and speed measuring window gaskets 15 are arranged between the speed measuring window 7 and the bottom plate 3 or the cylinder body 2.

In this embodiment, the metal material of the high-pressure sealed combustion experimental device is high-strength steel (45 #), the wall thickness of the cylinder 2 is 25mm, and the size of the device cavity 12 is phi 30mm × 60 mm. The detachable fixed connection is bolt connection, and the cover plate 1, the bottom plate 3 and the cylinder 2 are connected through 12.9-grade M16 fastening bolts 4. The cover plate 1 and the barrel 2, and the bottom plate 3 and the barrel 2 are respectively sealed by a cover plate sealing ring 14 and a bottom plate sealing ring 16, and the sealing rings are made of red copper. Under the action of the fastening bolt 4, the sealing ring is pressed and deformed to form a sealing experiment cavity.

Locating component includes epoxy 9, 9 covers of epoxy are located outside the test grain 8 the 9 overcoat of epoxy is equipped with sleeve 10, epoxy 9 and test grain 8 all with the window 7 that tests the speed is fixed. The packed explosive column test explosive column 8 is a PBX explosive column having a size of Φ 20mm × 40 mm.

The ignition window 6 is sapphire glass embedded above the cylinder 2, and aims to realize non-contact type ignition laser through the window and ensure the high-pressure tightness of the high-pressure closed combustion experimental device, the size of the ignition window is phi 20mm multiplied by 20mm, and ignition laser beams enter the surface of the ignition test grain 8 from the window. And an ignition window gasket 13 is arranged between the ignition window 6 and the cover plate 1 and the cylinder body 2 and mainly plays a role in protecting the window and sealing.

The speed measuring window 7 is made of sapphire glass embedded below the cylinder 2, the purpose is to realize non-contact real-time measurement of the speed of the explosive column in the cavity through the window, the high-pressure tightness of the high-pressure closed combustion experimental device and the external interference of a sample are guaranteed, the size of the high-pressure closed combustion experimental device is phi 50mm multiplied by 20mm, terahertz waves enter from the window and penetrate through the explosive from the bottom of the explosive column 8, and therefore the moving speed of a combustion surface is measured. And a speed measuring window gasket 15 is arranged between the speed measuring window 7 and the bottom plate 3 and between the speed measuring window 7 and the barrel body 2, and mainly plays a role in protecting the window and sealing.

The speed measuring unit comprises a terahertz wave source, a transmission and collection optical path and an orthogonal probe, wherein,

the terahertz wave source is used for emitting terahertz waves, focusing the terahertz waves and irradiating the terahertz waves into the high-pressure sealed combustion experimental device;

the transmission and collection optical path is used for transmitting the terahertz waves emitted by the terahertz wave source to the high-pressure sealed combustion experimental device, collecting the terahertz waves transmitted back by a combustion interface in the high-pressure sealed combustion experimental device and transmitting the terahertz waves to the orthogonal probe;

and the orthogonal probe is used for receiving the terahertz waves transmitted back from the high-pressure closed combustion experimental device, generating and outputting orthogonal IQ interference signals, and recording the orthogonal IQ interference signals by an oscilloscope.

In the embodiment, the orthogonal probe is used as a receiver of the terahertz wave, so that the terahertz wave can be effectively received and used as data for measuring the speed of combustion.

The ignition unit in this embodiment is a laser irradiation ignition unit, and the laser irradiation ignition unit includes a control system, a laser host and a light beam transmission optical cable. The control system is used for setting the power, the light emitting frequency and the light emitting duration of the ignition laser beam, the control system is connected to the laser host by utilizing a network cable and adopting a TCP/IP communication protocol, the control software generates all setting instructions to the laser, and the laser host emits high-energy laser through the light beam transmission optical cable after receiving the ignition instructions; the laser host comprises an external trigger channel used for inputting a trigger signal of the synchronous machine. The real-time gas product pressure measuring unit comprises a high-frequency pressure sensor and an oscilloscope. And the oscilloscope starts to record the product pressure data acquired by the pressure sensor after acquiring the trigger instruction of the synchronous machine. The control system in this embodiment is a control system capable of large-scale configuration in the prior art.

In the embodiment, for the PBX block explosive, the end face of the explosive column is ignited by laser irradiation in the closed combustion device, so that a thermal conduction combustion reaction is formed at the end face and the explosive column propagates downwards along the axis of the explosive column. By utilizing a terahertz wave Doppler interference velocity measurement technology and a high-frequency pressure sensor, a sensor with the model of PCB-109C12 can be adopted to synchronously measure the retreating speed of the combustion surface of the explosive column and the pressure change of gas products in the closed combustion device. The explosive burning rate measurement and the product pressure measurement are subjected to time sequence synchronization through a synchronization machine, and the light emitting time of the ignition laser is taken as zero time. And taking the measured burning rate data moment as a reference, and obtaining the product pressure condition at the corresponding moment by an interpolation method to finally obtain the burning rate-pressure relation of the explosive.

In the embodiment, a terahertz Doppler interference velocity measurement system with the frequency of 0.21THz is used for testing, so that the delta x is approximately equal to 0.08 mm-0.1 mm, namely, the corresponding combustion speed can be obtained when the explosive combustion interface is advanced by about 0.1 mm. Therefore, a more dense effective speed measuring point can be obtained by adopting the terahertz Doppler interference speed measuring system. In addition, the time difference delta t between the interference signal peak and the valley can be accurately extracted through methods such as curve fitting, and therefore high speed measurement accuracy can be achieved.

Example 2:

as shown in fig. 1 to 3, on the basis of embodiment 1, the non-contact measurement experiment method for the explosive burning rate of terahertz waves includes the following steps:

s1: preparing a grain and packaging and fixing the grain into the high-pressure closed combustion experimental device;

s2: assembling a high-pressure closed combustion experimental device, and checking the sealing property;

s3: installing a pressure sensor; the ignition laser and the ignition unit are aligned, the indicating light of the ignition laser is vertically and downwards incident into the ignition window from the ignition window through the reflector, and the light spot of the indicating light is adjusted to be positioned in the center of the window; the speed measuring terahertz wave and the speed measuring unit are used for focusing light, indicating light of the speed measuring terahertz wave is vertically upwards incident into the speed measuring window 7 from the speed measuring window 7 through the reflector, and an indicating light spot is adjusted to be located in the center of the window;

s4: arranging an oscilloscope and a synchronizer;

s5: and sending an ignition instruction and recording test data of each system.

When the ignition agent 11 is arranged, the ignition agent 11 is laid on the ignition end face of the test grain 8.

In this embodiment, a synchronizer is respectively connected to the laser, the oscilloscope and the external trigger channel of the terahertz wave receiver, so that the non-contact laser irradiation ignition unit, the real-time gas product measurement unit and the terahertz wave doppler interference velocity measurement unit can be triggered simultaneously. Ignition laser emitted by the laser is incident to the closed combustion device from the right upper side through the reflector, and reaches the upper surface of the test explosive column through the ignition window. The pressure sensor is arranged on the high-pressure closed combustion device and is connected with the oscilloscope through a signal wire, and the measured product pressure signal is recorded and stored by the oscilloscope. The speed measurement terahertz wave emitted by the terahertz wave source enters the closed combustion device from the right lower part through the reflector and reaches the combustion surface through the speed measurement window and the penetration powder column. The waves reflected by the combustion surface are recorded by a receiver through an optical assembly.

FIG. 4 shows the measured pressure increase signal of the explosive gas product under closed combustion over time; FIG. 5 shows the measured change in the rate of explosive burn with time during the pressure increase of the gaseous product; the combustion pressure-velocity relationship shown in fig. 6 is obtained by correlating fig. 4 and fig. 5 with time, and the abscissa in fig. 6 represents the gas product pressure and the ordinate represents the explosive combustion velocity. As can be seen from fig. 4 and 5: the non-contact measurement experiment device for the explosive burning rate has good signal quality, can obtain high-precision burning rate historical signals and gas product pressure changes corresponding to the high-precision burning rate historical signals, and proves that the non-contact measurement experiment device and the non-contact measurement experiment method for the explosive burning rate have the characteristics of high measurement precision, rich single-shot experiment data and the like.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.