A critical pressure testing system and method for explosive combustion flame entering gap

Abstract

The present invention discloses a critical pressure testing system and method for detecting the entry of explosive combustion flames into gaps. The system comprises a main reaction device, a pressure testing unit, an ignition unit, and a photographic unit. The main reaction device comprises a reaction cell, a viewing window, and a gland. The pressure testing unit comprises a pressure sensor, a charge amplifier, and an oscilloscope. The ignition unit comprises an igniter, an optical fiber, and a laser. The photographic unit comprises a high-speed camera and a data collector. The testing unit also comprises a synchronous signal trigger for controlling the pressure testing unit and the photographic unit. The pressure testing unit and the ignition unit are both connected to the main reaction device, the photographic unit is connected to the synchronous signal trigger, and the pressure testing unit and the ignition unit are each connected to the synchronous signal trigger. The system and method provide a new option for distinguishing the safety of explosives with different formulas and can more accurately determine the relative accident risks of explosives with different formulas or storage periods.

Description

Technical Field

[0001] The present invention relates to the technical field of energetic material safety assessment, and in particular to a critical pressure testing system and method for explosive combustion flames entering a gap. Background Art

[0002] When accidents occur during the production, transportation, use, and disposal of explosives, they may experience combustion, deflagration, or even detonation reactions. The key physical process for these high-intensity reactions is the transition from laminar surface combustion to convective combustion, which increases the combustion surface area. However, this physical process requires two basic conditions: the presence of cracks or crevices in the explosive matrix, and the entry of the combustion flame into these cracks. During an accident, explosives can fracture under heat or mechanical loads, forming cracks. After ignition, the combustion flame can only enter these cracks at a certain pressure threshold, known as the critical pressure. This pressure varies under different conditions and is primarily related to the explosive's physical and chemical properties and the size of the crack structure. Therefore, measuring the critical pressure at which the combustion flame enters a crack not only helps to screen explosives with superior safety performance but also provides a more reliable basis for assessing the relative accident risks of explosives with different formulations or storage periods. Currently, there is a lack of a test method for measuring the critical pressure at which the combustion flame enters a crack. Summary of the Invention

[0003] The object of the present invention is to provide a critical pressure testing system and method for explosive combustion flames entering a gap. The method has a wide pressure measurement range, is simple to operate, and has high reliability. The system and method provide a new option for distinguishing the safety of explosives with different formulas and can more accurately judge the relative accident risks of explosives with different formulas or storage periods.

[0004] In order to achieve the above technical effects, the present invention provides the following technical solutions:

[0005] A critical pressure testing system for explosive combustion flames entering a gap comprises a main reaction device, a pressure testing unit, an ignition unit and a photographic unit. The main reaction device comprises a reaction pool, a window and a pressure cover. The pressure testing unit comprises a pressure sensor, a charge amplifier and an oscilloscope. The ignition unit comprises an igniter, an optical fiber and a laser. The photographic unit comprises a high-speed camera and a data collector. The testing unit also comprises a synchronous signal trigger for controlling the pressure testing unit and the photographic unit to collect data. The pressure testing unit and the ignition unit are both connected to the main reaction device. The photographic unit is connected to the synchronous signal trigger. The pressure testing unit and the ignition unit are respectively connected to the synchronous signal trigger.

[0006] A further technical solution is that a threaded hole is designed at the bottom of the reaction cell cavity and is sealed with a pressure sensor, a threaded hole is designed at the end face of the reaction cell and is sealed with the optical fiber, and the upper end face of the reaction cell is squeezed and sealed with the window; the pressure sensor is connected to the charge amplifier, the charge amplifier is connected to the oscilloscope, and the oscilloscope is connected to the synchronization signal trigger; the two ends of the optical fiber are respectively connected to one end of the igniter and the laser, the other end of the igniter is connected to the sample, and the laser is connected to the synchronization signal trigger; the high-speed camera is respectively connected to the data collector and the synchronization signal trigger.

[0007] A further technical solution is that the main reaction device also includes a seal, an adjustment block and a sample. The upper end of the reaction pool is open, and two stepped grooves are designed inside, namely an upper groove and a lower groove. The lower groove of the reaction pool is connected to the seal, the adjustment block and the sample. The sample is connected to the adjustment block through the seal, the adjustment block is connected to the reaction pool through the seal, the sample end face is connected to the igniter, the bottom of the lower groove cavity of the reaction pool is connected to the pressure sensor through a threaded hole, the upper groove of the reaction pool is connected to the window, the window is connected to the pressure cover, and the pressure cover is connected to the reaction pool by bolts.

[0008] A further technical solution is that there are gaps between the samples, the gaps are open and penetrating, and the gap width is in the range of 50 μm to 1 mm.

[0009] A further technical solution is that the volume of the cavity of the lower groove of the reaction pool accounts for 40% to 60% of the total volume of the lower groove.

[0010] The present invention also provides a critical pressure test method for explosive combustion flame entering a gap, comprising the following steps: (1) selecting a suitable adjustment block according to the gap size, and installing the sample and the adjustment block in a reaction pool through a seal; (2) installing an igniter on the end face of the sample, and installing a pressure sensor and an optical fiber on the bottom face and the end face of the reaction pool respectively; (3) installing a window on the upper part of the reaction pool, installing a pressure cover on the upper end of the window, and connecting the pressure cover and the reaction pool by bolts to press the window and the reaction pool; (4) connecting a pressure test unit, a photographic unit and an ignition unit, and connecting them to a signal synchronization trigger; (5) conducting a test, sending a laser signal to start ignition, and at the same time triggering the synchronization signal trigger, and the test system collecting data under the triggering of the synchronization signal trigger; (6) obtaining the critical pressure of the sample combustion flame entering the gap according to the test results.

[0011] The system uses laser remote ignition for high safety. The sample gap size is easily adjustable and controllable, and the system has excellent sealing performance. The system design features visual observation, combined with data testing, resulting in highly reliable test results. Furthermore, the method can measure the critical pressure of explosive flames entering the gap for various gap sizes. The gap size range is wide (50 μm to 1 mm), and the gap structure size is easily adjustable and controllable. The system also features a simple structure, low cost, and high reliability.

[0012] Compared with existing technologies, the present invention offers the following advantages: This method effectively measures the critical pressure at which the burning flame of an explosive enters a gap, enabling comparison and screening of explosives with superior safety performance. Using the test system of the present invention, a study determined the critical pressure at which the burning flame enters a gap for typical explosives with varying gap sizes, providing a basis for determining the relative accident risks of different explosive formulations. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of the test system structure of the present invention;

[0014] Figure 2 A top view of the main reaction device of the present invention;

[0015] Figure 3 It is a side view of the main reaction device of the present invention.

[0016] In the figure, 1-reaction cell; 2-pressure sensor; 3-optical fiber; 4-igniter; 5-sample; 6-charge amplifier; 7-oscilloscope; 8-data acquisition device; 9-synchronization signal trigger; 10-high-speed camera; 11-window; 12-pressure cover; 13-laser; 14-seal; 15-adjustment block; 16-sample gap; 17-bolt. DETAILED DESCRIPTION

[0017] The present invention will be further explained and illustrated below with reference to the accompanying drawings and specific embodiments.

[0018] Example 1

[0019] like Figure 1 As shown, Figure 1 A system diagram of the test method of the present invention is given, and its components mainly include: a main reaction device, which includes a reaction pool 1, a window 11, and a pressure cover 12; a pressure testing unit connected to the main reaction device to measure the reaction pressure of the sample, which includes a pressure sensor 2, a charge amplifier 6, and an oscilloscope 7; an ignition unit connected to the main reaction device to ignite the sample, which includes an igniter 4, an optical fiber 3, and a laser 13; a photography unit for testing the flame propagation process of the sample combustion, which includes a high-speed camera 10 and a data acquisition unit 8; and a synchronization signal trigger 9 for controlling the pressure testing unit and the photography unit to collect data.

[0020] A threaded hole is designed at the bottom of the cavity of the reaction pool 1 and is connected and sealed with the pressure sensor 2. A threaded hole is designed at the end face of the reaction pool 1 and is connected and sealed with the optical fiber 3. The upper end face of the reaction pool 1 is squeezed and sealed with the window; the pressure sensor 2 is connected to the charge amplifier 6, the charge amplifier 6 is connected to the oscilloscope 7, and the oscilloscope 7 is connected to the synchronization signal trigger 9; the optical fiber 3 is connected to the igniter 4 and the laser 13, the igniter 4 is connected to the sample 5, and the laser 13 is connected to the synchronization signal trigger 9; the high-speed camera 10 is connected to the data collector 8, and the high-speed camera 10 is connected to the synchronization signal trigger 9.

[0021] like Figure 2 and Figure 3 As shown, the main reaction device also includes a seal, an adjustment block, and a sample. The reaction cell 1, adjustment block 15, and sample 5 are rectangular in shape. The reaction cell 1 is open at the top and has a two-stepped internal groove. The lower groove connects to the seal 14, adjustment block 15, and sample 5. The sample 5 is connected to the adjustment block 15 via the seal 14, and the adjustment block 15 is connected to the reaction cell 1 via the seal 14. The end face of the sample 5 is connected to the igniter 4, which is connected to the optical fiber 3. The optical fiber 3 is partially threaded and connected to the reaction cell 1. The threaded hole at the bottom of the lower groove of the reaction cell 1 is connected to the pressure sensor 2. The upper groove of the reaction cell 1 is connected to the rectangular window 11, which is connected to the pressure cover 12. The pressure cover 12 is connected to the reaction cell 1 via bolts 17. The sample gap size 16 is formed by splicing two samples together, and the width of the sample gap is controlled by the thickness of the adjustment block 15. The volume of the lower groove of the sample cell 1 accounts for 40% to 60% of the total volume of the lower groove.

[0022] Example 2

[0023] The present embodiment provides a method for testing the critical pressure of explosive combustion flame entering a gap, comprising the following steps: (1) selecting a suitable adjustment block according to the gap size, and installing the sample and the adjustment block in a reaction pool through a seal; (2) installing an igniter on the end face of the sample, and installing a pressure sensor and an optical fiber on the bottom face and the end face of the reaction pool, respectively; (3) installing a window on the upper part of the reaction pool, installing a pressure cover on the upper end of the window, and connecting the pressure cover and the reaction pool by bolts to press the window and the reaction pool; (4) connecting a pressure test unit, a photographic unit and an ignition unit, and connecting them to a signal synchronization trigger; (5) conducting a test, sending a laser signal to start ignition, and at the same time triggering the synchronization signal trigger, and the test unit collecting data under the triggering of the synchronization signal trigger; (6) obtaining the critical pressure of the sample combustion flame entering the gap based on the test results.

[0024] Criteria for test results: The moment when the sample combustion flame begins to enter the gap is observed by a high-speed camera, and the pressure data at the corresponding moment is the critical pressure at which the sample combustion flame enters the gap.

[0025] Although the present invention is described herein with reference to illustrative embodiments of the present invention, the above embodiments are merely preferred embodiments of the present invention, and the embodiments of the present invention are not limited to the above embodiments. It should be understood that those skilled in the art can design many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A critical pressure test system for explosive combustion flame entering a gap, characterized in that: The invention comprises a main reaction device, a pressure test unit, an ignition unit and a photographic unit, wherein the main reaction device comprises a reaction pool, a window and a pressure cover, the pressure test unit comprises a pressure sensor, a charge amplifier and an oscilloscope, the ignition unit comprises an igniter, an optical fiber and a laser, the photographic unit comprises a high-speed camera and a data collector, the test unit further comprises a synchronization signal trigger for controlling the pressure test unit and the photographic unit to collect data, the pressure test unit and the ignition unit are both connected to the main reaction device, the photographic unit is connected to the synchronization signal trigger, and the pressure test unit and the ignition unit are respectively connected to the synchronization signal trigger; the main reaction device further comprises a sealing member, The adjustment block and the sample, the upper end of the reaction pool is open, and two stepped grooves are designed inside, namely the upper groove and the lower groove. The lower groove of the reaction pool is connected to the seal, the adjustment block, and the sample. The sample is connected to the adjustment block through the seal, and the adjustment block is connected to the reaction pool through the seal. The end face of the sample is connected to the igniter. The bottom of the cavity of the lower groove of the reaction pool is connected to the pressure sensor through a threaded hole. The upper groove of the reaction pool is connected to the window, and the window is connected to the pressure cover. The pressure cover is connected to the reaction pool by bolts; there is a gap between the samples, the gap shape is an open through, and the gap width is in the range of 50μm~1mm.

2. The critical pressure testing system for explosive combustion flame entering a gap according to claim 1, characterized in that: The bottom of the reaction pool cavity is reliably sealed and connected to the pressure sensor, the end face of the reaction pool is sealed and connected to the optical fiber, and the upper end face of the reaction pool is squeezed and sealed with the window; the pressure sensor is connected to the charge amplifier, the charge amplifier is connected to the oscilloscope, and the oscilloscope is connected to the synchronization signal trigger; the two ends of the optical fiber are respectively connected to one end of the igniter and the laser, the other end of the igniter is connected to the sample, and the laser is connected to the synchronization signal trigger; the high-speed camera is respectively connected to the data collector and the synchronization signal trigger.

3. The critical pressure testing system for explosive combustion flame entering a gap according to claim 1, characterized in that: The cavity volume of the lower groove of the reaction pool accounts for 40% to 60% of the total volume of the lower groove.

4. A method for testing the critical pressure of explosive combustion flame entering a gap, characterized in that: The test method is implemented based on the pressure test system according to any one of claims 1 to 3, and comprises the following steps: (1) installing the sample and the adjustment block in the reaction pool through a seal; (2) installing an igniter on the end face of the sample, and installing a pressure sensor and an optical fiber on the bottom and end face of the reaction pool respectively; (3) installing a window on the upper part of the reaction pool, installing a pressure cover on the upper end of the window, and connecting the pressure cover and the reaction pool by bolts to press the window and the reaction pool; (4) connecting the pressure test unit, the photographic unit and the ignition unit, and connecting them with a signal synchronization trigger; (5) conducting a test, sending a laser signal to start ignition, and triggering the synchronization signal trigger at the same time, and the test unit collecting data under the triggering of the synchronization signal trigger; (6) obtaining the critical pressure of the sample combustion flame entering the gap based on the test results.

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