A system and method for testing the explosion characteristics of a dust combustible gas mixture system in a shock tube

Abstract

The application discloses a kind of explosion characteristic test system and method of dust combustible gas mixed system in shock tube, comprising: shock tube test device, multiple observation windows are provided along the axial direction, for high-speed camera to shoot dust winch, flame formation and propagation state;Gas inlet system is used to fill the combustible gas of specified volume fraction into shock tube test device;Pressure data acquisition system and high-speed camera are used to collect pressure signal and flame propagation visual data in explosion process respectively;Ignition system includes synchronous ignition controller, multi-way ignition device and multi-way winch device;The synchronous ignition controller includes PLC controller, digital input / output module, analog input module and control execution module;Winch device is used to generate jet to winch combustible dust laid on the bottom of shock tube;Ignition device is used to ignite dust and combustible gas mixed system.The application can realize the synchronous accurate collection of pressure and flame data.

Description

Technical Field

[0001] This invention belongs to the field of explosion characteristic testing technology, specifically relating to an explosion characteristic testing system and method for a dust / combustible gas mixture system inside a shock tube, applicable to explosion risk assessment, mechanism research, and safety protection technology development and verification in scenarios where dust and combustible gas coexist. Background Technology

[0002] In industrial production, scenarios where dust and combustible gases coexist are widespread. Explosions in such mixtures can easily cause serious casualties and property damage, making accurate testing of their explosive characteristics crucial. Currently, existing explosion testing devices for dust / combustible gas mixtures have several shortcomings: some devices cannot flexibly adjust the shock tube length to adapt to different experimental requirements, resulting in poor controllability of dust entrainment and difficulty in simulating different dust suspension states in real-world scenarios; some devices use a single ignition method, failing to meet ignition requirements under different experimental conditions, and the synchronous acquisition accuracy of pressure and flame propagation data is insufficient, leading to poor accuracy and comprehensiveness of test results. Furthermore, the structural design of existing devices is not flexible enough, making disassembly and assembly inconvenient, and resulting in low testing efficiency, making it difficult to meet the diverse needs of explosion characteristic research. To address these shortcomings of existing technologies, there is an urgent need for an explosion characteristic testing system and method that can solve these problems and achieve accurate testing. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a test system and method for the explosion characteristics of a dust / combustible gas mixture system in a shock tube, so as to achieve accurate and comprehensive testing of the explosion characteristics of the dust / combustible gas mixture system, improve the flexibility and efficiency of the test, and meet diverse test needs.

[0004] The technical solution to achieve the purpose of this invention is as follows:

[0005] An explosion characteristic testing system for a dust-combustible gas mixture system inside a shock tube, comprising:

[0006] The shock tube test device is equipped with multiple observation windows along the axial direction for high-speed photography to capture the dust swirling, flame formation and propagation.

[0007] The air intake system is used to fill the shock tube test apparatus with a specified volume fraction of combustible gas.

[0008] The pressure data acquisition system and the high-speed camera are used to acquire pressure signals and flame propagation visualization data during the explosion process, respectively.

[0009] The ignition system includes a synchronous ignition controller, a multi-channel ignition device, and a multi-channel winch device. The synchronous ignition controller includes a PLC controller, a digital input / output module, an analog input module, and a control execution module. The PLC controller enables human-machine interaction via a touchscreen. The digital input / output module receives power-on, emergency stop, and reset control signals and transmits these signals to the PLC controller. The PLC controller sends synchronous control commands to the control execution module. The control execution module synchronously controls the starting actions of the ignition device and the winch device according to the synchronous control commands.

[0010] The digital input ports of the PLC controller are connected to operation buttons, including: an ignition start button for receiving ignition start commands, a low-voltage energy storage button for receiving low-voltage energy storage commands, a high-voltage energy storage button for receiving high-voltage energy storage commands, a reset button for receiving system reset commands, and an emergency stop button for receiving emergency stop commands.

[0011] During ignition, depending on the ignition type, first press the low-voltage energy storage button or the high-voltage energy storage button. Pressing the low-voltage energy storage button allows the controller to execute the low-voltage ignition command, while pressing the high-voltage energy storage button allows the high-voltage ignition command to be executed. The voltage is then boosted to the required high voltage through a capacitor to achieve energy storage. Then, press the ignition start button to connect the power supply to the corresponding ignition interface.

[0012] The PLC controller body and digital output module constitute a digital output circuit, which drives various actuators via relay groups:

[0013] The PLC controller's multiple digital output ports are connected to multiple low-voltage ignition circuits and multiple high-voltage energy storage circuits via multiple relays, respectively, to control the on / off state of multiple low-voltage ignition devices and multiple required high-voltage outputs.

[0014] The PLC controller's multiple digital output ports are connected to multiple high-voltage energy storage circuits via relays to control the on / off state of multiple required high-voltage outputs.

[0015] The digital output module's multiple digital output ports are connected to multiple high-voltage ignition circuits and multiple solenoid valve circuits via multiple relays, respectively, to control the on / off state of the multiple high-voltage ignition devices and multiple solenoid valves.

[0016] The solenoid valve is used to control the on / off state of the hoisting device; the hoisting device is used to generate a jet to hoist the combustible dust laid at the bottom of the shock tube; the ignition device is used to ignite the mixture of dust and combustible gas.

[0017] The significant advantages of this invention compared to existing technologies are:

[0018] 1) The shock tube structure with multi-section flange connection improves the flexibility of the test device and can be adapted to different test length requirements;

[0019] 2) Multiple ignition methods and adjustable dust hoisting effect can simulate the mixed system state under different actual scenarios; pressure and flame data are collected simultaneously, which improves the accuracy and comprehensiveness of test results;

[0020] 3) The overall structure is reasonably designed and easy to assemble and disassemble, which effectively improves the efficiency of the test and can provide reliable support for the explosion risk management, mechanism research and safety protection technology development of dust / combustible gas mixture systems. Attached Figure Description

[0021] Figure 1 This diagram illustrates a general schematic of a system and method for testing the explosion characteristics of a dust / combustible gas mixture in a shock tube, according to an embodiment of the present invention.

[0022] Figure 2 A schematic diagram of the shock tube explosion device according to an embodiment of the present invention is shown.

[0023] Figure 3 A schematic diagram of the winch device structure of the ignition system according to an embodiment of the present invention is shown.

[0024] Figure 4 A schematic diagram of the shock tube inlet structure according to an embodiment of the present invention is shown.

[0025] Figure 5 The following is an illustration of the interface for setting the low-pressure ignition delay time and ignition time of the ignition test controller according to an embodiment of the present invention.

[0026] Figure 6 The high-voltage ignition delay time and ignition time control interface of the ignition test controller according to an embodiment of the present invention are shown.

[0027] Figure 7 The interface for setting the solenoid valve delay start time and opening time of the ignition controller according to an embodiment of the present invention is shown.

[0028] Figure 8 A circuit diagram of an ignition controller according to an embodiment of the present invention is shown.

[0029] In the diagram: 1. Hoisting device; 101 Straight pipe; 102 Compression fitting; 103 Elbow; 104 External threaded fitting; 105 Sealing flange; 106 Check valve; 107 Fitting; 108 Solenoid valve; 109 Quick-connect fitting; 2. Shock tube test device; 3. Shock tube inlet interface; 301 Fitting; 302 High-pressure ball valve; 303 Fitting; 304 Four-way fitting; 305 Vacuum pressure gauge; 306 Fitting; 307 High-pressure ball valve; 308 Quick-connect fitting. Detailed Implementation

[0030] To more clearly illustrate the purpose, technical solution, and advantages of this invention, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes and to facilitate understanding and reading by those skilled in the art. They are not intended to limit the implementation conditions of this invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0031] like Figure 1 As shown, the present invention provides a shock tube dust / combustible gas mixture system explosion characteristic testing system, including shock tube test device 2, ignition system, air intake system, pressure data acquisition system, high-speed camera and computer. The systems work together to complete dust hoisting, mixing, ignition, synchronous acquisition and analysis of test data, and the overall system connection relationship.

[0032] The ignition system is the core execution unit, comprising a synchronous ignition controller, wiring, an ignition device, and a winch device 1. The synchronous ignition controller has three types of interfaces: a low-pressure interface, a high-pressure interface, and a solenoid valve interface. The low-pressure and high-pressure interfaces are connected to the ignition device via wiring; the solenoid valve interface is connected to the solenoid valve via wiring and is used to control the on / off state of the solenoid valve in the winch device. The intake system is used to fill the shock tube test device 2 with a specified volume fraction of combustible gas. The pressure data acquisition system and high-speed camera are used to acquire pressure signals and flame propagation visualization data during the explosion process, respectively. The computer is used to receive, store, and analyze the acquired data to obtain the explosion characteristic parameters of the mixture.

[0033] The shock tube test device 2 is the core cavity of the test, and its structure is shown in Figure 2. It is composed of multiple shock tubes connected by flange sealing. In this embodiment, a shock tube with an inner diameter of 200 mm, a wall thickness of 20 mm, and a single section length of 2000 mm is selected. The number of tube sections can be increased or decreased according to the test requirements to meet the test requirements of different explosion propagation distances.

[0034] The shock tube test device 2 is divided into observation section 1 and observation section 2 along the axial direction. A large square tempered glass observation window with a size of 100 mm × 600 mm is opened on the front of observation section 1 for high-speed camera to capture dust swirling, flame formation and propagation. Circular tempered glass observation windows with a diameter of 50 mm and a spacing of 280 mm are opened at equal intervals along the axial direction on observation section 2. In this embodiment, 18 circular observation windows are set for capturing detailed images of local flame propagation and multi-point monitoring.

[0035] The upper part of the shock tube test device 2 is machined with multiple M20 threaded connection holes along the axial direction, including pressure sensor mounting interfaces, air intake system interfaces, and ignition device interfaces: there are 21 pressure sensor mounting interfaces with a spacing of 280 mm, used to install pressure sensors; there is one air intake system interface, located in the middle of the shock tube, used to connect the air intake system; there is one ignition device interface, located at one end of the shock tube, used to install the ignition device. Each threaded connection hole is equipped with a sealing gasket to ensure the airtightness of the tube body.

[0036] The ignition system includes a synchronous ignition controller, wires, a multi-channel ignition device, and a multi-channel hoisting device 1, which can realize adjustable ignition parameters, switching between multiple ignition modes, and controllable dust hoisting effect. The structure and working principle of each component are as follows:

[0037] This synchronous ignition controller uses an S7-200 SMART ST20 programmable PLC controller as its core, and is equipped with digital input / output modules, analog input modules, and control execution modules. The controller achieves human-machine interaction through a touch screen. Its circuit connection relationship is as follows: Figure 8 As shown.

[0038] The digital input / output module (DIP) receives control signals such as power-on, emergency stop, and reset, and transmits these signals to the programmable logic controller (PLC). Simultaneously, the DIP module receives ignition controller status signals output by the PLC. Specifically, the DIP module may include wires, a start button, an energy storage button, and an emergency stop button. The DIP module is connected via wires to the start button, emergency stop button, power-on indicator light, running indicator light, and emergency stop indicator light on the control panel, respectively, to receive user control commands and display the system's operating status.

[0039] The programmable PLC controller sends synchronization control commands to the control execution module based on received initialization information, monitoring data, and instructions from the host computer. The control execution module then synchronizes the opening actions of the ignition device and the solenoid valve according to these synchronization control commands.

[0040] The digital input ports (I0.0~I0.4) of the S7-200 SMART ST20 PLC controller are connected to the operation buttons via wires:

[0041] The I0.0 port is connected to the ignition start button SB1 to receive ignition start commands;

[0042] The I0.1 port is connected to the low-voltage energy storage button SB2 to receive low-voltage energy storage commands;

[0043] The I0.2 port is connected to the high-voltage energy storage button SB3 to receive high-voltage energy storage commands;

[0044] The I0.3 port is connected to the reset button SB4 to receive system reset commands;

[0045] The I0.4 port is connected to the emergency stop button SB5 to receive emergency stop commands.

[0046] The aforementioned digital input module transmits control signals such as power-on, emergency stop, reset, energy storage, and ignition start to the PLC controller. It also displays the system's operating status via indicator lights. During ignition, depending on the ignition type, first press the low-voltage energy storage button SB2 or the high-voltage energy storage button SB3. Pressing the low-voltage energy storage button SB2 allows the PLC controller to execute the low-voltage ignition command, while pressing the high-voltage energy storage button SB3 allows the high-voltage ignition command to be executed. The 24V voltage is then boosted to 220V via a capacitor to achieve energy storage. Finally, pressing the ignition start button SB1 connects the power supply to the corresponding ignition interface.

[0047] The PLC controller body and the extended EM-QT16 digital output module constitute a digital output circuit, which drives each actuator via a relay group:

[0048] The digital output ports (Q0.0~Q0.4) of the PLC controller body are connected to the low-voltage ignition circuits 1~5 respectively through relays (1KA~5KA) to control the on / off of multiple low-voltage ignition devices.

[0049] The digital output ports (Q0.5~Q0.6) of the PLC controller body are connected to the No. 1 and No. 2 high-voltage energy storage circuits respectively through relays (6KA~7KA) to control the on / off of multiple 220 V voltage outputs;

[0050] The digital output ports (Q8.0~Q8.1) of the extended EM-QT16 module are connected to the high-voltage ignition circuits 1 and 2 respectively via relays (9KA, 10KA) to control the on / off state of multiple high-voltage ignition devices.

[0051] The digital output ports (Q8.2~Q8.7, Q9.0~Q9.3) of the extended EM-QT16 module are connected to the jet solenoid valve circuits 1~10 respectively via relays (11KA~19KA) to control the synchronous opening of multiple jet solenoid valves;

[0052] The control execution module consists of the aforementioned relay group, which realizes electrical isolation between the PLC control signal and the high-voltage execution circuit, and synchronously completes the control of the ignition device and the solenoid valve according to the synchronous control command output by the PLC.

[0053] This circuit uses a P24V DC power supply, with N0V as the common neutral line, providing a stable power supply for the PLC controller, expansion modules, and control execution loops. The PLC controller can send synchronous control commands to the digital output module based on received initialization information, monitoring data, and touchscreen / host computer instructions, enabling parameter setting, command transmission, status monitoring, and data interaction during the test process.

[0054] The controller supports custom configuration of ignition voltage (24 V low voltage, 220 V high voltage) and ignition time (0~1000 ms continuously adjustable). Its low-voltage ignition parameter setting interface is shown below. Figure 5 As shown, the high-voltage ignition parameter setting interface is as follows: Figure 6 As shown in the interface above, the ignition start delay time and ignition duration of different ignition channels can be manually set.

[0055] The controller supports custom configuration of the solenoid valve opening and closing delay time and opening time (0~5000 ms continuously adjustable). Its solenoid valve parameter setting interface is shown in Figure 7. In this interface, the jet delay time and jet duration of different serial solenoid valves can be manually set.

[0056] The ignition device is installed at the ignition device interface (threaded hole) on the left end of the shock tube test device 2. It supports three ignition methods: chemical ignition head ignition, high-temperature hot spot ignition, and electric spark ignition. It can be quickly switched according to the test requirements. The specific implementation methods are as follows: Chemical ignition head ignition: A copper ignition electrode is fixed at the threaded hole, and a chemical ignition head is bound to the electrode. The ignition head is ignited by the output of a low-voltage pulse signal from the synchronous ignition controller. High-temperature hot spot ignition: A nickel-chromium resistance wire is sleeved on the copper ignition electrode. The resistance value of the resistance wire can be selected as 5 Ω, 10 Ω, or 15 Ω. The controller outputs a constant current to heat the resistance wire, and the mixture is ignited through the high-temperature hot spot. Electric spark ignition: A special electric spark igniter is installed at the threaded hole. The controller outputs 220 V high voltage electricity, and the igniter generates a high-voltage electric spark to directly ignite the dust / combustible gas mixture.

[0057] The structure of the hoisting device 1 is as follows: Figure 3 As shown, it consists of a solenoid valve 108, a one-way valve 106, an external threaded connector 104, an elbow 103, a compression fitting 102, a straight pipe 101, a sealing flange 105, a connector 107, and a quick-connect connector 109. Each component is fixed to the reserved interface of the shock tube test device 2 through the sealing flange 105. The outlet of the straight pipe 101 is set at a 45° angle to the shock tube axis and is obliquely downward to ensure that the jet can effectively pick up the dust at the bottom of the tube.

[0058] The quick-connect connector 109 is connected to the air inlet of the solenoid valve 108 for connecting to an external air source; the air outlet of the solenoid valve 108 is connected to the air inlet of the one-way valve 106 through the connector 107. The one-way valve 106 is used to prevent backflow of air and ensure the stability of the air path.

[0059] The external threaded connector 104 is used to achieve a sealed connection between the one-way valve 106 and the elbow 103, and the compression fitting 102 is used to achieve a sealed and tight connection between the elbow 103 and the straight pipe 101.

[0060] The external threaded connector 104 passes through the sealing flange 105 and extends into the shock tube. The sealing flange 105 is fitted on the left side of the shock tube test device and is bolted to the left side of the shock tube test device.

[0061] In this embodiment, the solenoid valve 108 is selected with a working pressure of 0.1~2.0 MPa, and its opening time is precisely controlled by the synchronous ignition controller. The high-pressure gas enters the hoisting device 1 through the quick-connect connector 109, and passes through the solenoid valve 108, connector 107, check valve 106, external thread connector 104, and elbow 103 in sequence. Then, it forms a high-speed jet through the straight pipe 101 to hoist the combustible dust laid at the bottom of the shock tube.

[0062] By adjusting the intake pressure (0.3~1.0 MPa) and the opening time of the solenoid valve 108 (50~500 ms), the intake volume and gas jet intensity can be changed, thereby achieving an adjustable dust suspension state and simulating the dust suspension state in different actual industrial scenarios.

[0063] The structure of the intake system is as follows Figure 4 As shown, it includes shock tube inlet interface 3, connectors 301 / 303 / 306, high-pressure ball valves 302 / 307, four-way connector 304, vacuum pressure gauge 305, and quick-connect connector 308, which are used to monitor the pressure changes inside the shock tube in real time. The quick-connect connector 308 is connected to combustible gas cylinders, inert gas cylinders, and dry air cylinders, respectively.

[0064] The shock tube inlet interface 3 is connected in sequence to the lower end interface of the four-way connector 304 via connector 301, high-pressure ball valve 302, connector 303, and four-way connector 304, forming the main air passage between the air intake system and the shock tube.

[0065] The upper interface of the four-way connector 304 is connected to a vacuum pressure gauge 305 for real-time monitoring of pressure changes inside the shock tube.

[0066] The right end of the four-way connector 304 is connected to the quick-connect connector 308 via connector 306, high-pressure ball valve 307, to form an air inlet. The quick-connect connector 308 is connected to combustible gas cylinders, inert gas cylinders, and dry air cylinders respectively, so as to realize the switching and control of the air inlet of multiple gases.

[0067] The left end of the four-way connector 304 has the same connection method as the right end, forming an air outlet for connecting to the shock tube or subsequent pipeline.

[0068] The high-pressure ball valves 302 and 307 are used to control the opening and closing of each gas path, and the vacuum pressure gauge 305 provides real-time feedback on the pressure status inside the tube, thus achieving accurate filling, pressure monitoring and safe control of the gas inside the shock tube.

[0069] The core function of the intake system is to accurately fill the shock tube test device 2 with a specified volume fraction of combustible gas. Each high-pressure ball valve works together to achieve functions such as drawing negative pressure inside the tube, gas filling, and pressure stabilization. All connection parts adopt a sealed structure to ensure the airtightness of the gas filling process.

[0070] The pressure data acquisition system consists of piezoelectric pressure sensors, a signal conditioner, and a data acquisition unit. In this embodiment, 19 piezoelectric pressure sensors with a range of 0~2 MPa are selected and installed in the 19 pressure sensor mounting interfaces of the shock tube. The signal conditioner is used to amplify, filter, and reduce noise of the raw signals acquired by the pressure sensors. The data acquisition unit has a sampling frequency of 1 MHz and converts the processed pressure signal into a digital signal, which is then transmitted to the computer in real time.

[0071] The high-speed camera uses an industrial-grade high-speed camera with a frame rate of 10,000 fps. It is placed on the outside of the glass observation windows of observation section one and observation section two of the shock tube test device 2. It simultaneously captures the dust swirling state, flame formation and propagation process, and dust combustion state during the ignition process. The captured image / video data is transmitted to the computer in real time via a data cable to achieve synchronous acquisition with pressure data.

[0072] Based on the above testing system, taking an aluminum powder / hydrogen mixture system as an example, the explosion characteristic testing method of the present invention is described in detail, and the specific steps are as follows:

[0073] According to the test requirements, three sections of circular stainless steel shock tubes were selected and connected by flange sealing to assemble shock tube test device 2; pressure sensor, ignition device, winch device 1, and air intake system were installed in the corresponding threaded connection holes of the shock tubes, and the flanges and interface bolts were tightened; all valves were closed, and 0.6 MPa of dry air was introduced into the shock tubes. The pressure was monitored for 30 minutes by pressure gauge 305. If the pressure inside the tube did not drop, the airtightness of the shock tube was confirmed to be good, and subsequent tests could be carried out.

[0074] Spread an appropriate amount of dried aluminum powder evenly on the bottom of the shock tube test device 2, ensuring that there is no dust accumulation or missed areas.

[0075] Open the high-pressure ball valve on the air outlet of the air intake system, evacuate the shock tube test device 2 to a vacuum state, and then close the valve; open the high-pressure ball valve on the air intake interface, and sequentially fill it with an appropriate volume fraction of dry air, inert gas (if necessary), and combustible gas, and then close the valve.

[0076] All test parameters were set via the touchscreen of the synchronous ignition controller: ignition method was selected as electric spark ignition, ignition voltage was 220 V, and ignition time was 100 ms; the solenoid valve opening time of the winch device was 200 ms, and the intake pressure was 0.6 MPa; the sampling frequency of the pressure data acquisition system was 1 MHz, and the frame rate of the high-speed camera was 10000 fps; after the parameters were set, the ignition system, pressure data acquisition system, and high-speed camera were all put into standby mode.

[0077] The test start command is issued by the synchronous ignition controller. The solenoid valve 108 opens for a preset time of 200 ms. The 0.6MPa high-pressure gas forms a high-speed jet through the hoisting device 1, which hoists the aluminum powder at the bottom of the shock tube to form a uniform aluminum powder / hydrogen mixture system. After a delay of 50 ms, the ignition device ignites the dust / combustible gas mixture system, achieving precise synchronization between dust hoisting and ignition actions.

[0078] At the moment of ignition, the 19 pressure sensors of the pressure data acquisition system collect pressure signals from different monitoring points of the shock tube in real time. After being processed by the signal conditioner and data acquisition card, the signals are transmitted to the computer. At the same time, the high-speed camera captures visual data of dust swirl, flame formation and propagation, and transmits it to the computer in real time, realizing the synchronous acquisition and storage of pressure data and visual data.

[0079] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art can adjust the parameters of the system components and the details of the test steps according to actual test requirements. All adjustments made within the design concept of the present invention should be included in the protection scope of the present invention.

Claims

1. A test system for the explosion characteristics of a dust-combustible gas mixture system inside a shock tube, characterized in that, include: The shock tube test device is equipped with multiple observation windows along the axial direction for high-speed photography to capture the dust swirling, flame formation and propagation. The air intake system is used to fill the shock tube test apparatus with a specified volume fraction of combustible gas. The pressure data acquisition system and the high-speed camera are used to acquire pressure signals and flame propagation visualization data during the explosion process, respectively. The ignition system includes a synchronous ignition controller, a multi-channel ignition device, and a multi-channel winch device. The synchronous ignition controller includes a PLC controller, a digital input / output module, an analog input module, and a control execution module. The PLC controller enables human-machine interaction via a touchscreen. The digital input / output module receives power-on, emergency stop, and reset control signals and transmits these signals to the PLC controller. The PLC controller sends synchronous control commands to the control execution module. The control execution module synchronously controls the starting actions of the ignition device and the winch device according to the synchronous control commands. The digital input ports of the PLC controller are connected to operation buttons, including: an ignition start button for receiving ignition start commands, a low-voltage energy storage button for receiving low-voltage energy storage commands, a high-voltage energy storage button for receiving high-voltage energy storage commands, a reset button for receiving system reset commands, and an emergency stop button for receiving emergency stop commands. During ignition, depending on the ignition type, first press the low-voltage energy storage button or the high-voltage energy storage button. Pressing the low-voltage energy storage button allows the controller to execute the low-voltage ignition command, while pressing the high-voltage energy storage button allows the high-voltage ignition command to be executed. The voltage is then boosted to the required high voltage through a capacitor to achieve energy storage. Then, press the ignition start button to connect the power supply to the corresponding ignition interface. The PLC controller body and digital output module constitute a digital output circuit, which drives various actuators via relay groups: The PLC controller's multiple digital output ports are connected to multiple low-voltage ignition circuits and multiple high-voltage energy storage circuits via multiple relays, respectively, to control the on / off state of multiple low-voltage ignition devices and multiple required high-voltage outputs. The PLC controller's multiple digital output ports are connected to multiple high-voltage energy storage circuits via relays to control the on / off state of multiple required high-voltage outputs. The digital output module's multiple digital output ports are connected to multiple high-voltage ignition circuits and multiple solenoid valve circuits via multiple relays, respectively, to control the on / off state of the multiple high-voltage ignition devices and multiple solenoid valves. The solenoid valve is used to control the on / off state of the hoisting device; the hoisting device is used to generate a jet to hoist the combustible dust laid at the bottom of the shock tube; the ignition device is used to ignite the mixture of dust and combustible gas.

2. The explosion characteristic testing system for a dust-combustible gas mixture system inside a shock tube according to claim 1, characterized in that, The hoisting device consists of a solenoid valve, a one-way valve, an external threaded connector, an elbow, a compression fitting, a straight pipe, a sealing flange, a connector, and a quick-connect connector. The hoisting device is fixed to the reserved interface of the shock tube test device through the sealing flange. The outlet of the straight pipe is at a 45° angle to the shock tube axis and is obliquely downward to ensure that the jet can effectively hoist the dust at the bottom of the tube. The quick-connect connector is connected to the air inlet of the solenoid valve for connecting an external air source. The air outlet of the solenoid valve is connected to the air inlet of the one-way valve through the connector. The external threaded connector is used to achieve a sealed connection between the one-way valve and the elbow, and the compression fitting is used to achieve a sealed and tight connection between the elbow and the straight pipe. The external threaded connector passes through the sealing flange and extends into the shock tube.

3. The explosion characteristic testing system for a dust-combustible gas mixture system inside a shock tube according to claim 1, characterized in that, The ignition device supports three ignition methods: chemical ignition head ignition, high-temperature hot spot ignition, and electric spark ignition. Chemical ignition involves fixing an ignition electrode to the ignition device interface, attaching a chemical ignition head to the electrode, and igniting the ignition head by outputting a low-voltage pulse signal from a synchronous ignition controller. High-temperature hot spot ignition involves attaching a resistance wire to the ignition electrode, and the synchronous ignition controller outputs a constant current to heat the resistance wire, igniting the mixture of dust and combustible gas. Electric spark ignition involves installing an electric spark igniter at the ignition device interface, and the synchronous ignition controller outputs the required high-voltage electricity. The electric spark igniter generates an electric spark, directly igniting the mixture of dust and combustible gas.

4. The explosion characteristic testing system for a dust-combustible gas mixture system inside a shock tube according to claim 1, characterized in that, The air intake system includes a shock tube air intake interface, a four-way connector, a vacuum pressure gauge, and a quick-connect connector. The shock tube inlet is connected in sequence to the lower end of the four-way connector via the first connector, the first high-pressure ball valve, the second connector, and the first connector, forming the main air passage between the air intake system and the shock tube test device. The upper end of the four-way connector is connected to a vacuum pressure gauge for real-time monitoring of pressure changes inside the shock tube. The side end of the four-way connector is connected to the quick-connect connector via the third connector, the second high-pressure ball valve, and the quick-connect connector, forming the air intake interface. The quick-connect connector is connected to a combustible gas cylinder, an inert gas cylinder, and a dry air cylinder, respectively, to achieve switching and control of the air intake of various gases.

5. The explosion characteristic testing system for a dust-combustible gas mixture system inside a shock tube according to claim 1, characterized in that, The shock tube test device is divided into observation section one and observation section two along the axial direction: a square tempered glass observation window is opened on the front of observation section one for high-speed camera to capture dust swirling, flame formation and propagation; multiple circular tempered glass observation windows are opened at equal intervals along the axial direction on observation section two for capturing detailed images of local flame propagation and multi-point monitoring.

6. The explosion characteristic testing system for a dust-combustible gas mixture system inside a shock tube according to claim 1, characterized in that, The shock tube test apparatus is composed of multiple shock tube sections connected by flange sealing.

7. An explosion characteristic test for a dust-combustible gas mixture system inside a shock tube, utilizing the explosion characteristic test system for a dust-combustible gas mixture system inside a shock tube as described in any one of claims 1-6, characterized in that, include: Dry air is introduced into the shock tube test device, and the pressure is monitored by the pressure data acquisition system. If the pressure does not drop within the set time, the airtightness is confirmed to be good, so that subsequent tests can be carried out. The dried powder is evenly spread on the bottom of the shock tube test device; Open the air intake system, evacuate the shock tube test device to a vacuum state, and then fill it with the required volume fraction of dry air, inert gas, and combustible gas in sequence before closing the air intake system. The test parameters are set by the synchronous ignition controller: ignition method, ignition voltage, ignition time, winch opening time, intake pressure, sampling frequency of the pressure data acquisition system and frame rate of the camera. After setting the parameters, set the ignition system, pressure data acquisition system, and camera to standby mode. The test start command is issued by the synchronous ignition controller. The hoisting device forms a jet to hoist the powder at the bottom of the shock tube test device, forming a uniform powder and combustible gas mixture. After a delay, the ignition device ignites the dust and combustible gas mixture, achieving precise synchronization between dust hoisting and ignition. At the moment of ignition, the pressure data acquisition system collects pressure signals from different monitoring points of the shock tube test device in real time. After being processed by the signal conditioner and data acquisition card, the signals are transmitted to the computer. At the same time, the camera captures visual data of dust swirling, flame formation and propagation, and transmits it to the computer in real time, realizing the synchronous acquisition and storage of pressure data and visual data.

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