A device for generating dripping flames and an experimental method for studying dripping fire ignition

Abstract

The present application provides an experimental device for producing a dripping flame and an experimental method for studying the ignition of a dripping fire, the experimental device comprising: a frame; a melting pot for placing the material to be tested; a heating device for melting the material to be tested into a molten state; a dripping tube for causing the molten material to be tested to drip to form molten droplets; a power device for controlling the dripping of a single molten droplet; an ignition device for igniting the molten droplets to form a dripping fire; a sample placement device for adjusting the relative position of the sample to be ignited and the dripping fire; and a data acquisition device for collecting ignition data. Through the cooperation of the heating device, the power device and the sample placement device, important physical parameters such as the mass of the molten droplets formed by the material to be tested, the dripping frequency, the combustion state and the dripping distance can be controlled, and the ignition data of the dripping fire can be collected through the ignition device and the data acquisition device, providing a reliable experimental scheme for exploring the ignition mechanism of the dripping fire.

Description

Technical Field

[0001] The present application belongs to the technical field of combustion performance experiments, and more specifically, to a device for generating dripping flames and an experimental method for studying dripping fire ignition. Background Art

[0002] Thermoplastics are a type of high molecular weight organic polymer that melts and converts into a liquid state when heated. When the gravity of the molten plastic liquid overcomes its surface tension, droplets will fall. These droplets usually carry flames during air combustion or fire, so these droplets with flames are called dripping fires. Nowadays, thermoplastic materials such as polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP) and expanded polystyrene (EPS) are widely used in the insulation layer of the exterior walls of buildings, decorative materials and wire insulation layers. When a fire occurs, the combustion of thermoplastic materials will produce molten droplets, which carry flames and drip to form dripping fires. The dripping fire has the opportunity to ignite other combustibles during the dripping process, triggering new fire sources, thereby accelerating the spread and development of the fire. Therefore, it is urgent to conduct a series of studies on the characteristics and mechanisms of dripping fires to provide a scientific basis for scientifically controlling the development of dripping fires in fires.

[0003] However, there is little research on the dripping fire phenomenon and the corresponding ignition mechanism. Dripping fire is usually generated by gravity. In addition, the phase transition caused by temperature changes makes the physical parameters such as the surface tension of the molten liquid sensitive to temperature changes. The general research device suspends the thermoplastic material sample in the air, then ignites the sample to obtain dripping fire during the combustion process, and studies the dripping fire. However, in this research device, the size and quantity of dripping fire during the combustion process of the sample are uncertain, which makes it very difficult to quantitatively control the shape, size, dripping frequency, etc. of the dripping fire, which is not conducive to studying the relevant parameters of the dripping fire. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a device for generating dripping flames, so as to solve the technical problem that the research on dripping fires formed by spontaneous combustion of thermoplastics is difficult in the prior art.

[0005] To achieve the above purpose, the technical solution adopted in this application is: a device for generating dripping flames, comprising:

[0006] frame;

[0007] A melting tank, arranged on the frame and used for placing the material to be tested;

[0008] A heating device, used for heating the melting tank to melt the material to be tested into a molten state;

[0009] A dripping pipe, provided on the melting tank and used to make the molten material to be tested drip to form molten liquid droplets;

[0010] A power device, used for applying power to the melting tank to control the formation and dripping of the molten liquid droplets;

[0011] An ignition device, used to ignite the molten liquid droplets to form dripping fire;

[0012] A sample placement device, disposed below the melting tank and used to adjust the relative position of the sample to be ignited and the dripping fire;

[0013] The data acquisition device is used to acquire the ignition data of the ignition process of the dripping fire on the sample to be ignited.

[0014] In one embodiment, the molten tank includes a hollow tank body, a cover plate sealing the tank body, and a piston movably arranged in the tank body, the piston divides the cavity in the tank body into an upper cavity and a lower cavity, the power device is connected to the upper cavity and is used to control the movement of the piston, the material to be tested is contained in the lower cavity, and the drip tube is connected to the lower cavity.

[0015] In one embodiment, the heating device comprises a power supply, a temperature controller, a thermocouple and a heating tube, and the thermocouple and the heating tube are arranged on the melting tank.

[0016] In one embodiment, the power device includes an interface connected to the upper chamber, a pressurizing component and a decompressing component connected to the interface, and a control component for controlling the operating frequency of the pressurizing component and the decompressing component.

[0017] In one embodiment, the boosting assembly includes a high-pressure gas cylinder, a rough pressure reducing valve, a switch, a precision pressure reducing valve and a first high-speed solenoid valve connected in sequence through a first pressure pipeline, and the pressure reducing assembly includes a vacuum pump, a pressure stabilizing cylinder and a second high-speed solenoid valve connected in sequence through a second pressure pipeline, and the first pressure pipeline and the second pressure pipeline are both connected to the interface.

[0018] In one embodiment, the control component includes a single chip microcomputer, and a first MOS tube and a second MOS tube electrically connected to the single chip microcomputer, the first MOS tube is connected to the first high-speed solenoid valve, and the second MOS tube is connected to the second high-speed solenoid valve.

[0019] In one embodiment, the dripping pipe is a metal pipe, and the dripping pipe is detachably arranged on the melting tank.

[0020] In one embodiment, the sample placement device includes a three-dimensional sample rack and a sample stage. The sample stage is arranged on the three-dimensional sample rack and located below the melting tank. The sample to be ignited is placed on the sample stage.

[0021] In one embodiment, the data acquisition device includes a high-speed camera, a weighing sensor and a temperature sensor. The weighing sensor is arranged on the three-dimensional sample holder and is used to detect the weight change of the sample table. The temperature sensor is arranged on the sample table and is used to detect the temperature change of the sample to be ignited.

[0022] Another object of the present invention is to provide an experimental method for studying dripping fire ignition, comprising the following steps:

[0023] S1. placing the material to be tested in a melting tank, placing the sample to be ignited on a sample placement device, and adjusting the relative position of the sample to be ignited below the melting tank by the sample placement device;

[0024] S2, heating the melting tank by a heating device to make the material to be tested in a molten state;

[0025] S3, using a power device to make the molten material to be tested drip regularly from the melting tank through the dripping pipe to form molten liquid droplets;

[0026] S4, igniting the molten liquid droplets by an ignition device to form dripping fire;

[0027] S5. Collecting the ignition data of the dripping fire during the dripping process and after dripping on the sample to be ignited through a data acquisition device.

[0028] The beneficial effects of a device for generating a dripping flame and an experimental method for studying the ignition of a dripping fire provided in the present application are that through the cooperation of a heating device, a power device and a sample placement device, important physical parameters such as the size of molten droplets formed by the dripping of the test material through the dripping tube, the dripping frequency, the dripping temperature and the dripping distance can be controlled, and the formation and ignition data of the dripping fire are collected through an ignition device and a data acquisition device, providing a reliable experimental scheme for exploring the ignition mechanism of the dripping fire, and the operation of the experimental equipment also has the advantages of simple operation and high experimental accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0030] Figure 1 A schematic diagram of the structure of a device for generating dripping flames provided in an embodiment of the present application;

[0031] Figure 2 A schematic diagram of the working process of the device for generating dripping flame provided in an embodiment of the present application;

[0032] Figure 3 A schematic flow chart of an experimental method for studying dripping fire ignition provided in an embodiment of the present application.

[0033] Among them, the reference numerals in the figure are:

[0034] 1. Frame; 11. Base; 12. Screw; 13. Fixed plate; 14. Nut; 2. Melting tank; 21. Tank body; 22. Cover plate; 23. Piston; 24. Experimental materials; 3. Heating device; 31. Thermocouple; 32. Heating tube; 4. Dropping tube; 41. Dropping fire; 5. Power device; 51. Interface; 52. Pressurization assembly; 521. High-pressure gas cylinder; 522. Rough pressure reducing valve; 523. Switch; 524. Precision pressure reducing valve; 525. The first high-speed solenoid valve; 53, pressure reducing assembly; 531, vacuum pump; 532, voltage stabilizing cylinder; 533, the second high-speed solenoid valve; 54, control assembly; 541, single-chip microcomputer; 542, the first MOS tube; 543, the second MOS tube; 6, ignition device; 7, sample placement device; 71, three-dimensional sample rack; 72, sample table; 73, sample to be ignited; 8, data acquisition device; 81, high-speed camera; 82, weighing sensor; 83, temperature sensor. DETAILED DESCRIPTION

[0035] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0036] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0037] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0039] like Figure 1 and Figure 2 As shown, a device for generating dripping flames provided in an embodiment of the present application is now introduced in detail, and the device for generating dripping flames can generate a dripping fire 41 with a dripping flame, and can also collect and analyze the ignition data of the dripping fire 41 igniting the sample 73 to be ignited. The device for generating dripping flames includes: a frame 1, a melting tank 2, a heating device 3, a dripping pipe 4, a power device 5, an ignition device 6, a sample placement device 7, and a data acquisition device 8.

[0040] In this embodiment, the melting tank 2 is arranged on the frame 1, and the melting tank 2 is used to place the material 24 to be tested and isolate the material 24 to be tested from the outside world, so as to prevent the material 24 to be tested from self-igniting. Among them, the material 24 to be tested is a thermoplastic plastic, specifically, the material 24 to be tested is PE, PVC, PP or EPS. During the experiment, the dripping fire 41 of PE, PVC, PP and EPS can be studied respectively. The heating device 3 is used to heat the melting tank 2 to melt the material 24 to be tested in the melting tank 2 into a molten state, and the heating device 3 is also used to control the temperature of the material 24 to be tested in the molten state. The dripping pipe 4 is arranged on the melting tank 2 and is used to make the material 24 to be tested in the molten state drip to form molten droplets. The dripping pipe 4 is used to realize a single drop of molten droplets, which is used to reduce the mutual interference between the outside world and the molten droplets, and ensure the accuracy of the experimental research. The power device 5 is used to apply power to the melting tank 2 to control the formation and dripping of the molten droplets; the power device 5 can control the size and dripping frequency of the molten droplets, which is convenient for studying different molten droplets. The ignition device 6 is used to ignite the dripping molten liquid droplets to form a dripping fire 41, wherein the ignition device 6 can ignite the molten liquid droplets to form a dripping fire 41 with flames, or can not ignite the molten liquid droplets to form a dripping fire 41 without flames. The sample placement device 7 is arranged below the melting tank 2 and is used to adjust the relative position of the sample 73 to be ignited. The sample placement device 7 is also used to adjust the dripping distance of the dripping fire 41 dripping to the sample 73 to be ignited, so as to study the influence of the dripping distance on the ignition of the sample 73 to be ignited by the dripping fire 41. Wherein, the sample 73 to be ignited is combustible paper, foam or other combustibles, which is used to study the ignition conditions of different dripping fires 41 on different samples 73 to be ignited, so as to analyze the conditions of the dripping fire 41 forming a new fire source. The data acquisition device 8 is used to collect the ignition data of the ignition process of the dripping fire 41 on the sample 73 to be ignited, wherein the ignition data includes but is not limited to the weight of the dripping fire 41, the combustion temperature, the flame shape and the phenomenon of igniting the sample 73 to be ignited.

[0041] An embodiment of the present application provides a device for generating a dripping flame. Through the cooperation of a heating device 3, a power device 5 and a sample placement device 7, important physical parameters such as the size, dripping frequency, dripping temperature and dripping distance of molten droplets formed by the test material 24 through the dripping tube 4 can be controlled. The formation and ignition data of the dripping fire 41 can be collected through the ignition device 6 and the data acquisition device 8, thereby providing a reliable experimental scheme for exploring the ignition mechanism of the dripping fire 41. In addition, the experimental equipment has the advantages of simple operation and high experimental accuracy.

[0042] like Figure 1As shown, in this embodiment, the melting tank 2 includes a hollow tank body 21, a cover plate 22 that seals the tank body 21, and a piston 23 that is movably arranged in the tank body 21. The piston 23 divides the cavity in the tank body 21 into an upper cavity and a lower cavity. The power device 5 is connected to the upper cavity and is used to control the movement of the piston 23. The material 24 to be tested is contained in the lower cavity, and the dropper 4 is connected to the lower cavity. Specifically, the melting tank 2 is a stainless steel tank body, and the cover plate 22 and the piston 23 are both detachably arranged with the tank body 21. During the experiment, the granular or powdered material 24 to be tested is first placed in the tank body 21, and then the piston 23 is inserted into the tank body 21 and the cover plate 22 is used to seal the tank body 21. The power device 5 controls the movement of the piston 23 by controlling the air pressure in the upper chamber. When the air pressure in the upper chamber is greater than the external atmospheric pressure, the piston 23 moves downward to squeeze out the material to be tested 24 in a molten state and form molten droplets through the dropper 4; when the air pressure in the upper chamber is less than the external atmospheric pressure, the piston 23 moves upward so that the external atmospheric pressure exerts an upward pressure on the material to be tested 24 in a molten state, thereby preventing the dropper 4 from producing uncontrollable molten droplets.

[0043] like Figure 1 and Figure 2 As shown, in this embodiment, the heating device 3 includes: a power supply, a temperature controller (not shown in the figure), a thermocouple 31 and a heating tube 32, wherein the power supply is a laboratory power supply, the temperature controller is a PID temperature controller, the temperature controller is used to control the temperature of the material to be tested 24 in the melting tank 2, and the thermocouple 31 and the heating tube 32 are both arranged on the melting tank 2. Specifically, a receiving groove is provided on the side wall of the melting tank 2, the heating tube 32 is arranged in the receiving groove and is used to heat the melting tank 2 so that the material to be tested 24 is in a molten state, and the thermocouple 31 is arranged at the bottom of the tank body 21 to measure the real-time temperature of the material to be tested 24, and the measured real-time temperature is fed back to the temperature controller, so that the temperature controller controls the working state of the heating tube 32 (heating the material to be tested 24 or stopping heating the material to be tested 24), thereby achieving the purpose of controlling the dripping temperature of the molten droplets.

[0044] like Figure 1 and Figure 2As shown, in this embodiment, the power device 5 includes: an interface 51 connected to the upper chamber, a booster assembly 52 and a decompression assembly 53 connected to the interface 51, and a control assembly 54 for controlling the operating frequency of the booster assembly 52 and the decompression assembly 53. The booster assembly 52 is used to make the air pressure in the upper chamber greater than the external atmospheric pressure, so as to drive the piston 23 to move downward and squeeze out the molten liquid droplets; the decompression assembly 53 is used to make the air pressure in the upper chamber less than the external atmospheric pressure, so as to drive the piston 23 to move upward and stop the molten liquid droplets from dripping. The control assembly 54 is used to control the working state of the booster assembly 52 and the decompression assembly 53, so as to realize the controllable frequency of the up and down movement of the piston 23, so as to achieve the purpose of controlling the dripping size and dripping frequency of the molten liquid droplets.

[0045] Specifically, Figure 2 As shown, in this embodiment, the booster assembly 52 includes: a high-pressure gas cylinder 521, a rough pressure reducing valve 522, a switch 523, a precision pressure reducing valve 524 and a first high-speed solenoid valve 525 connected in sequence through a first pressure pipeline. The first pressure pipeline is connected to the interface 51, the high-pressure gas cylinder 521 is used to provide high-pressure gas, the switch 523 is used to control the opening and closing of the first pressure pipeline, the rough pressure reducing valve 522 and the precision pressure reducing valve 524 are used to stably control the pressure of the high-pressure gas in the first pressure pipeline, and the first high-speed solenoid valve 525 is used to quickly realize the action time and power of the high-pressure gas on the piston 23, thereby controlling the action intensity and duration of the piston 23 to extrude the molten droplets.

[0046] Specifically, Figure 2 As shown, in this embodiment, the decompression assembly 53 includes: a vacuum pump 531, a pressure stabilizing cylinder 532 and a second high-speed electromagnetic valve 533 connected in sequence through a second pressure pipeline. The second pressure pipeline is connected to the interface 51. When the air pressure in the upper chamber needs to be reduced, the second high-speed electromagnetic valve 533 is opened, so that the vacuum pump 531 is connected to the upper chamber of the melting tank 2. The vacuum pump 531 works to discharge the air pressure in the upper chamber to form a negative pressure, so that the piston 23 moves upward to prevent the molten liquid from dripping. The pressure stabilizing cylinder 532 is used to ensure the stability of the pressure during the pressure relief process.

[0047] The control component 54 is a single-chip control system, specifically including a single-chip 541, and a first MOS tube 542 and a second MOS tube 543 electrically connected to the single-chip 541, the first MOS tube 542 is connected to the first high-speed electromagnetic valve 525, and the second MOS tube 543 is connected to the second high-speed electromagnetic valve 533. The working pulse width and working frequency of the first MOS tube 542 and the second MOS tube 543 can be set in the single-chip 541, so as to achieve the purpose of controlling the working frequency of the first high-speed electromagnetic valve 525 and the second high-speed electromagnetic valve 533, and realize the control of the dripping size and dripping frequency of the molten droplets. In this embodiment, the single-chip system can also control the working state of the heating device 3 and the ignition device 6, so that the whole experimental process is smoother. In this embodiment, the control component 54 is realized by a computer as a carrier, which is convenient for manually inputting and changing the operating data of the single-chip 541. The single-chip control system is used to accurately control the duration and frequency of the action of the supercharging component 52 and the decompression component 53 on the piston 23, so as to control the size and dripping frequency of the generated molten droplets.

[0048] In this embodiment, the drip tube 4 is a metal tube, and the drip tube 4 is detachably arranged on the melting tank 2. The drip tube 4 has a channel for the molten material 24 to drip to form molten droplets. The drip tube 4 is detachably arranged to facilitate replacement of drip tubes 4 with different channel diameters so as to study different molten droplets. In other embodiments, a valve is provided on the drip tube 4, and the valve is used to control the opening and closing of the drip tube 4. During the experiment, the valve is in a normally open state, and after the experiment is completed, the valve is in a normally closed state.

[0049] In this embodiment, the ignition device 6 at least includes a combustible gas tank, an ignition rod and a mixer. The combustible gas in the combustible gas tank is mixed with air by the mixer and ignited by the ignition rod. The ignited mixed gas is used to ignite the molten droplets to form a dripping fire 41. In this embodiment, an annular air outlet ring is provided at the ignition end of the ignition rod, and a plurality of air outlet holes are provided on the annular air outlet ring. The annular air outlet ring is used to form an annular flame, which can be used to simulate the influence of the external environment flame on the dripping fire 41. The ignition frequency of the ignition device 6 is controlled by the single chip system so that the ignition frequency of the ignition device 6 is consistent with the dripping frequency of the molten droplets.

[0050] like Figure 1 As shown, in this embodiment, the sample placement device 7 includes: a three-dimensional sample rack 71 and a sample table 72. The sample table 72 is arranged on the three-dimensional sample rack 71 and is located below the melting tank 2. The sample 73 to be ignited is placed on the sample table 72. The three-dimensional sample rack 71 is used to adjust the distance between the sample table 72 and the drip tube 4 and the angle at which the sample 73 to be ignited is placed on the sample table 72, which refers to the angle between the sample 73 to be ignited and the horizontal reference plane.

[0051] Specifically, Figure 1 As shown, the frame 1 of this embodiment includes a base 11, a plurality of screws 12 arranged on the base 11, a plurality of fixed plates 13 sleeved on the screws 12 and used to fix the molten tank 2, and a plurality of nuts 14 for adjusting the position of the fixed plate 13, and the fixed plate 13 is a steel plate. In other embodiments, the molten tank 2 is fixed to the fixed plate 13 by a plurality of metal pipes so that the molten tank 2 is suspended, which can reduce the heat transfer of the molten tank 2. In this embodiment, the three-dimensional sample holder 71 includes a mounting plate sleeved on the screw 12 and a nut 14 for adjusting the position of the mounting plate on the screw 12, the aperture of the mounting plate is larger than the diameter of the screw 12, so that the mounting plate can be in an inclined state, and the sample stage 72 is fixed on the mounting plate. In other embodiments, the three-dimensional sample rack 71 includes a mounting plate and a plurality of cylinders supporting the mounting plate, the piston rod of the cylinder is hinged to the mounting plate, at least two cylinders are provided, and the plurality of cylinders are fixed on the base 11, and the plurality of cylinders can work independently, so that the lifting and tilting of the mounting plate can be controlled, thereby realizing the height and angle adjustment of the sample 73 to be ignited.

[0052] like Figure 1 As shown, in this embodiment, the data acquisition device 8 includes: a high-speed camera 81, a weighing sensor 82 and a temperature sensor 83. Among them, the weighing sensor 82 is arranged on the three-dimensional sample rack 71 and is used to detect the weight change of the sample table 72, and the weight change includes the weight change before and after the dripping fire 41 drips on the sample to be ignited 73. The temperature sensor 83 is arranged on the sample table 72 and is used to detect the temperature change of the sample to be ignited 73. The high-speed camera 81 is arranged on the side of the rack 1 and is used to shoot the dripping of molten droplets, the formation of the dripping fire 41, the flame shape of the dripping fire 41, and the dripping fire 41 igniting the sample to be ignited 73. The high-speed camera 81, the weighing sensor 82 and the temperature sensor 83 are all connected to the single-chip control system, and the collected data are transmitted to the computer so that the experimenter can analyze the collected data.

[0053] The device for generating dripping flames provided in the embodiment of the present application has the advantages of small size, easy operation, controllable parameters affecting the dripping fire 41 such as the size of the dripping fire 41 and the dripping height, and accurate research data.

[0054] like Figure 3 As shown, the embodiment of the present application also provides an experimental method for studying dripping fire ignition, which is implemented by the above-mentioned device for generating dripping flames. The experimental method includes the following steps:

[0055] S1. Place the material to be tested 24 in the melting tank 2, place the sample to be ignited 73 on the sample placement device 7, and adjust the relative position of the burning sample below the melting tank 2 through the sample placement device 7; in step S1, determine the dripping distance of the dripping fire 41.

[0056] S2, heating the melting tank 2 by the heating device 3 to make the material 24 to be tested in a molten state; in step S2, it is used to determine the dripping temperature that can form the dripping fire 41.

[0057] S3, using the power device 5 to make the molten material 24 to be tested drip regularly from the melting tank 2 through the dripping pipe 4 to form molten liquid droplets; in step S3, it is used to determine the dripping size and dripping frequency of the dripping fire 41.

[0058] S4, igniting the molten liquid droplets by the ignition device 6 to form a dripping fire 41; in S4, it is used to determine whether the dripping fire 41 is formed, and to judge the influence of the dripping fire 41 with flame and the dripping fire 41 without flame on the formation of a new fire source (i.e., the ignition probability of igniting the sample 73 to be ignited).

[0059] S5. The data acquisition device 8 is used to collect the ignition data of the dripping fire 41 during the dripping process and after dripping on the sample 73 to be ignited; in step S5, the ignition data of the dripping fire 41 is collected and sorted, so as to compare and analyze different dripping fires 41, so as to study the formation of new fire sources in the combustion process of different thermoplastics.

[0060] Specifically, in step S1, the cover plate 22 and the piston 23 are first taken out, and then a certain mass of particles of the material to be tested 24 are added into the tank body 21, and the piston 23 is returned to its position and the cover plate 22 is sealed. The distance between the three-dimensional sample holder 71 and the dripping tube 4 is adjusted by the nut 14, so as to determine the dripping distance between the sample to be ignited 73 and the dripping tube 4.

[0061] Specifically, in step S2, the melting tank 2 is heated by the heating tube 32, and the heating temperature is set to 400°C. When the temperature of the melting tank 2 reaches the set temperature, the timing is set to 10 minutes, so that the material to be tested 24 in the tank body 21 is fully melted and the temperature is evenly mixed. At this time, the temperature of the melting tank 2 is monitored by the temperature controller and the thermocouple 31.

[0062] Specifically, in step S3, the single-chip microcomputer 541 outputs a first pulse signal through the first MOS tube 542 according to the preset pulse width and frequency, such as a pulse width of 0.15s and a frequency of 1.5Hz, to control the opening of the first high-speed electromagnetic valve 525, so that the high-pressure gas in the high-pressure gas cylinder 521 enters the tank body 21 after passing through the rough pressure reducing valve 522 and the precision pressure reducing valve 524, and pushes the piston 23 to move downward, thereby squeezing out the molten droplets; when the first pulse signal emitted by the first MOS tube 542 ends, the second MOS tube 543 outputs a second pulse signal to control the opening of the second high-speed electromagnetic valve 533, and the vacuum pump 531 works, and the gas in the tank body 21 is extracted after being stabilized by the pressure stabilizing cylinder 532, so that the upper chamber in the tank body 21 forms a negative pressure, and the piston 23 moves upward, thereby interrupting the dripping of the molten droplets. By setting different pulse widths and frequencies for the single-chip microcomputer 541, the size and frequency of the dripping of the dripping fire 41 can be achieved.

[0063] Specifically, in step S4, the single chip computer 541 is also used to control the ignition device 6 to ignite the molten droplets according to the designed pulse width and frequency to form a dripping fire 41, so as to perform an ignition experiment on the sample to be ignited 73 below and calculate the ignition probability of the sample to be ignited 73.

[0064] Specifically, in step S5 , the high-speed camera 81 , the weighing sensor 82 and the temperature sensor 83 in the data acquisition device 8 respectively collect the dripping process, the combustion process and the temperature, mass and other change data of the dripping fire 41 .

[0065] The experimental device for generating dripping flames and the experimental method for studying the ignition of dripping fires provided in the embodiments of the present application have the following effective effects: 1. The dripping fires 41 of different materials (PE, PVC, PP or EPS) can be tested for the ignition of different samples 73 to be ignited (combustible paper or foam) under the condition that important physical parameters such as droplet size, frequency, temperature and dripping distance can be controlled, providing a reliable experimental scheme for exploring the ignition mechanism of the dripping fire 41; 2. The size, frequency, temperature and dripping distance of the droplets in the dripping fire 41 can be accurately controlled through the single-chip microcomputer control system, providing a test basis for the study of the dripping fire 41 and ensuring the accuracy of the test; 3. The melting tank 2. When the material to be tested 24 is heated to a molten state, it is isolated from the outside world to prevent the material to be tested 24 from self-igniting during the heating process, thereby ensuring that the formation of the dripping fire 41 is controllable; 4. The heating device 3 can control the temperature of the molten tank 2 at a set temperature, thereby ensuring the stability of the temperature of the material to be tested 24 and providing a guarantee for the generation of molten droplets of controllable size; 5. The power device 5 realizes the formation of molten droplets by controlling the activity of the piston 23, thereby ensuring that the size and frequency of the molten droplets are controllable; 6. The ignition device 6 is separately arranged, thereby providing the possibility of studying the influence of flame on the dripping fire 41; 7. Through the data acquisition device 8, a variety of experimental data can be collected on the dripping fire 41 in all directions, and the operation is simple.

[0066] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An experimental device for producing dripping flames, characterized in that: include: frame; A melting tank, arranged on the frame and used for placing the material to be tested; wherein the material to be tested is a thermoplastic; A heating device, used for heating the melting tank to melt the material to be tested into a molten state; A dropper, provided on the melting tank and used to make the molten material to be tested drip to form a single molten droplet; A power device, used to apply power to the piston in the melting tank to control the frequency of its reciprocating motion, thereby controlling the formation and dripping frequency of the molten liquid droplets; An ignition device, used to ignite the molten liquid droplets to form a dripping fire; the ignition device ignites the molten liquid droplets using a combustible gas; A sample placement device, disposed below the melting tank and used to adjust the relative position of the sample to be ignited and the dripping fire as well as the dripping height; A data acquisition device, used for acquiring ignition data of the ignition process of the dripping fire on the sample to be ignited; The melting tank comprises a hollow tank body, a cover plate sealing the tank body and a piston movably arranged in the tank body, the piston divides the cavity in the tank body into an upper cavity and a lower cavity, the power device is connected to the upper cavity and is used to control the movement of the piston, the material to be tested is contained in the lower cavity, and the dropper is connected to the lower cavity; the power device comprises an interface connected to the upper cavity, a pressurizing component and a decompressing component connected to the interface, and a control component for controlling the action frequency of the pressurizing component and the decompressing component; the power device controls the movement of the piston by controlling the air pressure in the upper cavity, when the air pressure in the upper cavity is greater than the external atmospheric pressure, the piston moves downward, squeezes the material to be tested in a molten state through the dropper and forms molten droplets, when the air pressure in the upper cavity is less than the external atmospheric pressure, the piston moves upward, at this time, the external atmospheric pressure increases the upward pressure on the material to be tested in a molten state, so as to hinder the generation of molten droplets; The boosting component includes a high-pressure gas cylinder, a rough pressure reducing valve, a switch, a precision pressure reducing valve and a first high-speed solenoid valve connected in sequence through a first pressure pipeline; the pressure reducing component includes a vacuum pump, a pressure stabilizing cylinder and a second high-speed solenoid valve connected in sequence through a second pressure pipeline; the first pressure pipeline and the second pressure pipeline are both connected to the interface; the boosting component is used to make the air pressure in the upper chamber greater than the external atmospheric pressure, so as to drive the piston to move downward and extrude molten droplets; the pressure reducing component is used to make the air pressure in the upper chamber less than the external atmospheric pressure, so as to drive the piston to move upward and prevent the occurrence of droplets; the control component is used to control the working states of the boosting component and the pressure reducing component, so as to realize the controllable frequency of the up and down movement of the piston.

2. The experimental device for producing dripping flames according to claim 1, characterized in that: The heating device comprises a power supply, a temperature controller, a thermocouple and a heating tube, and the thermocouple and the heating tube are arranged on the melting tank.

3. The experimental device for producing dripping flames according to claim 1, characterized in that: The control component includes a single chip microcomputer, a first MOS tube and a second MOS tube, wherein the first MOS tube is connected to the first high-speed solenoid valve, and the second MOS tube is connected to the second high-speed solenoid valve.

4. The experimental device for producing dripping flames according to any one of claims 1 to 3, characterized in that: The dripping pipe is a metal pipe, and the dripping pipe is detachably arranged on the melting tank.

5. The experimental device for producing dripping flames according to any one of claims 1 to 3, characterized in that: The sample placement device comprises a three-dimensional sample rack and a sample stage. The sample stage is arranged on the three-dimensional sample rack and is located below the melting pot. The sample to be ignited is placed on the sample stage.

6. The experimental device for producing dripping flames according to any one of claims 5, characterized in that: The data acquisition device includes a high-speed camera, a weighing sensor and a temperature sensor. The weighing sensor is arranged on the three-dimensional sample rack and is used to detect the weight change of the sample table. The temperature sensor is arranged on the sample table and is used to detect the temperature change of the sample to be ignited.

7. An experimental method for studying dripping fire ignition, characterized in that: The following steps are involved: S1. placing a material to be tested in a melting tank, placing a sample to be ignited on a sample placement device, and adjusting the relative position and dripping height of the sample to be ignited below the melting tank by the sample placement device; wherein the material to be tested is a thermoplastic; S2. Heating the melting tank by a heating device to make the material to be tested in a molten state; the final heating temperature is lower than the auto-ignition temperature to avoid the flow and auto-ignition of the molten fuel; S3, using a power device to make the molten material to be tested drip regularly from the melting tank to form a single molten droplet; wherein the power device can apply power to the piston in the melting tank to control the frequency of its reciprocating motion, thereby controlling the formation and dripping frequency of the molten droplets; S4, igniting the molten liquid droplets by an ignition device to form a dripping fire; the ignition device ignites the molten liquid droplets by using a combustible gas; S5, collecting ignition data of the dripping fire during the dripping process and after dripping on the sample to be ignited through a data acquisition device; The melting tank comprises a hollow tank body, a cover plate sealing the tank body and a piston movably arranged in the tank body, the piston divides the cavity in the tank body into an upper cavity and a lower cavity, the power device is connected to the upper cavity and is used to control the movement of the piston, the material to be tested is contained in the lower cavity, and the dropper is connected to the lower cavity; the power device comprises an interface connected to the upper cavity, a pressurizing component and a decompressing component connected to the interface, and a control component for controlling the action frequency of the pressurizing component and the decompressing component; the power device controls the movement of the piston by controlling the air pressure in the upper cavity, when the air pressure in the upper cavity is greater than the external atmospheric pressure, the piston moves downward, squeezes the material to be tested in a molten state through the dropper and forms molten droplets, when the air pressure in the upper cavity is less than the external atmospheric pressure, the piston moves upward, at this time, the external atmospheric pressure increases the upward pressure on the material to be tested in a molten state, so as to hinder the generation of molten droplets; The boosting component includes a high-pressure gas cylinder, a rough pressure reducing valve, a switch, a precision pressure reducing valve and a first high-speed solenoid valve connected in sequence through a first pressure pipeline; the pressure reducing component includes a vacuum pump, a pressure stabilizing cylinder and a second high-speed solenoid valve connected in sequence through a second pressure pipeline; the first pressure pipeline and the second pressure pipeline are both connected to the interface; the boosting component is used to make the air pressure in the upper chamber greater than the external atmospheric pressure, so as to drive the piston to move downward and extrude molten droplets; the pressure reducing component is used to make the air pressure in the upper chamber less than the external atmospheric pressure, so as to drive the piston to move upward and prevent the occurrence of droplets; the control component is used to control the working states of the boosting component and the pressure reducing component, so as to realize the controllable frequency of the up and down movement of the piston.

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