A Test Device and Method for the Limiting Oxygen Concentration of Combustible Liquids

Abstract

The present invention discloses a test device and method for the limiting oxygen concentration of combustible liquids, comprising: an electrolyte supply system, which includes an adjustable-height placement platform and a constant-pressure liquid supply module; a combustion system, which includes a base and a combustion tube. A partition is fixedly connected to the middle position inside the combustion tube, and an ignition module is detachably connected to the center position of the top surface of the partition. A wick tube is arranged inside the ignition module, and a wick is provided at the top end of the wick tube. A rectification module is respectively arranged on the top surface of the partition and the bottom inside the combustion tube. An experimental darkroom is installed on the top surface of the base; a gas distribution system, an intake pipe is installed at the bottom of the combustion tube; a control system, the gas distribution system is connected to the control system; an optical measurement and analysis system, the optical measurement and analysis system is installed inside the experimental darkroom; a waste liquid recovery module is installed at the bottom of the base, and a discharge pipe is installed at the bottom of the combustion tube. The constant-pressure liquid supply module of the present invention can ensure that the electrolyte with a stable pressure is provided for the wick tube, guaranteeing the accuracy and repeatability of the test results.

Description

Technical Field

[0001] The present invention relates to the technical field of limiting oxygen concentration testing, and particularly to a device and method for testing the limiting oxygen concentration of combustible liquids. Background Art

[0002] The flammability evaluation indexes of single-component liquids usually include the upper or lower flammability limit (UFL / LFL), flash point (FP), auto-ignition temperature (AIT), heat of combustion (∆Hc), etc. However, it is difficult to quantitatively characterize the flammability of multi-component mixed liquids through the above characteristics. For mixed liquid samples with specific ratios, such as battery organic electrolyte solvents, existing studies usually use the self-extinguishing time (SET) to evaluate their flammability, or use a linear flame propagation test modified based on ASTM D5306 or a flame extinction probability test. Most self-extinguishing time experiments (SET) directly ignite the solvent or a swab dipped in the solvent by an open flame method, and the results are greatly affected by the ignition source and liquid volatilization. The latter two methods can only give qualitative analysis results (flammable, difficult to burn, and non-flammable in three grades) due to uncertain experimental conditions.

[0003] The limiting oxygen concentration at which a material ignites or extinguishes can become a key index for evaluating the flammability of gaseous fuels, volatile solvents, and solid materials. In order to conduct quantitative analysis of the flammability limit of combustible mixed solutions, especially lithium-ion battery electrolytes composed of various chemical components (solvents, additives, and lithium salts) in specific proportions, the limiting oxygen concentration is a more suitable evaluation criterion for quantifying its flammability. Different flash points are parameters related to the physical properties of combustible liquid evaporation, and the limiting oxygen concentration of material combustion is more related to the chemical properties in the combustion reaction of combustible liquids. If the oxygen concentration can be controlled below these limits, fuel combustion can be prevented; at the same time, combustible liquids with higher limiting oxygen concentration values also prove to have better flame retardant effects. In addition, from the perspective of combustion testing methods, for the combustion of electrolytes involving evaporation and decomposition of multi-component fuels, a simple non-premixed flame system is more conducive to intuitive observation and continuous repeated tests. Therefore, we call the lowest air oxygen concentration that maintains continuous combustion of a combustible material the limiting oxygen index.

[0004] Existing limiting oxygen index measurement devices are based on the ISO4589 standard, mainly used for measuring the limiting oxygen index of flat and rod-shaped solid materials, mostly using specimen clamps to hold the object to be measured, and for liquids, small disks or small cups are mostly used to directly ignite. This measurement method is greatly affected by the volatilization of the liquid, and for mixed liquids, the concentration of high-boiling components will gradually increase due to the distillation effect, which is not conducive to accurate quantitative analysis.

[0005] Different from the combustion of solids and gases, when liquids burn, the stable supply of fuel is more difficult and important (especially in experiments mainly based on diffusion combustion). During current tests, the limiting oxygen concentration data measured by first placing the liquid fuel to be tested in a container such as a small cup and igniting it are easily affected by factors such as thermal radiation feedback, adhesion of high-viscosity components, and selective volatilization of low-boiling components, resulting in inaccurate measurement results. At the same time, the limitation of the quantity of a single portion of fuel makes it impossible to continuously conduct combustion experiments, and it is difficult to guarantee the data accuracy and repeatability. Existing oxygen index meters usually discard the experimental materials after one experiment, with poor economy and harm to the environment, which is worthy of improvement. In addition, the wick combustion method used in previous paper experiments is also affected by radiative heat feedback.

[0006] Obtaining an accurate oxygen index requires stable environmental conditions. Although traditional limiting oxygen index meters will determine the axial flow rate, the specific value is approximately 5 cm / s, but they will not change the axial flow rate of the gas. This instrument provides a variable axial flow rate, and the flow field is difficult to analyze, resulting in difficulties in studying the flame extinction mechanism. For other traditional types of limiting oxygen index analyzers, usually only a specific oxygen index value can be obtained, and it is impossible to deeply analyze the data in combination with phenomena, including further analysis by relating to specific flame phenomena, parameters such as the rectified flow field velocity, etc.

[0007] Based on the above technical problems, the present invention provides a test device and method for the limiting oxygen concentration of combustible liquids. Summary of the Invention

[0008] The purpose of the present invention is to provide a test device and method for the limiting oxygen concentration of combustible liquids to solve the problems existing in the prior art.

[0009] To achieve the above purpose, the present invention provides the following solution: The present invention provides a test device for the limiting oxygen concentration of combustible liquids, including:

[0010] An electrolyte supply system, the electrolyte supply system includes an adjustable-height placement platform and a constant-pressure liquid supply module;

[0011] A combustion system, the combustion system includes a base and a combustion tube, a partition is fixedly connected to the bottom of the combustion tube, a plurality of through holes are opened on the partition, an ignition module is detachably connected to the center position of the top surface of the partition, a wick tube is arranged inside the ignition module, a wick is provided at the top end of the wick tube, and the constant-pressure liquid supply module is connected to the wick tube; an experimental darkroom is installed on the top surface of the base;

[0012] A gas rectification chamber, the gas rectification chamber is installed on the base, and a rectification module is arranged inside the gas rectification chamber;

[0013] A gas distribution system, an intake pipe is installed at the bottom of the gas rectification chamber, and the output end of the gas distribution system is connected to one end of the intake pipe;

[0014] A control system, the gas distribution system is connected to the control system;

[0015] An optical measurement and analysis system, the optical measurement and analysis system is installed in the experimental darkroom, and the optical measurement and analysis system is connected to the terminal system;

[0016] Wherein, a waste liquid recovery module is installed at the bottom of the base.

[0017] According to the flammable liquid limiting oxygen concentration test device provided by the present invention, the adjustable height placement platform includes:

[0018] Vertical frames, there are two groups of vertical frames, and the two groups of vertical frames are arranged in parallel;

[0019] Sliding tables, the sliding tables are respectively connected to the vertical frames in a vertical sliding manner;

[0020] A positioning component, the positioning component includes a positioning bolt, a positioning hole is formed on the side of the sliding table, the positioning bolt is threadedly connected in the positioning hole, and the positioning bolt abuts against the vertical frame;

[0021] Wherein, scale lines are provided on the vertical frames.

[0022] According to the flammable liquid limiting oxygen concentration test device provided by the present invention, the constant pressure liquid supply module includes:

[0023] A liquid storage tank, the liquid storage tank is placed on one of the adjustable height placement platforms;

[0024] A liquid level control tank, the liquid level control tank is placed on the other adjustable height placement platform;

[0025] A switchable funnel, the switchable funnel is vertically inserted into the pipe orifice of the liquid storage tank;

[0026] A liquid outlet pipe, the liquid outlet pipe is fixed at the bottom end of the side of the liquid storage tank, one end of the liquid outlet pipe is inserted into the liquid level control tank, and a control valve I is installed on the liquid outlet pipe;

[0027] A constant pressure pipe, one end of the constant pressure pipe is inserted into the liquid storage tank, and the other end of the constant pressure pipe is inserted into the liquid level control tank;

[0028] Wherein, the liquid level control tank is connected to the wick tube through a delivery pipe, one end of the delivery pipe is fixed at the bottom end of the side of the liquid level control tank, and a control valve II is installed on the delivery pipe.

[0029] According to the flammable liquid limiting oxygen concentration testing device provided by the present invention, the ignition module includes:

[0030] A combustion base, the combustion base is fixed at the center position of the top surface of the partition plate, and the wick tube is fixed on the top surface of the combustion base;

[0031] A fixed sleeve, the fixed sleeve is threadedly connected to the combustion base, and a through hole is provided at the center position of the top of the fixed sleeve;

[0032] A heat insulation sleeve, the heat insulation sleeve is coaxially arranged inside the fixed sleeve;

[0033] A heating wire, the heating wire is arranged on the inner wall of the heat insulation sleeve;

[0034] An atomizer, the atomizer is installed on the inner top wall of the fixed sleeve, and the atomizer is arranged corresponding to the through hole.

[0035] According to the flammable liquid limiting oxygen concentration testing device provided by the present invention, the rectification module includes:

[0036] A glass bead rectification layer, the glass bead rectification layer is laid at the bottom of the gas rectification chamber;

[0037] A honeycomb hole plate layer I, the honeycomb hole plate layer I is arranged above the glass bead rectification layer;

[0038] A honeycomb hole plate layer II, the honeycomb hole plate layer II is arranged on the top surface of the partition plate.

[0039] According to the flammable liquid limiting oxygen concentration testing device provided by the present invention, the gas distribution system includes:

[0040] A gas storage tank, several groups of the gas storage tanks are provided;

[0041] A gas mixing tank, several of the gas storage tanks are all connected to the gas mixing tank through pipelines;

[0042] A flowmeter, the flowmeters are respectively arranged on several groups of the pipelines;

[0043] Wherein, one end of the air inlet pipe is connected to the gas mixing tank, and an air supply pump is installed on the air inlet pipe.

[0044] According to the flammable liquid limiting oxygen concentration testing device provided by the present invention, the optical measurement and analysis system includes:

[0045] A camera, the camera is installed in the experimental darkroom through a support frame;

[0046] An optical fiber probe, the optical fiber probe is installed on the side wall of the darkroom, and the optical fiber probe is connected to a micro spectrometer;

[0047] A sheet light source emitter, and the sheet light source emitter is installed in the darkroom.

[0048] According to the flammable liquid limiting oxygen concentration testing device provided by the present invention, the waste liquid recovery module includes:

[0049] A recovery bottle, the recovery bottle is placed on the base, and the recovery bottle is located below the gas rectification chamber;

[0050] A discharge pipe is installed at the bottom of the gas rectification chamber, and the discharge pipe is arranged corresponding to the recovery bottle

[0051] A control valve III, and the control valve III is installed on the discharge pipe.

[0052] A method for testing the limiting oxygen concentration of a flammable liquid includes the following steps:

[0053] Step 1, assemble the experimental device, pre-soak the wick, and insert the wick into the top of the wick tube after the wick meets the experimental requirements;

[0054] Step 2, inject the experimental liquid into the constant pressure liquid supply module, open the constant pressure liquid supply module until the liquid fills the delivery pipe and there is no air residue, and check that the upper end of the wick is wet;

[0055] Step 3, the gas distribution system works, controls the gas distribution concentration, gas flow rate and flow rate through the control system, inputs the mixed gas into the gas rectification chamber, realizes uniform gas distribution through the rectification module, and then enters the combustion tube through the partition;

[0056] Step 4, use an igniter to ignite the atomized droplets to obtain a stable flame, and judge the stability of the flame through the optical measurement and analysis system;

[0057] Step 5, after judging that the flame and the flow rate are stable, the test of the limiting oxygen index can be started. Use a method similar to the dichotomy to determine the limiting oxygen index of liquid fuels such as electrolytes. In the first experiment, reduce it by 5% vol each time. According to the replacement time of the new mixed gas in the gas supply system, the test duration under given conditions is at least one minute. If the flame continues to burn for more than one minute, it is judged as the "continuous combustion" state and further reduction of oxygen is required. Otherwise, if the flame goes out within one minute, it is judged as the "extinguished" state. After initially obtaining the approximate range of the oxygen index, the second experiment can directly drop from the initial high concentration to near the upper limit of the oxygen concentration obtained in the first experiment, and reduce the oxygen concentration by 1% vol each time to obtain a more accurate oxygen concentration range. And so on, in the third and subsequent experiments, reduce it by 0.1% vol each time to obtain the limiting oxygen index of liquid atomized combustion. Repeat the experiment multiple times and take the average value to obtain the limiting oxygen index value range.

[0058] The present invention discloses the following technical effects:

[0059] 1) The constant-pressure liquid supply module can ensure that the electrolyte with stable pressure is provided for the wick tube, avoiding the unstable electrolyte flow caused by the fluctuation of the liquid supply pressure, which in turn affects the combustion process of the combustible liquid, and ensuring the accuracy and repeatability of the test results.

[0060] 2) The adjustable-height placement platform can adjust the height of the constant-pressure liquid supply module according to actual needs, facilitating the adaptive installation with other components such as the combustion system, improving the flexibility and versatility of the device, and facilitating the reasonable layout in different experimental scenarios.

[0061] 3) The detachable ignition module is convenient for installation, replacement and maintenance, ensuring the reliability and stability of the ignition process. The cooperation between the wick tube and the wick can precisely control the ignition position and combustion state of the combustible liquid.

[0062] 4) The rectification module on the top surface of the partition and in the gas rectification chamber can rectify the airflow entering the combustion tube, making the gas flow more uniform and stable, reducing the influence of turbulence and eddy currents on the combustion process, improving the combustion efficiency, ensuring the stability and consistency of the combustion process, and being conducive to accurately measuring the limiting oxygen concentration of the combustible liquid.

[0063] 5) The experimental darkroom provides a good working environment for the optical measurement and analysis system, avoiding external light interference, ensuring that the optical measurement and analysis system can accurately capture and analyze the optical signals during the combustion process, and improving the measurement accuracy and reliability.

[0064] 6) The gas distribution system is connected to the control system, which can precisely control the ratio of oxygen and other gases entering the combustion tube, meet the requirements of testing the limiting oxygen concentration of different combustible liquids, and achieve the accurate study of the combustion characteristics of combustible liquids in different oxygen concentration environments.

[0065] 7) Through the integrated control of the gas distribution system by the control system, the automation and intelligence of the gas ratio are realized, improving the convenience and accuracy of the experimental operation, and reducing the influence of human factors on the experimental results.

[0066] 8) The optical measurement and analysis system installed in the experimental darkroom can collect the optical signals during the combustion process in real time and accurately, such as flame color, brightness, spectrum, etc., and transmit the collected data to the terminal system for analysis and processing, providing rich data support for studying the combustion mechanism and limiting oxygen concentration of combustible liquids.

[0067] 9) The terminal system can deeply analyze the data collected by the optical measurement and analysis system, accurately calculate the limiting oxygen concentration of the combustible liquid by establishing mathematical models and algorithms, and simulate and predict the combustion process, providing a scientific basis for the safe use and fire prevention and control of combustible liquids.

[0068] 10) The drain pipes corresponding to the waste liquid recovery module and the gas rectification chamber installed at the bottom of the base can collect and recycle the waste liquid generated during the combustion process in a timely and effective manner, avoiding environmental pollution caused by the waste liquid and reducing the safety risks during the experiment, meeting the requirements of environmental protection and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0070] Figure 1 It is a schematic structural diagram of the device for testing the limiting oxygen concentration of combustible liquids of the present invention;

[0071] Figure 2 It is a front view of the combustion system of the present invention;

[0072] Figure 3 It is an axonometric view of the combustion system of the present invention;

[0073] Figure 4 It is an axonometric view of the ignition module of the present invention;

[0074] Figure 5 It is an axonometric view of the ignition module of the present invention;

[0075] Figure 6 It is a front view of the ignition module of the present invention;

[0076] Figure 7 It is a schematic structural diagram of the base of the present invention.

[0077] Among them, 1. electrolyte supply system; 2. combustion system; 3. gas mixing system; 4. optical measurement and analysis system; 5. waste liquid recovery module; 101. vertical frame; 102. sliding table; 103. positioning bolt; 111. liquid storage tank; 112. liquid level control tank; 113. switchable funnel; 114. liquid outlet pipe; 115. control valve I; 116. constant pressure pipe; 117. conveying pipe; 118. control valve II; 201. combustion base; 202. fixed sleeve; 203. heat insulation sleeve; 204. heating wire; 205. atomizer; 211. wick tube; 212. wick; 221. glass bead rectification layer; 222. honeycomb hole plate layer I; 223. honeycomb hole plate layer II; 231. base; 232. combustion tube; 233. partition board; 241. gas rectification chamber; 301. gas storage tank; 302. gas mixing tank; 303. flow meter; 401. camera; 402. optical fiber probe; 403. sheet light source emitter; 501. recovery bottle; 502. control valve III. Detailed implementation manners

[0078] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0079] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0080] Refer to Figure 1-7 , the present invention provides a test device for the limiting oxygen concentration of a combustible liquid, including:

[0081] An electrolyte supply system 1, which includes an adjustable-height placement platform and a constant-pressure liquid supply module. The constant-pressure liquid supply module is placed on the adjustable-height placement platform;

[0082] A combustion system 2, which includes a base 231 and a combustion tube 232. The combustion tube 232 is vertically detachably connected to the top surface of the base 231. A partition 233 is fixedly connected to the bottom of the combustion tube 232. A plurality of through holes are formed in the partition 233. An ignition module is detachably connected to the center position of the top surface of the partition 233. A wick tube 211 is arranged in the ignition module. A wick 212 is provided at the top end of the wick tube 211. The output end of the constant-pressure liquid supply module is connected to the bottom end of the wick tube 211 through a delivery tube 117; An experimental darkroom is installed on the top surface of the base 231; In order to prevent the poor temporary absorption of liquid by the wick 212, the wick 212 made of various materials such as cotton, glass fiber, and porous ceramic can be soaked for 24 hours first;

[0083] The combustion tube 232 can be made of glass or acrylic. The inner diameter of the glass barrel is 100 mm, the tube length is 220 mm, and a 5-mm hole is provided at the position corresponding to the optical fiber probe 402 above the wick 212 on the barrel.

[0084] The outer diameter of the wick tube 211 is 12 mm, the inner diameter is 6 mm, and the height is 30 mm. A heating wire 204 attachment groove is provided on the outer wall, and the heating wire 204 can be used for heating.

[0085] A gas rectification chamber 241, which is installed on the base 231 and is located below the combustion tube 232. A rectification module is arranged in the gas rectification chamber 241;

[0086] A gas distribution system 3. An intake pipe is installed at the bottom of the gas rectification chamber 241. The output end of the gas distribution system 3 is connected to one end of the intake pipe;

[0087] A control system, and the gas distribution system 3 is connected to the control system;

[0088] An optical measurement and analysis system 4, the optical measurement and analysis system 4 is installed in the experimental darkroom, and the optical measurement and analysis system 4 is connected to the terminal system;

[0089] Wherein, a waste liquid recovery module 5 is installed at the bottom of the base 231, a discharge pipe is installed at the bottom of the gas rectification chamber 241, and the discharge pipe is arranged corresponding to the waste liquid recovery module 5.

[0090] Considering factors such as the volatility and certain corrosiveness of the experimental liquid, improving the service life of the experimental device and facilitating cleaning, etc., the base 231 is made of 304 stainless steel, with dimensions of approximately 350mm Χ 350mm Χ 180mm. The front of the base 231 is made into a door lock structure that can be opened and closed to facilitate the placement and removal of the recovery bottle 501, waste liquid collection, and internal cleaning. There are rubber feet at the bottom to provide support and have a certain anti-vibration interference effect.

[0091] The control system uses a self-designed standard electrical control cabinet. The electrical control cabinet adopts a metal frame structure and is built-in with control software to realize equipment power supply and function control. Electrical control function components are installed inside the electrical control cabinet. The system uses a programmable logic controller and an analog quantity module to realize test data acquisition and action control. The operation software is mainly used to set and display the gas flow rate and oxygen concentration, and record test data such as flow rate, oxygen concentration and other parameters, and has a data curve display function and a storage function.

[0092] The oxygen concentration configuration and supply system is a device that automatically configures the corresponding oxygen concentration by a programmable logic controller equipped with an analog quantity module, mass flow controllers for oxygen and nitrogen, and a mixing tank 302.

[0093] The wick 212 is a cotton wick or a glass fiber wick with a diameter of 5mm.

[0094] Wherein the gas flow rate is adjustable from 5 - 20 cm / s, and the oxygen concentration is adjustable from 0 - 100%.

[0095] When the inner diameter of the combustion tube 232 is fixed at 80mm:

[0096] The total gas flow rate corresponding to a gas flow rate of 5 cm / s is: 15.12 L / min;

[0097] The total gas flow rate corresponding to a gas flow rate of 10 cm / s is: 30.24 L / min;

[0098] The total gas flow rate corresponding to a gas flow rate of 20 cm / s is: 60.48 L / min;

[0099] The mass flow control measurement range is 65 L / min;

[0100] For a further optimized solution, the adjustable-height placement platform includes:

[0101] Vertical frames 101, with two sets of vertical frames 101 arranged in parallel;

[0102] Sliding tables 102, with sliding tables 102 vertically and slidably connected to the vertical frames 101 respectively;

[0103] Positioning components, the positioning components include positioning bolts 103, positioning holes are opened on the sides of the sliding tables 102, the positioning bolts 103 are threadedly connected in the positioning holes, and the positioning bolts 103 are in contact with the vertical frames 101;

[0104] Among them, scale lines are provided on the vertical frames 101.

[0105] For a further optimized solution, the constant-pressure liquid supply module includes:

[0106] Liquid storage tank 111, the liquid storage tank 111 is placed on one of the adjustable-height placement platforms;

[0107] Liquid level control tank 112, the liquid level control tank 112 is placed on the other adjustable-height placement platform;

[0108] Switchable funnel 113, the switchable funnel 113 is vertically inserted into the pipe orifice of the liquid storage tank 111;

[0109] Liquid outlet pipe 114, the liquid outlet pipe 114 is fixed to the bottom end of the side of the liquid storage tank 111, one end of the liquid outlet pipe 114 is inserted into the liquid level control tank 112, and a control valve I 115 is installed on the liquid outlet pipe 114;

[0110] Constant-pressure pipe 116, one end of the constant-pressure pipe 116 is inserted into the liquid storage tank 111, and the other end of the constant-pressure pipe 116 is inserted into the liquid level control tank 112;

[0111] Among them, one end of the delivery pipe 117 is fixed to the bottom end of the side of the liquid level control tank 112, and a control valve II 118 is installed on the delivery pipe 117.

[0112] The bottom of the liquid level control tank 112 is equipped with an interface directly connected to the wick 212 burner. (Note: The volume of the liquid sample tank is 250 ml, and the volume of the liquid level control tank 112 is 100 ml. Considering factors such as convenient observation, connection, and not being easily damaged, the connecting pipes of the tank bodies and the pipes from the tank bodies to the wick 212 interface are made of fluorine-containing hose material.)

[0113] For a further optimized solution, the ignition module includes:

[0114] The combustion base 201 is fixed at the center of the top surface of the partition plate 233, and the wick tube 211 is fixed on the top surface of the combustion base 201;

[0115] The fixing sleeve 202 is threadedly connected to the combustion base 201, and a through hole is provided at the center of the top of the fixing sleeve 202;

[0116] The heat insulation sleeve 203 is coaxially arranged inside the fixing sleeve 202;

[0117] The heating wire 204 is arranged on the inner wall of the heat insulation sleeve 203;

[0118] The atomizer 205 is installed on the inner top wall of the fixing sleeve 202, and the atomizer 205 is arranged corresponding to the through hole.

[0119] The heat insulation sleeve 203: The inner diameter is 15 mm, the outer diameter is 17 mm, and it can be made of PVC plastic with a length of 31 mm. It can be directly inserted into the groove on the base table and fixed. There is a card slot on the combustion base 201, and the heat insulation sleeve 203 is snapped into the card slot.

[0120] The atomizer 205: Adopts an ultrasonic microporous atomization sheet, and releases the electrolyte spray by flapping and wetting the surface of the wick 212 through high-frequency oscillation. Generally, the inner diameter is less than 20 mm.

[0121] The fixing sleeve 202: The inner diameter is 20 mm, the outer diameter is 24 mm, and the height is 36 mm. It can be threadedly connected to the lower combustion base, and the height can be adjusted by the thread to provide a downward pressure on the wick 212 so that the wick 212 is closely attached to the high-frequency oscillation atomizer 205.

[0122] For a further optimized solution, the rectification module includes:

[0123] The glass bead rectification layer 221 is laid at the bottom of the gas rectification chamber 241;

[0124] The honeycomb hole plate layer I 222 is arranged above the glass bead rectification layer 221;

[0125] The honeycomb hole plate layer II 223 is arranged on the top surface of the partition plate 233.

[0126] For a further optimized solution, the gas distribution system 3 includes:

[0127] The gas storage tank 301 is provided with several groups;

[0128] The gas mixing tank 302, and several gas storage tanks 301 are all connected to the gas mixing tank 302 through pipelines;

[0129] Flow meters 303 are respectively arranged on several groups of pipelines;

[0130] One end of the intake pipe is connected to the gas mixing tank 302, and a gas supply pump is installed on the intake pipe.

[0131] For a further optimized solution, the optical measurement and analysis system 4 includes:

[0132] A camera 401, which is installed in the experimental darkroom through a support frame;

[0133] An optical fiber probe 402, which is installed on the side wall of the darkroom, and the optical fiber probe 402 is connected to a micro spectrometer;

[0134] A sheet light source emitter 403, which is installed in the darkroom.

[0135] The camera 401 is a modern digital camera with high sensitivity and high frame rate. A modular darkroom that can be easily disassembled can be installed above the combustion base 231. A probe-type micro spectrometer is used, and the detection angle is about 120°. The darkroom consists of a frame that can be easily disassembled and a black curtain. The curtain surrounds the left, right, rear, and top of the frame. A reserved air outlet for the combustion tube 232 is opened on the top surface, and a black net is covered above the air outlet.

[0136] For a further optimized solution, the waste liquid recovery module 5 includes:

[0137] A recovery bottle 501, which is placed on the base 231, and the recovery bottle 501 is located below the gas rectification chamber 241;

[0138] A control valve III 502, which is installed on the discharge pipe.

[0139] A method for testing the limiting oxygen concentration of a combustible liquid includes the following steps:

[0140] Step 1, assemble the experimental device, pre-soak the wick 212, and insert the wick 212 into the top of the wick tube 211 after the wick 212 meets the experimental requirements;

[0141] Step 2, inject the experimental liquid into the constant pressure liquid supply module, open the constant pressure liquid supply module until the liquid fills the delivery pipe 117 and there is no air residue, and check that the upper end of the wick 212 is wet; after placing the wick 212 and checking that the upper end of the wick 212 is wet, place the high-frequency oscillating atomizer 205 above it, insert it into the heat insulation sleeve 203 cylinder and preliminarily fix it. Determine the position of the atomizer 205 directly above the inner wall of the heat insulation sleeve 203 cylinder. When it is necessary to heat the experimental liquid, the power supply of the heating wire 204 can be turned on. Finally, screw the fixed sleeve 202, which is threadedly connected to the lower seat of the sleeve, rotate and fix it, and provide a downward pressure on the atomizer 205 through the sleeve so that the atomizer 205 is in close contact with the upper part of the wick 212.

[0142] Turn on the atomizer 205 above the wick 212. As the experiment progresses, the liquid level in the liquid level control bottle will remain stable due to the air pressure. The wick 212 will continuously and steadily suck up the liquid, continuously atomize the droplets, and provide fuel upward.

[0143] Step 3: The gas distribution system 3 operates. The gas distribution concentration, gas flow rate, and flow are controlled through the control system. The mixed gas is input into the gas rectification chamber 241, and uniform gas distribution is achieved through the rectification module. Then, it enters the combustion tube 232 through the partition 233. Open the valves of the oxygen and nitrogen cylinders, and use the microcomputer main control electronics to control the flow rate and flow of the two into the gas mixing tank 302. Thus, the oxygen concentration and flow rate entering the combustion tube 232 can be controlled. The adjustable gas flow rate range of this instrument is about 5 cm / s - 20 cm / s. In view of experimental experience and relevant operating specifications, the commonly used gas flow rate is 10 cm / s.

[0144] Step 4: Use an igniter to ignite the atomized droplets to obtain a stable flame, and judge the stability of the flame through the optical measurement and analysis system 4. The stability of the flame can be judged by two criteria. One is to judge with a camera and the naked eye, and the other is to judge the stability of the flame using the real-time flame spectrum data obtained by a microprobe.

[0145] Step 5: After judging that the flame and flow rate are stable, the test of the limiting oxygen index can be started. Use a method similar to the dichotomy to determine the limiting oxygen index of liquid fuels such as electrolytes. In the first experiment, each time it is reduced by 5% vol. According to the replacement time of the newly mixed gas in the gas supply system, the test duration under given conditions is at least one minute. If the flame continues to burn for more than one minute, it is judged as the "continuous combustion" state, and oxygen needs to be further reduced. Otherwise, if the flame goes out within one minute, it is judged as the "extinguished" state. After initially obtaining the approximate range of the oxygen index, in the second experiment, it can be directly reduced from the initial high concentration to near the upper limit of the oxygen concentration obtained in the first experiment, and each time the oxygen concentration is reduced by 1% vol to obtain a more accurate oxygen concentration range. And so on, in the third and subsequent experiments, each time the oxygen concentration is reduced by 0.1% vol to obtain the limiting oxygen index of liquid atomized combustion. Repeat the experiment multiple times and take the average value to obtain the limiting oxygen index value range.

[0146] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying 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 construed as a limitation on the present invention.

[0147] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A test device for the limiting oxygen concentration of a combustible liquid, characterized in that, Including: An electrolyte supply system (1), the electrolyte supply system (1) includes an adjustable-height placement platform and a constant-pressure liquid supply module; A combustion system (2), the combustion system (2) includes a base (231) and a combustion tube (232), the bottom of the combustion tube (232) is fixedly connected with a partition plate (233), a plurality of through holes are opened on the partition plate (233), a ignition module is detachably connected to the center position of the top surface of the partition plate (233), a wick tube (211) is arranged in the ignition module, a wick (212) is arranged at the top end of the wick tube (211), and the constant-pressure liquid supply module is connected to the wick tube (211); An experimental darkroom is installed on the top surface of the base (231); A gas rectification chamber (241), the gas rectification chamber (241) is installed on the base (231), and a rectification module is arranged in the gas rectification chamber (241); A gas distribution system (3), an air inlet pipe is installed at the bottom of the gas rectification chamber (241), and the output end of the gas distribution system (3) is connected to one end of the air inlet pipe; A control system, the gas distribution system (3) is connected to the control system; An optical measurement and analysis system (4), the optical measurement and analysis system (4) is installed in the experimental darkroom, and the optical measurement and analysis system (4) is connected to the terminal system; Wherein, a waste liquid recovery module (5) is installed at the bottom of the base (231); The adjustable-height placement platform includes: Vertical frames (101), there are two groups of the vertical frames (101), and the two groups of vertical frames (101) are arranged in parallel; Sliding tables (102), sliding tables (102) are respectively vertically slidably connected to the vertical frames (101); A positioning component, the positioning component includes a positioning bolt (103), a positioning hole is opened on the side surface of the sliding table (102), the positioning bolt (103) is threadedly connected in the positioning hole, and the positioning bolt (103) abuts against the vertical frame (101); Wherein, scale lines are arranged on the vertical frame (101); The constant-pressure liquid supply module includes: A liquid storage tank (111), the liquid storage tank (111) is placed on one of the adjustable-height placement platforms; A liquid level control tank (112), the liquid level control tank (112) is placed on the other adjustable-height placement platform; A switchable funnel (113), the switchable funnel (113) is vertically inserted into the pipe orifice of the liquid storage tank (111); A liquid outlet pipe (114), the liquid outlet pipe (114) is fixed at the bottom end of the side surface of the liquid storage tank (111), one end of the liquid outlet pipe (114) is inserted into the liquid level control tank (112), and a control valve I (115) is installed on the liquid outlet pipe (114); A constant-pressure pipe (116), one end of the constant-pressure pipe (116) is inserted into the liquid storage tank (111), and the other end of the constant-pressure pipe (116) is inserted into the liquid level control tank (112); Among them, the liquid level control tank (112) is connected to the wick tube (211) through a delivery pipe (117). One end of the delivery pipe (117) is fixed to the bottom end of the side surface of the liquid level control tank (112), and a control valve II (118) is installed on the delivery pipe (117). The ignition module includes: A combustion base (201), the combustion base (201) is fixed at the center position of the top surface of the partition plate (233), and the wick tube (211) is fixed on the top surface of the combustion base (201). A fixed sleeve (202), the fixed sleeve (202) is threadedly connected to the combustion base (201), and a through hole is provided at the center position of the top of the fixed sleeve (202). A heat insulation sleeve (203), the heat insulation sleeve (203) is coaxially arranged inside the fixed sleeve (202). A heating wire (204), the heating wire (204) is arranged on the inner wall of the heat insulation sleeve (203). An atomizer (205), the atomizer (205) is installed on the inner top wall of the fixed sleeve (202), and the atomizer (205) is arranged corresponding to the through hole.

2. The flammable liquid limiting oxygen concentration testing device according to claim 1, wherein, The rectification module includes: A glass bead rectification layer (221), the glass bead rectification layer (221) is laid on the bottom of the gas rectification chamber (241). A honeycomb hole plate layer I (222), the honeycomb hole plate layer I (222) is arranged above the glass bead rectification layer (221). A honeycomb hole plate layer II (223), the honeycomb hole plate layer II (223) is arranged on the top surface of the partition plate (233).

3. The flammable liquid limiting oxygen concentration testing device according to claim 1, characterized in that, The gas distribution system (3) includes: A gas storage tank (301), several groups of the gas storage tanks (301) are provided. A gas mixing tank (302), several of the gas storage tanks (301) are all connected to the gas mixing tank (302) through pipelines. Flow meters (303), the flow meters (303) are respectively arranged on several groups of the pipelines. Among them, one end of the air inlet pipe is connected to the gas mixing tank (302), and an air supply pump is installed on the air inlet pipe.

4. The flammable liquid limiting oxygen concentration testing device according to claim 1, characterized in that, The optical measurement and analysis system (4) includes: A camera (401), the camera (401) is installed in the experimental darkroom through a support frame. An optical fiber probe (402), the optical fiber probe (402) is installed on the side wall of the darkroom, and the optical fiber probe (402) is connected to a micro spectrometer. A sheet light source emitter (403), the sheet light source emitter (403) is installed in the darkroom.

5. The flammable liquid limiting oxygen concentration testing device according to claim 1, wherein The waste liquid recovery module (5) includes: A recovery bottle (501), the recovery bottle (501) is placed on the base (231), and the recovery bottle (501) is located below the gas rectification chamber (241). A discharge pipe is installed at the bottom of the gas rectification chamber (241), and the discharge pipe is arranged corresponding to the recovery bottle (501). A control valve III (502), the control valve III (502) is installed on the discharge pipe.

6. A method for testing the limiting oxygen concentration of a combustible liquid, based on the combustible liquid limiting oxygen concentration testing device according to any one of claims 1-5, characterized in that, Including the following steps: Step 1: Assemble the experimental device, pre-soak the wick (212), and insert the wick (212) into the top of the wick tube (211) after the wick (212) meets the experimental requirements. Step 2: Inject the experimental liquid into the constant-pressure liquid supply module, and turn on the constant-pressure liquid supply module until the liquid fills the delivery pipe (117) and there is no air residue, and check that the upper end of the wick (212) is wet. Step 3: The gas distribution system (3) operates. Control the gas distribution concentration, gas flow rate, and flow rate through the control system. The mixed gas is input into the gas rectification chamber (241), and uniform gas distribution is achieved through the rectification module, and then enters the combustion tube (232) through the partition plate (233). Step 4: Use an igniter to ignite the atomized droplets to obtain a stable flame, and judge the stability of the flame through the optical measurement and analysis system (4). Step 5: After judging that the flame and flow rate are stable, the test of the limiting oxygen index can be started. Use a method similar to the dichotomy to determine the limiting oxygen index of liquid fuels such as electrolytes. In the first experiment, reduce it by 5% vol each time. According to the replacement time of the new mixed gas in the gas supply system, the test duration under given conditions is at least one minute. If the flame continues to burn for more than one minute, it is judged as the "continuous combustion" state, and the oxygen needs to be further reduced. Otherwise, if the flame goes out within one minute, it is judged as the "extinguished" state. After initially obtaining the approximate range of the oxygen index, the second experiment can be directly reduced from the initial high concentration to near the upper limit of the oxygen concentration obtained in the first experiment, and reduce the oxygen concentration by 1% vol each time to obtain a more accurate oxygen concentration range. And so on, in the third and subsequent experiments, reduce it by 0.1% vol each time to obtain the limiting oxygen index of liquid atomization combustion. Repeat the experiment multiple times and take the average value to obtain the limiting oxygen index value range.

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