Liquid oil film fire propagation test apparatus and method

Abstract

The application discloses a kind of liquid oil film fire spread test device and method, the present scheme includes test system and measurement system, wherein: test system provides the environmental support of liquid oil film combustion;Measurement system is used to measure the combustion parameter in the combustion process of liquid oil film;Test system includes combustion chamber, combustion substrate, rectifier and gas supply assembly, combustion substrate is arranged at the bottom of combustion chamber, rectifier is connected between gas supply assembly and combustion substrate, to provide uniform oxygen-rich environment for combustion substrate.The liquid oil film fire spread test device of the application, the combustion substrate is arranged at the bottom of the combustion chamber, and the rectifier is connected between the gas supply assembly and the combustion substrate to provide a uniform oxygen-rich environment for the combustion substrate.As can be seen, the test device of the application can provide a uniform oxygen-rich environment for combustion, thus improving the test accuracy of liquid oil film fire spread in an oxygen-rich normal pressure environment.

Description

Technical Field

[0001] This invention relates to the field of liquid fire spread testing technology, and in particular to a liquid oil film fire spread testing device and method. Background Technology

[0002] High-thrust rockets using liquid oxygen / kerosene engines as boosters are currently the mainstay launch vehicles. Among the various accident risks at space launch sites, propellant leaks leading to fires and explosions are the most serious catastrophic accidents. Liquid oxygen and kerosene have high boiling points and are mainly liquid after leakage. When liquid oxygen and kerosene drip onto the ground, they form an oil pool of a certain thickness or adhere to the surface of the rocket body and working platform, forming an oil film on the solid walls. When liquid oxygen leaks, it creates an oxygen-rich environment in a certain space. If kerosene and liquid oxygen leak simultaneously, the combustible vapors from the liquid oxygen and kerosene that evaporate on the rocket body surface or working platform mix with the high concentration of oxygen. Under forced ignition from external ignition sources such as electric sparks, open flames, or high-temperature hot walls, it is highly likely to cause fire, explosion, and fire spread.

[0003] Currently, experimental devices and methods used to determine the spread of fire on liquid surfaces generally simulate the fire spread of liquid fuel in a high-temperature initial environment, and cannot scientifically and effectively analyze the characteristics of fire spread of liquid oil films under oxygen-rich and normal-pressure conditions.

[0004] Therefore, it is essential to design a liquid oil film fire propagation testing device and method to improve the testing accuracy of liquid oil film fire propagation under oxygen-rich atmospheric pressure environment. Summary of the Invention

[0005] This invention proposes a liquid oil film fire propagation testing device and method to improve the testing accuracy of liquid oil film fire propagation under oxygen-rich atmospheric pressure environment.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a liquid oil film fire propagation testing device, comprising a testing system and a measurement system, wherein:

[0008] The test system provides environmental support for liquid oil film combustion;

[0009] The measurement system is used to measure combustion parameters during the combustion process of a liquid oil film;

[0010] The test system includes a combustion chamber, a combustion plate, a rectifier, and an air supply assembly. The combustion plate is located at the bottom of the combustion chamber, and the rectifier is connected between the air supply assembly and the combustion plate to provide a uniform oxygen-rich environment for the combustion plate.

[0011] Preferably, in the liquid oil film fire spread test device of the present invention, the rectifier includes a rectifier housing, a uniformly distributed rectifier layer, an air inlet, and a buffer cavity, wherein the uniformly distributed rectifier layer is arranged on the top of the rectifier housing and close to the combustion substrate; the air inlet is arranged on the bottom of the rectifier housing for communication with the air supply assembly; and a buffer cavity is provided between the air inlet and the uniformly distributed rectifier layer.

[0012] Preferably, in the liquid oil film fire spread test device of the present invention, the uniformly distributed rectifying layer includes a ceramic ball layer and an aluminum honeycomb core layer stacked along the height direction, wherein the aluminum honeycomb core layer is close to the combustion substrate.

[0013] Preferably, in the liquid oil film fire propagation testing device of the present invention, the gas supply component includes a pressurized oxygen cylinder, a pressurized nitrogen cylinder, a first pressure reducing valve, a second pressure reducing valve, a first mass flow controller, a second mass flow controller, a proportional mixing valve, a third mass flow controller, and an oxygen concentration sensor. The pressurized oxygen cylinder, the first pressure reducing valve, and the first mass flow controller are connected in sequence, as are the pressurized nitrogen cylinder, the second pressure reducing valve, and the second mass flow controller. Both the first and second mass flow controllers are connected to one side of the proportional mixing valve, which is connected to the third mass flow controller. The third mass flow controller is connected to the air inlet via a pipeline. The oxygen concentration sensor is installed in the combustion chamber to detect the oxygen concentration within the combustion chamber.

[0014] Preferably, in the liquid oil film fire spread test device of the present invention, the third mass flow controller is connected to multiple air inlets through a tree-like pipeline.

[0015] Preferably, in the liquid oil film fire spread testing device of the present invention, the combustion chamber includes a combustion chamber frame and fire-resistant glass, the fire-resistant glass is embedded around the combustion chamber frame, and the combustion substrate is located at the bottom of the combustion chamber frame.

[0016] Preferably, in the liquid oil film fire spread test device of the present invention, a tilt angle adjustment component is provided between the combustion substrate and the combustion chamber to adjust the tilt angle of the combustion substrate.

[0017] Preferably, in the liquid oil film fire spread testing device of the present invention, the tilt angle adjustment assembly includes a first horizontal bar, a first vertical bar, a second vertical bar, a first angle gauge, a second angle gauge, and a clamp. The first horizontal bar is arranged on the top of the combustion chamber frame, the first end of the first vertical bar is hinged to the first angle gauge, and the height of the first vertical bar is adjustable on the first horizontal bar. The first end of the second vertical bar is hinged to the second angle gauge, and the height of the second end of the second vertical bar is adjustable on the first horizontal bar. The clamp is installed on the first angle gauge and the second angle gauge to clamp the combustion substrate.

[0018] Preferably, in the liquid oil film fire spread test device of the present invention, the test system includes a smoke exhaust assembly, wherein the smoke exhaust assembly includes a smoke hood located above the combustion chamber and a variable frequency fire exhaust fan installed at the exhaust port of the smoke hood.

[0019] Preferably, in the liquid oil film fire propagation testing device of the present invention, the test system includes an ignition assembly, which includes an electric ignition assembly and a hot wire ignition assembly. The electric ignition assembly includes an ignition host and an ignition electrode. The energy of a single electric spark produced by the ignition electrode is adjusted by adjusting the output voltage of the ignition host, and the total ignition energy is adjusted by adjusting the duration. It is used for ignition of liquid fuels in oxygen-rich concentrations. The hot wire ignition assembly includes an ignition host and a hot wire. When operating at full power, the temperature of the hot wire can reach over 1200°C. It is used for ignition of liquid fuels in air and oxygen-deficient concentrations.

[0020] Preferably, in the liquid oil film fire spread testing device of the present invention, the measurement system includes a temperature measurement component, an image acquisition component, and a flow field display component, wherein the temperature measurement component is used to measure the combustion temperature; the image acquisition component is used to record the fire spread phenomenon, the fire spread pulsation frequency, the fire spread speed, the liquid film temperature, and the flame temperature; and the flow field display component is used to record the flame-induced flow field and surface flow.

[0021] Preferably, in the liquid oil film fire spread testing device of the present invention, the temperature measurement component includes a moving component, a thermocouple frame, and thermocouples. The moving component includes a second horizontal bar and a third vertical bar. The second horizontal bar is arranged on the combustion chamber, and the first end of the third vertical bar is rotatably connected to the thermocouple frame. The height of the third vertical bar is adjustable on the second horizontal bar. The thermocouples are arranged side by side on the thermocouple frame.

[0022] Preferably, in the liquid oil film fire spread testing device of the present invention, the image acquisition component includes a camera and an infrared thermal imager. The camera records the fire spread phenomenon, the fire spread pulsation frequency, and the fire spread speed; the infrared thermal imager records the liquid film temperature and the flame temperature.

[0023] Preferably, in the liquid oil film fire spread testing device of the present invention, the flow field display component includes a parallel light source, a Fresnel lens and a high-speed camera, and the high-speed camera records the flame-induced flow field and surface flow.

[0024] In a second aspect, the present invention provides a method for testing the spread of a liquid oil film fire, the method being based on a liquid oil film fire spread testing apparatus as described in any of the above claims, and the method comprising the following steps:

[0025] 1) Determine the combustion substrate;

[0026] 2) Arrange the combustion plate at the bottom of the combustion chamber;

[0027] 3) Adjust the measurement system;

[0028] 4) Liquid fuel is dripped onto the surface of the combustion substrate using a micropipette to form a liquid oil film;

[0029] 5) Turn on the air supply assembly to provide a uniform oxygen-rich environment by passing the air through the rectifier into the combustion chamber;

[0030] 6) Ignition;

[0031] 7) Turn on the measurement system and measure the combustion parameters during the liquid oil film combustion process.

[0032] As can be seen from the above technical solution, in the liquid oil film fire propagation testing device of the present invention, the combustion substrate is arranged at the bottom of the combustion chamber, and the rectifier is connected between the gas supply component and the combustion substrate to provide a uniform oxygen-rich environment for the combustion substrate. Therefore, the testing device of the present invention can provide a uniform oxygen-rich environment for combustion, thus improving the testing accuracy of liquid oil film fire propagation under oxygen-rich atmospheric pressure conditions. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort, and the present invention can be applied to other similar scenarios based on the provided drawings. Unless obvious from the linguistic context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0034] Figure 1 This is a partial schematic diagram of a liquid oil film fire propagation testing device provided in an embodiment of the present invention;

[0035] Figure 2 A schematic diagram of a rectifier in a liquid oil film fire propagation testing device provided in an embodiment of the present invention;

[0036] Figure 3 This is a three-dimensional schematic diagram of a liquid oil film fire spread testing device provided in an embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of the flow field display component in a liquid oil film fire propagation testing device provided in an embodiment of the present invention;

[0038] Figure 5 This is a schematic flowchart of a liquid oil film fire propagation test method provided in an embodiment of the present invention;

[0039] Among them, 100 is the combustion chamber, 200 is the combustion base plate, 300 is the rectifier, 400 is the air supply component, 500 is the ignition component, 600 is the smoke exhaust component, 700 is the temperature measurement component, 800 is the image acquisition component, and 900 is the flow field display component.

[0040] 101 is the combustion chamber frame, and 102 is fire-resistant glass;

[0041] 201 is the first horizontal bar, 202 is the first vertical bar, and 203 is the second vertical bar;

[0042] 301 is the rectifier housing, 302 is the aluminum honeycomb core layer, 303 is the ceramic ball layer, 304 is the buffer cavity, and 305 is the air inlet;

[0043] 401 is a pressurized oxygen cylinder, 402 is a pressurized nitrogen cylinder, 403 is a first pressure reducing valve, 404 is a second pressure reducing valve, 405 is a proportional mixing valve, 406 is a third mass flow controller, and 407 is an oxygen concentration sensor.

[0044] 601 is a smoke hood, and 602 is a variable frequency fire exhaust fan;

[0045] 701 is a thermocouple, 702 is an NI acquisition module, 703 is a thermocouple frame, 704 is a moving component, 7041 is a second horizontal bar, and 7042 is a third vertical bar.

[0046] 801 is a camera, and 8012 is an infrared thermal imager;

[0047] 901 is a high-speed camera, 902 is a Fresnel lens, 903 is a parallel light source, 904 is an incandescent lamp, and 905 is a Fresnel lens. Detailed Implementation

[0048] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. The described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0049] like Figure 1As shown. This invention provides a liquid oil film fire propagation testing device, including a testing system and a measurement system, wherein: the testing system provides environmental support for liquid oil film combustion; the measurement system is used to measure combustion parameters during the liquid oil film combustion process; the testing system includes a combustion chamber 100, a combustion substrate 200, a rectifier 300, and an air supply assembly 400, the combustion substrate 200 is arranged at the bottom of the combustion chamber 100, and the rectifier 300 is connected between the air supply assembly 400 and the combustion substrate 200 to provide a uniform oxygen-rich environment for the combustion substrate 200.

[0050] In the liquid oil film fire propagation testing device of the present invention, the combustion substrate 200 is arranged at the bottom of the combustion chamber 100, and the rectifier 300 is connected between the gas supply assembly 400 and the combustion substrate 200 to provide a uniform oxygen-rich environment for the combustion substrate 200. Therefore, the testing device of the present invention can provide a uniform oxygen-rich environment for combustion, thus improving the testing accuracy of liquid oil film fire propagation under oxygen-rich atmospheric pressure conditions.

[0051] It should be noted that the combustion substrate 200 is used to support the liquid oil film. The combustion substrate 200 is a metal plate with a width of 1cm to 4cm, a length of 10cm to 30cm, and a thickness of 0.2mm to 1mm.

[0052] like Figure 2 As shown, the rectifier 300 includes a rectifier housing 301, a uniformly distributed rectifier layer, an air inlet 305, and a buffer cavity 304. The uniformly distributed rectifier layer is arranged at the top of the rectifier housing 301 and close to the combustion plate 200. The air inlet 305 is arranged at the bottom of the rectifier housing 301 and is used to communicate with the gas supply assembly 400. The buffer cavity 304 is located between the air inlet 305 and the uniformly distributed rectifier layer. The gas supplied by the gas supply assembly 400 enters the buffer cavity 304 through the air inlet 305 and is temporarily stored in the buffer cavity 304. The gas temporarily stored in the buffer cavity 304 is more evenly mixed under the rectification effect of the uniformly distributed rectifier layer, providing a uniform oxygen-rich environment for the combustion plate 200.

[0053] The rectifier 300 measures 52cm×52cm×20cm and has four air inlets. The lowest internal layer has a 10cm high cavity. Above the buffer cavity 304, multiple layers of high-porosity materials, such as a uniformly distributed rectifier layer, are stacked vertically to disperse and rectify the air supplied through the air inlets across the entire surface, enabling the air to diffuse evenly and at a low speed into the combustion chamber 100.

[0054] As described above, the function of the uniformly distributed rectifier layer is to uniformly supply gas to the combustion substrate 200. In some embodiments of the present invention, the uniformly distributed rectifier layer includes a ceramic sphere layer 303 and an aluminum honeycomb core layer 302 stacked along the height direction, wherein the aluminum honeycomb core layer 302 is close to the combustion substrate 200. In the illustration, the aluminum honeycomb core layer 302 has two layers, and the ceramic sphere layer 303 has one layer, wherein the one layer of ceramic spheres 303 is located between the two layers of aluminum honeycomb core layers 302. The embodiments of the present invention are not limited to the number and arrangement shown in the illustrations. The aluminum honeycomb core layer 302 is filled with aluminum honeycomb core, and the ceramic sphere layer 303 is filled with ceramic spheres; both the aluminum honeycomb core and the ceramic spheres are high-porosity materials.

[0055] See Figure 3 The gas supply assembly 400 provides oxygen support for liquid oil film combustion. In some embodiments of the present invention, the gas supply assembly 400 includes a pressurized oxygen cylinder 401, a pressurized nitrogen cylinder 402, a first pressure reducing valve 403, a second pressure reducing valve 404, a first mass flow controller, a second mass flow controller, a proportional mixing valve 405, a third mass flow controller 406, and an oxygen concentration sensor 407. The pressurized oxygen cylinder 401, the first pressure reducing valve 403, and the first mass flow controller are connected in sequence, as are the pressurized nitrogen cylinder 402, the second pressure reducing valve 404, and the second mass flow controller. Both the first and second mass flow controllers are connected to one side of the proportional mixing valve 405, which is connected to the third mass flow controller 406. The third mass flow controller 406 is connected to the air inlet 305 via a pipeline. The oxygen concentration sensor 407 is disposed in the combustion chamber 100 to detect the oxygen concentration within the combustion chamber 100.

[0056] Nitrogen and oxygen are stored in corresponding pressurized nitrogen cylinder 402 and pressurized oxygen cylinder 401, respectively. The oxygen in pressurized oxygen cylinder 401 is released under the action of the first pressure reducing valve 403, and the nitrogen in pressurized nitrogen cylinder 402 is released under the action of the second pressure reducing valve 404. The oxygen / nitrogen flow rate is regulated by the first mass flow controller, the second mass flow controller and the third mass flow controller 406. The oxygen / nitrogen is mixed in proportion by the proportional mixing valve 405. The resulting mixed gas enters the combustion chamber 100 relatively uniformly through the multi-layer porous medium in the rectifier 300.

[0057] It should be noted that the pressurized oxygen cylinder 401 has a volume of 40L and a pressure of 10MPa; the pressurized nitrogen cylinder 402 has a volume of 40L and a pressure of 10MPa; the first and second mass flow controllers have a range of 0-60SLM; the proportional mixing valve 405 has dimensions of 40cm×20cm×20cm; the third mass flow controller 406 has a range of 0-100SLM; and the oxygen concentration sensor 407 monitors the real-time oxygen concentration in the combustion chamber 100. Of course, the oxygen cylinder, nitrogen cylinder 402, first pressure reducing valve 403, second pressure reducing valve 404, first mass flow controller, second mass flow controller, proportional mixing valve 405, third mass flow controller 406, and oxygen concentration sensor 407 in the embodiments of the present invention are not limited to the above specifications. Any specification that has the corresponding functions of the oxygen cylinder, nitrogen cylinder 402, first pressure reducing valve 403, second pressure reducing valve 404, first mass flow controller, second mass flow controller, proportional mixing valve 405, third mass flow controller 406, and oxygen concentration sensor 407 is within the protection scope of the present invention.

[0058] The third mass flow controller 406 is connected to multiple air inlets 305 via a tree-like pipeline.

[0059] The combustion chamber 100 provides space support for combustion. In some embodiments of the present invention, the combustion chamber 100 includes a combustion chamber frame 101 and a fire-resistant glass 102. The fire-resistant glass 102 is embedded around the combustion chamber frame 101, and the combustion substrate 200 is located at the bottom of the combustion chamber frame 101.

[0060] In order to test oil films at different tilt angles, in some embodiments of the present invention, a tilt angle adjustment component is provided between the combustion substrate 200 and the combustion chamber 100 to adjust the tilt angle of the combustion substrate 200.

[0061] In some embodiments of the present invention, the tilt angle adjustment assembly includes a first horizontal bar 201, a first vertical bar 202, a second vertical bar 203, a first angle gauge, a second angle gauge, and a clamp. The first horizontal bar 201 is disposed on the top of the combustion chamber frame 101. The first end of the first vertical bar 202 is hinged to the first angle gauge, and the height of the first vertical bar 202 is adjustable on the first horizontal bar 201. The first end of the second vertical bar 203 is hinged to the second angle gauge, and the height of the second vertical bar 203 is adjustable on the first horizontal bar 201. The clamp is mounted on the first and second angle gauges to clamp the combustion substrate 200. By adjusting the height of the first vertical bar 202 relative to the first horizontal bar 201 and the height of the second vertical bar 203 relative to the first horizontal bar 201, the height difference between the first ends of the first vertical bar 202 and the first ends of the second vertical bar 203 can be adjusted, thereby adjusting the tilt angle of the combustion substrate 200.

[0062] The basic tilt angle of combustion is obtained by observing the first and second angle gauges.

[0063] In some embodiments of the present invention, the test system includes a smoke exhaust assembly 600, wherein the smoke exhaust assembly 600 includes a smoke collection hood 601 located above the combustion chamber 100 and a variable frequency fire-fighting smoke exhaust fan 602 installed at the exhaust port of the smoke collection hood 601. The smoke collection hood 601 has a coverage dimension of 2m × 2m; the variable frequency fire-fighting smoke exhaust fan 602 has a smoke exhaust air volume of 8000m³ / h. 3 / h.

[0064] In some embodiments of the present invention, the experimental system includes an ignition assembly 500, which comprises an electric ignition assembly 500 and a hot-wire ignition assembly 500. The electric ignition assembly 500 includes an ignition host and an ignition electrode. The energy of a single spark produced by the ignition electrode is adjusted by regulating the output voltage of the ignition host, and the total ignition energy can be adjusted by regulating the duration. This assembly is used for igniting liquid fuels in oxygen-rich environments. The ignition host is a KYGB-D type igniter developed by Xi'an Kehui Thermal Engineering Institute. The energy of a single spark produced by the ignition electrode (35mJ-20J) is adjusted by regulating the output voltage on the host panel, and the total ignition energy can be adjusted by regulating the duration. The hot-wire ignition assembly 500 includes an ignition host and a hot wire. At full power operation, the hot wire temperature can reach over 1200℃, and this assembly is used for igniting liquid fuels in air and oxygen-deficient environments.

[0065] The measurement system is used to measure combustion parameters during the combustion process of liquid oil film. The measurement system includes any one or more of the following: temperature measurement component 700, image acquisition component 800, and flow field display component 900. The temperature measurement component 700 is used to measure the combustion temperature; the image acquisition component 800 is used to record the fire spread phenomenon, fire spread pulsation frequency, fire spread speed, liquid film temperature, and flame temperature; and the flow field display component 900 is used to record the flame-induced flow field and surface flow.

[0066] When the measurement system includes a temperature measurement component 700, the temperature measurement component 700 includes an NI acquisition module 705, a moving component 704, a thermocouple frame 703, and thermocouples 701. The moving component 704 includes a second horizontal bar 7041 and a third vertical bar 7042. The second horizontal bar 7041 is arranged on the combustion chamber 100. The first end of the third vertical bar 7042 is rotatably connected to the thermocouple frame 703, and the height of the third vertical bar 7042 is adjustable on the second horizontal bar 7041. Thermocouples 701 are arranged side-by-side on the thermocouple frame 703. The horizontal spacing of the thermocouples 701 is 5m, and the vertical spacing is 2cm.

[0067] The temperature signal acquired by the thermocouple is converted into a voltage signal and acquired by the NI acquisition module.

[0068] The PXI module developed by NI can achieve high-speed data acquisition, and the specific implementation method is as follows:

[0069] Hardware of the high-speed data acquisition card: The NI PXI module achieves high-speed data acquisition through a high-speed ADC (analog-to-digital converter) and FPGA (field-programmable gate array) chip, which can achieve a data acquisition speed of millions of samples per second.

[0070] High-speed data acquisition card driver software: NI has developed driver software for various operating systems, including Windows, Linux, and Mac OS. The driver software enables hardware control and data acquisition, and provides multiple programming interfaces such as LabVIEW, MATLAB, C / C++, and Python, facilitating data processing and analysis for users.

[0071] Synchronization of high-speed data acquisition cards: PXI modules can be synchronized via the PXI bus, and multiple modules can share clock and trigger signals to achieve high-precision and high-stability data acquisition.

[0072] Data storage for high-speed data acquisition cards: NI PXI modules support various data storage methods, including RAM, disk, SSD, RAID, etc., allowing users to choose the appropriate storage method based on application requirements. NI also provides various software tools for data storage and transmission, such as NI-SCOPE, NI-DMM, and NI-DAQmx.

[0073] In summary, the NI PXI module achieves high-speed data acquisition through various means such as hardware, driver software, synchronization, and data storage, and can meet the needs of various engineering applications.

[0074] When the measurement system includes an image acquisition component 800, the image acquisition component 800 includes a camera 801 and an infrared thermal imager 802. The camera 801 records the fire spread phenomenon, the fire spread pulsation frequency, and the fire spread speed; the infrared thermal imager 802 records the liquid film temperature and the flame temperature.

[0075] When the measurement system includes a flow field display component 900, the flow field display component 900 includes a parallel light source 903, a Fresnel lens 902, and a high-speed camera 901. The high-speed camera 901 records the flame-induced flow field and surface flow. The parallel light source 903, the combustion chamber 100, the Fresnel lens 902, and the high-speed camera 901 are arranged in sequence.

[0076] See Figure 4 The parallel light source 903 includes a Fresnel lens 905 and an incandescent lamp 904. The light beam emitted by the incandescent lamp 904 forms a parallel light beam after passing through the Fresnel lens 905.

[0077] See Figure 5 This invention provides a method for testing the spread of liquid oil film fire. The method is based on the liquid oil film fire spread testing device as described above, and includes the following steps:

[0078] S1. Determine the combustion substrate 200.

[0079] The dimensions of the combustion substrate 200 are determined based on the obtained test results. Typically, the combustion substrate 200 is a metal plate with a width of 1cm to 4cm, a length of 10cm to 30cm, and a thickness of 0.2mm to 1mm. For example, if a series of combustion parameters of a liquid oil film are obtained for a combustion substrate 200 with dimensions of 1.5cm × 15cm × 0.5mm, then the dimensions of the combustion substrate 200 are determined to be 1.5cm × 15cm × 0.5mm.

[0080] To improve safety during the testing process, the circuitry and air supply lines are checked before this step.

[0081] S2. Arrange the combustion substrate 200 at the bottom of the combustion chamber 100.

[0082] The combustion substrate 200 is arranged at the bottom of the combustion chamber 100 and above the rectifier 300. The combustion substrate can be arranged according to test requirements, such as horizontal or inclined. When inclined, the test device includes an inclined angle adjustment assembly, which includes a first horizontal bar 201, a first vertical bar 202, a second vertical bar 203, a first angle gauge, a second angle gauge, and a clamp. The first horizontal bar 201 is arranged at the top of the combustion chamber frame 101. The first end of the first vertical bar 202 is hinged to the first angle gauge, and the height of the first vertical bar 202 is adjustable on the first horizontal bar 201. The first end of the second vertical bar 203 is hinged to the second angle gauge, and the height of the second vertical bar 203 is adjustable on the first horizontal bar 201. The clamp is mounted on the first and second angle gauges to clamp the combustion substrate 200. By adjusting the height of the first vertical rod 202 relative to the first horizontal rod 201 and the height of the second vertical rod 203 relative to the first horizontal rod 201, the height difference between the first end of the first vertical rod 202 and the first end of the second vertical rod 203 can be adjusted, thereby adjusting the tilt angle of the combustion substrate 200.

[0083] S3. Adjust the measurement system.

[0084] The measurement system is used to measure combustion parameters during the combustion process of liquid oil film. The measurement system includes any one or more of the following: temperature measurement component 700, image acquisition component 800, and flow field display component 900. The temperature measurement component 700 is used to measure the combustion temperature; the image acquisition component 800 is used to record the fire spread phenomenon, fire spread pulsation frequency, fire spread speed, liquid film temperature, and flame temperature; and the flow field display component 900 is used to record the flame-induced flow field and surface flow.

[0085] When the measurement system includes a temperature measuring component 700, the temperature measuring component 700 includes a moving component 704, a thermocouple frame 703, and thermocouples 701. The moving component 704 includes a second horizontal bar 7041 and a third vertical bar 7042. The second horizontal bar 7041 is arranged on the combustion chamber 100. The first end of the third vertical bar 7042 is rotatably connected to the thermocouple frame 703, and the height of the third vertical bar 7042 is adjustable on the second horizontal bar 7041. Thermocouples 701 are arranged side-by-side on the thermocouple frame 703. The horizontal spacing of the thermocouples 701 is 5m, and the vertical spacing is 2cm.

[0086] When the measurement system includes an image acquisition component 800, the image acquisition component 800 includes a camera 801 and an infrared thermal imager 802. The camera 801 records the fire spread phenomenon, the fire spread pulsation frequency, and the fire spread speed; the infrared thermal imager 802 records the liquid film temperature and the flame temperature.

[0087] When the measurement system includes a flow field display component 900, the flow field display component 900 includes a parallel light source 903, a Fresnel lens 902 and a high-speed camera 901, and the high-speed camera 901 records the flame-induced flow field and surface flow.

[0088] Adjusting the measurement system specifically includes adjusting the thermocouple 701 to the required experimental position, calibrating the optical path, adjusting the camera 801 in the combustion chamber and image acquisition component 800 and the high-speed camera 901 in the flow field display component 900 to the same height, and focusing the camera 801 and the high-speed camera 901.

[0089] S4. Liquid fuel is dripped onto the surface of the combustion substrate 200 using a micropipette to form a liquid oil film.

[0090] Liquid fuel was dripped onto the surface of the combustion substrate 200 using a micropipette. After dripping, the oil film thickness at various points on the combustion substrate 200 was calibrated using a non-contact film thickness gauge until the required thickness was achieved.

[0091] S5. Open the air supply assembly 400 and allow the air to enter the combustion chamber 100 through the rectifier 300 to provide a uniform oxygen-rich environment.

[0092] The gas supply assembly 400 includes a pressurized oxygen cylinder 401, a pressurized nitrogen cylinder 402, a first pressure reducing valve 403, a second pressure reducing valve 404, a first mass flow controller, a second mass flow controller, a proportional mixing valve 405, a third mass flow controller 406, and an oxygen concentration sensor 407. The pressurized oxygen cylinder 401, the first pressure reducing valve 403, and the first mass flow controller are connected in sequence; the pressurized nitrogen cylinder 402, the second pressure reducing valve 404, and the second mass flow controller are also connected in sequence. Both the first and second mass flow controllers are connected to one side of the proportional mixing valve 405, which is connected to the third mass flow controller 406. The third mass flow controller 406 is connected to the air inlet 305 via a pipeline. The oxygen concentration sensor 407 is installed in the combustion chamber 100 to detect the oxygen concentration within the combustion chamber 100.

[0093] Nitrogen and oxygen are stored in corresponding pressurized nitrogen cylinder 402 and pressurized oxygen cylinder 401, respectively. The oxygen in pressurized oxygen cylinder 401 is released under the action of the first pressure reducing valve 403, and the nitrogen in pressurized nitrogen cylinder 402 is released under the action of the second pressure reducing valve 404. The oxygen / nitrogen flow rate is regulated by the first mass flow controller, the second mass flow controller and the third mass flow controller 406. The oxygen / nitrogen is mixed in proportion by the proportional mixing valve 405. The resulting mixed gas enters the combustion chamber 100 relatively uniformly through the multi-layer porous medium in the rectifier 300 to provide a uniform oxygen-rich environment.

[0094] Specifically, the first pressure reducing valve 403 and the second pressure reducing valve 404 are opened, and the flow rates of the first mass flow controller and the second branch flow controller are adjusted to allow the gas to enter the proportional mixing valve 405. The oxygen concentration sensor 407 detects the oxygen concentration in the combustion chamber 100 until the preset oxygen / nitrogen ratio in the combustion chamber 100 is reached and stabilized.

[0095] S6, Ignition.

[0096] The ignition mechanism is an ignition assembly 500, which includes an electric ignition assembly 500 and a hot-wire ignition assembly 500. The electric ignition assembly 500 includes an ignition host and an ignition electrode. The energy of a single spark produced by the ignition electrode is adjusted by regulating the output voltage of the ignition host, and the total ignition energy can be adjusted by regulating the duration. This assembly is used for igniting liquid fuels in oxygen-rich environments. The ignition host is a KYGB-D type igniter developed by Xi'an Kehui Thermal Engineering Institute. The energy of a single spark produced by the ignition electrode (35mJ-20J) is adjusted by regulating the output voltage on the host panel, and the total ignition energy can be adjusted by regulating the duration. The hot-wire ignition assembly 500 includes an ignition host and a hot wire. At full power operation, the hot wire temperature can reach over 1200℃, and this assembly is used for igniting liquid fuels in air and oxygen-deficient environments.

[0097] Move the ignition electrode / hot wire to one end above the combustion substrate 200 and turn on the ignition host.

[0098] S7. Open the measuring component and measure the combustion parameters during the liquid oil film combustion process.

[0099] Furthermore, the testing method also includes the following steps:

[0100] The maximum ignition energy is used to continuously ignite or heat the surface of the oil film at one end of the combustion substrate 200 until combustion occurs.

[0101] When the liquid oil film ignites, the ignition assembly 500 is turned off. The flame spreads a certain distance from the ignition end to the other side of the combustion substrate 200 and then extinguishes or spreads to the other end of the combustion substrate 200, which can be considered as the end of the experiment.

[0102] Turn off the gas supply component 400 and the data acquisition component, turn on the smoke exhaust component 600, and after the temperature and gas composition in the combustion chamber return to normal atmospheric conditions, clean the residual liquid fuel on the combustion plate 200 and clean the experimental device. After cleaning and smoke exhaust are completed, change the experimental conditions and repeat the above steps to carry out another set of experiments.

[0103] Record experimental data such as the spread of oil film fire on the combustion substrate 200 under all oxygen concentrations, temperature, fire spread rate, and flame pulsation frequency, and perform quantitative analysis to assess the fire hazard of liquids in an oxygen-rich environment.

[0104] The liquid oil film fire propagation testing device and method provided by the present invention have the following beneficial effects:

[0105] This invention can test the fire spread behavior of liquid oil film under experimental conditions such as different liquid oil layer thicknesses, different ambient atmospheres (21% O2 to 100% O2 concentration), different combustion substrate 200 thicknesses (0.2 mm to 1 mm), and different combustion substrate 200 angles (0° to 90°). It can monitor liquid fire spread characteristic parameters such as flame morphology and height, main flame and flash flame pulsation frequency, surface flow thickness, and fire spread speed during the liquid fire spread process under different conditions. It studies the influence law of liquid oil film fire spread characteristics under multiple factors, explores its heat transfer mechanism and dynamic mechanism, quantitatively assesses the danger of liquid fire under oxygen-enriched normal pressure environment, and explores liquid fire control technology under oxygen-enriched environment.

[0106] The gas supply component 400 described in this invention effectively controls the oxygen-nitrogen ratio of the gas components entering the combustion chamber 100. The multi-layer porous medium in the rectifier 300 reduces the flow velocity from below, maintaining a consistent gas composition throughout the top-open combustion chamber 100. At the same time, the continuous low-speed gas supply from below, along with the combustion process, ensures that the oxygen consumed during flame combustion can be replenished in a timely manner, avoids significant impact on flame combustion, and prevents explosions caused by combustion under high oxygen concentrations.

[0107] The flow field display component 900 in this invention utilizes the basic principle of the shadow method. Compared to schlieren components, it simplifies the optical path and significantly reduces measurement costs. The shadow method is a type of optical display that projects a beam of light (scattered or parallel light) through a flow test area onto a screen (or through a lens). If the fluid in the test area is undisturbed and has a uniform density, the brightness on the screen is uniform. If the fluid is disturbed, the light is deflected due to density changes, and the projected light deviates from its original position on the screen, resulting in dark fringes. This method can generally be used to qualitatively observe shock waves, boundary layers, wakes, vortices, etc.

[0108] The invention has a simple and ingenious overall structure, a clear design concept, and a complete overall architecture and functional settings, which can ensure the safety and data reliability of oxygen-enriched fire experiments.

[0109] It should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0110] It should be understood that the terms "system," "device," "unit," and / or "module" used in this invention are methods for distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0111] As indicated in this invention and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0112] In the description of the embodiments of the present invention, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of the present invention, "multiple" refers to two or more.

[0113] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0114] This invention uses flowcharts to illustrate the operations performed by the system according to embodiments of the invention. It should be understood that the preceding or following operations are not necessarily performed precisely in sequence. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes, or one or more steps can be removed from them.

[0115] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed, and is not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. The scope of the invention is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in the present invention.

Claims

1. A liquid oil film fire propagation testing device, characterized in that: Includes testing systems and measurement systems, among which: The test system provides an environment that supports the combustion of liquid oil films. The measurement system is used to measure combustion parameters during the combustion process of a liquid oil film; The test system includes a combustion chamber, a combustion substrate, a rectifier, and an air supply assembly. The combustion substrate is arranged at the bottom of the combustion chamber to support the liquid oil film. The rectifier is connected between the air supply assembly and the combustion substrate to provide a uniform oxygen-rich environment for the combustion substrate. A tilt angle adjustment assembly is provided between the combustion substrate and the combustion chamber to adjust the tilt angle of the combustion substrate. The tilt angle adjustment assembly includes a first horizontal bar, a first vertical bar, a second vertical bar, a first angle gauge, a second angle gauge, and a clamp. The first horizontal bar is arranged at the top of the combustion chamber frame. The first end of the first vertical bar is hinged to the first angle gauge, and the height of the first vertical bar is adjustable on the first horizontal bar. The first end of the second vertical bar is hinged to the second angle gauge, and the height of the second end of the second vertical bar is adjustable on the first horizontal bar. The clamp is mounted on the first angle gauge and the second angle gauge to clamp the combustion substrate. The rectifier includes a rectifier housing, a uniformly distributed rectifier layer, an air inlet, and a buffer cavity. The uniformly distributed rectifier layer is arranged on the top of the rectifier housing and close to the combustion plate. The air inlet is arranged on the bottom of the rectifier housing and is used to communicate with the air supply assembly. A buffer cavity is provided between the air inlet and the uniformly distributed rectifier layer. The uniformly distributed rectifier layer includes a ceramic sphere layer and an aluminum honeycomb core layer stacked along the height direction, wherein the aluminum honeycomb core layer is close to the combustion substrate.

2. The liquid oil film fire propagation testing device as described in claim 1, characterized in that: The gas supply assembly includes a pressurized oxygen cylinder, a pressurized nitrogen cylinder, a first pressure reducing valve, a second pressure reducing valve, a first mass flow controller, a second mass flow controller, a proportional mixing valve, a third mass flow controller, and an oxygen concentration sensor. The pressurized oxygen cylinder, the first pressure reducing valve, and the first mass flow controller are connected in sequence, as are the pressurized nitrogen cylinder, the second pressure reducing valve, and the second mass flow controller. Both the first and second mass flow controllers are connected to one side of the proportional mixing valve, which is connected to the third mass flow controller. The third mass flow controller is connected to the air inlet via a pipeline. The oxygen concentration sensor is located in the combustion chamber to detect the oxygen concentration within the combustion chamber.

3. The liquid oil film fire propagation testing device as described in claim 2, characterized in that: The third mass flow controller is connected to multiple air inlets via a tree-like pipeline.

4. The liquid oil film fire propagation testing device as described in claim 1, characterized in that: The combustion chamber includes a combustion chamber frame and fire-resistant glass, the fire-resistant glass being embedded around the combustion chamber frame, and the combustion substrate being located at the bottom of the combustion chamber frame.

5. The liquid oil film fire propagation testing device as described in claim 1, characterized in that: The test system includes a smoke extraction assembly. The smoke exhaust assembly includes a smoke hood located above the combustion chamber and a variable frequency fire-fighting smoke exhaust fan installed at the exhaust port of the smoke hood.

6. The liquid oil film fire propagation testing device as described in claim 1, characterized in that: The test system includes an ignition assembly, which comprises an electric ignition assembly and a hot-wire ignition assembly. The electric ignition assembly includes an ignition host and an ignition electrode. The energy of a single spark produced by the ignition electrode is adjusted by regulating the output voltage of the ignition host, and the total ignition energy can be adjusted by regulating the duration. This assembly is used for igniting liquid fuels in oxygen-rich environments. The hot-wire ignition assembly includes an ignition host and a hot wire. When operating at full power, the hot wire temperature can reach over 1200°C. This assembly is used for igniting liquid fuels in air and oxygen-deficient environments.

7. The liquid oil film fire spread testing device as described in claim 1, characterized in that: The measurement system includes a temperature measurement component, an image acquisition component, and a flow field display component. The temperature measurement component is used to measure the combustion temperature; the image acquisition component is used to record the fire spread phenomenon, fire spread pulsation frequency, fire spread velocity, liquid film temperature, and flame temperature; and the flow field display component is used to record the flame-induced flow field and surface flow.

8. The liquid oil film fire propagation testing device as described in claim 7, characterized in that: The temperature measurement assembly includes a moving component, a thermocouple frame, and thermocouples. The moving component includes a second horizontal bar and a third vertical bar. The second horizontal bar is arranged on the combustion chamber, and the first end of the third vertical bar is rotatably connected to the thermocouple frame. The height of the third vertical bar is adjustable on the second horizontal bar. The thermocouples are arranged side by side on the thermocouple frame.

9. The liquid oil film fire propagation testing device as described in claim 7, characterized in that: The image acquisition component includes a camera and an infrared thermal imager. The camera records the fire spread phenomenon, the fire spread pulsation frequency, and the fire spread speed; the infrared thermal imager records the liquid film temperature and the flame temperature.

10. The liquid oil film fire propagation testing device as described in claim 7, characterized in that: The flow field display component includes a parallel light source, a Fresnel lens, and a high-speed camera, which records the flame-induced flow field and surface flow.

11. A method for testing the spread of fire in a liquid oil film, characterized in that: The method is based on the liquid oil film fire propagation test apparatus as described in any one of claims 1 to 10, and the method includes the following steps: 1) Determine the combustion substrate; 2) Arrange the combustion plate at the bottom of the combustion chamber; 3) Adjust the measurement system; 4) Liquid fuel is dripped onto the surface of the combustion substrate using a micropipette to form a liquid oil film; 5) Turn on the air supply assembly to provide a uniform oxygen-rich environment by allowing the air to enter the combustion chamber through the rectifier; 6) Ignition; 7) Turn on the measurement system and measure the combustion parameters during the liquid oil film combustion process.

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