Branched tunnel fire ventilation and smoke exhaust experimental device and experimental method

Abstract

The invention provides a forked tunnel fire ventilation and smoke exhaust experimental device and experimental method, and relates to the technical field of tunnel fire ventilation and smoke exhaust. The device comprises a bifurcated tunnel model, the bifurcated tunnel model comprises a main tunnel and ramps communicated with the main tunnel, a detachable smoke exhaust vertical shaft is installed on a ceiling of the main tunnel, a lateral smoke exhaust port is formed in the side wall of the main tunnel, and the smoke exhaust vertical shaft is opened and closed through a movable plate door and can be replaced by vertical shafts of different sizes or angles; the ventilation system comprises a jet fan mounted at the ventilation opening and is used for simulating different ventilation modes; the experimental test system comprises a temperature acquisition system and a wind speed acquisition system, the temperature acquisition system measures temperature through a plurality of thermocouples arranged on the ceiling, and the wind speed acquisition system measures wind speed distribution through a wind speed probe array arranged on the cross section of the tunnel; and the fire source device provides an experimental fire source. According to the embodiment provided by the invention, the accuracy of the ventilation and smoke exhaust experiment result in the bifurcated tunnel scene is improved, and diversified experiment requirements are met.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel fire ventilation and smoke exhaust, and particularly to an experimental device and method for tunnel fire ventilation and smoke exhaust in a bifurcated tunnel. Background Art

[0002] In the research on tunnel fires, existing technologies mostly construct experimental devices for ventilation and smoke exhaust models based on tunnels with simple structures (such as straight single-hole tunnels), and establish smoke control models by measuring parameters such as temperature fields and wind speed fields. However, due to the complex geometric characteristics and significant flow field interference of bifurcated traffic tunnels (such as the intersection structure of the main tunnel and ramps), their fire ventilation and smoke exhaust characteristics are significantly different from those of simple tunnels.

[0003] Currently, existing tunnel fire ventilation and smoke exhaust models do not consider the smoke diversion and confluence effects caused by the bifurcated structure. For example, when a fire occurs in a ramp, the smoke may invade the main tunnel through the bifurcation, and when a fire occurs in the main tunnel, the smoke is likely to form eddies in the bifurcation area. Existing theories cannot accurately predict the critical wind speed or smoke exhaust efficiency in such scenarios. In addition, existing technologies mostly adopt fixed longitudinal jet ventilation and lack the coordinated control ability of lateral smoke exhaust ports or shafts. Summary of the Invention

[0004] The present invention provides an experimental device and method for tunnel fire ventilation and smoke exhaust in a bifurcated tunnel to solve the defects in the existing tunnel fire ventilation and smoke exhaust models that do not consider the smoke diversion and confluence effects caused by the bifurcated structure and lack the coordinated control ability of lateral smoke exhaust ports or shafts, so that the experimental results of fire ventilation and smoke exhaust in the bifurcated tunnel scenario are more accurate and can meet diverse experimental requirements.

[0005] The present invention provides an experimental device for tunnel fire ventilation and smoke exhaust in a bifurcated tunnel, including: a bifurcated tunnel model including a main tunnel and a ramp communicating therewith, a detachable smoke exhaust shaft is installed on the ceiling of the main tunnel, a lateral smoke exhaust port is provided on the side wall of the main tunnel, the smoke exhaust shaft is opened and closed through a trap door and can be replaced with shafts of different sizes or angles; a ventilation system including a jet fan installed at a ventilation port for simulating different ventilation modes; an experimental test system including a temperature acquisition system and a wind speed acquisition system, the temperature acquisition system measures the temperature through a plurality of thermocouples arranged on the ceiling, and the wind speed acquisition system measures the wind speed distribution through an array of wind speed probes arranged on the tunnel cross-section; a fire source device for providing an experimental fire source.

[0006] According to the experimental device for tunnel fire ventilation and smoke exhaust in a bifurcated tunnel provided by the present invention, the fire source device uses an oil pool fire as the experimental fire source, and changes the combustion rate by changing the area of the oil pan.

[0007] According to the experimental device for fire ventilation and smoke exhaust of a bifurcated tunnel provided by the present invention, the bifurcated tunnel model is a scaled-down model with a preset ratio. The side wall of the main tunnel far from the lateral smoke exhaust port and the side wall of the ramp are partially made of a double-layer transparent fireproof glass structure. The side wall part, ceiling and bottom part of the ceiling of the main tunnel near the lateral smoke exhaust port are all three-layer heat insulation structures composed of a first iron plate, a gypsum board and a second iron plate. A trap door with a bolt is provided at the bottom of the main tunnel, and the trap door is used for the installation and debugging of equipment.

[0008] According to the experimental device for fire ventilation and smoke exhaust of a bifurcated tunnel provided by the present invention, the jet fans include jet fans installed at the entrances and exits at both ends of the main tunnel, jet fans installed at the ramp entrances, and jet fans installed at each lateral smoke exhaust port. Each jet fan is independently controlled to adjust the rotation speed and is used to simulate the longitudinal ventilation mode, semi-transverse ventilation mode, and combined ventilation mode.

[0009] According to the experimental device for fire ventilation and smoke exhaust of a bifurcated tunnel provided by the present invention, the temperature acquisition system uses K-type armored thermocouples. The probes are inserted into the ceiling at a preset distance, and the number of measurement points is greater than the preset number. The data collected by the temperature acquisition system is transmitted to the computer in real time through a multi-channel data acquisition instrument.

[0010] According to the experimental device for fire ventilation and smoke exhaust of a bifurcated tunnel provided by the present invention, the wind speed acquisition system includes a thermosensitive wind speed probe array. The data collected by the wind speed acquisition system is combined with the temperature data to calculate the critical wind speed and / or optimize the ventilation strategy. Among them, the ventilation strategy at least includes the longitudinal ventilation mode, the semi-transverse ventilation mode, and the combined ventilation mode.

[0011] According to the experimental device for fire ventilation and smoke exhaust of a bifurcated tunnel provided by the present invention, the opening and closing states of the smoke exhaust shaft and the lateral smoke exhaust ports can be dynamically adjusted to switch between the longitudinal ventilation mode, semi-transverse ventilation mode, and combined ventilation mode, and adapt to the smoke exhaust requirements under different fire scenarios.

[0012] The present invention also provides a method for experimental modeling of fire ventilation and smoke exhaust of a bifurcated tunnel based on the above experimental device for fire ventilation and smoke exhaust of a bifurcated tunnel, including: selecting the installation or closing of the smoke exhaust shaft according to the experimental requirements, and sealing the unused lateral smoke exhaust ports; adjusting the rotation speed and operation mode of the jet fans to start ventilation based on a preset ventilation strategy, where the ventilation strategy at least includes the longitudinal ventilation mode, the semi-transverse ventilation mode, and the combined ventilation mode; setting the fire source position, power and fuel type through the fire source device, and closing the trap door after ignition; collecting the temperature and wind speed distribution data in real time and analyzing the law of smoke diffusion; dynamically switching the ventilation mode of the ventilation strategy according to the data collected in real time to optimize the smoke exhaust efficiency.

[0013] According to the experimental method for fire ventilation and smoke exhaust in a bifurcated tunnel provided by the present invention, the real-time collection of temperature and wind speed distribution data and the analysis of the smoke diffusion law include: determining a physical quantity for quantifying the ventilation and smoke exhaust effects of different ventilation modes through the collected temperature data.

[0014] According to the experimental method for fire ventilation and smoke exhaust in a bifurcated tunnel provided by the present invention, the dynamic switching of the ventilation mode of the ventilation strategy according to the real-time collected data to optimize the smoke exhaust efficiency includes: obtaining the wind speed distribution of different cross-sections of the bifurcated tunnel model through the collected wind speed distribution data; based on the wind speed distribution and the collected temperature data, adjusting the combination of jet fans, the opening and closing states of the smoke exhaust shafts, and switching the ventilation mode to generate a smoke exhaust optimization strategy.

[0015] The experimental device and method for fire ventilation and smoke exhaust in a bifurcated tunnel provided by the present invention consider the smoke diversion and confluence effects caused by the bifurcated structure and establish a bifurcated tunnel model, making the experimental results of fire ventilation and smoke exhaust in the bifurcated tunnel scenario more accurate. Through the detachable smoke exhaust shaft and the lateral smoke exhaust openings arranged on the side wall of the main tunnel, diverse experimental requirements can be met. Brief Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 is a schematic diagram of the experimental device for fire ventilation and smoke exhaust in a bifurcated tunnel provided by the present invention.

[0018] Figure 2 is a schematic diagram of the jet fan in the main tunnel provided by the present invention.

[0019] Figure 3 is a schematic diagram of the lateral air exhaust port fan provided by the present invention.

[0020] Figure 4 is a schematic diagram of the experimental test system provided by the present invention.

[0021] Figure 5 is a schematic diagram of the wind speed measurement array provided by the present invention.

[0022] Figure 6 is a schematic flow diagram of the experimental method for fire ventilation and smoke exhaust in a bifurcated tunnel provided by the present invention. Detailed Embodiments

[0023] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, the terms such as "a", "an" or "the" do not denote a quantity limitation, but mean that there is at least one. The terms such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0025] The terms related to the present invention are briefly explained below.

[0026] The following Figures 1-6 describes the bifurcation tunnel fire ventilation and smoke exhaust experimental device and experimental method of the present invention.

[0027] Referring to Figure 1 , Figure 1 is a schematic diagram of the bifurcation tunnel fire ventilation and smoke exhaust experimental device provided by the present invention. It should be noted that Figure 1 the dimensions, examples and quantity data of some parts in are exemplary and can be adjusted according to actual needs. The bifurcation tunnel fire ventilation and smoke exhaust experimental device includes:

[0028] A bifurcation tunnel model, including a main tunnel and a ramp communicating therewith. A detachable smoke exhaust shaft is installed on the ceiling of the main tunnel, and a lateral smoke exhaust opening is provided on the side wall of the main tunnel. The smoke exhaust shaft is opened and closed through a trap door and can be replaced with shafts of different sizes or angles; the cross-sectional dimensions of the main tunnel and the ramp can be the same or scaled according to the actual engineering ratio. In addition, a plurality of smoke exhaust shafts and chimneys, as well as lateral smoke exhaust openings, can be arranged at equal intervals, or the quantity and spacing can be set according to the actual project. A ventilation system, including a jet fan installed at the ventilation opening for simulating different ventilation modes; the ventilation opening can include the entrances and exits at both ends of the main tunnel, the ramp entrance and the lateral smoke exhaust opening, and others The experimental test system includes a temperature acquisition system and a wind speed acquisition system. The temperature acquisition system measures the temperature through multiple thermocouples arranged on the ceiling, and the wind speed acquisition system measures the wind speed distribution through an array of wind speed probes arranged in the tunnel cross-section. A fire source device is used to provide an experimental fire source.

[0029] In addition, the whole device can be supported by a stainless steel bracket with a certain height, such as 0.5 m high. The height of each leg of the bracket can be adjusted to level the device.

[0030] In some optional implementation manners, the fire source device uses an oil pool fire as the experimental fire source or other liquid fuel combustion devices. When using an oil pool fire, the combustion rate can be changed by changing the area of the oil pan. The fuel can be selected from liquid fuels such as methanol, ethanol, n-heptane, gasoline, and aviation kerosene.

[0031] In some optional implementation manners, the bifurcated tunnel model is a scaled-down model with a preset ratio. The side wall of the main tunnel far from the lateral smoke exhaust port and the side wall part of the ramp adopt a double-layer transparent fireproof glass structure. The side wall part, ceiling part, and bottom part of the ceiling near the lateral smoke exhaust port of the main tunnel are all three-layer heat insulation structures composed of a first iron plate, a gypsum board, and a second iron plate. A trap door with a bolt is provided at the bottom of the main tunnel, and the trap door is used for the installation and debugging of equipment. The first iron plate and the second iron plate are only for distinction purposes and are not specifically limited here. The three-layer heat insulation structure is a three-layer structure composed of an iron plate - gypsum board - iron plate.

[0032] As an example, based on the actual tunnel project, a small-scale fire experiment model of a bifurcated tunnel with a scale ratio of 1:12 can be established. The main body of the device includes a main tunnel and a ramp with the same cross-sectional size. Four smoke exhaust shafts and chimneys of the same size are equidistantly installed on the ceiling of the main tunnel, and four lateral smoke exhaust ports of the same size are equidistantly installed on the side walls. The specific dimensions of each structure are shown in Figure 1 . The ceiling, the bottom of the ceiling, and the side wall on one side of the smoke exhaust port of the main tunnel are three-layer structures of iron plate - gypsum board - iron plate, and there is an air gap between the two layers to achieve a heat insulation effect; the side wall on the other side of the main tunnel and the side wall of the ramp are made of double-layer transparent fireproof glass, and there is an air gap between the two layers for heat insulation. A number of trap doors with bolts are opened at the bottom of the main tunnel to facilitate the installation and debugging of the internal equipment of the device and the preparation operation before the experiment. The trap doors are closed during the experiment.

[0033] In some alternative implementations, the jet fans include those installed at the entrances and exits at both ends of the main tunnel, those installed at the ramp entrances, and those installed at each lateral smoke exhaust opening. Each jet fan is independently controlled to adjust its rotational speed, and is used to simulate longitudinal ventilation, semi-transverse ventilation, and combined ventilation modes. As an example, one jet fan of the same model is installed at each of the entrances and exits at both ends of the main tunnel and at the ramp entrances to simulate longitudinal mechanical ventilation in an actual tunnel; one jet fan of the same model is installed at each of the 4 lateral smoke exhaust openings, and the rest is sealed to simulate the negative pressure at the lateral smoke exhaust openings in an actual tunnel. Each fan can be independently switched on and off and its rotational speed can be adjusted. The specific fan layout can be referred to Figure 2 and Figure 3 .

[0034] In some alternative implementations, the specific distribution of the thermocouples and the wind speed measurement array in the experimental test system can be as shown in Figure 4 . The temperature acquisition system uses K-type armored thermocouples. The probes are inserted into the ceiling at a preset distance, and the number of measurement points is greater than the preset number. The data collected by the temperature acquisition system is transmitted to the computer in real time through a multi-channel data acquisition instrument. The temperature acquisition system is used to measure the temperature field near the tunnel ceiling and can include thermocouples, data acquisition instruments, and data acquisition computers. As an example, the thermocouples can be WRNK-191 type K-type armored thermocouples with a measurement range of 0 - 800 °C, a probe diameter of 1 mm, a measurement error of ±0.75 °C. The probes are all inserted 1.5 cm into the tunnel ceiling, and there are 124 measurement points in total. They are connected to 2 data acquisition instruments of the same model through transmission cables coated with an insulating and heat-insulating outer layer, and then the data acquisition instruments are connected to the data acquisition computer. The data acquisition instrument can be a TOPRIE TP700 multi-channel data acquisition instrument with 64 channels, and there are several low-voltage power supply interfaces that can be connected to the wind speed acquisition module. By measuring the temperature, the temperature distribution near the tunnel ceiling can be obtained, and physical quantities such as smoke flow velocity and heat release rate of the fire source can be obtained through processing, which are used to quantify the ventilation and smoke exhaust effects of different ventilation modes.

[0035] In some alternative implementations, the wind speed acquisition system includes a thermosensitive wind speed probe array. The data collected by the wind speed acquisition system is combined with the temperature data to calculate the critical wind speed and / or optimize the ventilation strategy. The wind speed acquisition system is used to measure the wind speed at fixed positions in the tunnel and can include wind speed measurement probes, wind speed acquisition modules, data acquisition instruments, and data acquisition computers. As an example, several thermosensitive wind speed probes arranged in the same cross-section can be used to form as shown in Figure 5The shown wind speed measurement array has a probe range of 0 - 30 m / s, a measurement error of ±0.1 m / s, and a sampling frequency of 1 Hz. After the probe is connected to the wind speed acquisition module, it is then connected to the low-voltage power supply interface of the TOPRIE TP700 multi-channel data acquisition instrument, and the data is transmitted to the data acquisition computer in real time through the data acquisition instrument. By measuring the wind speed, the wind speed distribution of different cross-sections of the tunnel can be obtained. After processing and combining with temperature data, physical quantities such as the critical wind speed can be obtained, which are used to study the optimization strategy of the ventilation mode.

[0036] In some optional implementation manners, the opening and closing states of the smoke exhaust shaft and the lateral smoke exhaust openings can be dynamically adjusted to switch between the longitudinal ventilation mode, the semi-transverse ventilation mode, and the combined ventilation mode, and to adapt to the smoke exhaust requirements in different fire scenarios. A trap door is designed on the smoke exhaust shaft at the top of the device, which can be closed when not in use; when the lateral ventilation openings are not in use, they can be sealed with heat-insulating cotton with a fireproof layer and aluminum foil tape. The smoke exhaust shaft can be disassembled, and smoke exhaust shafts of different sizes and angles can be selected for installation according to actual application requirements. By combining the use of jet fans, smoke exhaust shafts, and lateral smoke exhaust openings, the longitudinal and transverse coordinated ventilation modes can be simulated in the tunnel fire experiment and dynamically switched between different modes, and the smoke prevention and exhaust design in different fire scenarios can be studied and optimized.

[0037] The experimental device for fire ventilation and smoke exhaust in a bifurcated tunnel provided by the present invention takes into account the smoke diversion and confluence effects caused by the bifurcated structure and establishes a bifurcated tunnel model, making the experimental results of fire ventilation and smoke exhaust in the bifurcated tunnel scenario more accurate. Through the detachable smoke exhaust shaft and the lateral smoke exhaust openings provided on the side wall of the main tunnel, diverse experimental requirements can be met.

[0038] The following describes the method for fire ventilation and smoke exhaust experiment in a bifurcated tunnel provided by the present invention. The method for fire ventilation and smoke exhaust experiment in a bifurcated tunnel described below can be mutually referred to the experimental device for fire ventilation and smoke exhaust in a bifurcated tunnel described above.

[0039] Figure 6 is a schematic flowchart of the method for fire ventilation and smoke exhaust experiment in a bifurcated tunnel provided by the present invention. As Figure 6 shown, the method includes the following: Step 601: Select the installation or closing of the smoke exhaust shaft according to the experimental requirements, and seal the unused lateral smoke exhaust openings. For example, if the ventilation shaft is not used, the trap door at the top of the device can be closed.

[0040] Step 602: Adjust the rotation speed and operation mode of the jet fan, and start ventilation based on a preset ventilation strategy, where the ventilation strategy at least includes the longitudinal ventilation mode, the semi-transverse ventilation mode, and the combined ventilation mode.

[0041] Step 603: Set the position, power, and fuel type of the fire source through the fire source device, and close the trap door after ignition.

[0042] Taking an oil pool fire as an example, liquid fuel, oil pan size, and fire source position can be selected. Add fuel and arrange the fire source through the trap door at the bottom of the device. After igniting with a lighter, close the trap door.

[0043] Step 604: Collect temperature and wind speed distribution data in real time and analyze the law of smoke diffusion.

[0044] Step 605: Dynamically switch the ventilation mode of the ventilation strategy according to the data collected in real time to optimize the smoke exhaust efficiency. According to the experimental conditions, the air volume and operation mode of the jet fans in the main tunnel can be adjusted.

[0045] In some alternative implementation manners, collecting temperature and wind speed distribution data in real time and analyzing the law of smoke diffusion include: determining a physical quantity for quantifying the ventilation and smoke exhaust effects of different ventilation modes through the collected temperature data.

[0046] In some alternative implementation manners, dynamically switching the ventilation mode of the ventilation strategy according to the data collected in real time to optimize the smoke exhaust efficiency includes: obtaining the wind speed distribution of different cross-sections of the bifurcated tunnel model through the collected wind speed distribution data; based on the wind speed distribution and the collected temperature data, adjusting the combination of jet fans, the opening and closing states of the smoke exhaust shafts, and switching the ventilation mode to generate a smoke exhaust optimization strategy. The smoke exhaust optimization strategy can flexibly switch between the longitudinal ventilation mode, the semi-transverse ventilation mode, and the combined ventilation mode according to actual needs, so as to achieve better ventilation effects in the bifurcated tunnel.

[0047] In some embodiments of the present invention, the longitudinal ventilation mode is to set ventilation shafts or vents in the tunnel and use natural wind or mechanical ventilation equipment to make the air flow longitudinally along the tunnel, thereby achieving the purpose of ventilation. This method is suitable for long tunnels and can effectively exhaust the air and / or smoke in the tunnel.

[0048] The semi-transverse ventilation mode is to set ventilation shafts or vents on one side of the tunnel, introduce fresh air into the tunnel through mechanical ventilation equipment, and at the same time exhaust the air and / or smoke from the tunnel. This method is suitable for short tunnels and can provide better ventilation effects.

[0049] The combined ventilation mode can be flexibly adjusted according to factors such as the length of the tunnel, traffic flow, and terrain conditions to provide the best ventilation effect. It can choose to use longitudinal ventilation, semi-transverse ventilation, or a combination of both according to the actual situation to meet the ventilation requirements in different situations.

[0050] The experimental method for fire ventilation and smoke exhaust in a bifurcated tunnel provided by the present invention collects environmental parameters such as wind speed, temperature, smoke concentration, and harmful gas concentration in the tunnel in real time, and processes and analyzes these data. According to the preset ventilation mode switching conditions and decision logic, when the monitored environmental parameters meet the switching conditions of a certain ventilation mode, an instruction is automatically issued to switch the ventilation mode. For example: When a fire occurs and the smoke concentration rises rapidly, immediately switch to the combined ventilation mode, and at the same time adjust the fan combination and the opening and closing state of the vertical shaft to increase the smoke exhaust intensity to ensure the smooth progress of personnel evacuation and rescue work; As the fire weakens and the smoke gradually dissipates, gradually switch back to the normal ventilation mode according to the real-time monitoring data to restore the normal tunnel operation environment.

[0051] In some embodiments of the present invention, under normal traffic conditions, if the wind speed distribution in the tunnel is relatively stable and the temperature is low, the longitudinal ventilation mode is adopted to reduce energy consumption.

[0052] In some embodiments of the present invention, the generated smoke exhaust optimization strategy is integrated into the ventilation control system of the bifurcated tunnel, and real-time control and adjustment of equipment such as jet fans and smoke exhaust vertical shafts are achieved through automation control devices (such as programmable logic controllers PLC, distributed control systems DCS, etc.). Ensure that the control system has high reliability, stability, and safety, and can accurately execute the optimization strategy under various complex working conditions.

[0053] In some embodiments of the present invention, it further includes: during the actual tunnel operation process, comprehensively monitor and evaluate the effect after implementing the smoke exhaust optimization strategy. By comparing parameters such as the wind speed distribution, temperature change, smoke concentration diffusion situation, and energy consumption index in the tunnel before and after optimization, verify the effectiveness and feasibility of the optimization strategy.

[0054] According to the verification results, further adjust and improve the smoke exhaust optimization strategy. If it is found that the strategy fails to achieve the expected effect in some cases, analyze the reasons and correct the relevant models and parameters to improve the adaptability and optimization performance of the strategy.

[0055] The experimental method for fire ventilation and smoke exhaust in a bifurcated tunnel provided by the present invention takes into account the smoke diversion and confluence effects caused by the bifurcated structure, establishes a bifurcated tunnel model, makes the experimental results of fire ventilation and smoke exhaust in the bifurcated tunnel scenario more accurate, and can meet diverse experimental requirements through the detachable smoke exhaust vertical shaft and the lateral smoke exhaust openings provided on the side wall of the main tunnel.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An experimental device for fire ventilation and smoke exhaust in a bifurcated tunnel, characterized in that Comprising: A bifurcated tunnel model, including a main tunnel and a ramp connected thereto. A detachable smoke exhaust shaft is installed on the ceiling of the main tunnel. Lateral smoke exhaust openings are provided on the side walls of the main tunnel. The smoke exhaust shaft is opened and closed through a trap door and can be replaced with shafts of different sizes or angles; A ventilation system, including jet fans installed at ventilation openings, for simulating different ventilation modes; An experimental test system, including a temperature acquisition system and a wind speed acquisition system. The temperature acquisition system measures temperature through a plurality of thermocouples arranged on the ceiling. The wind speed acquisition system measures the wind speed distribution through an array of wind speed probes arranged in the tunnel cross-section; A fire source device, for providing an experimental fire source.

2. The experimental device for fire ventilation and smoke exhaust of a bifurcated tunnel according to claim 1, wherein The fire source device uses an oil pool fire as the experimental fire source, and changes the combustion rate by changing the area of the oil pan.

3. The experimental device for fire ventilation and smoke exhaust of a bifurcated tunnel according to claim 1, characterized in that, The bifurcated tunnel model is a scaled-down model in a preset ratio. The side walls of the main tunnel far from the lateral smoke exhaust openings and the side walls of the ramp are partially made of a double-layer transparent fireproof glass structure. The side wall part, the ceiling part and the bottom part of the ceiling of the main tunnel near the lateral smoke exhaust openings are all three-layer heat insulation structures composed of a first iron plate, a gypsum board and a second iron plate. A trap door with a bolt is provided at the bottom of the main tunnel, and the trap door is used for the installation and debugging of equipment.

4. The experimental device for fire ventilation and smoke exhaust of a bifurcated tunnel according to claim 1, characterized in that, The jet fans include jet fans installed at the two ends of the main tunnel, jet fans installed at the ramp entrance, and jet fans installed at each lateral smoke exhaust opening. Each jet fan is independently controlled to adjust the rotation speed, for simulating longitudinal ventilation mode, semi-transverse ventilation mode, combined ventilation mode.

5. The bifurcated tunnel fire ventilation and smoke exhaust experimental device according to claim 1, characterized in that The temperature acquisition system uses K-type armored thermocouples, the probes are inserted into the ceiling at a preset distance, the number of measurement points is greater than the preset number, and the data collected by the temperature acquisition system is transmitted to the computer in real time through a multi-channel data acquisition instrument.

6. The experimental device for fire ventilation and smoke exhaust of a bifurcated tunnel according to claim 4, wherein The wind speed acquisition system includes a thermosensitive wind speed probe array. The data collected by the wind speed acquisition system is combined with the temperature data for calculating the critical wind speed and / or optimizing the ventilation strategy. Among them, the ventilation strategy at least includes the longitudinal ventilation mode, the semi-transverse ventilation mode, the combined ventilation mode.

7. The experimental device for fire ventilation and smoke exhaust of a bifurcated tunnel according to claim 1, wherein, The opening and closing states of the smoke exhaust shaft and the lateral smoke exhaust openings can be dynamically adjusted to switch between the longitudinal ventilation mode, the semi-transverse ventilation mode, the combined ventilation mode, and adapt to the smoke exhaust requirements under different fire scenarios.

8. An experimental method for fire ventilation and smoke exhaust in a bifurcated tunnel based on the experimental device for fire ventilation and smoke exhaust in a bifurcated tunnel according to any one of claims 1-7, characterized in that, Including the following steps: Select the installation or closing of the smoke exhaust shaft according to the experimental requirements, and seal the unused lateral smoke exhaust openings; Adjust the rotation speed and operation mode of the jet fans to start ventilation based on a preset ventilation strategy. Among them, the ventilation strategy at least includes the longitudinal ventilation mode, the semi-transverse ventilation mode, the combined ventilation mode; Set the fire source position, power and fuel type through the fire source device, and close the trap door after ignition; Collect temperature and wind speed distribution data in real time, and analyze the law of smoke diffusion; Dynamically switch the ventilation mode of the ventilation strategy according to the data collected in real time, and optimize the smoke exhaust efficiency.

9. The experimental method for fire ventilation and smoke exhaust of a bifurcated tunnel according to claim 8, wherein The collecting temperature and wind speed distribution data in real time and analyzing the law of smoke diffusion includes: Determine the physical quantity for quantifying the ventilation and smoke exhaust effects of different ventilation modes through the collected temperature data.

10. The experimental method for fire ventilation and smoke exhaust of a bifurcated tunnel according to claim 9, characterized in that, Dynamically switching the ventilation mode of the ventilation strategy according to the real-time collected data to optimize the smoke exhaust efficiency, including: Obtaining the wind speed distribution of different cross-sections of the bifurcated tunnel model through the collected wind speed distribution data; Based on the wind speed distribution and the collected temperature data, adjusting the combination of jet fans, the opening and closing states of the smoke exhaust shafts, and switching the ventilation mode of the ventilation strategy to generate a smoke exhaust optimization strategy.

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