Multi-layer tunnel fire experimental test platform and method

Abstract

The present invention provides a multi-layer tunnel fire experiment test platform and method, which can fully restore the fire scene and facilitate the quantification of smoke exhaust performance indicators under different fire scenes and smoke exhaust modes. The platform includes: a tunnel model part; a fire source simulation part; a longitudinal ventilation and smoke exhaust simulation part, which is used to simulate the longitudinal ventilation and smoke exhaust in the tunnel; a top key smoke exhaust simulation part, which is used to simulate the top smoke exhaust in the tunnel; a side key smoke exhaust simulation part, which is used to simulate the side smoke exhaust in the tunnel; a branch pipe key smoke exhaust simulation part, which is used to simulate the branch pipe smoke exhaust in the tunnel; an external exhaust processing part, which collects and processes the smoke exhausted by each smoke exhaust method; an airflow monitoring part, which includes: a lane monitoring unit for real-time monitoring of the wind speed distribution in the tunnel, and a flue monitoring unit for real-time monitoring of the wind speed and wind pressure changes in the flue; a temperature monitoring part, which monitors the temperature field changes in the tunnel in real time, and a quality monitoring part, which is set on the fire source experimental rack and monitors the quality changes of the fuel in the fire source generator in real time.

Description

Technical Field

[0001] The invention belongs to the technical field of fire safety, and in particular relates to a multi-layer tunnel fire experiment test platform and method. Background Art

[0002] Tunnels are narrow underground spaces that people dig for the development of transportation or the placement of certain items. Tunnels can greatly shorten driving distances, save passengers' time, improve freight efficiency, and greatly increase the convenience of transportation. Multi-layer tunnels are increasingly used due to their high space utilization, but at the same time, multi-layer tunnels have greater traffic volume and more complex pipeline facilities. In particular, the popularity of electric vehicles has increased the fire load in tunnels, and multi-layer tunnels have greater fire safety hazards.

[0003] At present, there are few studies on the characteristics of fire and smoke in multi-layer (at least two-layer) tunnels and their prevention and control technologies. Compared with single-layer tunnels, multi-layer tunnels have more complex structures and cross-sectional forms, and the evolution of fire and smoke is more complex, making fire fighting and rescue more difficult. Due to too many restrictions and high costs for conducting on-site experiments in engineering projects, it is difficult to obtain a large amount of experimental data, and it is impossible to accurately grasp the evolution of parameters such as smoke, temperature, flow rate, and visibility that affect the safe evacuation of personnel in tunnel fires; fires may occur at various locations in the tunnel, and the relative positions of the exhaust ports are varied. The current tunnel fire experiments are not systematic and comprehensive enough for the above situations. At the same time, the existing tunnel model experimental platform cannot simultaneously realize experimental tests of different ventilation and smoke exhaust methods, so it is urgent to develop a multifunctional tunnel experimental platform. Summary of the invention

[0004] The present invention is made to solve the above-mentioned problems, and its purpose is to provide a multi-layer tunnel fire experiment test platform and method, which has strong operability, can fully restore the fire scene, is easy to quantify the smoke exhaust performance indicators under different fire scenes and smoke exhaust modes, and has high accuracy and strong reliability.

[0005] In order to achieve the above purpose, the present invention adopts the following scheme:

[0006] <Platform>

[0007] The present invention provides a multi-layer tunnel fire experiment test platform, which is characterized by comprising:

[0008] The tunnel model part includes: a multi-layer lane for simulating a multi-layer tunnel, and an arc-shaped outer wall for simulating the outer wall of the tunnel, surrounding the two side walls and the top wall in the length direction of the lane and arranged at a certain distance;

[0009] The fire source simulation section includes two fire source simulation units, which are respectively arranged on each lane and are used to simulate the fire source; each fire source simulation unit includes: a fire source generator, a fire source experimental frame supporting and installing the fire source generator and having an adjustable spatial position;

[0010] The longitudinal ventilation and smoke exhaust simulation part is used to simulate the longitudinal ventilation and smoke exhaust in the tunnel, and comprises: a variable frequency axial flow air supply unit which is arranged at one end of the tunnel model part and supplies air to the lane with adjustable wind speed, a plurality of air outlet shielding plates which are arranged between the air outlet side of the variable frequency axial flow air supply unit and the entrance of each layer of lane and can independently adjust the air outlet area, and a plurality of rectifying nets which are respectively arranged in front of the plurality of air outlet shielding plates for rectifying;

[0011] The top focused smoke exhaust simulation part is used to simulate the top smoke exhaust in the tunnel, and comprises: at least one top smoke exhaust port formed on the top wall of the top lane, a top smoke exhaust channel surrounded by the arc-shaped outer wall and the top wall of the top lane, and a top smoke exhaust fan connected to the top smoke exhaust channel;

[0012] The side focused smoke exhaust simulation part is used to simulate the side smoke exhaust in the tunnel, and includes: a side smoke exhaust port formed on the side wall of each lane, a side smoke exhaust channel surrounded by an arc-shaped outer wall and the side wall of the multi-layer lane, and a side smoke exhaust fan connected to the side smoke exhaust channel;

[0013] The branch pipe key smoke exhaust simulation part is used to simulate the branch pipe smoke exhaust in the tunnel, including: multiple smoke exhaust branch pipes extending from the side wall of each lane to the top smoke exhaust duct and connected with the lane and the top smoke exhaust duct;

[0014] The external exhaust treatment unit collects and treats the smoke discharged by various exhaust methods;

[0015] The airflow monitoring unit includes: a lane monitoring unit for real-time monitoring of the wind speed distribution in the tunnel, and a flue monitoring unit for real-time monitoring of the wind speed and wind pressure changes in the flue; the lane monitoring unit includes a plurality of high-temperature resistant hot wire wind speed sensors arranged in the front, middle and rear sections along each layer of the lane, and a plurality of wind speed measuring points are evenly arranged on the cross section of the wind measuring section, which should include a measuring point at the center of the cross section; the flue monitoring unit includes a plurality of flue detectors arranged in the top flue and the side flue, and the location of the flue detectors should be in the section between the two smoke exhaust ports;

[0016] The temperature monitoring unit monitors the temperature field changes in the tunnel in real time, including: multiple thermocouple trees set in each lane to monitor the temperature at different heights and different longitudinal positions in real time. The density of thermocouples should be inversely proportional to the distance from the fire source; and

[0017] The quality monitoring unit is installed on the fire source test stand to monitor in real time the quality changes of the fuel after the fire source generator burns the fuel.

[0018] Preferably, the multi-layer tunnel fire experimental test platform provided by the present invention may also include: a critical safety height calculation unit, which calculates the critical safety height under the corresponding smoke exhaust mode based on the data obtained from the experiment; the critical safety height calculation formula of the four smoke exhaust modes of longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust is as follows:

[0019]

[0020] In the formula, α 纵向 , β 纵向 , 纵向 , γ 纵向 , α 支管 , β 支管 , 支管 , γ 支管 , α 侧部 , β 侧部 , 侧部 , γ 侧部 , α 顶部 , β 顶部 , 顶部 , γ 顶部 are the coefficients obtained by fitting the vertical temperature data for longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust; H 纵向 , H 支管 , H 侧部 , H 顶部 are the critical safety heights under four smoke exhaust modes; T 临界 It is the critical safety temperature under safe evacuation conditions; when only longitudinal ventilation and smoke exhaust are used, the top smoke exhaust port is not opened, and the smoke overflows from the other end of the lane and enters the smoke hood;

[0021] The comparison and judgment section compares the critical safety heights under different smoke exhaust methods and determines the optimized smoke exhaust strategy; the larger the critical safety height, the better the smoke control effect under this smoke exhaust method.

[0022] Preferably, in the multi-layer tunnel fire experimental test platform provided by the present invention, in the critical safety height calculation unit, for the case where longitudinal ventilation smoke exhaust and any key smoke exhaust method are combined for smoke exhaust, the following formula is used to calculate the critical safety height H of the combined smoke exhaust: 组合 :

[0023]

[0024] Q s-重点排烟 =W*L 0hi *(HH 0 )-W*L 重点排烟 *(HH 重点排烟 ) (3)

[0025]

[0026] In the formula, Q s-重点排烟 It indicates the smoke volume discharged under branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust. W is the tunnel width, H is the tunnel height, L is the tunnel height. 重点排烟 , H 重点排烟 They are the smoke spreading distance and critical safety height under the key smoke exhaust mode; H 组合 Indicates the critical safety height under the combination of longitudinal ventilation smoke exhaust and key smoke exhaust; H 0 Indicates the critical safety height when there is no smoke exhaust; α 0 and β 0 is the coefficient obtained by fitting the vertical temperature data when there is no smoke exhaust; L 0hi It is the distance of smoke spread without smoke exhaust mode;

[0027] When a combined ventilation and smoke exhaust method is used, the comparison and judgment department determines the optimal tunnel fire control strategy based on different emergency rescue needs by comparing the critical safety heights under different combinations.

[0028] Preferably, the multi-layer tunnel fire experimental test platform provided by the present invention may further include: a spreading distance calculation unit, which calculates the smoke spreading distance under the corresponding smoke exhaust mode based on the data obtained from the experiment; the smoke spreading distance calculation formula of the four smoke exhaust modes of longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust is as follows:

[0029]

[0030] For the case of combined smoke exhaust with longitudinal ventilation and any key smoke exhaust method, the smoke spread distance L under the combined smoke exhaust method is calculated using the following formula: 组合hi :

[0031]

[0032] Where V l is the vertical ventilation and smoke exhaust wind speed, Q v The mechanical exhaust volume is the key exhaust volume, A 0 is the area of ​​the smoke exhaust port; ψ 纵向 ,ξ 纵向 , 支管 ,ξ 支管 , 侧部 ,ξ 侧部 , 顶部 ,ξ 顶部 are the coefficients obtained by fitting the temperature data for longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust; L 纵向上游hi , L 支管上游hi , L 侧部上游hi, L 顶部上游hi are the smoke spreading distances upstream of the fire source under the four smoke exhaust modes. According to the above method, the smoke spreading distances downstream of the fire source under no smoke exhaust and four different smoke exhaust modes are L 0下游hi , L 纵向下游hi , L 支管下游hi , L 侧部下游hi , L 顶部下游hi , the sum of the upstream and downstream spread distances of the fire source is the smoke spread distance, that is, L 0hi , L 纵向hi , L 支管hi , L 侧部hi , L 顶部hi .

[0033] Preferably, in the multi-layer tunnel fire experimental test platform provided by the present invention, the comparison and judgment unit compares the critical safety height, smoke spread distance, temperature field change and energy consumption of the smoke exhaust equipment under different smoke exhaust modes, and determines the optimized smoke exhaust strategy based on the fire control target.

[0034] Preferably, the multi-layer tunnel fire experiment test platform provided by the present invention may also include: an observation part, including: a tunnel observation side whose arc-shaped outer wall is formed of transparent high-temperature resistant material, a lane observation side whose side walls of the upper and lower lanes are formed of transparent high-temperature resistant material, a plurality of strip sheet light sources installed on the side walls of the lane, with the same height as the lane height and irradiating toward the observation side, and a high-definition camera arranged in the lane, facing the strip light source; and an inspection part, which is used for allowing the operator to install and adjust the fire source and detection instrument in the model, including: a plurality of inspection operation ports arranged on the bottom plate of each layer of lanes and an inspection cover detachably covered on the inspection operation port. The use of sheet light sources and high-definition cameras can record the height of the smoke layer and the distance of smoke spread in real time, and can also calculate the changes of the height of the smoke layer and the distance of smoke spread over time based on a large number of thermocouple detection points in the tunnel and temperature as a criterion. The two methods complement each other and improve the accuracy of the experiment.

[0035] Preferably, in the multi-layer tunnel fire experimental test platform provided by the present invention, the external exhaust treatment part includes: a smoke hood for collecting smoke exhausted by the other end of the tunnel model part, the side smoke exhaust fan and the top smoke exhaust fan, a smoke exhaust duct whose inlet is connected to the outlet of the smoke hood, a smoke filter unit arranged in the smoke exhaust duct for filtering the smoke, and an outdoor smoke exhaust fan connected to the outlet of the smoke filter unit for discharging the filtered smoke to the outside.

[0036] Preferably, in the multi-layer tunnel fire experimental test platform provided by the present invention, the variable frequency axial flow air supply unit includes: a variable frequency axial flow fan, a wind speed transmitter for monitoring the air supply speed of the variable frequency axial flow fan, and an air supply pipe whose outlet is connected to one end of the tunnel model part, whose inlet is connected to the air supply port of the variable frequency axial flow fan, and whose size gradually increases from the inlet to the outlet; the rectifier network is in a honeycomb shape and includes a plurality of hexagonal grid units, each unit is made of stainless steel sheets, and is used to stabilize the gas flow field and avoid turbulence.

[0037] Preferably, in the multi-layer tunnel fire experiment test platform provided by the present invention, the inlet of the smoke exhaust branch pipe is spaced apart from the side smoke exhaust port; the fire source generator is a fuel tray for burning fuel; the fire source test frame includes a fire source sliding guide rail, a level, multiple horizontal brackets, multiple longitudinal brackets, multiple vertical brackets and multiple pins, the fire source sliding guide rail allows the fuel tray to slide freely, the level is used to keep the fuel tray horizontal, and each bracket is provided with a series of mounting holes spaced apart along the long axis direction; the horizontal bracket, the longitudinal bracket and the vertical bracket are all connected by pins and mounting holes, and the length, width and height of the fire source test frame are adjusted by adjusting the number of connections of the brackets in the horizontal and longitudinal directions and fixing the horizontal brackets and the longitudinal brackets at the mounting holes at the corresponding long axis distances with pins, thereby adjusting the movable range of the fire source generator.

[0038] <Method>

[0039] Furthermore, the present invention also provides a multi-layer tunnel fire experiment test method, which uses any of the multi-layer tunnel fire experiment test platforms described in the above <Platform> to conduct a fire experiment.

[0040] Functions and Effects of the Invention

[0041] The multi-layer tunnel fire experimental test platform and method provided by the present invention can take into account all ventilation and smoke exhaust methods (longitudinal ventilation and smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust) of existing multi-layer tunnels and the combination of these different ventilation and smoke exhaust methods. The experimental platform obtains the temperature and smoke spread characteristics in the tunnel during longitudinal ventilation and smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust, top focused smoke exhaust and combined smoke exhaust methods, and compares and analyzes the smoke control effects of different smoke exhaust methods, which can provide experimental basis for smoke exhaust strategies in engineering practice; it makes up for the problem that the existing tunnels, especially the multi-layer tunnel fire experimental platform, cannot realize the comprehensive comparative test experiment of multiple smoke exhaust methods, provides a solution for the scientific research of tunnel fires, and also provides a scientific basis for the construction of actual projects and fire rescue. The present invention is highly operable, can fully restore the complex situation of the real fire scene, is easy to quantify the smoke exhaust performance indicators under different fire scenes and smoke exhaust modes, has high accuracy and strong reliability.

[0042] Moreover, the present invention can realize the free arrangement and experimental determination of the fire source position in the tunnel, can calculate the heat release rate of the fire source in real time through the mass loss rate, can analyze the temperature field change in the tunnel, the height of the smoke layer and the spread distance of the smoke at different heights in real time. It can also monitor the wind speed and volume value of the tunnel and the flue in real time, and realize the precise control of the wind speed of the tunnel and the flue through the variable frequency axial flow air supply unit.

[0043] In particular, the present invention can calculate the critical safety height corresponding to safe evacuation based on the platform experimental data, and thus propose the optimal tunnel fire control strategy based on the emergency rescue demand target by comparing the critical safety heights under different single smoke exhaust methods or different combined smoke exhaust methods, thereby providing a scientific basis for optimizing the control of tunnel fire smoke. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a structural schematic diagram of a multi-layer tunnel fire experiment test platform involved in an embodiment of the present invention;

[0045] Figure 2 It is a structural schematic diagram of a fire source simulation unit involved in an embodiment of the present invention;

[0046] Figure 3 It is a partial structural side view of a multi-layer tunnel fire experiment test platform involved in an embodiment of the present invention.

[0047] In the figure, 100-fire experiment test platform; 10-tunnel model part, 10a-upper lane, 10b-lower lane, 10c-tunnel model outer wall, 10d-lane partition, 10e-fireproof glass side wall, 10f-calcium silicon board side wall, 10g-model support frame, 10h-bottom plate; 11-fire source simulation part, 111-fuel tray, 112-fire source test frame, 112a-fire source sliding guide rail, 112 a-1-rail cross brace, 112b-level, 112b-1-horizontal adjustment bolt, 112c-horizontal bracket, 112d-longitudinal bracket, 112e-vertical bracket, 112f-positioning pin, 112g-pin hole, 112h-U-shaped slot; 12-longitudinal ventilation and smoke exhaust simulation unit, 121-variable frequency axial flow air supply unit, 122-fan shielding plate, 121a-variable frequency axial flow fan, 121 b-wind speed transmitter, 121c-air supply pipe, 123-rectifier network; 13-top key smoke exhaust simulation part, 13a-top smoke exhaust port, 13b-top smoke exhaust duct, 13c-top smoke exhaust fan; 14-side key smoke exhaust simulation part, 14a-side smoke exhaust port, 14b-side smoke exhaust duct, 14c-side smoke exhaust fan; 15-branch key smoke exhaust simulation part, 15a-smoke exhaust branch pipe; 16-external exhaust treatment part , 16a-smoke hood, 16b-smoke exhaust duct, 16c-smoke filter, 16d-outdoor smoke exhaust fan; 17-observation section, 17a-light source, 17b-camera; 18-maintenance section, 18a-manhole; 19-airflow monitoring section, 19a-hot wire anemometer, 19b-Pitot tube, 19c-bidirectional pressure probe; 20-temperature monitoring section, 20a-thermocouple tree; 21-quality monitoring section. DETAILED DESCRIPTION

[0048] The specific implementation scheme of the multi-layer tunnel fire experiment test platform and method according to the present invention is described in detail below with reference to the accompanying drawings.

[0049] <Example>

[0050] This embodiment is described by simulating a double-layer tunnel as an example. Figures 1 to 3 As shown, the multi-layer tunnel fire experiment test platform 100 adopted in this embodiment includes a tunnel model part 10, a fire source simulation part 11, a longitudinal ventilation and smoke exhaust simulation part 12, a top key smoke exhaust simulation part 13, a side key smoke exhaust simulation part 14, a branch pipe key smoke exhaust simulation part 15, an external exhaust processing part 16, an observation part 17, a maintenance part 18, an airflow monitoring part 19, a temperature monitoring part 20, a quality monitoring part 21, a spread distance calculation part, a critical safety height calculation part, a comparison and judgment part, an input display part and a control part.

[0051] The tunnel model 10 includes an upper lane 10a, a lower lane 10b and a curved outer wall 10c. The upper lane 10a and the lower lane 10b simulate the upper and lower tunnels respectively. The curved outer wall 10c is used to simulate the outer wall of the tunnel, surrounding the two side walls in the length direction of the lane ( Figure 1 The upper lane 10a and one side of the lower lane 10b ( Figure 1 Middle front side, Figure 3 The upper lane 10a and the lane partition 10d between the upper lane 10a and the lower lane 10b are made of non-combustible calcium silicate board.

[0052] The fire source simulation unit 11 includes two fire source simulation units, which are respectively arranged on each lane for simulating the fire source. Figure 2 As shown, each fire source simulation unit includes a fire source generator 111 and a fire source test frame 112. The fire source generator 111 is a fuel tray for burning fuel. The fire source test frame 112 supports and installs the fire source generator 111 and has an adjustable spatial position. It includes a fire source sliding guide rail 112a, a level 112b, a plurality of horizontal brackets 112c, a plurality of longitudinal brackets 112d, a plurality of vertical brackets 112e and a plurality of pins 112f. The fire source sliding guide rail 112a allows the fuel tray 111 to slide freely. A level 112b is installed on the support surface where the fuel tray 111 is located. The horizontal adjustment bolt 112b-1 can ensure that the fuel tray remains horizontal. A series of mounting holes 112g (pin holes) are provided on each bracket at intervals along the long axis direction. The horizontal bracket 112c, the longitudinal bracket 112d and the vertical bracket 112e are all connected by the pin 112f and the mounting hole 112g. By adjusting the number of bracket connections in the horizontal and longitudinal directions and fixing the horizontal bracket 112c and the longitudinal bracket 112d at the mounting hole 112g at the corresponding long axis distance using the pin 112f, the length, width and height of the fire source test frame 112 can be adjusted, and then the movable range of the fire source generator 111 can be adjusted. By adjusting the fire source test frame 112, the fire source position in the lane can be freely set in height and horizontal direction. Specifically, if Figure 2As shown, the fire source is placed in the fuel tray 111, and the fuel tray 111 is mounted on the fire source sliding guide rail 112a, and can move with the fire source sliding guide rail 112a; a U-shaped card slot 112h is set at one end of the horizontal bracket 112c, and the fire source sliding guide rail 112 is placed in the U-shaped card slot 112h and connected to the horizontal bracket 112c; multiple horizontal brackets 112c can be connected to the pin 112f and the pin 112f to achieve the position adjustment of the fire source in the horizontal direction. A U-shaped card slot 112h is also set at the other end of the horizontal bracket 112c, and is fixedly connected to the longitudinal bracket 112d through the pin 112f and the mounting hole 112g; the longitudinal bracket 112d is fixedly connected to the vertical bracket 112e through a nut, and a fixed base and an upper top plate are set on the vertical bracket 112e to enhance the stability of the fire source experimental stand. Furthermore, a plurality of horizontal brackets 112c may be connected to the longitudinal bracket 112d via the pins 112f and the mounting holes 112g to achieve the arrangement and experimental determination of a long-distance fire source.

[0053] like Figure 1 As shown, the longitudinal ventilation and smoke exhaust simulation unit 12 is used to simulate the longitudinal ventilation and smoke exhaust in the tunnel, and includes a variable frequency axial flow air supply unit 121, two air outlet baffles 122, and two rectifier nets 123. The variable frequency axial flow air supply unit 121 is arranged at one end of the tunnel model part 10 to supply air into the lane with adjustable wind speed; the variable frequency axial flow air supply unit 121 comprises a variable frequency axial flow fan 121a, a wind speed transmitter 121b and an air supply pipe 121c; the wind speed transmitter 121b is used to monitor the air supply speed of the variable frequency axial flow fan 121a; the air supply pipe 121c is in a cubic trapezoidal shape, and the inner diameter gradually increases from the inlet to the outlet, the outlet is connected to one end of the tunnel model part 10, and the inlet is connected to the air supply port of the variable frequency axial flow fan 121a; the variable frequency axial flow fan 121a is connected to the upper lane 10a and the lower lane 10b through the air supply pipe 121c, and provides a variety of longitudinal wind speeds for the upper lane 10a and the lower lane 10b respectively and independently through two air outlet baffles 122. Two air outlet baffles 122 are respectively arranged between the air outlet side of the variable frequency axial flow air delivery unit and the entrances of the upper and lower lanes, and the air outlet area can be adjusted independently. In this embodiment, the air outlet baffles 122 are shutter valves. Two rectifier nets 123 are respectively arranged in front of the upper and lower air outlet baffles 122 for rectification; in this embodiment, the rectifier net 123 is honeycomb-shaped and includes a plurality of hexagonal grid units, each unit is made of stainless steel sheets, and is used to stabilize the gas flow field and avoid turbulence. The variable frequency axial flow air supply unit 121 accurately controls the fan inverter through fuzzy adaptive PID algorithm feedback. The algorithm collects tunnel or flue wind speed data information through a wind speed sensor, determines the deviation E between the current wind speed real-time value and the set value, and the change of the current deviation and the last deviation, performs fuzzy reasoning according to the given fuzzy rules, and finally defuzzifies the fuzzy parameters, outputs PID control parameters, and realizes the preset adjustment of tunnel and flue wind speed.

[0054] The top focused smoke exhaust simulation part 13 is used to simulate the top smoke exhaust in the tunnel, and includes multiple top smoke exhaust ports 13a, top smoke exhaust channels 13b and top smoke exhaust fans 13c. Multiple top smoke exhaust ports 13a are formed on the top wall of the upper lane 10a along the longitudinal direction of the tunnel. Shutters and switch valves are installed at the smoke exhaust ports, and the opening degree of the smoke exhaust ports can be adjusted. The top smoke exhaust channel 13b is surrounded by the arc-shaped outer wall 10c and the top wall of the upper lane 10a; one end of the top smoke exhaust channel 13b is blocked with a calcium silicate board, and the other end is connected to the external exhaust treatment part 16. The top smoke exhaust fan 13c is installed at the tail end of the top smoke exhaust channel 13b and is connected to the top smoke exhaust channel 13b through a pipe.

[0055] like Figure 1 and 3 As shown, the side focused smoke exhaust simulation part 14 is used to simulate the side smoke exhaust in the tunnel, and includes a plurality of side smoke exhaust ports 14a, a side smoke exhaust channel 14b and a side smoke exhaust fan 14c. The plurality of side smoke exhaust ports 14a are formed on the side wall of each lane along the longitudinal direction of the tunnel ( Figure 1 Mid-front side wall, Figure 3 The right side wall is a fireproof glass side 10e), and the opening degree can be adjusted. The side smoke exhaust channel 14b is surrounded by the arc outer wall 10c and the side walls of the upper and lower lanes. Figure 3 The entire side space to the right of the middle fireproof glass side 10e is used as a smoke exhaust channel for smoke exhaust. A side smoke exhaust fan 14c is installed at the rear end of the side smoke exhaust channel 14b and is connected to the side smoke exhaust channel 14b through a pipeline.

[0056] The branch pipe smoke exhaust simulation unit 15 is used to simulate the branch pipe smoke exhaust in the tunnel, so that the smoke is discharged to the top smoke exhaust duct 13b through the branch pipe. The branch pipe smoke exhaust simulation unit 15 includes a plurality of smoke exhaust branch pipes 15a. The smoke exhaust branch pipes 15a are formed on the side wall of the lower lane 10b along the longitudinal direction of the tunnel ( Figure 1 Middle and rear side wall, Figure 3 The left side wall of the middle lane is the calcium silicate board side 10f), and shutters are installed at the smoke exhaust port, and a switch valve is set, which can be selectively opened according to the needs of the experiment, and the degree of opening can be adjusted; each smoke exhaust branch pipe 15a extends from the side wall of the lower lane 10b to the top smoke exhaust duct 13b, and is connected to the lane and the top smoke exhaust duct 13b, and is located in the side space between the lower lane 10b and the top smoke exhaust duct 13b. The entrance of the smoke exhaust branch pipe 15a and the side smoke exhaust port 14a should be set at intervals.

[0057] By adjusting the number and opening degree of the smoke exhaust ports, the influence of the number and opening area of ​​the smoke exhaust ports on the smoke exhaust effect of the tunnel can be explored. While keeping the same opening mode of the smoke exhaust ports, the smoke control effects of the smoke exhaust branch pipe, side smoke exhaust and top smoke exhaust can be compared and analyzed.

[0058] like Figure 1 As shown, the external exhaust treatment unit 16 collects and processes the smoke exhausted by each exhaust method, and it includes a smoke hood 16a, a smoke exhaust pipe 16b, a smoke filter unit 16c and an outdoor smoke exhaust fan 16d. The smoke hood 16a collects all smoke generated in the tunnel, including smoke exhausted by the other end of the tunnel model part 10, the side smoke exhaust fan 14c and the top smoke exhaust fan 13c. The inlet of the smoke exhaust pipe 16b is connected to the outlet of the smoke hood 16a. The smoke filter unit 16c is arranged in the smoke exhaust pipe 16b to filter the smoke. The outdoor smoke exhaust fan 16d is connected to the outlet of the smoke filter unit 16c to discharge the smoke that has been filtered and treated to meet environmental protection requirements to the outside. In addition, when longitudinal ventilation and smoke exhaust are performed alone, the smoke directly escapes from the other end of the tunnel model part 10 and enters the smoke hood 16a; when longitudinal ventilation and smoke exhaust are combined with key smoke exhaust, the smoke passes through the smoke exhaust port to the smoke exhaust duct and then enters the smoke hood 16a.

[0059] The observation section 17 includes a tunnel observation side, a lane observation side, a plurality of strip light sources 17a and two high-definition cameras 17b. The tunnel observation side is formed by the curved outer wall 10c using transparent high-temperature resistant materials (fireproof glass). The lane observation side is formed by the side walls of the upper and lower lanes using transparent high-temperature resistant materials, which is the fireproof glass side 10e. A plurality of strip light sources 17a are installed on the side walls of the lane, with the same height as the lane height and irradiating toward the observation side. Two high-definition cameras 17b are respectively arranged in the two lanes, facing the strip light sources 17a, for real-time recording of the smoke movement characteristics in the tunnel (smoke layer height, spread range, concentration, etc.). The smoke flow inside the tunnel can be conveniently observed from the outside through the tunnel observation side and the lane observation side.

[0060] The inspection section 18 is used for operators to install and adjust the fire source, experimental instruments and equipment in the model, and includes a plurality of inspection operation ports 18a and inspection covers. The plurality of inspection operation ports 18a are provided on the bottom plate 10h of each layer of the lane, and are used for operators to enter the lane. The inspection cover is detachably covered on the inspection operation port 18a, and the inspection operation port 18a is closed after the inspection operation is completed.

[0061] The airflow monitoring unit 19 includes a lane monitoring unit and a flue monitoring unit. The lane monitoring unit monitors the wind speed distribution in the tunnel in real time, and includes a plurality of high temperature resistant hot wire wind speed sensors 19a arranged in the front, middle and rear sections along each layer of the lane, which can monitor the wind speed distribution in the tunnel in real time; a plurality of wind speed measuring points are evenly arranged on the cross section of the wind measuring section, which should include a measuring point at the center of the cross section. The flue monitoring unit monitors the wind speed and wind pressure changes in the flue in real time, and includes a plurality of flue detectors 19b arranged in the top flue and the side flue; in this embodiment, a pitot tube is used as the flue detector 19b, which can monitor the wind speed and wind pressure changes in the tunnel in real time; the position of the flue detector 19b should be located in the section between the two smoke exhaust ports, and the distance from the smoke exhaust port is greater than 5 times the characteristic length of the smoke exhaust port. In addition, the flue monitoring unit can also include a plurality of bidirectional gas pressure probes 19c arranged on the cross section of the smoke exhaust pipe, which can calculate the volume flow rate of the gas flowing through the position through the speed of multiple points.

[0062] The temperature monitoring unit 20 monitors the changes of the temperature field in the tunnel in real time, and includes a plurality of thermocouple trees 20a. The plurality of thermocouple trees 20a are arranged in each lane to monitor the temperature at different heights and different longitudinal positions in real time. The density of thermocouple arrangement should be inversely proportional to the distance from the fire source. For example, a thermocouple tree 20a is arranged at the smoke exhaust port, and a thermocouple tree 20a is arranged at a certain distance at the top of the lane. The interval distance does not exceed 1 times the tunnel height, and the real-time changes of the temperature field in the tunnel are monitored in real time.

[0063] The quality monitoring unit 21 is disposed on the fire source test frame 112 to monitor the quality change (mass loss rate) of the fuel in real time for calculating the heat release rate of the fuel. In this embodiment, the quality monitoring unit 21 is a mass sensor disposed under the fuel tray 111 .

[0064] Based on the data obtained above, the wind speed of the tunnel section is calculated using a hot wire anemometer and a pitot tube. The calculation formula for the average wind speed of the section is as follows:

[0065]

[0066] The error S is calculated as follows:

[0067]

[0068] Where N is the total number of measuring points on the section; v i represents the measured value of the i-th measuring point on the section, Represents the average value of all measurement points.

[0069] Based on the Froude similarity principle, the fuel heat release rate obtained in small size can be applied to actual engineering. The principle is as follows:

[0070]

[0071] Where x m represents the length or width of the small-size tunnel model, x f represents the actual length or width of the tunnel, λ l Represents the similarity ratio, Q f is the heat release rate of an actual tunnel fire, Q m is the heat release rate of a small-sized tunnel fire. In the experiment, the heat release rate of the fuel is calculated as follows:

[0072]

[0073] In the formula, Q m is the heat release rate of the fire, h is the fuel combustion efficiency, m is the mass loss rate of the fuel, and ΔH is the calorific value of the fuel.

[0074] The smoke spreading distance calculation unit calculates the smoke spreading distance under the corresponding smoke exhaust mode based on the data obtained from the experiment.

[0075] During the experiment, the vertical ventilation and smoke exhaust speed is V l The mechanical exhaust volume of the key exhaust volume is Q v The area of ​​the smoke outlet is A 0 .

[0076] Multiple thermocouple trees arranged in the tunnel can monitor the temperature at different heights and different longitudinal positions in real time. Taking the experiment without smoke exhaust as an example, upstream of the fire source, at a certain height h i At , the smoke temperature rise changes with the distance from the fire source as follows:

[0077]

[0078] Where, ΔT 0 is the temperature rise at this position when there is no smoke exhaust, ψ 0 , 0 are the fitting coefficients of experimental data, and x represents the distance from the fire source.

[0079] Taking ΔT=C as the criterion for smoke reaching this position, then at h i The distance that smoke spreads upstream of the fire source at this moment is:

[0080]

[0081] Furthermore, the smoke spread distance can be calculated for longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust:

[0082] The calculation formula for smoke spread distance of four smoke exhaust modes, namely longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust, is as follows:

[0083]

[0084] For the case of combined smoke exhaust by longitudinal ventilation and key smoke exhaust, the smoke spread distance L under the combined smoke exhaust method is calculated using the following formula: 组合hi :

[0085]

[0086] Where V l is the vertical ventilation and smoke exhaust wind speed, Q v The mechanical exhaust volume is the key exhaust volume, A 0 is the area of ​​the smoke exhaust port; ψ 纵向 , 纵向 , 支管 , 支管 , 侧部 , 侧部 , 顶部 , 顶部 are the coefficients obtained by fitting the temperature data for longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust; L 纵向上游hi , L 支管上游hi , L 侧部上游hi , L 顶部上游hi are the smoke spreading distances upstream of the fire source under the four smoke exhaust modes. According to the above method, the smoke spreading distances downstream of the fire source under no smoke exhaust and four different smoke exhaust modes are L 0下游hi , L 纵向下游hi , L 支管下游hi , L 侧部下游hi , L 顶部下游hi , the sum of the upstream and downstream spread distances of the fire source is the smoke spread distance, that is, L 0hi , L 纵向hi , L 支管hi , L 侧部hi , L 顶部hi . V ind is the induced wind speed; the height represented by hi is the critical height for longitudinal ventilation and smoke exhaust mode.

[0087] The critical safety height calculation unit calculates the critical safety height under the corresponding smoke exhaust mode based on the data obtained from the experiment.

[0088] In actual engineering design, the smoke temperature at a height of 1.8m is usually not higher than 60℃ (333K in international units) as the evaluation standard for safe evacuation of personnel. In this small-scale tunnel model, the calculation of 60℃ (i.e., T 临界=333K), and then converted to the height of the full-scale tunnel by Froude's scaling rule, which is the critical safety height. The larger the critical safety height, the better the smoke control effect under this smoke exhaust method.

[0089] The temperature data without any smoke exhaust is recorded as T 0 , the temperature data measured in the longitudinal ventilation and smoke exhaust mode is T 纵向 , the temperature data measured in the branch pipe key exhaust mode is T 支管 , the temperature data measured in the side focused smoke exhaust mode is T 侧部 , the temperature data measured in the top focused smoke exhaust mode is T 顶部 .

[0090] During the experiment, the thermocouple tree 23 arranges multiple thermocouples vertically, and the temperature data measured at different heights are (z 1 , T 01 )、(z 2 , T 02 )…(z n , T 0n ), the above data can be fitted to obtain the functional relationship between vertical temperature and height:

[0091]

[0092] Where α 0 , β 0 , 0 , γ 0 It is the coefficient obtained by fitting the vertical temperature data when there is no smoke exhaust.

[0093] Based on the functional relationship between the vertical temperature and the height when there is no smoke exhaust, the critical safety height is calculated:

[0094]

[0095] The calculation formula for the critical safety height for longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust is as follows:

[0096]

[0097] In the formula, α 纵向 , β 纵向 , 纵向 , γ 纵向 , α 支管 , β 支管 , 支管 , γ 支管 , α 侧部 , β 侧部 , 侧部 , γ侧部 , α 顶部 , β 顶部 , 顶部 , γ 顶部 are the coefficients obtained by fitting the vertical temperature data for longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust; H 纵向 , H 支管 , H 侧部 , H 顶部 are the critical safety heights under four smoke exhaust modes; T 临界 It is the critical safety temperature under safe evacuation conditions; when only longitudinal ventilation and smoke exhaust are used, the top smoke exhaust port is not opened, and smoke overflows from the other end of the lane and enters the smoke hood 16a;

[0098] In the critical safety height calculation section, for the case where longitudinal ventilation smoke exhaust is combined with any key smoke exhaust method, the critical safety height H of the combined smoke exhaust is calculated using the following formula: 组合 :

[0099]

[0100] When a combined ventilation and smoke exhaust method is used, the critical safety height under different smoke exhaust methods is obtained for subsequent comparative analysis, which is conducive to proposing the most optimized tunnel fire control strategy for different emergency rescue needs.

[0101] When using focused smoke exhaust, a large amount of air is exhausted from the exhaust port due to smoke penetration and boundary layer separation, and the smoke exhaust volume is not equal to the focused smoke exhaust volume. By comparing the smoke spread distance and critical safety height when using focused smoke exhaust and no smoke exhaust, the smoke exhaust volume can be determined:

[0102] Q s-重点排烟 =W*L 0hi *(HH 0 )-W*L 重点排烟 *(HH 重点排烟 ) (14)

[0103]

[0104] In the formula, Q s-重点排烟 It indicates the smoke volume discharged under branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust. W is the tunnel width, H is the tunnel height, L is the tunnel height. 重点排烟 , H 重点排烟 are the smoke spreading distance and critical safety height under the key smoke exhaust mode, calculated by formula 7 and 12 respectively; H 组合 It indicates the critical safety height under the combination of longitudinal ventilation smoke exhaust and three types of key smoke exhaust; H 0Indicates the critical safety height when there is no smoke exhaust; α 0 and β 0 is the coefficient obtained by fitting the vertical temperature data when there is no smoke exhaust; L 0hi It is the smoke spread distance without smoke exhaust.

[0105] The comparison and judgment department compares the critical safety height, smoke spread distance, temperature field changes and energy consumption of smoke exhaust equipment under different smoke exhaust methods and various combined smoke exhaust methods, and determines the optimized smoke exhaust strategy based on the fire control target. When the combined ventilation and smoke exhaust method is adopted, the comparison and judgment department determines the optimal tunnel fire control strategy for different emergency rescue needs by comparing the critical safety height under different combinations. In addition, the temperature field data can be used to obtain the regular curve of the critical safety height and smoke spread distance in the tunnel changing over time.

[0106] The input display unit is used to allow the user to input operation instructions, and according to the corresponding operation instructions, the operation status, input data, output data and operation data of the above-mentioned parts are displayed in the form of text, table, trend chart or three-dimensional dynamic model.

[0107] The control unit is connected in communication with the fire source simulation unit 11, the longitudinal ventilation and smoke exhaust simulation unit 12, the top key smoke exhaust simulation unit 13, the side key smoke exhaust simulation unit 14, the branch pipe key smoke exhaust simulation unit 15, the external exhaust processing unit 16, the observation unit 17, the maintenance unit 18, the airflow monitoring unit 19, the temperature monitoring unit 20, the quality monitoring unit 21, the spread distance calculation unit, the critical safety height calculation unit, the comparison and judgment unit, and the input and display unit to control their operations.

[0108] Based on the above structure, the method for conducting a double-layer tunnel fire experiment using the multi-layer tunnel fire experiment test platform 10 of this embodiment is as follows:

[0109] First, based on the double-layer tunnel to be simulated, build Figures 1 to 3 A multi-layer tunnel fire experiment test platform 10 is shown.

[0110] Then, according to the specific fire scene, the corresponding fire source fuel and fire source position are set through the fire source simulation unit 11, and the longitudinal ventilation and smoke exhaust simulation unit 12, the top key smoke exhaust simulation unit 13, the side key smoke exhaust simulation unit 14, and the branch pipe key smoke exhaust simulation unit 15 are used to simulate the smoke exhaust situation individually or in combination, which can simulate the complex ventilation and smoke exhaust environment generated in the tunnel and restore the real scene as much as possible.

[0111] After the observation unit 17 is set up in each smoke exhaust mode simulation, each unit is started to operate and the experiment is carried out.

[0112] During the experiment, the exhaust treatment unit 16 safely treats the smoke and then exhausts it. The observation unit 17, the maintenance unit 18, the airflow monitoring unit 19, the temperature monitoring unit 20, and the quality monitoring unit 21 monitor the progress of the experiment in real time to obtain the corresponding experimental data (multiple types of sensors measure the mass loss rate, temperature, pressure and wind speed of the fire source in real time, revealing the temperature, thermal radiation, wind speed and smoke distribution of the tunnel fire scene). The spread distance calculation unit and the critical safety height calculation unit calculate the spread distance calculation unit and the critical safety height respectively based on the experimental data.

[0113] Finally, after performing various predetermined smoke exhaust simulation methods, the comparison and judgment unit compares the critical safety heights, smoke spread distances, temperature field changes and energy consumption of smoke exhaust equipment under different smoke exhaust methods and various combined smoke exhaust methods, and determines the optimized smoke exhaust strategy based on the fire control target; in addition, the input display unit can also display these situations to the operator to allow the operator to determine the smoke exhaust strategy.

[0114] The above embodiments are merely examples of the technical solutions of the present invention. The multi-layer tunnel fire experiment test platform and method involved in the present invention are not limited to the contents described in the above embodiments, but are subject to the scope defined by the claims. Any modification, supplement or equivalent replacement made by technicians in the field of the present invention based on the embodiment is within the scope of protection required by the claims of the present invention.

Claims

1. Multi-layer tunnel fire experiment test platform, It is characterized in that include: The tunnel model part includes: a multi-layer lane corresponding to each layer of the tunnel arranged in the simulated height direction, and an arc-shaped outer wall for simulating the outer wall of the tunnel, surrounding the two side walls and the top wall in the length direction of the lane and arranged at a certain distance; The fire source simulation part includes a plurality of fire source simulation units, which are respectively arranged on the lanes on each floor and are used to simulate the fire source; each of the fire source simulation units includes: a fire source generator, and a fire source experimental frame on which the fire source generator is supported and installed and whose spatial position is adjustable; A longitudinal ventilation and smoke exhaust simulation part, used to simulate longitudinal ventilation and smoke exhaust in a tunnel, comprising: a variable frequency axial flow air supply unit arranged at one end of the tunnel model part, supplying air into the lane with an adjustable wind speed, a plurality of air outlet shielding plates arranged between the air outlet side of the variable frequency axial flow air supply unit and the entrance of each layer of the lane, which can independently adjust the air outlet area, and a plurality of rectifying nets respectively arranged in front of the plurality of air outlet shielding plates for rectifying; The top focused smoke exhaust simulation part is used to simulate the top smoke exhaust in the tunnel, and comprises: at least one top smoke exhaust port formed on the top wall of the top lane, a top smoke exhaust channel surrounded by the arc-shaped outer wall and the top wall of the top lane, and a top smoke exhaust fan connected to the top smoke exhaust channel; The side focused smoke exhaust simulation part is used to simulate the side smoke exhaust in the tunnel, and comprises: a side smoke exhaust port formed on the side wall of each layer of the lane, a side smoke exhaust channel surrounded by the arc-shaped outer wall and the side wall of the multi-layer lane, and a side smoke exhaust fan connected to the side smoke exhaust channel; The branch pipe key smoke exhaust simulation part is used to simulate the branch pipe smoke exhaust in the tunnel, and comprises: a plurality of smoke exhaust branch pipes respectively extending from the side wall of the lane to the top smoke exhaust channel and connected with the lane and the top smoke exhaust channel; The external exhaust treatment unit collects and treats the smoke discharged by various exhaust methods; The airflow monitoring unit includes: a lane monitoring unit for real-time monitoring of the wind speed distribution in the tunnel, and a flue monitoring unit for real-time monitoring of the wind speed and wind pressure changes in the flue; the lane monitoring unit includes a plurality of high-temperature resistant hot wire wind speed sensors arranged in the front, middle and rear sections along each layer of the lane, and a plurality of wind speed measuring points are evenly arranged on the cross section of the wind measuring section, which should include a measuring point at the center of the cross section; the flue monitoring unit includes a plurality of flue detectors arranged in the top smoke exhaust channel and the side smoke exhaust channel, and the position of the flue detector should be located in the section between the two smoke exhaust ports; The temperature monitoring unit monitors the temperature field changes in the tunnel in real time, including: multiple thermocouple trees set in each lane to monitor the temperature at different heights and different longitudinal positions in real time. The density of thermocouples should be inversely proportional to the distance from the fire source; and The quality monitoring unit is installed on the fire source test stand to monitor the quality change of the fuel after the fire source generator burns the fuel in real time; The critical safety height calculation section calculates the critical safety height under the corresponding smoke exhaust mode based on the data obtained from the experiment; the critical safety height calculation formulas for the four smoke exhaust modes, namely longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust, are as follows: In the formula, α 纵向 , β 纵向 , 纵向 , γ 纵向 , α 支管 , β 支管 , 支管 , γ 支管 , α 侧部 , β 侧部 , 侧部 , γ 侧部 , α 顶部 , β 顶部 , 顶部 , γ 顶部 are the coefficients obtained by fitting the vertical temperature data for longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust; H 纵向 , H 支管 , H 侧部 , H 顶部 are the critical safety heights under four smoke exhaust modes; T 临界 It is the critical safety temperature under safe evacuation conditions; when only longitudinal ventilation and smoke exhaust are used, the top smoke exhaust port is not opened, and smoke overflows from the other end of the lane and enters the smoke hood; The comparison and judgment department compares the critical safety heights under different smoke exhaust methods and determines the optimized smoke exhaust strategy; The larger the critical safety height, the better the smoke control effect under this smoke exhaust method.

2. The multi-layer tunnel fire experiment test platform according to claim 1 is characterized by: in, In the critical safety height calculation unit, for the case where longitudinal ventilation smoke exhaust and any key smoke exhaust method are combined for smoke exhaust, the critical safety height H of the combined smoke exhaust is calculated using the following formula: 组合 : Q s-重点排烟 =W*L 0hi *(H-H 0 )-W*L 重点排烟 *(H-H 重点排烟 )(3) In the formula, Q s-重点排烟 It indicates the smoke volume discharged under branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust. W is the tunnel width, H is the tunnel height, L is the tunnel height. 重点排烟 , H 重点排烟 They are the smoke spreading distance and critical safety height under the key smoke exhaust mode; H 组合 Indicates the critical safety height under the combination of longitudinal ventilation smoke exhaust and key smoke exhaust; H 0 Indicates the critical safety height when there is no smoke exhaust; α 0 and β 0 is the coefficient obtained by fitting the vertical temperature data when there is no smoke exhaust; L 0hi is the smoke spreading distance without smoke exhaust; L 组合hi Indicates the smoke spread distance under the combined smoke exhaust mode; λ l represents similarity ratio; When a combined ventilation and smoke exhaust method is adopted, the comparison and judgment unit determines the most optimized tunnel fire control strategy according to different emergency rescue needs by comparing the critical safety heights under different combination situations.

3. The multi-layer tunnel fire experiment test platform according to claim 2, It is characterized in that Also includes: The smoke spreading distance calculation section calculates the smoke spreading distance under the corresponding smoke exhaust mode based on the data obtained from the experiment; the smoke spreading distance calculation formula for the four smoke exhaust modes, namely longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust, is as follows: For the case of combined smoke exhaust by longitudinal ventilation and any key smoke exhaust method, the smoke spread distance L under the combined smoke exhaust method is calculated using the following formula: 组合hi : V ind =Q v / A 0 (7) Where V l is the vertical ventilation smoke exhaust wind speed, Q v The mechanical exhaust volume is the key exhaust volume, A 0 is the area of ​​the smoke exhaust port; ψ 纵向 , 纵向 , 支管 , 支管 , 侧部 , 侧部 , 顶部 , 顶部 are the coefficients obtained by fitting the temperature data for longitudinal ventilation smoke exhaust, branch pipe focused smoke exhaust, side focused smoke exhaust and top focused smoke exhaust; L 纵向上游hi , L 支管上游hi , L 侧部上游hi , L 顶部上游hi They are the smoke spreading distances upstream of the fire source under the four smoke exhaust modes. According to the above formula, the smoke spreading distances downstream of the fire source under no smoke exhaust and four different smoke exhaust modes are L 0下游hi , L 纵向下游hi , L 支管下游hi , L 侧部下游hi , L 顶部下游hi , the sum of the upstream and downstream spread distances of the fire source is the smoke spread distance, that is, L 0hi , L 纵向hi , L 支管hi , L 侧部hi , L 顶部hi .

4. The multi-layer tunnel fire experiment test platform according to claim 2 is characterized by: in, The comparison and judgment unit compares the critical safety height, smoke spread distance, temperature field change and energy consumption of smoke exhaust equipment under different smoke exhaust modes, and determines the optimized smoke exhaust strategy based on the fire control target.

5. The multi-layer tunnel fire experiment test platform according to claim 1, It is characterized in that Also includes: The observation part comprises: a tunnel observation side whose arc-shaped outer wall is formed of a transparent high-temperature resistant material, a lane observation side whose side wall of the multi-layer lane is formed of a transparent high-temperature resistant material, a plurality of strip-shaped sheet light sources installed on the side wall of the lane, having the same height as the lane and irradiating toward the observation side, and a high-definition camera arranged in the lane and facing the strip-shaped light sources; and The maintenance part is used for allowing the operator to install and adjust the fire source and detection instruments in the model, and comprises: a plurality of maintenance operation ports arranged on the bottom plate of the lanes at each level and a maintenance cover detachably covered on the maintenance operation ports.

6. The multi-layer tunnel fire experiment test platform according to claim 1 is characterized by: in, The external exhaust treatment part includes: a smoke collecting hood for collecting smoke exhausted by the other end of the tunnel model part, the side smoke exhaust fan and the top smoke exhaust fan, a smoke exhaust duct whose inlet is connected to the outlet of the smoke collecting hood, a smoke filter unit arranged in the smoke exhaust duct for filtering the smoke, and an outdoor smoke exhaust fan connected to the outlet of the smoke filter unit for exhausting the filtered smoke to the outside.

7. The multi-layer tunnel fire experiment test platform according to claim 1 is characterized by: in, The variable frequency axial flow air supply unit comprises: a variable frequency axial flow fan, a wind speed transmitter for monitoring the air supply speed of the variable frequency axial flow fan, and an air supply pipe whose outlet is connected to one end of the tunnel model part, whose inlet is connected to the air supply port of the variable frequency axial flow fan, and whose size gradually increases from the inlet to the outlet; The rectifying net is honeycomb-shaped and includes a plurality of hexagonal grid units, each unit being made of stainless steel sheets and used for stabilizing the gas flow field and avoiding turbulence.

8. The multi-layer tunnel fire experiment test platform according to claim 1 is characterized by: in, The inlet of the smoke exhaust branch pipe is spaced apart from the side smoke exhaust port; The fire source generator is a fuel tray for burning fuel; the fire source test stand includes a fire source sliding rail, a level, a plurality of horizontal brackets, a plurality of longitudinal brackets, a plurality of vertical brackets and a plurality of pins; the fire source sliding rail allows the fuel tray to slide freely; the level is used to keep the fuel tray horizontal; each bracket is provided with a series of mounting holes spaced along the long axis direction; The horizontal bracket, the longitudinal bracket and the vertical bracket are all connected through the pins and the mounting holes. The length, width and height of the fire source test stand are adjusted by adjusting the number of connections of the brackets in the horizontal and longitudinal directions and fixing the horizontal bracket and the longitudinal bracket at the mounting holes of the corresponding long axis distances with pins, thereby adjusting the movable range of the fire source generator.

9. Multi-layer tunnel fire test method, Features: A fire experiment is carried out using the multi-layer tunnel fire experiment test platform described in any one of claims 1 to 8.

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