Experimental measurement device and method for fluid channeling ratio with variable relative position of adjacent tunnel portal

Abstract

The invention discloses a fluid channeling ratio experimental measurement device with variable relative positions of adjacent tunnel portal, which comprises an upstream tunnel model, a downstream tunnel model and an adjacent tunnel middle section, and is characterized in that the adjacent tunnel middle section is formed by arranging a plurality of middle section road plates with different corners side by side, and through the combination of the middle section road plates with different corners, the relative positions of the adjacent tunnel portal can be changed. The upstream tunnel body can be in lap joint with an upstream tunnel bottom plate and a downstream tunnel bottom plate to form adjacent tunnel middle sections with different curvatures, deflection angles and lengths, an upstream tunnel top fan mechanism is arranged on the upper half portion of an inlet of the upstream tunnel body, and an upstream tunnel bottom fan mechanism is arranged on the lower half portion of the inlet of the upstream tunnel body. A downstream tunnel fan mechanism is arranged at an outlet of the downstream tunnel model, and a combustion tray and a fuming device are arranged above the middle section of the upstream tunnel bottom plate. The system and the method are used for studying how to reduce fluid channeling of fire smoke and motor vehicle pollutants of adjacent tunnels and guiding design of the adjacent tunnels so as to improve design reliability.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel ventilation and smoke exhaust, and specifically relates to an experimental measurement device and method for a crossflow ratio with a variable relative position of an adjacent tunnel opening, which is used to simulate the crossflow of traffic pollutants and fire smoke and provide a reference for the design of adjacent tunnels. Background Art

[0002] In recent years, with the rapid development of mountain highway networks, a large number of highway tunnels have been built in canyons, mountains and hilly areas with complex terrain. For longitudinally ventilated tunnels, when the distance between two tunnels L≤250m, they can be defined as adjacent tunnels. In adjacent tunnels, traffic pollutants and fire smoke from the exit of the upstream tunnel may flow to the downstream tunnel. The problem of polluted wind flow should be considered when designing adjacent tunnels.

[0003] For adjacent tunnels, when pollutants from the upstream tunnel outlet flow to the downstream tunnel entrance, the required air volume of the downstream tunnel dilution air will increase, and the fan operating cost of the downstream tunnel will increase. Under fire conditions, the crossflow of fire smoke directly increases the safety risk of the downstream tunnel. Whether from an economic or safety perspective, the pollutant crossflow ratio of adjacent tunnels should be minimized. The crossflow ratio of adjacent tunnels is mainly affected by three factors: the size of the tunnel opening, the relative position of the tunnel opening, and the speed ratio between the upstream tunnel exit and the downstream tunnel entrance. When the upstream tunnel exit and the downstream tunnel entrance of the adjacent tunnel are in the same straight line, the pollutant crossflow ratio is the highest. As the deflection angle of the upstream tunnel exit and the downstream tunnel entrance increases, the pollutant crossflow ratio also changes. The influence of the deflection angle on the crossflow ratio needs further study.

[0004] During the design phase of adjacent tunnels, designers can change the relative positions of the upstream tunnel exit and the downstream tunnel entrance of the tunnel group so that they are staggered by an angle, and further study the influence of the relative deflection angle of the upstream tunnel exit and the downstream tunnel entrance on the crossflow ratio to reduce the crossflow ratio of the adjacent tunnel. However, there is no model test device that can be used in the prior art. A crossflow ratio experimental measurement device and method with variable relative positions of adjacent tunnel openings is urgently needed in the prior art to guide the reasonable design of adjacent tunnels. Summary of the invention

[0005] The first purpose of the present invention is to overcome the shortcomings of the prior art and provide a crossflow ratio experimental measurement device with a variable relative position adjacent to a tunnel opening.

[0006] The first object of the present invention is achieved through the following technical solutions: A cross-flow ratio experimental measurement device with a variable relative position adjacent to a tunnel entrance, comprising an upstream tunnel model and a downstream tunnel model, and further comprising an adjacent tunnel intermediate section located between the upstream tunnel model and the downstream tunnel model. The upstream tunnel model includes an upstream tunnel bottom plate and an upstream tunnel body disposed on the upstream tunnel bottom plate. The downstream tunnel model includes a downstream tunnel bottom plate and a downstream tunnel body disposed on the downstream tunnel bottom plate. The adjacent tunnel intermediate section is composed of a plurality of intermediate section road plates with different angles of rotation arranged side by side. The adjacent two intermediate section road plates and between the intermediate section road plates and the upstream tunnel bottom plate and the downstream tunnel bottom plate are inserted and matched with each other. A fireproof lining cloth is disposed above the adjacent tunnel intermediate section. An upstream tunnel top fan mechanism is disposed in the upper half of the entrance of the upstream tunnel body. A downstream tunnel bottom fan mechanism is disposed in the lower half of the entrance of the upstream tunnel body. A downstream tunnel fan mechanism is disposed at the exit of the downstream tunnel model. A combustion tray and a smoke generating device are disposed above the middle section of the upstream tunnel bottom plate. An upstream tunnel thermocouple is disposed on the top of the upstream tunnel body. The upstream tunnel thermocouple is electrically connected to an upstream tunnel thermocouple data acquisition instrument. An upstream particle counter supporting funnel and an upstream laser sheet light source are disposed at the top of the exit of the upstream tunnel body. The upstream particle counter supporting funnel is connected to an upstream particle counter. An upstream hot-wire anemometer is disposed at the exit of the upstream tunnel body. A downstream tunnel thermocouple is disposed on the top of the downstream tunnel body. The downstream tunnel thermocouple is electrically connected to a downstream tunnel thermocouple data acquisition instrument. A downstream particle counter supporting funnel and a downstream laser sheet light source are disposed at the top of the entrance of the downstream tunnel body. The downstream particle counter supporting funnel is connected to a downstream particle counter. A downstream hot-wire anemometer is disposed at the entrance of the downstream tunnel body.

[0007] The intermediate section road plates are intermediate section road plates with a 1° angle of rotation, 2° angle of rotation, 5° angle of rotation, 15° angle of rotation, 45° angle of rotation or 90° angle of rotation.

[0008] Insert edges and slots corresponding to the insert edges are respectively disposed on the left and right sides of each intermediate section road plate. Slots and insert edges are respectively disposed on the end edge of the upstream tunnel bottom plate and the start edge of the downstream tunnel bottom plate.

[0009] The upstream tunnel top fan mechanism includes an upstream tunnel top fan, an upstream tunnel top fan frequency converter electrically connected to the upstream tunnel top fan, and a top fan rectifying section disposed downstream of the upstream tunnel top fan. The upstream tunnel top fan and the top of the top fan rectifying section are both connected to a top fan hoisting fixing rope.

[0010] The upstream tunnel bottom fan mechanism includes an upstream tunnel bottom fan, an upstream tunnel bottom fan frequency converter electrically connected to the upstream tunnel bottom fan, and a bottom fan rectifying section disposed downstream of the upstream tunnel bottom fan. Both the upstream tunnel bottom fan and the bottom fan rectifying section are disposed on the upstream tunnel support.

[0011] The upstream tunnel model is disposed on the upstream tunnel support, the downstream tunnel model is disposed on the downstream tunnel support, and the adjacent tunnel middle section is disposed on the support table.

[0012] The downstream tunnel fan mechanism includes a downstream tunnel axial flow fan and a downstream tunnel fan frequency converter electrically connected to the downstream tunnel axial flow fan.

[0013] The second object of the present invention is to overcome the deficiencies of the prior art and provide a method for experimentally measuring the cross-flow ratio with variable relative positions of adjacent tunnel openings.

[0014] The second object of the present invention is achieved by the following technical solution: A method for experimentally measuring the cross-flow ratio with variable relative positions of adjacent tunnel openings, which adopts an experimental measurement device for the cross-flow ratio with variable relative positions of adjacent tunnel openings, and includes the following steps: 1) Conduct a preliminary experiment. Ignite the smoke generating device on an open outdoor site and sample the flue gas using a particle counter. Count the number of PM10, PM2.5, and PM1 particles generated by the smoke generation of the smoke generating device. Measure that the PM10 in the sample is α (particles / L), the PM2.5 is β (particles / L), and the PM1 is γ (particles / L). Calculate the PM10 quantity proportion r1, the PM2.5 quantity proportion r2, and the PM1 quantity proportion r3. The calculation formulas are respectively: ; ; ; 2) Place the smoke generating device in the upstream tunnel model and generate smoke. When conducting a fire condition experiment, place the combustion tray upstream of the smoke generating device, with the combustion tray adjacent to the smoke generating device. Set the combustion cross-sectional area according to the experimental needs and ignite the fuel in the combustion tray to provide thermal buoyancy for the fire smoke emitted by the smoke generating device. 3) Start the upstream tunnel top fan, the upstream tunnel bottom fan, and the downstream tunnel axial flow fan. According to the experimental conditions, adjust the ventilation volume of each fan through the frequency converter. After adjusting the flow field to the required conditions, run stably for 5 minutes to make the airflow reach a steady state. When analyzing the cross-flow of fire smoke, start the upstream tunnel top fan and turn off the upstream tunnel bottom fan. According to the temperature value collected by the thermocouple in the upstream tunnel, obtain the upstream tunnel smoke backflow length, and adjust the ventilation volume of the upstream tunnel top fan to obtain the critical wind speed. This is the ideal condition for tunnel fire fighting and rescue. When analyzing the cross - flow of traffic pollutants in a naturally ventilated tunnel, turn off the top fan of the upstream tunnel and start the bottom fan of the upstream tunnel. According to the different traffic volumes of the tunnel, adjust the air supply volume of the bottom fan of the upstream tunnel to simulate the piston wind under different traffic volumes. When analyzing the cross - flow of traffic pollutants in a forced - ventilated tunnel, start both the top fan and the bottom fan of the upstream tunnel simultaneously. According to the actual tunnel conditions, adjust the air supply volumes of the top and bottom fans to simulate the internal flow field in the tunnel under the combined action of the fan operation and the vehicle piston wind. 4) Calculate the cross - flow ratio of fire smoke or traffic pollutants through the upstream particle counter and the downstream particle counter; Observe the upstream particle counter and measure the particulate matter concentrations of the gas at the top of the upstream tunnel exit as: PM10 = a1 (mg / L), PM2.5 = a2 (mg / L), PM1 = a3 (mg / L); Observe the downstream particle counter and measure the particulate matter concentrations of the gas at the top of the downstream tunnel entrance as PM10 = b1 (mg / L), PM2.5 = b2 (mg / L), PM1 = b3 (mg / L), and calculate the comprehensive cross - flow ratio: ; where r1 is the proportion of PM10 quantity, r2 is the proportion of PM2.5 quantity, r3 is the proportion of PM1 quantity, and the calculation methods of r1, r2, and r3 are as described in step 1). Use the upstream laser sheet light source and the downstream laser sheet light source to observe the thickness of the fire smoke layer at the upstream tunnel exit and the downstream tunnel entrance; Obtain the cross - section wind speed ratio at the upstream tunnel exit and the downstream tunnel entrance through the upstream hot - wire anemometer and the downstream hot - wire anemometer, and adjust the air volume of each fan to obtain the cross - flow ratio of fire smoke or traffic pollutants at different wind speed ratios. 5) Obtain the cross - flow ratio of fire smoke or traffic pollutants at different relative positions between the upstream tunnel exit and the downstream tunnel entrance through different side - by - side combination arrangement methods of multiple intermediate - section road plates with different angles.

[0015] The beneficial effects of the present invention are as follows: 1. In the present invention, variable-frequency fans are provided at both the top and bottom of the upstream tunnel, which are rectified independently to simulate the longitudinal ventilation (at the top) and natural ventilation (at the bottom) in the tunnel. The axial-flow fan at the outlet of the adjacent downstream tunnel is directly used to provide negative pressure at the outlet, thus constituting the internal environment model of the adjacent tunnels. In engineering applications, when the tunnel is long, variable-frequency fans at the top of the tunnel are usually used for ventilation. For shorter tunnels, axial-flow fans are usually not installed in engineering, and natural ventilation is adopted. When mechanical ventilation is used in the tunnel, the wind speed at the top of the flow field in the tunnel is greater than that at the bottom; when natural ventilation is used in the tunnel, due to the piston wind brought by the driving vehicles, the wind speed at the bottom of the flow field in the tunnel is greater than that at the top. This device can adjust the flow rates of the upper and lower variable-frequency fans according to the test conditions and rectify them separately to simulate the flow field in the tunnel under the conditions of mechanical ventilation and natural ventilation in the upstream tunnel. For the downstream tunnel, due to the fluid characteristics of negative-pressure ventilation, only an axial-flow fan needs to be installed at the end of the downstream tunnel, and a rectifying device is not required, so that a relatively uniform negative pressure can be achieved at the entrance of the downstream tunnel. The present invention realizes the biological reproduction of the internal air flow fields in the upstream and downstream tunnels of the adjacent tunnel model, determines the wind speed ratio conditions at the outlet of the upstream tunnel and the entrance of the downstream tunnel during the operation period, and provides guidance for the relevant engineering design of adjacent tunnels.

[0016] 2. In the present invention, through different assembly and combination methods of multiple intermediate-section road plates with different angles at the middle section of the adjacent tunnels, the distance and relative deflection angle between the outlet of the upstream tunnel and the entrance of the downstream tunnel can be adjusted arbitrarily. The adjacent intermediate-section road plates are connected and matched through the mortise-and-tenon splicing edges at the edges of these intermediate-section road plates. A fireproof lining cloth is covered above the middle section of the adjacent tunnels to adjust the roughness of the middle section surface. In engineering applications, the relative deflection angle between the outlet of the upstream tunnel and the entrance of the downstream tunnel directly affects the pollutant cross-flow ratio. The present invention is a model test device for the pollutant cross-flow ratio. By changing the relative deflection angle between the outlet of the upstream tunnel and the entrance of the downstream tunnel, it studies how to reduce the cross-flow of fire smoke and motor vehicle pollutants in adjacent tunnels, provides timely feedback and guidance for the design of adjacent tunnels, and improves the design reliability.

[0017] 3. The present invention adopts a measurement system of upstream and downstream particle counters and double-slice light sources. The particle concentrations at the outlet of the upstream tunnel and the entrance of the downstream tunnel are quantitatively analyzed through the particle counters, and the upstream and downstream pollutant cross-flow ratios are calculated in real time, as well as the bending conditions of the middle section of the adjacent tunnels, filling the blank of quantitative experiments. Laser sheet light sources are arranged at the upstream and downstream of the adjacent tunnels respectively. The laser sheet light sources are respectively placed on the extension lines of the upstream and downstream tunnel axes, so that the thickness of the fire smoke layer at the outlet of the upstream tunnel and the entrance of the downstream tunnel can be observed, supplementing the quantitative test results of the particle counters.

[0018] 4. In terms of smoke control, the position of the simulated fire source is variable, and various scenarios can be simulated, such as a fire occurring in the upstream tunnel, at different distances and different deflection angles from the tunnel entrance in the middle curved section of the adjacent tunnel. This experimental platform can provide experimental data for experiments at different fire positions, such as different distances and deflection angles, through quantitative calculation with a particle counter and qualitative analysis of the smoke layer thickness upstream and downstream.

[0019] 5. The present invention can simulate the smoke and traffic pollutant cross-flow in the adjacent tunnel of the middle curved section respectively. In both operating conditions, a smoke generating device is used to generate particles. In the fire operating condition, a combustion tray filled with methanol or ethanol is used for combustion upstream of the smoke generating device to provide heat source and smoke buoyancy. In the traffic pollutant operating condition, only the smoke generating device is used. Description of the Drawings

[0020] Figure 1 It is a schematic diagram of the overall structure of the cross-flow ratio experimental measurement device with variable relative positions of the adjacent tunnel entrances; Figure 2 Schematic diagrams of the road plates in the middle section of the adjacent tunnel; among them, (a) is the road plate in the middle section of the adjacent tunnel with a 1° turning angle, (b) is the road plate in the middle section of the adjacent tunnel with a 2° turning angle, (c) is the road plate in the middle section of the adjacent tunnel with a 5° turning angle, (d) is the road plate in the middle section of the adjacent tunnel with a 15° turning angle, (e) is the road plate in the middle section of the adjacent tunnel with a 45° turning angle, and (f) is the road plate in the middle section of the adjacent tunnel with a 90° turning angle; Figure 3 Variable-frequency ventilation device for the upstream tunnel; among them, (a) is the variable-frequency ventilation device at the top of the upstream tunnel; (b) is the variable-frequency ventilation device at the bottom of the upstream tunnel; Figure 4 It is a model of the upstream tunnel; Figure 5 It is a model of the downstream tunnel; Figure 6 It is a schematic diagram of the cooperation mode of the upstream tunnel model, the middle section of the adjacent tunnel and the downstream tunnel model.

[0021] In the figure: 1 - Inverter for the top fan in the upstream tunnel; 2 - Inverter for the bottom fan in the upstream tunnel; 3 - Top fan in the upstream tunnel; 4 - Bottom fan in the upstream tunnel; 5 - Hoisting and fixing ropes for the top fan; 6 - Support for the upstream tunnel; 7 - Rectifying section for the top fan; 8 - Rectifying section for the bottom fan; 9 - Thermocouple data collector for the upstream tunnel; 10 - Thermocouple in the upstream tunnel; 11 - Combustion tray; 12 - Smoke generating device; 13 - Particle counter in the upstream tunnel; 14 - Funnel for the particle counter in the upstream tunnel; 15 - Laser sheet light source in the upstream tunnel; 16 - Thermal anemometer in the upstream tunnel; 17 - Particle counter in the downstream tunnel; 18 - Funnel for the particle counter in the downstream tunnel; 19 - Laser sheet light source in the downstream tunnel; 20 - Thermal anemometer in the downstream tunnel; 21 - Thermocouple in the downstream tunnel; 22 - Thermocouple data collector for the downstream tunnel; 23 - Axial flow fan in the downstream tunnel; 24 - Inverter for the fan in the downstream tunnel; 25 - Support for the downstream tunnel; 26 - Intermediate section plate with a 1° corner; 27 - Intermediate section plate with a 2° corner; 28 - Intermediate section plate with a 5° corner; 29 - Intermediate section plate with a 15° corner; 30 - Intermediate section plate with a 45° corner; 31 - Intermediate section plate with a 90° corner; 32 - Fireproof lining; 33 - Support table; 34 - Upstream tunnel body; 35 - Upstream tunnel floor; 36 - Downstream tunnel body; 37 - Downstream tunnel floor; 38 - Insert edge; 39 - Insert slot. Detailed implementation mode

[0022] The present invention will be described in detail below with reference to the accompanying drawings.

[0023] As Figures 1-6 shown, a cross - flow ratio experimental measurement device with variable relative positions of adjacent tunnel openings includes an upstream tunnel model and a downstream tunnel model, and also includes an adjacent tunnel intermediate section located between the upstream tunnel model and the downstream tunnel model. The upstream tunnel model includes an upstream tunnel floor 35 and an upstream tunnel body 34 provided on the upstream tunnel floor 35. The downstream tunnel model includes a downstream tunnel floor 37 and a downstream tunnel body 36 provided on the downstream tunnel floor 37. The adjacent tunnel intermediate section is composed of a plurality of intermediate section plates with different angles arranged side by side. The adjacent two intermediate section plates and between the intermediate section plates and the upstream tunnel floor 35 and the downstream tunnel floor 37 are mutually inserted and matched. A fireproof lining 32 is provided above the adjacent tunnel intermediate section to adjust the surface roughness of the adjacent tunnel intermediate section. An upstream tunnel top fan mechanism is provided in the upper half of the entrance of the upstream tunnel body 34, and an upstream tunnel bottom fan mechanism is provided in the lower half of the entrance of the upstream tunnel body 34. A downstream tunnel fan mechanism is provided at the exit of the downstream tunnel model; see Figure 4, above the middle section of the upstream tunnel floor slab 35, there is a combustion tray 11 and a smoke generating device 12. At the top of the upstream tunnel body 34, there is an upstream tunnel thermocouple 10, which is electrically connected to the upstream tunnel thermocouple data acquisition instrument 9. The temperature data is collected in real time through the upstream tunnel thermocouple data acquisition instrument 9. At the top of the outlet of the upstream tunnel body 34, there is an upstream particle counter matching funnel 14 and an upstream laser sheet light source 15. The upstream particle counter matching funnel 14 is connected to the upstream particle counter 13 to collect the flue gas at the top of the upstream tunnel outlet and measure the concentration of particles with different particle sizes. At the outlet of the upstream tunnel body 34, there is an upstream hot-wire anemometer 16 (a set of three) to measure the average wind speed of the upstream tunnel outlet section; see Figure 5 , at the top of the downstream tunnel body 36, there is a downstream tunnel thermocouple 21, which is electrically connected to the downstream tunnel thermocouple data acquisition instrument 22. The temperature data is collected in real time through the downstream tunnel thermocouple data acquisition instrument 22. At the top of the inlet of the downstream tunnel body 36, there is a downstream particle counter matching funnel 18 and a downstream laser sheet light source 19. The downstream particle counter matching funnel 18 is connected to the downstream particle counter 17 to collect the flue gas at the top of the downstream tunnel inlet and measure the concentration of particles with different particle sizes. At the inlet of the downstream tunnel body 36, there is a downstream hot-wire anemometer 20 (a set of three) to measure the average wind speed of the downstream tunnel inlet section.

[0024] See Figure 2 , the intermediate section road plates include the intermediate section road plate 26 with a 1° corner, the intermediate section road plate 27 with a 2° corner, the intermediate section road plate 28 with a 5° corner, the intermediate section road plate 29 with a 15° corner, the intermediate section road plate 30 with a 45° corner or the intermediate section road plate 31 with a 90° corner. This corner is formed by the included angle between the left and right side edges of the intermediate section road plate. At the left and right sides of each intermediate section road plate, there are respectively provided with insertion edges 38 and slots 39 corresponding to the insertion edges 38. At the end edge of the upstream tunnel floor slab 35, there is a slot 39, and at the starting edge of the downstream tunnel floor slab 37, there is an insertion edge 38. By combining intermediate section road plates with different corners, it can be lapped with the upstream tunnel floor slab 35 and the downstream tunnel floor slab 37 to form adjacent tunnel intermediate sections with different curvatures, deflection angles and lengths. After lapping multiple intermediate section road plates with different corners, the accumulated deflection angle is the total deflection angle between the upstream tunnel inlet and the downstream tunnel outlet. For example Figure 6 a 21° deflection angle between the upstream tunnel inlet and the downstream tunnel outlet is achieved.

[0025] Before conducting the experiment, a preliminary experiment is first carried out: counting the number of particles with different particle sizes generated by the smoke generating device 12. On an open outdoor site, the smoke generating device is lit, and a particle counter is used to sample the flue gas to analyze the number of particles with different particle sizes in the flue gas. Only the numbers of PM10, PM2.5, and PM1 particles are counted, and the proportion r1 of the number of PM10 particles, the proportion r2 of the number of PM2.5 particles, and the proportion r3 of the number of PM1 particles are calculated. The particle counter can display the number of particles (particles / L) or the concentration of particles (mg / L). In the preliminary experiment, the number of particles (particles / L) is used to calculate the proportion of particles with different particle sizes. The smoke generating device uses existing smoke generating fuel, usually mugwort. The proportion of the numbers of PM10, PM2.5, and PM1 particles emitted by the same kind of smoke generating fuel is fixed. The purpose of the preliminary experiment is to obtain the proportions r1, r2, and r3 of the numbers of PM10, PM2.5, and PM1 particles, which are used to calculate the cross-flow ratio in the subsequent experimental process.

[0026] During the experiment, when using the particle counter to measure and calculate the cross-flow ratio, the flow field should be adjusted to the required working condition and then run stably for 5 minutes to make the air flow reach a stable state. Secondly, place the smoke generating device 12 in the upstream tunnel and generate smoke. Then, using the concentration of particles (mg / L) as the measurement unit, observe the upstream particle counter 13 and the downstream particle counter 17. The particulate matter concentration of the gas at the top of the upstream tunnel outlet measured by the upstream particle counter 13 is: PM10 = a1 (mg / L), PM2.5 = a2 (mg / L), PM1 = a3 (mg / L), and the particulate matter concentration of the gas at the top of the downstream tunnel inlet measured by the downstream particle counter 17 is PM10 = b1 (mg / L), PM2.5 = b2 (mg / L), PM1 = b3 (mg / L). The calculation method of the pollutant cross-flow ratio is as follows: ; Among them, r1 is the percentage of the number of PM10 particles in the total number of particles, r2 is the percentage of the number of PM2.5 particles in the total number of particles, r3 is the percentage of the number of PM1 particles in the total number of particles, and r1 + r2 + r3 = 1.

[0027] By adjusting the air volume of the fan, the cross-flow ratios with different speed ratios between the upstream tunnel outlet and the downstream tunnel inlet are obtained. The cross-sectional wind speed ratio between the upstream tunnel outlet and the downstream tunnel inlet is calculated from the average value measured by the upstream hot-wire anemometer 16 and the average value measured by the downstream hot-wire anemometer 20.

[0028] The upstream tunnel top fan mechanism includes the upstream tunnel top fan 3, the upstream tunnel top fan frequency converter 1 electrically connected to the upstream tunnel top fan 3, and the top fan rectification section 7 provided downstream of the upstream tunnel top fan 3. The tops of the upstream tunnel top fan 3 and the top fan rectification section 7 are both connected to the top fan hoisting and fixing ropes 5. The air volume sent by the upstream tunnel top fan 3 is adjusted through the upstream tunnel top fan frequency converter 1, and the sent air then passes through the top fan rectification section 7, where the swirling flow is converted into a relatively stable air current.

[0029] The upstream tunnel bottom fan mechanism includes the upstream tunnel bottom fan 4, the upstream tunnel bottom fan frequency converter 2 electrically connected to the upstream tunnel bottom fan 4, and the bottom fan rectification section 8 provided downstream of the upstream tunnel bottom fan 4. The upstream tunnel bottom fan 4 and the bottom fan rectification section 8 are both arranged on the upstream tunnel support 6. The air volume sent by the upstream tunnel bottom fan 4 is adjusted through the upstream tunnel bottom fan frequency converter 2, and the sent air then passes through the bottom fan rectification section 8, where the swirling flow is converted into a relatively stable air current.

[0030] When analyzing the cross-flow of fire smoke and traffic pollutants in the upstream tunnel, the setting strategies of the upstream tunnel top fan 3 and the upstream tunnel bottom fan 4 are different: 1) Under the real tunnel fire condition, the vehicle driving stops, and the high-temperature fire smoke rises to the tunnel top. The tunnel top fan operates at high power. The power of the fan should just avoid the backflow of fire smoke upstream, and people can escape from the upstream direction of the tunnel. At this time, the wind speed in the tunnel is the critical wind speed, and the critical wind speed is also the minimum wind speed to meet the tunnel fire safety.

[0031] When the experimental device conducts the experiment under the fire condition, it mimics the real tunnel environment, starts the upstream tunnel top fan 3, and closes the upstream tunnel bottom fan 4. According to the temperature value collected by the upstream tunnel thermocouple 10, the smoke backflow length of the upstream tunnel is obtained, and the ventilation volume of the upstream tunnel top fan 3 is adjusted to obtain the critical wind speed. At this time, the ventilation condition required for the fire environment is obtained; 2) Under the real tunnel pollutant diffusion condition, the pollutants do not rise to the tunnel top due to high temperature but diffuse evenly in the tunnel. Traffic pollutants are generated by vehicle exhaust, including CO, NOx, and dust. According to different vehicle types, traffic flow densities, and vehicle speeds in the tunnel, the piston wind speeds caused by vehicles are different, and the diffusion effects of pollutants in the tunnel are also different. There are two ventilation methods in the tunnel, forced ventilation and natural ventilation. Forced ventilation is completed by the tunnel top fan to dilute the pollutant concentration in the tunnel. Natural ventilation only dilutes the pollutant concentration through the piston wind brought by vehicle driving. According to the ventilation method in the tunnel, when analyzing the traffic pollutant diffusion, the following strategies are adopted: 1) For a naturally ventilated tunnel, turn off the upstream tunnel top fan 3 and start the upstream tunnel bottom fan 4. Adjust the air supply volume of the upstream tunnel bottom fan 4 according to different tunnel traffic volumes to simulate the piston wind under different traffic volumes.

[0032] 2) For a forced-ventilated tunnel, start both the upstream tunnel top fan 3 and the upstream tunnel bottom fan 4 simultaneously. Adjust the air supply volumes of the top and bottom fans according to the actual tunnel conditions to simulate the internal flow field of the tunnel under the combined action of fan operation and vehicle piston wind.

[0033] The upstream tunnel model is set on the upstream tunnel support 6, the downstream tunnel model is set on the downstream tunnel support 25, and the adjacent tunnel middle section is set on the support table 33.

[0034] The downstream tunnel fan mechanism includes a downstream tunnel axial flow fan 23 and a downstream tunnel fan frequency converter 24 electrically connected to the downstream tunnel axial flow fan 23. Adjust the air volume of the downstream tunnel axial flow fan 23 through the downstream tunnel fan frequency converter 24. Since the fluid flow of negative pressure ventilation is relatively stable, only setting the downstream tunnel axial flow fan 23 at the downstream tunnel outlet can provide a relatively uniform negative pressure flow field at the downstream tunnel inlet to meet the requirements of engineering tests.

[0035] The present invention also provides a method for experimentally measuring the cross-flow ratio with variable relative positions of adjacent tunnel openings, which adopts an experimental measuring device for the cross-flow ratio with variable relative positions of adjacent tunnel openings, and includes the following steps: 1) Conduct a preliminary experiment. Light the smoke generating device on an outdoor open site and sample the flue gas using a particle counter. Count the numbers of PM10, PM2.5, and PM1 particles generated by the smoke of the smoke generating device, measure that PM10 in the sample is α (pieces / L), PM2.5 is β (pieces / L), and PM1 is γ (pieces / L), and calculate the PM10 quantity proportion r1, PM2.5 quantity proportion r2, and PM1 quantity proportion r3; the calculation formulas are respectively: ; ; ; 2) Place the smoke generating device 12 in the upstream tunnel model and generate smoke; if conducting a fire condition experiment, place the combustion tray 11 upstream of the smoke generating device 12, with the combustion tray 11 adjacent to the smoke generating device 12. Set the combustion cross-sectional area according to the experimental needs and light the fuel in the combustion tray 11 to provide thermal buoyancy for the fire smoke emitted by the smoke generating device 12. 3) Start the upstream tunnel top fan 3, the upstream tunnel bottom fan 4, and the downstream tunnel axial flow fan 23. Adjust the ventilation volumes of each fan through the frequency converter according to the experimental conditions. After adjusting the flow field to the required conditions, operate stably for 5 minutes to make the air flow reach a steady state. When analyzing the cross - flow of fire smoke, start the upstream tunnel top fan 3 and close the upstream tunnel bottom fan 4. According to the temperature value collected by the upstream tunnel thermocouple 10, obtain the smoke back - flow length of the upstream tunnel, and adjust the ventilation volume of the upstream tunnel top fan 3 to obtain the critical wind speed. At this time, it is the ideal working condition for tunnel fire fighting and rescue; When analyzing the cross - flow of traffic pollutants in a naturally ventilated tunnel, close the upstream tunnel top fan 3 and start the upstream tunnel bottom fan 4. According to the different traffic volumes of the tunnel, adjust the air supply volume of the upstream tunnel bottom fan 4 to simulate the piston wind under different traffic volumes; When analyzing the cross - flow of traffic pollutants in a forced - ventilated tunnel, start both the upstream tunnel top fan 3 and the upstream tunnel bottom fan 4 at the same time. According to the actual tunnel working conditions, adjust the air supply volumes of the top and bottom fans to simulate the internal flow field of the tunnel under the combined action of fan operation and vehicle piston wind; 4) Calculate the cross - flow ratio of fire smoke or traffic pollutants through the upstream particle counter 13 and the downstream particle counter 17; Observe the upstream particle counter 13, and measure the particulate matter concentrations of the gas at the top of the upstream tunnel outlet as: PM10 = a1 (mg / L), PM2.5 = a2 (mg / L), PM1 = a3 (mg / L); Observe the downstream particle counter 17, and measure the particulate matter concentrations of the gas at the top of the downstream tunnel inlet as PM10 = b1 (mg / L), PM2.5 = b2 (mg / L), PM1 = b3 (mg / L), and calculate the comprehensive cross - flow ratio: ; where r1 is the proportion of PM10 quantity, r2 is the proportion of PM2.5 quantity, r3 is the proportion of PM1 quantity, and the calculation methods of r1, r2, and r3 are as described in step 1); Use the upstream laser sheet light source 15 and the downstream laser sheet light source 19 to observe the thickness of the fire smoke layer at the upstream tunnel outlet and the downstream tunnel inlet; Obtain the cross - section wind speed ratio at the upstream tunnel outlet and the downstream tunnel inlet through the upstream hot - wire anemometer 16 and the downstream hot - wire anemometer 20, and adjust the air volume of each fan to obtain the cross - flow ratio of fire smoke or traffic pollutants with different wind speed ratios; 5) Obtain the cross - flow ratio of fire smoke or traffic pollutants at different relative positions (curvature, deflection angle, length) between the upstream tunnel outlet and the downstream tunnel inlet through different side - by - side combination arrangement methods of multiple intermediate - section road plates with different rotation angles.

[0036] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than a limitation on the protection scope of the present invention. Any simple modification or equivalent replacement of the technical solution of the present invention by those of ordinary skill in the art shall not depart from the essence and scope of the technical solution of the present invention.

Claims

1. An experimental measurement device for the flow-through ratio with variable relative positions adjacent to the tunnel portal, comprising an upstream tunnel model and a downstream tunnel model, characterized in that: It also includes an adjacent tunnel middle section located between the upstream tunnel model and the downstream tunnel model. The upstream tunnel model includes an upstream tunnel bottom plate and an upstream tunnel body provided on the upstream tunnel bottom plate. The downstream tunnel model includes a downstream tunnel bottom plate and a downstream tunnel body provided on the downstream tunnel bottom plate. The adjacent tunnel middle section is composed of a plurality of middle section road plates with different angles of rotation arranged side by side. The adjacent two middle section road plates and between the middle section road plates and the upstream tunnel bottom plate and the downstream tunnel bottom plate are plugged and matched with each other. A fireproof lining cloth is provided above the adjacent tunnel middle section. An upstream tunnel top fan mechanism is provided in the upper half of the entrance of the upstream tunnel body. A downstream tunnel bottom fan mechanism is provided in the lower half of the entrance of the upstream tunnel body. A downstream tunnel fan mechanism is provided at the exit of the downstream tunnel model. A combustion tray and a smoke generating device are provided above the middle section of the upstream tunnel bottom plate. An upstream tunnel thermocouple is provided at the top of the upstream tunnel body. The upstream tunnel thermocouple is electrically connected to an upstream tunnel thermocouple data collector. An upstream particle counter matching funnel and an upstream laser sheet light source are provided at the top of the exit of the upstream tunnel body. The upstream particle counter matching funnel is connected to an upstream particle counter. An upstream hot wire anemometer is provided at the exit of the upstream tunnel body. A downstream tunnel thermocouple is provided at the top of the downstream tunnel body. The downstream tunnel thermocouple is electrically connected to a downstream tunnel thermocouple data collector. A downstream particle counter matching funnel and a downstream laser sheet light source are provided at the top of the entrance of the downstream tunnel body. The downstream particle counter matching funnel is connected to a downstream particle counter. A downstream hot wire anemometer is provided at the entrance of the downstream tunnel body.

2. The cross-flow ratio experimental measurement device with variable relative positions of adjacent tunnel openings according to claim 1, wherein: The middle section road plates are middle section road plates with a 1° angle of rotation, 2° angle of rotation, 5° angle of rotation, 15° angle of rotation, 45° angle of rotation or 90° angle of rotation.

3. The cross-flow ratio experimental measurement device with variable relative positions of adjacent tunnel openings according to claim 2, characterized in that: Insert edges and slots corresponding to the insert edges are respectively provided on the left and right sides of each middle section road plate. Slots and insert edges are respectively provided on the end edge of the upstream tunnel bottom plate and the start edge of the downstream tunnel bottom plate.

4. The experimental measurement device for the cross-flow ratio with variable relative positions of adjacent tunnel openings according to claim 3, characterized in that: The upstream tunnel top fan mechanism includes an upstream tunnel top fan, an upstream tunnel top fan frequency converter electrically connected to the upstream tunnel top fan, and a top fan rectifying section provided downstream of the upstream tunnel top fan. The upstream tunnel top fan and the top of the top fan rectifying section are both connected to a top fan hoisting fixing rope.

5. The experimental measurement device for the cross-flow ratio with variable relative positions of adjacent tunnel openings according to claim 4, characterized in that: The upstream tunnel bottom fan mechanism includes an upstream tunnel bottom fan, an upstream tunnel bottom fan frequency converter electrically connected to the upstream tunnel bottom fan, and a bottom fan rectifying section provided downstream of the upstream tunnel bottom fan. The upstream tunnel bottom fan and the bottom fan rectifying section are both provided on an upstream tunnel support.

6. The experimental measurement device for the cross-flow ratio with variable relative positions of adjacent tunnel openings according to claim 5, characterized in that: The upstream tunnel model is provided on the upstream tunnel support, the downstream tunnel model is provided on the downstream tunnel support, and the adjacent tunnel middle section is provided on a support table.

7. The cross-flow ratio experimental measurement device with variable relative positions of adjacent tunnel openings according to claim 6, characterized in that: The downstream tunnel fan mechanism includes a downstream tunnel axial flow fan and a downstream tunnel fan frequency converter electrically connected to the downstream tunnel axial flow fan.

8. An experimental measurement method for the flow-through ratio with variable relative positions adjacent to the tunnel portal, characterized in that: The variable cross-flow ratio experimental measurement device with variable relative positions of adjacent tunnel openings described in claim 7 is adopted, including the following steps: 1) Conduct a preliminary experiment. Ignite the smoke generating device on an outdoor open ground and sample the flue gas using a particle counter. Count the number of PM10, PM2.5, and PM1 particles generated by the smoke generating device. Measure that the PM10 in the sample is α (particles / L), PM2.5 is β (particles / L), and PM1 is γ (particles / L). Calculate the proportion of PM10 quantity r1, the proportion of PM2.5 quantity r2, and the proportion of PM1 quantity r3. The calculation formulas are as follows: ； ； ； 2) Place the smoke generating device in the upstream tunnel model and generate smoke. When conducting a fire condition experiment, place the combustion tray upstream of the smoke generating device, with the combustion tray adjacent to the smoke generating device. Set the combustion cross-sectional area according to the experimental needs and ignite the fuel in the combustion tray to provide thermal buoyancy for the fire smoke emitted by the smoke generating device. 3) Start the upstream tunnel top fan, the upstream tunnel bottom fan, and the downstream tunnel axial flow fan. According to the experimental conditions, adjust the ventilation volume of each fan through the frequency converter. After adjusting the flow field to the required conditions, operate stably for 5 minutes to make the air flow reach a steady state. When analyzing the cross-flow of fire smoke, start the upstream tunnel top fan and close the upstream tunnel bottom fan. According to the temperature value collected by the thermocouple in the upstream tunnel, obtain the length of the flue gas backflow in the upstream tunnel, and adjust the ventilation volume of the upstream tunnel top fan to obtain the critical wind speed. This is the ideal condition for tunnel fire fighting and rescue. When analyzing the cross-flow of traffic pollutants in a naturally ventilated tunnel, close the upstream tunnel top fan and start the upstream tunnel bottom fan. According to different tunnel traffic volumes, adjust the air supply volume of the upstream tunnel bottom fan to simulate the piston wind under different traffic volumes. When analyzing the cross-flow of traffic pollutants in a forced-ventilated tunnel, start both the upstream tunnel top fan and the upstream tunnel bottom fan at the same time. According to the actual tunnel conditions, adjust the air supply volumes of the top and bottom fans to simulate the internal flow field of the tunnel under the combined action of fan operation and vehicle piston wind. 4) Calculate the cross-flow ratio of fire smoke or traffic pollutants through the upstream particle counter and the downstream particle counter. Observe the upstream particle counter and measure the particulate matter concentration of the gas at the top of the upstream tunnel outlet as: PM10 = a1 (mg / L), PM2.5 = a2 (mg / L), PM1 = a3 (mg / L); observe the downstream particle counter and measure the particulate matter concentration of the gas at the top of the downstream tunnel inlet as PM10 = b1 (mg / L), PM2.5 = b2 (mg / L), PM1 = b3 (mg / L), and calculate the comprehensive cross-flow ratio: ； Among them, r1 is the proportion of PM10 quantity, r2 is the proportion of PM2.5 quantity, r3 is the proportion of PM1 quantity, and the calculation methods of r1, r2, and r3 are as described in step 1). Use the upstream laser sheet light source and the downstream laser sheet light source to observe the thickness of the fire smoke layer at the upstream tunnel exit and the downstream tunnel entrance; obtain the cross-sectional wind speed ratio at the upstream tunnel exit and the downstream tunnel entrance through the upstream hot-wire anemometer and the downstream hot-wire anemometer, and adjust the air volume of each fan to obtain the cross-flow ratio of fire smoke or traffic pollutants with different wind speed ratios. 5) Obtain the cross-flow ratio of fire smoke or traffic pollutants at different relative positions between the upstream tunnel exit and the downstream tunnel entrance through different side-by-side combination arrangements of multiple intermediate section road plates with different angles of rotation.

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