Simulation test device and method for fluid channeling ratio of adjacent tunnels in combination with boundary conditions

Abstract

The invention discloses an adjacent tunnel fluid channeling ratio simulation test device and method combined with boundary conditions, the adjacent tunnel fluid channeling ratio simulation test device combined with the boundary conditions comprises an upstream tunnel model, a downstream tunnel model and a middle section road surface, and the side surface of the middle section road surface is provided with a crosswind simulation mechanism. And a full-spectrum lamp is arranged above the middle section of the road surface. The invention further relates to an adjacent tunnel fluid channeling ratio simulation test method in combination with the boundary conditions. According to the method, the sulfur hexafluoride (SF6) concentration is used as a basis for quantitatively calculating the fluid channeling ratio, fluid channeling analysis of traffic pollutants and high-temperature fire smoke can be combined, and a more accurate adjacent tunnel pollutant fluid channeling ratio is obtained by combining terrain wind environment boundary conditions and pavement thermal environment boundary conditions; and more reliable experimental data is provided for the design of adjacent tunnels and the type selection of ventilation and fire fighting equipment.

Description

Technical Field

[0001] This invention belongs to the technical field of tunnel ventilation and smoke exhaust experimental devices, specifically relating to a simulation test device and method for the crossflow ratio of adjacent tunnels combined with boundary conditions, used to simulate the crossflow of traffic pollutants and fire smoke, providing a reference for the ventilation and fire protection design of adjacent tunnels. Background Technology

[0002] With the continuous improvement of road networks in mountainous areas of my country, the number of tunnels is increasing year by year. During road network construction, due to the short distances between adjacent mountains in some canyons and hilly areas, a large number of longitudinally adjacent tunnels have emerged. When the distance L between adjacent tunnels is ≤250m, traffic pollutants and fire smoke from the upstream tunnel exit can flow into the downstream tunnel. my country's "Detailed Design Specifications for Ventilation of Highway Tunnels" (JTG / T D70 / 2-02-2014) clearly stipulates the permissible CO concentration during tunnel operation. For longitudinally adjacent tunnels, the "cross-flow" phenomenon of pollutants from upstream tunnels diffusing into downstream tunnels must be considered during the design process. To ensure that the air quality of downstream tunnels meets the specifications, their ventilation systems often require additional airflow to effectively dilute pollutants entering from upstream. Against this backdrop, accurately determining the pollutant cross-flow ratio between adjacent tunnels becomes a crucial prerequisite for ventilation design and engineering decisions. Obtaining crossflow ratio data that matches actual working conditions not only helps provide a scientific basis for selecting downstream tunnel ventilation equipment and avoids excessive or insufficient ventilation capacity, but also enables the optimization of system configuration, thereby effectively controlling initial investment and long-term operating energy consumption while ensuring safety.

[0003] In existing technologies, crossflow ratio data between adjacent tunnels are mostly obtained using numerical simulation methods. However, the boundary conditions in numerical simulation examples often deviate from actual operating conditions, and the accumulation of errors during the numerical simulation process further reduces the reliability of the simulation results. Currently, scaled-down experimental platforms for the crossflow ratio of pollutants in tunnel groups focus on the similarity of size and dynamics in the model, but neglect deviations from actual operating conditions in terms of solar radiation and the influence of surrounding terrain. Regarding solar radiation, the middle section of adjacent tunnels absorbs solar radiation and heats the air, causing the streamline trajectory of pollutants diffused from upstream tunnels to deflect, thus changing the crossflow ratio. Currently, no experimental platform or numerical simulation method considers the heat absorption, heat storage, and air heating of the middle section of the road surface. Regarding the influence of surrounding terrain, mountains can cause the wind speed and angle of crosswinds in canyons to deviate from meteorological values. Under actual terrain conditions, changes in canyon crosswind parameters can significantly alter the crossflow ratio, and currently, no experimental platform or numerical simulation method considers correction methods for canyon crosswinds under different terrain conditions.

[0004] In model tests, considering the road surface thermal environment and topographical wind environment can make the boundary conditions of the experimental platform closer to the real environment, thereby improving the accuracy of the crossflow ratio test results. Therefore, there is an urgent need in the existing technology for a simulation test device and method for the crossflow ratio of adjacent tunnels that incorporates boundary conditions. Summary of the Invention

[0005] The primary objective of this invention is to overcome the shortcomings of existing technologies and provide a simulation test device for the crossflow ratio of adjacent tunnels that incorporates boundary conditions, thereby improving the accuracy of crossflow ratio test results.

[0006] The first objective of this invention is achieved through the following technical solution: a simulation test device for the crossflow ratio of adjacent tunnels combined with boundary conditions, comprising an upstream tunnel model, a downstream tunnel model, and an intermediate road surface located between the upstream and downstream tunnel models. Support legs are provided at the bottom of the upstream tunnel model, the downstream tunnel model, and the intermediate road surface. An upstream tunnel fan mechanism is provided at the entrance of the upstream tunnel model. The upstream tunnel model is equipped with a sulfur hexafluoride (SF6) release device, the outlet of which is located at the upstream tunnel fan mechanism. An upstream tunnel concentration meter funnel and an upstream tunnel hot-wire anemometer are provided at the outlet of the upstream tunnel model. The upstream tunnel concentration meter funnel is connected to an upstream tunnel SF6 concentration tester. A crosswind simulation mechanism is provided on the side of the intermediate road surface, and a full-spectrum lamp is provided above the intermediate road surface. A downstream tunnel concentration meter funnel and a downstream tunnel hot-wire anemometer are provided at the entrance of the downstream tunnel model. The downstream tunnel concentration meter funnel is connected to a downstream tunnel SF6 concentration tester. A downstream tunnel fan is provided at the outlet of the downstream tunnel model.

[0007] The intermediate road surface includes, from bottom to top, an intermediate road subbase, an intermediate road base layer, and an intermediate road surface layer.

[0008] Multiple crosswind simulation mechanisms are arranged side by side on the side of the middle section of the road.

[0009] The crosswind simulation mechanism includes a crosswind fan, a crosswind static pressure box, a crosswind rectification section, and louvers arranged sequentially from back to front, with the louvers located near the middle section of the road surface.

[0010] The upstream tunnel ventilation mechanism includes an upstream tunnel ventilation fan and an upstream tunnel rectifier section located in front of the upstream tunnel ventilation fan. The outlet of the sulfur hexafluoride release device is located between the upstream tunnel ventilation fan and the upstream tunnel rectifier section.

[0011] A combustion tray is installed above the middle section of the bottom surface of the upstream tunnel model.

[0012] A laser sheet light source is provided on the top surface of the exit of the upstream tunnel model, and the laser sheet light source is located directly above the central axis of the upstream tunnel model.

[0013] The second objective of this invention is to overcome the shortcomings of the prior art and provide a device and method for simulating the crossflow ratio of adjacent tunnels by combining boundary conditions, so as to improve the accuracy of the crossflow ratio test results.

[0014] The second objective of this invention is achieved through the following technical solution: a method for simulating the crossflow ratio of adjacent tunnels under boundary conditions, which employs the aforementioned device for simulating the crossflow ratio of adjacent tunnels under boundary conditions. The method for simulating the crossflow ratio between adjacent tunnels by incorporating boundary conditions includes the following steps: 1) Based on the size ratio between the simulation test device and the actual working conditions, and in accordance with the similarity criterion of the Fernold number, the ratio of the crosswind speed, crosswind deflection angle, mid-section road surface temperature, mid-section road surface light intensity, and fire source power of the simulation test device to the actual working conditions is obtained. 2) Set boundary conditions for terrain and wind environment and road surface thermal environment; Setting terrain and wind environment boundary conditions includes the following steps: The first step is to download the DEM topographic map of the project site from the website and convert the DEM data into a .stl solid model using GIS software. Next, download the meteorological parameters for the project site and, based on the wind rose diagram, determine the most frequent wind speed and direction during the simulation period, using these as representative wind speeds and directions. The wind speed is expressed as an exponential profile across the canyon and mountains, with the following expression:

[0015] In the formula, U z The wind speeds at different altitudes are represented by z; z represents the height of the ground wind speed profile; U G The representative wind speed of the weather station; z G Let U be the ground height at which the wind speed at the weather station is measured; from this formula, the wind speed U at different heights can be expressed. z Input into the CFD calculation software; The second step is to use CFD methods to simulate the wind environment of the physical terrain. The third step is to use CFD post-processing software to obtain the simulation results of wind speed and direction on the middle section of the road surface, and to obtain the experimental crosswind boundary conditions. The fourth step is to set the crosswind speed, crosswind deflection angle and actual working conditions based on the proportional relationship between the crosswind speed and crosswind deflection angle of the simulation test device and the actual working conditions. Setting the boundary conditions for the road surface thermal environment includes the following steps: The first step is to set up illuminance meters in an open area near the construction site and record the full spectrum of solar radiation intensity every hour. In actual working conditions, the full spectrum of light intensity is recorded from sunrise to the beginning of the simulated time period. The second step is to obtain the light intensity of each time period during the illumination time of the middle section of the road surface in the simulation test device based on the hourly full-spectrum light intensity recorded in the real working conditions and the ratio of the light intensity of the middle section of the road surface and the illumination time of the middle section of the road surface in the simulation test device to the real working conditions. The third step involves using a lighting control circuit to control the full-spectrum lamps to emit light according to the light intensity and duration of the middle section of the road surface, thus completing the heat storage before measuring the middle section of the road surface. 3) To begin the cross-flow ratio test, adjust the air supply volume of the upstream tunnel fan to regulate the wind speed at the upstream tunnel exit. The wind speed at the upstream tunnel exit is obtained from the upstream tunnel hot-wire anemometer. Adjust the air intake volume of the downstream tunnel fan to regulate the wind speed at the downstream tunnel entrance. The wind speed at the downstream tunnel entrance is obtained from the downstream tunnel hot-wire anemometer. When calculating the cross-flow ratio of traffic pollutants, collect sample gas from the top of the upstream tunnel using the funnel attached to the upstream tunnel concentration meter, and measure the upstream SF6 concentration C using the upstream tunnel SF6 concentration tester. up Sample gas was collected from the top of the downstream tunnel using a funnel-equipped downstream tunnel concentration meter, and the downstream SF6 concentration (C) was measured using a downstream tunnel SF6 concentration analyzer. down The formula for calculating the cross-flow ratio of traffic pollutants is as follows: λ=C down / C up , (λ<1).

[0016] The side length L of the simulation test device m All length dimensions L are based on actual working conditions. f The scale was reduced proportionally; the crosswind speed u of the simulated test device was measured. m Crosswind speed u under actual working conditions f The proportional relationship is u m / u f =(L m / L f ) 1 / 2 Crosswind deflection angle A of the simulated test device m Crosswind deflection angle A compared to actual working conditions f The proportional relationship is A m / A f =1; the mid-section road surface temperature T of the simulation test device m The mid-section road surface temperature T under actual working conditions f The proportional relationship is T m / T f =1; Lux, the light intensity of the road surface in the middle section of the simulation test device. mLux in real working conditions f The ratio of light intensity in the middle section of the road surface is Lux m / Lux f =(L m / L f ) 1 / 2 The ratio of the illumination time of the middle section of the road surface in the simulated test device to that in the actual working condition is t. m / t f =(L m / L f ) 1 / 2 The proportionality coefficient between the simulated test device's heat source power and the actual working condition's heat source power is Q. m / Q f =(L m / L f ) 5 / 2 .

[0017] When simulating smoke crossflow under fire conditions, ethanol in the combustion tray is ignited. The ignition power of the ethanol is set according to the ignition power of the simulation test device and the ignition power of the actual working conditions. Under different fire ventilation conditions, the fire smoke crossflow ratio is calculated by testing the SF6 concentration at the upstream tunnel outlet and the downstream tunnel entrance using the traffic pollutant crossflow ratio calculation formula.

[0018] The beneficial effects of this invention are: 1. Regarding the selection of the test gas for crosstalk ratio, this invention uses SF6 concentration as the basis for measuring the crosstalk ratio. SF6 concentration detection technology is relatively mature, and the sensor using NDIR (non-displacement infrared spectroscopy) to measure SF6 concentration is small in size, highly accurate, stable in operation, and provides reliable measurement results. In simulated fire conditions, SF6 does not participate in the combustion reaction, nor is it a product of the combustion reaction, making it suitable for measuring the crosstalk ratio under fire conditions.

[0019] 2. Regarding the wind environment of the canyon terrain, the CFD method was used to obtain the wind speed and direction of the middle section of the road. The experimental wind direction was adjusted by adjusting the opening angle of the louvers, and the experimental wind speed was adjusted by adjusting the air volume of the crosswind fan. This simulated the wind environment of the middle section of the road under the influence of real terrain. The crossflow using this method is more consistent with the field environment than the experiment, and the test results are more reliable.

[0020] 3. Regarding the thermal environment adjacent to the tunnel, the impact of the heat storage effect of the mid-section pavement on the crossflow ratio is considered for the first time. The thermal effect of the mid-section pavement can deflect the gas trajectory at the upstream tunnel exit. For the heat storage effect of the pavement, a scaled-down model experiment can obtain simulation results that more closely match real-world conditions. The heat storage effect of the pavement is affected by the periodic variations in solar radiation. A scaled-down model of the mid-section pavement is established by laying corresponding engineering materials in the surface layer, base layer, and subbase layer. A microcomputer-controlled full-spectrum lamp simulates the periodic solar radiation of the real environment to reproduce the heat storage effect of the pavement under actual working conditions. The pavement thermal environment obtained by this method is more consistent with the real-world environment compared to traditional experimental setups.

[0021] 4. In experimental applications, this device can simulate the cross-flow ratios of fire smoke and traffic pollutants under terrain wind conditions and road surface thermal conditions. Under fire conditions, ethanol in a combustion tray is used to provide a heat source and buoyancy for the smoke. Under traffic pollutant conditions, neither a combustion tray nor a heat source is required. SF6 is used as a tracer gas in both conditions, and its concentration is measured using an infrared spectroscopy sensor to calculate the cross-flow ratio. This experimental setup can obtain cross-flow ratios of pollutants from adjacent tunnels that more closely resemble actual field conditions, guiding tunnel design and ventilation equipment selection. Attached Figure Description

[0022] Figure 1 A schematic diagram of the overall structure of the simulation test device for the crossflow ratio of adjacent tunnels combined with boundary conditions; Figure 2 This is a schematic diagram of the upstream tunnel model; Figure 3 A schematic diagram of the structure of the middle section model; Figure 4 Schematic diagram of the downstream tunnel model; Figure 5 This is a schematic diagram of the crosswind simulation mechanism; Figure 6 This is a schematic diagram of the structure of a full-spectrum lamp.

[0023] In the diagram: 1-Upstream tunnel model; 2-Downstream tunnel model; 3-Support leg; 4-Upstream tunnel fan; 5-Upstream tunnel rectifier section; 6-Sulfur hexafluoride release device; 7-Combustion tray; 8-Full-spectrum lamp; 9-Lighting control circuit; 10-Upstream tunnel SF6 concentration tester; 11-Upstream tunnel concentration tester funnel; 12-Laser sheet light source; 13-Upstream tunnel hot-wire anemometer; 14-Louvre; 15-Crosswind rectifier section; 16-Crosswind static pressure box; 17-Crosswind fan; 18-Middle section surface layer; 19-Middle section base layer; 20-Middle section subbase layer; 21-Downstream tunnel SF6 concentration tester; 22-Downstream tunnel concentration tester funnel; 23-Downstream tunnel hot-wire anemometer; 24-Downstream tunnel fan; 25-Crosswind simulation mechanism. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings.

[0025] For longitudinally adjacent tunnels, when the distance L between the upstream tunnel exit and the downstream tunnel entrance is ≤250m, traffic pollutants and fire smoke can cross from the upstream tunnel to the downstream tunnel. Understanding the cross-flow ratio of pollutants between adjacent tunnels allows for the rational selection of ventilation and fire protection equipment for the downstream tunnel during the design phase, reducing equipment investment and fan operating costs. An accurate cross-flow ratio can also be used to calculate the required fresh air volume for diluting pollutants in the downstream tunnel, thereby minimizing safety hazards.

[0026] like Figure 1 , Figure 2 , Figure 4 , Figure 6 As shown, this invention provides a simulation test device for the crossflow ratio of adjacent tunnels combined with boundary conditions, including an upstream tunnel model 1, a downstream tunnel model 2, and an intermediate road surface section located between the upstream tunnel model 1 and the downstream tunnel model 2. Support legs 3 are provided at the bottom of the upstream tunnel model 1, the downstream tunnel model 2, and the intermediate road surface section. An upstream tunnel fan 4 mechanism is provided at the entrance of the upstream tunnel model 1. A sulfur hexafluoride (SF6) release device 6 is provided in the upstream tunnel model 1, with its outlet located at the upstream tunnel fan 4 mechanism. A [further details about the device are missing from the original text]. An upstream tunnel concentration meter funnel 11 and an upstream tunnel hot-wire anemometer 13 are provided. The upstream tunnel concentration meter funnel 11 is connected to an upstream tunnel SF6 concentration tester 10. A crosswind simulation mechanism 25 is provided on the side of the middle section of the road surface, and a full-spectrum lamp 8 is provided above the middle section of the road surface. A downstream tunnel concentration meter funnel 22 and a downstream tunnel hot-wire anemometer 23 are provided at the entrance of the downstream tunnel model 2. The downstream tunnel concentration meter funnel 22 is connected to a downstream tunnel SF6 concentration tester 21. A downstream tunnel fan 24 is provided at the exit of the downstream tunnel model 2.

[0027] The upstream tunnel model 1 uses an upstream tunnel fan 4 to provide longitudinal airflow. This longitudinal airflow mixes with the detection gas from the sulfur hexafluoride (SF6) release device 6 in the initial section of the upstream tunnel model 1, is rectified by the upstream tunnel rectifier section 5, and finally exits from the outlet of the upstream tunnel model 1. This invention uses the SF6 release device 6 to provide the concentration detection gas for calculating the crossflow ratio. A test hole is located at the top of the outlet of the upstream tunnel model 1, allowing the upstream tunnel concentration meter's funnel 11 to collect sample gas and measure the SF6 concentration in the upstream tunnel. At the top of the downstream tunnel entrance, a downstream tunnel concentration meter's funnel 22 collects sample gas and measures the SF6 concentration in the downstream tunnel. At the tunnel end, a downstream tunnel fan 24 (axial flow fan) extracts the gas, providing longitudinal ventilation within the downstream tunnel. The crossflow ratio can be calculated based on the ratio of the SF6 concentration in the downstream tunnel to that in the upstream tunnel.

[0028] The upstream tunnel fan 4 provides the upstream tunnel air velocity, and an upstream tunnel hot-wire anemometer 13 is installed at the upstream tunnel outlet to obtain the upstream tunnel air velocity. The downstream tunnel fan 24 provides the downstream tunnel air velocity, and a downstream tunnel hot-wire anemometer 23 is installed at the downstream tunnel inlet to obtain the downstream tunnel air velocity. The ratio of the air velocity at the upstream tunnel outlet to that at the downstream tunnel inlet significantly affects the pollutant crossflow ratio. By changing the rotational speeds of the upstream and downstream tunnel fans 24, different operating conditions with varying upstream and downstream tunnel air velocity ratios can be obtained.

[0029] like Figure 3 As shown, the intermediate road surface includes, from bottom to top, an intermediate road subbase 20, an intermediate road base layer 19, and an intermediate road surface layer 18. These three layers of the intermediate road surface simulate the structure of a real highway, thus its heat storage function is similar to that of a real highway. The full-spectrum lamps 8 are controlled by the lighting control circuit 9 to simulate the periodic solar radiation in real working conditions.

[0030] Multiple crosswind simulation mechanisms 25 are installed side-by-side on the sides of the middle section of the road. For example... Figure 5 As shown, the crosswind simulation mechanism 25 includes a crosswind fan 17, a crosswind static pressure box 16, a crosswind straightening section 15, and a louver 14 arranged sequentially from back to front. The louver 14 is located near the middle section of the road surface.

[0031] The crosswind fan 17 provides airflow according to the set requirements. The axial airflow from the crosswind fan 17 enters the crosswind static pressure box 16, increasing the static pressure and uniformizing the airflow energy. Then, it passes through the crosswind rectifier section 15 to further reduce turbulence, and finally, it blows out through the louvers 14 at the set louver angle, thus simulating the crosswind direction and speed. Before simulating the crosswind, the experimenter conducted CFD simulation analysis based on the local terrain model and meteorological parameters under the experimental conditions to obtain the wind speed and direction in the middle section of the adjacent tunnel. Based on the simulation calculation results, the experimenter set the opening angle of the louvers 14 and the airflow of the crosswind fan 17 to obtain results similar to the wind speed and direction under real terrain.

[0032] See Figure 2 The upstream tunnel ventilation fan 4 mechanism includes the upstream tunnel ventilation fan 4 and the upstream tunnel rectifier section 5 located in front of the upstream tunnel ventilation fan 4. The outlet of the sulfur hexafluoride release device 6 is located between the upstream tunnel ventilation fan 4 and the upstream tunnel rectifier section 5.

[0033] See Figure 1 A combustion tray 7 is installed above the middle section of the bottom surface of the upstream tunnel model 1. A laser sheet light source 12 is installed on the top surface of the exit of the upstream tunnel model 1, and the laser sheet light source 12 is located directly above the central axis of the upstream tunnel model 1. When simulating a fire, ethanol is ignited in the combustion tray 7 and the laser sheet light source 12 is turned on, allowing for direct observation of the thickness of the fire smoke layer and the flow of smoke plumes.

[0034] This invention also relates to a method for simulating and testing the crossflow ratio of adjacent tunnels in conjunction with boundary conditions, comprising the following steps: 1) Based on the size ratio between the simulation test device and the actual working conditions, and in accordance with the similarity criterion of the Fernold number, the ratio of the crosswind speed, crosswind deflection angle, mid-section road surface temperature, mid-section road surface light intensity, and fire source power of the simulation test device to the actual working conditions is obtained.

[0035] Numerical simulation and scaled-down model experiments have become important methods for studying crossflow ratios. However, the boundary conditions in numerical simulations often deviate from actual operating conditions, thus the persuasiveness of simulation results is usually lower than that of scaled-down model experiments. In the model experiment of crossflow in adjacent tunnels, the airflow at the upstream tunnel exit is subjected to the combined effects of inertial forces and road surface heating in the middle section, and under the influence of crosswinds, exhibits complex turbulence. This flow state is typically in the turbulent "self-model region," where the flow field properties are less affected by the Reynolds number. Under this complex turbulence, the Fr number becomes the main characteristic criterion number affecting the fluid flow state. Therefore, this experimental platform is designed using Fr number similarity. When building the experimental platform model, the scale relationship between the simulation test device and the actual operating conditions was set according to Table 1.

[0036] Table 1. Ratio between Simulated Test Device and Real Working Conditions name proportional relationship Geometric dimensions <![CDATA[x m / x f =L m / L f ]]> Crosswind speed <![CDATA[u m / and f =(L m / L f ) 1 / 2 ]]> Crosswind deflection angle <![CDATA[A m / A f =1]]> mid-section road surface temperature <![CDATA[T m / T f =1]]> Light intensity of the middle section of the road surface <![CDATA[Lux m / Luxury f =(L m / IT f ) 1 / 2 ]]> Sunlight duration of the middle section of the road <![CDATA[t m / t f =(L m / L f ) 1 / 2 ]]> Fire source power (fire conditions) <![CDATA[Q m / Q f =(L m / L f ) 5 / 2 ]]> In Table 1, L m The length L of the simulation test device. f This refers to the actual length of the upstream and downstream tunnels under actual working conditions. Geometrically, all sides of the simulation test device are proportionally scaled down to the actual tunnel dimensions. The simulation test device x... m Full-size x of upstream and downstream tunnels f The proportional relationship is x m / x f =L m / L f .

[0037] The motion characteristics of the simulation test device and the tunnel are similar using the Fr number, that is: ; To maintain equal Fr numbers, the crosswind speed u of the simulation test device is... m Crosswind speed u under actual working conditions f The proportional relationship is u m / u f =(L m / L f ) 1 / 2 The simulation test device maintains the same crosswind deflection angle as the tunnel, i.e., A. m / A f =1.

[0038] After considering the heat storage and heating effects of the middle section of the road surface, the corrected Fr number is: ; To maintain the corrected Fr number, the road surface temperature T in the middle section of the simulation test device is... m The mid-section road surface temperature T under actual working conditions f Maintain the same temperature, i.e., T m / T f =1.

[0039] The ratio of the side length of the simulation test device to the full-size side length of the upstream and downstream tunnels is x. m / x f =L m / L f Therefore, the area ratio is S. m / S f =(L m / L f ) 2 To maintain a constant road surface temperature, the ratio of light intensity (heating flux) is Lux. m / Lux f =(L m / Lf ) 1 / 2 The ratio of the illumination time of the middle section of the road surface in the simulation test device to the illumination time of the middle section of the road surface in the actual working condition is t. m / t f =(L m / L f ) 1 / 2 .

[0040] In the Vernord similarity experiment, the method for setting the fire source power has been sufficiently verified in numerous documents. The proportionality coefficient between the fire source power of the simulated test device and the fire source power under actual operating conditions is Q. m / Q f =(L m / L f ) 5 / 2 .

[0041] Current scaled-down model test benches for adjacent tunnels generally do not consider the influence of topographic wind environment boundary conditions and road surface thermal environment boundary conditions on pollutant cross-flow. The boundary conditions in existing experiments deviate from real-world conditions, reducing the accuracy of experimental tests. This invention improves the reliability of experimental results by incorporating boundary conditions that more closely resemble real-world conditions.

[0042] 2) Set boundary conditions for terrain and wind environment and road surface thermal environment; Setting terrain and wind environment boundary conditions includes the following steps: The first step is to download the DEM topographic map of the project site from the website (30m resolution is publicly available data; data with resolutions lower than 6m can be purchased from e-commerce platforms such as Taobao). Then, use GIS software to convert the DEM data into a .stl solid model. Next, download the meteorological parameters for the project site (local weather station data can be purchased from e-commerce platforms such as Taobao). Based on the wind rose diagram, determine the most frequent wind speed and direction during the simulation period, using these as representative wind speeds and directions. The wind speed is expressed as an exponential profile across the canyon and mountains, with the following expression:

[0043] In the formula, U z U represents wind speed at different altitudes; z represents the altitude of the ground wind speed profile (z is a variable, up to a maximum of 750m); G The representative wind speed of the weather station; z G Let U be the ground height (usually 10m) for the wind speed at the weather station; from this formula, the wind speed U at different heights can be expressed. z Input into the CFD calculation software; The second step is to use CFD methods to simulate the wind environment of the physical terrain. The third step is to use CFD post-processing software to obtain the simulation results of wind speed and direction on the middle section of the road surface, and to obtain the experimental crosswind boundary conditions. In the fourth step, according to the proportional relationship between the crosswind speed, crosswind deflection angle of the simulation test device and the real working condition, set the air supply volume of the crosswind fan 17 and the opening angle of the louver 14.

[0044] To set the boundary conditions of the road surface thermal environment, the following steps are included: In the first step, arrange illuminometers in the open area near the engineering site, and record the full-spectrum light intensity of solar radiation every hour. In the real working condition, record the full-spectrum light intensity starting from sunrise until before the simulation time period. In the second step, based on the hourly full-spectrum light intensity recorded in the real working condition and the proportional relationship between the light intensity and light time of the middle section of the road surface of the simulation test device and the real working condition, obtain the light intensity of each time period within the light time of the middle section of the road surface of the simulation test device. In the third step, use the lighting control circuit to control the full-spectrum lamp to emit light according to the light intensity and light time of the middle section of the road surface to complete the heat storage before the measurement of the middle section of the road surface.

[0045] 3) Start the test experiment of the cross-flow ratio. Adjust the air supply volume of the upstream tunnel fan 4 to adjust the wind speed at the upstream tunnel outlet, and the wind speed value at the upstream tunnel outlet is obtained by the hot-wire anemometer 13 in the upstream tunnel; adjust the air suction volume of the downstream tunnel fan 24 to adjust the wind speed at the downstream tunnel inlet, and the wind speed value at the downstream tunnel inlet is obtained by the hot-wire anemometer 23 in the downstream tunnel; when calculating the cross-flow ratio of traffic pollutants, collect the sample gas at the top of the upstream tunnel through the funnel 11 supporting the upstream tunnel concentration meter, and measure the upstream SF6 concentration C up ; collect the sample gas at the top of the downstream tunnel through the funnel 22 supporting the downstream tunnel concentration meter, and measure the downstream SF6 concentration C down ; the calculation formula for the cross-flow ratio of traffic pollutants is as follows: λ = C down / C up , (λ < 1).

[0046] The side lengths L of the simulation test device m are all reduced in proportion according to the length dimensions L of the real working condition f ; the proportional relationship between the crosswind speed u of the simulation test device m and the crosswind speed u of the real working condition f is u m / u f = (L m / L f ) 1 / 2 ; the proportional relationship between the crosswind deflection angle A of the simulation test device m and the crosswind deflection angle A of the real working condition f is Am / A f =1; the mid-section road surface temperature T of the simulation test device m The mid-section road surface temperature T under actual working conditions f The proportional relationship is T m / T f =1; Lux, the light intensity of the road surface in the middle section of the simulation test device. m Lux in real working conditions f The ratio of light intensity in the middle section of the road surface is Lux m / Lux f =(L m / L f ) 1 / 2 The ratio of the illumination time of the middle section of the road surface in the simulation test device to the illumination time of the middle section of the road surface in the actual working condition is t. m / t f =(L m / L f ) 1 / 2 The proportionality coefficient between the simulated test device's heat source power and the actual working condition's heat source power is Q. m / Q f =(L m / L f ) 5 / 2 .

[0047] When simulating smoke crossflow under fire conditions, ethanol in the combustion tray 7 is ignited. The ignition power of the burning ethanol is set according to the ignition power of the simulation test device and the ignition power of the actual working conditions. Under different fire ventilation conditions, the fire smoke crossflow ratio is calculated by testing the SF6 concentration at the upstream tunnel outlet and the downstream tunnel entrance, using the traffic pollutant crossflow ratio calculation formula.

[0048] In the analysis of smoke crossflow during a fire, vehicles are typically stationary, and the airflow within the tunnel is primarily generated by the tunnel ventilation fan. Under real-world conditions, the smoke exhaust velocity is designed by the tunnel architect based on the smoke extraction plan. Based on the similarity of the Fröder number, the smoke exhaust velocity u in the simulated test device tunnel is... m The exhaust velocity u under actual working conditions f The proportional relationship is u m / u f =(L m / L f ) 1 / 2Based on the designed smoke extraction scheme and the ratio between the smoke extraction velocity in the simulated test tunnel and the actual smoke extraction velocity under real-world conditions, the smoke extraction velocity in the simulated test tunnel is obtained. The air supply volume of the upstream tunnel fan 4 is adjusted to ensure that the air velocity in the upstream tunnel model 1 reaches the smoke extraction velocity. Typically, in a fire environment, the average air velocity at the downstream tunnel entrance is lower than the average air velocity at the upstream tunnel exit, and the operating strategies of the downstream tunnel fan 24 and the upstream tunnel fan 4 are inconsistent. Changing the ratio of the air velocity at the upstream tunnel entrance to the downstream tunnel exit is an important method for developing a reasonable smoke extraction scheme for adjacent tunnels. This experimental setup can adjust the downstream tunnel entrance air velocity by changing the air intake of the downstream tunnel fan 24, thereby changing the ratio of the downstream tunnel entrance air velocity to the upstream tunnel exit air velocity. Therefore, this experimental setup can verify the reasonable smoke extraction scheme for adjacent tunnels through experimental measurement.

[0049] When it is necessary to observe the trajectory of the smoke plume in a fire, a laser sheet light source 12 is used in conjunction with a smoke generator (usually mugwort), and the full-spectrum lamp 8 is turned off to facilitate observation of the smoke plume trajectory under the laser.

[0050] This invention uses sulfur hexafluoride (SF6) concentration as the basis for quantitative calculation of cross-flow ratio. It can be used for cross-flow analysis of traffic pollutants and high-temperature fire smoke. Combined with topographic wind environment boundary conditions and road surface thermal environment boundary conditions, it can obtain a more accurate cross-flow ratio of pollutants in adjacent tunnels, providing more reliable experimental data for the design of adjacent tunnels and the selection of ventilation and fire protection equipment.

[0051] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A simulation test device for the crossflow ratio of adjacent tunnels combined with boundary conditions, comprising an upstream tunnel model, a downstream tunnel model, and an intermediate road surface section located between the upstream tunnel model and the downstream tunnel model, wherein the bottom of the upstream tunnel model, the downstream tunnel model, and the intermediate road surface section are all provided with support legs, characterized in that: The upstream tunnel model is provided with an upstream tunnel fan mechanism at the inlet thereof, and is provided with a sulfur hexafluoride release device, an outlet of which is arranged at the upstream tunnel fan mechanism, and is provided with an upstream tunnel concentration instrument matched funnel and an upstream tunnel hot ball wind speed instrument at the outlet thereof, and the upstream tunnel concentration instrument matched funnel is connected with an upstream tunnel SF6 concentration tester.

2. The test apparatus for simulating the cross-flow between adjacent tunnels with boundary conditions according to claim 1, wherein: The intermediate section road surface is provided with a plurality of crosswind simulation mechanisms side by side on the side thereof.

3. The test apparatus for simulating the cross-flow between adjacent tunnels with boundary conditions according to claim 2, wherein: The crosswind simulation mechanism comprises, from back to front, a crosswind fan, a crosswind static pressure tank, a crosswind rectification section and a louver, and the louver is adjacent to the intermediate section road surface.

4. The test apparatus for simulating adjacent tunneling of claim 3, wherein: The upstream tunnel fan mechanism comprises an upstream tunnel fan and an upstream tunnel rectification section arranged on the front side of the upstream tunnel fan, and the outlet of the sulfur hexafluoride release device is arranged between the upstream tunnel fan and the upstream tunnel rectification section.

5. The test apparatus for simulating the cross-flow between adjacent tunnels with boundary conditions according to claim 4, wherein: The bottom surface of the upstream tunnel model is provided with a combustion tray above the middle section thereof.

6. The test apparatus for simulating adjacent tunneling of claim 5, wherein: The top surface of the outlet of the upstream tunnel model is provided with a laser sheet light source, which is located directly above the central axis of the upstream tunnel model.

7. The test apparatus for simulating the cross-flow between adjacent tunnels with boundary conditions according to claim 6, wherein: The adjacent tunnel cross-flow ratio simulation test method with the boundary condition adopts the adjacent tunnel cross-flow ratio simulation test device with the boundary condition of claim 7; 8. A method for testing a neighboring tunnel flow cross comparison simulation combined with boundary conditions, characterized in that: The adjacent tunnel cross-flow ratio simulation test method with the boundary condition comprises the following steps: 1) According to the size ratio relationship between the simulation test device and the real working condition, the crosswind speed, the crosswind deflection angle, the middle section road surface temperature, the middle section road surface light intensity and the fire source power of the simulation test device are obtained according to the Froude number similarity criterion, and the ratio relationship with the real working condition is obtained; 2) Set the terrain wind environment boundary condition and the road surface thermal environment boundary condition; Setting the terrain wind environment boundary condition comprises the following steps: Firstly, download the DEM topographic map of the engineering site on the website, and convert the DEM data into a.stl solid model through gis software; download the meteorological parameters of the engineering site, determine the highest frequency wind speed and wind direction in the simulation time period according to the wind rose diagram, and take the representative wind speed and wind direction; the wind speed blows through the canyon mountain in the form of an exponential profile, and the expression is: Secondly, simulate the solid terrain wind environment by using the CFD method; In the formula, U z The wind speeds at different altitudes are represented by z; z represents the height of the ground wind speed profile; U G The representative wind speed of the weather station; z G Let U be the ground height at which the wind speed at the weather station is measured; from this formula, the wind speed U at different heights can be expressed. z Input into the CFD calculation software; Thirdly, obtain the simulation results of the middle section road surface wind speed and wind direction by using the CFD post-processing software, and obtain the experimental crosswind boundary condition; Fourthly, complete the setting of the crosswind fan air supply amount and the louver opening angle according to the ratio relationship between the crosswind speed and the crosswind deflection angle of the simulation test device and the real working condition; Setting the road surface thermal environment boundary condition comprises the following steps: ​ First, arranging the illuminometer in the open area near the engineering site, recording the full-spectrum light intensity of solar radiation every hour, in the real working condition, recording the full-spectrum light intensity from sunrise, and recording to the simulation time period; Second, according to the hourly full-spectrum light intensity recorded in the real working condition, the middle section road surface light intensity of the simulation test device, the proportional relationship between the middle section road surface light time and the real working condition, the light intensity of each time period in the middle section road surface light time of the simulation test device is obtained; Third, the light control circuit is used to control the full-spectrum lamp to emit light according to the middle section road surface light intensity and light time, and the heat accumulation before the middle section road surface measurement is completed; 3) Start the test experiment of the channeling ratio, adjust the air supply amount of the upstream tunnel fan to adjust the outlet wind speed of the upstream tunnel, and the outlet wind speed value of the upstream tunnel is obtained by the upstream tunnel hot ball anemometer; Adjust the air suction amount of the downstream tunnel fan to adjust the inlet wind speed of the downstream tunnel, and the inlet wind speed value of the downstream tunnel is obtained by the downstream tunnel hot ball anemometer; When calculating the traffic pollutant cross-flow ratio, collect the sample gas at the top of the upstream tunnel through the funnel matched with the upstream tunnel concentration instrument, and measure the upstream SF6 concentration C up using the upstream tunnel SF6 concentration tester. down Collect the sample gas at the top of the downstream tunnel through the funnel matched with the downstream tunnel concentration instrument, and measure the downstream SF6 concentration C down using the downstream tunnel SF6 concentration tester. The traffic pollutant cross-flow ratio calculation formula is as follows: λ = C down / C up , (λ < 1).

9. The test apparatus for simulating the cross-flow between adjacent tunnels with boundary conditions according to claim 8, wherein: The length L of each side of the simulation test device m The length L of each side of the simulation test device f is reduced in proportion. Crosswind speed u of the simulation test device m Crosswind speed u under actual working conditions f The proportional relationship is u m / u f =(L m / L f ) 1 / 2 Crosswind deflection angle A of the simulated test device m Crosswind deflection angle A compared to actual working conditions f The proportional relationship is A m / A f =1; the mid-section road surface temperature T of the simulation test device m The mid-section road surface temperature T under actual working conditions f The proportional relationship is T m / T f =1; Lux, the light intensity of the road surface in the middle section of the simulation test device. m Lux in real-world working conditions f The ratio of light intensity in the middle section of the road surface is Lux m / Lux f =(L m / L f ) 1 / 2 The ratio of the illumination time of the middle section of the road surface in the simulated test device to that in the actual working condition is t. m / t f =(L m / L f ) 1 / 2 The proportionality coefficient between the simulated test device's heat source power and the actual working condition's heat source power is Q. m / Q f =(L m / L f ) 5 / 2 .

10. The test apparatus for simulating the cross-flow between adjacent tunnels with boundary conditions according to claim 8, wherein: When the smoke channeling occurs under the simulation fire condition, ignite the ethanol in the combustion tray, set the fire power of the burning ethanol according to the fire power of the simulation test device and the fire power of the real working condition, and calculate the fire smoke channeling ratio by testing the SF6 concentration of the upstream tunnel outlet and the downstream tunnel inlet under different fire ventilation conditions using the traffic pollutant channeling ratio calculation formula.

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