Experimental Study of Air Curtain Smoke Confinement and Vehicle Obstruction Effects in a Modular Scaled Tunnel Model

Investigation on the restrain effect of air curtain to the spilled flame and its heat flux of a compartment-facade fire

ABSTRACTThe complexity of urban tunnel structure increases the risk of tunnel fire, and the air curtain system plays an important role in controlling the spread of fire smoke and ensuring the safety of personnel. Based on theoretical analysis and tunnel model experiments, the isolation effect of different air curtain jet conditions on high‐temperature fire smoke in bifurcated tunnel was studied. The results show that the air curtain system can effectively isolate the high‐temperature smoke. For different firepower, compared to angle and thickness, wind speed has the best control effect on high‐temperature smoke. The control effect of air curtain thickness takes second place. The effect of angle change is the least obvious. Meanwhile, based on the analysis of experimental results, it was found that when the air curtain parameters are selected as wind speed of 2.5 m/s, angle of 15°, and thickness of 0.16 m, the air curtain system has better smoke prevention efficiency. Finally, dimensionless analysis yielded a power law equation relating upstream temperature rise, firepower, and wind speed. This supports theoretically analyzing the air curtain's smoke prevention effect.

In order to suppress the irregular diffusion of dust in the unloading process of grab ship unloaders, an air curtain soft-sealing system was designed that can effectively block the air flow and restrict the diffusion of pollutants and reduce the average mass fraction of pollutants outside the air curtain plane by 70.02%. The grab unloading model was constructed using the Computational Fluid Dynamics–Discrete Element Method (CFD-DEM) coupling method, and the diffusion law of the gas–solid two-phase flow field of the falling bulk material was studied. Moreover, the motion trajectory and velocity distribution of the particle flow field and air flow field were obtained, as well as the maximum air flow field velocity of five planes above the hopper. The three-dimensional model of the air curtain jet was used and simplified, and the air curtain parameters were set based on the maximum air flow field velocity. The barrier performance of the air curtain under different air curtain jet modes, jet widths, jet velocities and induced wind velocities was simulated by the control variable method. The results show that selecting the appropriate jet widths and jet velocities can significantly reduce dust diffusion; under different jet modes, the order of influence was blow and suction, unilateral blowing and bilateral blowing; under a certain range of induced wind velocities, the air curtain had an obvious blocking effect. These results can provide a reference for the design and improvement of dust suppression of the air curtain soft-sealing system.

Improvement of heat and smoke confinement using air curtains in informal shopping malls

Numerical study of the effect of air curtains on smoke blocking and leakage heat flux in tunnel fires

Wind effects on air curtain performance at building entrances

Air curtain in informal shopping malls: Optimization of the air curtain operating parameters for heat and smoke confinement

Numerical investigation of air curtain jet effect on the upper layer temperature evolution of a compartment fire and its transition

Experimental investigation on Influencing Factors of air curtain systems barrier efficiency for mine refuge chamber

Dust distribution and control in a coal roadway driven by an air curtain system: A numerical study

Numerical Simulation of Environmental Control for Relics Preservation in the Funerary Pit by Air Curtain System

Air curtain dust-collecting technology: An experimental study on the performance of a large-scale dust-collecting system

Based on the characteristics of tunnel fires, numerical simulations using the Fire Dynamics Simulator (FDS) were conducted to explore the distribution characteristics of temperature, visibility, and carbon monoxide (CO) concentration, as well as smoke control effectiveness, by combining natural smoke extraction through shafts with smoke control via air curtains.The influence of air curtain jet velocity and angle and the distance between the air curtain and the shaft on these parameters was investigated.Results indicate that the natural smoke extraction of shafts and smoke control via air curtains work synergistically.However, the smoke control efficiency of the air curtain decreases as the distance between the air curtain and the shaft decreases, while the smoke extraction efficiency of the shaft follows an opposite trend.The smoke control efficiency of the air curtain was found to improve by 96.5% compared to conditions without a shaft.When the fire power was set at 12 kW, optimal angles for smoke control and extraction were identified as 30, 20, and 0 for air curtain jet velocities of 6 m/s, 8 m/s, and 10 m/s, respectively.In comparison to conditions without an air curtain, the shaft extraction efficiency increased by 140%.The temperature under the tunnel ceiling within the shaft distance increased with the air curtain jet velocity, while the temperature distribution in the areas outside the shaft distance exhibited the opposite trend.At eye level within the tunnel space, temperature and CO concentration increased with the air curtain jet velocity.Visibility in the smoke control area improved with increasing air curtain jet velocity, while visibility in the evacuation area showed an opposite trend.The temperature in the tunnel evacuation area stabilized below 60, with visibility remaining above 10 m and CO concentration below 50 ppm, thereby meeting the escape requirements for personnel.These findings further validate the feasibility of the combined air curtain and shaft smoke extraction model, providing a foundation for the design of smoke control systems in complex tunnel fire scenarios.

Air curtain dust-collecting technology: Investigation of industrial application in tobacco factory of the air curtain dust-collecting system

The vertical emergency staircase of a deep-buried subway station has many problems such as long distance, difficulty in getting out of the ground, and expensive costs, which makes against for people to escape a fire. In the paper, taking the Chongqing Railway Line 10 Red Land Station as a model, a new smoke control strategy by eliminating the vertical emergency staircase and installing an air curtain over the long entrance corridor has been proposed. The Fire Dynamics Simulator (FDS) was used to investigate the air curtain parameters and to model a scenario where people use an air curtain passageway to escape. The Pathfinder software was used to simulate the movement of the flow of people. The results show that the air curtain can be used in long entrances and exits of metro stations without intermediate vertical evacuation staircases. When the distance between the air curtain and fire source is 1m, the best combination for blocking the smoke is as follows: air curtain jet speed of 15m/s, jet angle of 15°, and two air curtains interval of 12 m. While the distance between the air curtain and fire source is 4 m, and the best and most economical condition is the jet speed of 11 m/s, jet angle of 15°, and two air curtains with an interval of 12 m. This project could provide theoretical support for the extension of air curtain application to metro inter-district tunnels.