Effects of the solid curtains on natural ventilation performance in a subway tunnel

Huang, Yuandong; Gong, Xiao-lu; Peng, Yue-jiao; Kim, Chang-Nyung

doi:10.1016/j.tust.2013.08.009

Cited by 18 publications

(8 citation statements)

References 8 publications

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“…Xue et al [14] analysed the effect that the location of draft relief shafts and louvres had upon ventilation through numerical analysis and experimental measurements in an operational railway. Huang et al [15] used the model presented by Kim and Kim [8] to investigate the use of solid curtains at extreme ends of a tunnel in improving ventilation 55 performance. It was found that such devices could improve ventilation rates significantly but practical problems would make implementation difficult.…”

Section: Previous Workmentioning

confidence: 99%

“…This creates a high pressure region at the train front whilst at the back of the train a low pressure region is formed, along with the creation of a wake, which acts to suck air from behind the train. The pressure difference between the front and back induces air flow down 15 the side of the train.…”

Section: Introductionmentioning

confidence: 99%

“…The k −ǫ RNG model is utilised in this work due to it's suitability on the investigation of train induced air flows, in which it was found to perform well [14,15]. Near wall flows were modelled using the standard wall function, a wall function approach.…”

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confidence: 99%

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A validated numerical investigation of the effects of high blockage ratio and train and tunnel length upon underground railway aerodynamics

Cross

Hughes

Ingham

et al. 2015

Journal of Wind Engineering and Industrial Aerodynamics

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In order to ensure the safety and comfort of passengers and staff, an underground railway requires an extensive ventilation and cooling system. One mechanism for underground railway ventilation is the movement of air induced by trains, termed the 'piston effect'. This study investigated the effect of altering the blockage ratio of an underground train upon the ventilating air flows driven by a train. First a computational model was developed and validated with experimental data from literature. This model was scaled to represent an operational underground railway with high blockage ratio and the blockage ratio varied to evaluate the effects upon ventilation. The results of this study show that ventilating air flows can be increased significantly during periods of constant train motion and acceleration, by factors of 1.4 and 2 respectively, but that the train drag will increase at the same rate. During deceleration negligible increases in ventilation flows are found but drag increases by a factor of 4.

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Section: Previous Workmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A validated numerical investigation of the effects of high blockage ratio and train and tunnel length upon underground railway aerodynamics

Cross

Hughes

Ingham

et al. 2015

Journal of Wind Engineering and Industrial Aerodynamics

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show abstract

“…The k-RNG turbulence model is used in this work as it has been used previously for the investigation of train induced air flows where it performed well (Xue et al, 2014;Huang et al, 2013). Near wall modelling used the standard wall function, a wall function approach, to reduce the computational time in the transient calculations.…”

Section: Numerical Conditionsmentioning

confidence: 99%

Enhancing the piston effect in underground railway tunnels

Cross

Hughes

Ingham

et al. 2017

Tunnelling and Underground Space Technology

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a b s t r a c tThe air flows induced by train movement in tunnels can be used for the purposes of underground railway ventilation. The magnitude of such air flows depends strongly upon the blockage ratio (the ratio of the train and tunnel cross-sectional areas) of the train. This study investigates the impact on the generated air flows due to the alteration of the aerodynamic resistance of the train, as a means of varying the blockage ratio. The alteration in aerodynamic resistance was achieved by using an aerofoil at a variety of different angles of inclination. A two-dimensional computational fluid dynamics model of a train travelling through a tunnel was developed and validated using experimental data from literature. This model was then used to investigate the influence of an aerofoil upon the volume of displaced air and the effect upon the aerodynamic work done by the train (work done by the train due to air drag). The results of this study show that ventilating air flows can be increased by 3% using an aerofoil at a fixed angle of 10°without increasing aerodynamic work. Through using a combination of different angles during different phases of train motion, a maximum increase in air displacement of 8% can be achieved, while not increasing the aerodynamic work done by the train. This equates to the train generated air displacement delivering an extra 1:6 m 3 s À1 of air supply during the period of train motion.

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“…In the case of fire, the transportation of smoke along the tunnel is altered by its slope, length, traffic, etc., and the obstruction of the ventilation ports increase a different variable in the analysis of physical scenario apart from external weather conditions [17][18][19][20][21][22][23][24][25]. The complexity of the situation creates the need not only for the creation of general but for particular emergency response procedures [26].…”

Section: Introductionmentioning

confidence: 99%

CFD Simulation of Obstructed Ventilation Ports in a Subway Tunnel Section

Herrera¹,

Pineda²,

Silva-Rivera

et al. 2017

Int. j. simul. model.

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A CFD simulation of the air velocity in a subway tunnel section of 1400 m in length is presented. In this case of study; the simulation compares the air velocity changes when two of six natural ventilation ports are totally obstructed. They are required for hot air exhaust, smoke release and fresh air intake. The mechanical ventilation system is located inside the tunnel at 650 m from the end of a passenger platform and 750 m from the other, it is a non-symmetrical scenario. The simulation was carried in ANSYS® Fluent compared with NFPA calculation and considering geometries and dimensions of an actual subway section of the Mexico City. Four different numerical models were created to analyse eight different cases. The results indicate that the obstruction of the ports create a non-homogeneous distribution of the flow velocity inside the passenger platform with an approximate difference of 1.5 m/s. This value is very important in cases when the backlayering effect has to be avoided as in the case of smoke transportation, exhaust of smoke and the transport of dust or some other contaminant. The emergency procedures and the design of escape routes can be improved by considering the physical changes occurring when the ventilation ports are obstructed. Since the atmospheric pressure influence the direction and velocity of the flow coming from the non-obstructed vents.

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Effects of the solid curtains on natural ventilation performance in a subway tunnel

Cited by 18 publications

References 8 publications

A validated numerical investigation of the effects of high blockage ratio and train and tunnel length upon underground railway aerodynamics

A validated numerical investigation of the effects of high blockage ratio and train and tunnel length upon underground railway aerodynamics

Enhancing the piston effect in underground railway tunnels

CFD Simulation of Obstructed Ventilation Ports in a Subway Tunnel Section

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