A Numerical Study of the Train-Induced Unsteady Airflow in a Subway Tunnel with Natural Ventilation Ducts Using the Dynamic Layering Method

Huang, Yuandong; Gao, Wei; Kim, Chang-Nyung

doi:10.1016/s1001-6058(09)60042-1

Cited by 70 publications

(18 citation statements)

References 10 publications

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“…In tunnels, number, geometrical structure, linkage angle, and location of vent shafts and train frequencies directly affect the performance of piston winds [241,[259][260][261][262][263]. Additionally, barriers placed at tunnel outlets [264] and partitioning blocks installed along the middle of the tunnels [265] can improve ventilation performance.…”

Section: Complex Airflowsmentioning

confidence: 99%

Environmental and Health Effects of Ventilation in Subway Stations: A Literature Review

Wen

Leng

Shen

et al. 2020

IJERPH

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Environmental health in subway stations, a typical type of urban underground space, is becoming increasingly important. Ventilation is the principal measure for optimizing the complex physical environment in a subway station. This paper narratively reviews the environmental and health effects of subway ventilation and discusses the relevant engineering, environmental, and medical aspects in combination. Ventilation exerts a notable dual effect on environmental health in a subway station. On the one hand, ventilation controls temperature, humidity, and indoor air quality to ensure human comfort and health. On the other hand, ventilation also carries the potential risks of spreading air pollutants or fire smoke through the complex wind environment as well as produces continuous noise. Assessment and management of health risks associated with subway ventilation is essential to attain a healthy subway environment. This, however, requires exposure, threshold data, and thereby necessitates more research into long-term effects, and toxicity as well as epidemiological studies. Additionally, more research is needed to further examine the design and maintenance of ventilation systems. An understanding of the pathogenic mechanisms and aerodynamic characteristics of various pollutants can help formulate ventilation strategies to reduce pollutant concentrations. Moreover, current comprehensive underground space development affords a possibility for creating flexible spaces that optimize ventilation efficiency, acoustic comfort, and space perception.

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Section: Complex Airflowsmentioning

confidence: 99%

Environmental and Health Effects of Ventilation in Subway Stations: A Literature Review

Wen

Leng

Shen

et al. 2020

IJERPH

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“…The train movement was simulated using the dynamic layering option in the dynamic meshing component of Ansys Fluent, following the approach used by Huang et al (2010). The movement of the train is achieved by the near field region moving forward at the specified train speed, defined by a user defined function (UDF), with layers of cells added to the far field region behind the near field region and removed from the region in front of the near field region.…”

Section: Mesh Generationmentioning

confidence: 99%

“…In this work the PISO pressure-velocity coupling method is adopted to solve the governing equations, the QUICK interpolation scheme is used for the discretisation of the convection terms and the PRESTO scheme to treat the pressure interpolation. This approach was used by Huang et al (2010). The continuity, momentum, k and residual equations were monitored as the convergence criteria and set as 1 Â 10 À5 .…”

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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“…The moving zone slides over stationary zone at a defined velocity. Yang et al [13], Khayrullina et al [14] and Chen et al [15] applied the sliding mesh technique, while Huang et al [16], Liu et al [17], Zhang et al [18] and Izadi et al [19] applied the dynamic mesh technique. In this technique, the shape of the domain is changing with time due to the domain moving boundaries.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the effects of different parameters on the generated pressure waves inside the tunnels

et al. 2020

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In this research the train movement along the tunnel was simulated numerically, and the time evolution of the flow field in the tunnel was evaluated. The unsteady forms of continuity, Navier-Stokes, and energy equations were applied to solve the compressible viscous flow using the dynamic mesh technique. The importance of using a compressible flow model, even for the low Mach number flow case, was demonstrated. It was shown that even in low train speeds; a compressible model is preferred, as it can predict the pressure fluctuations, while an incompressible model may only be used for predicting the mean pressure. However, in cases where pressure fluctuations are not important, the incompressible model can be used especially for a train with low acceleration. When the trains accelerate, it was found that the initial slope of the pressure curve is proportional to the train acceleration. Therefore, the increase in the train acceleration increases the maximum pressure rise. Also, the first pressure rise depends on the velocity of the train tail as it enters the tunnel. In addition, the earlier equations in the literature for computing the maximum pressure rise, can properly predict the pressure rise of accelerating trains if the train tail velocity, as it enters the tunnel, is used as the velocity scale.

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A Numerical Study of the Train-Induced Unsteady Airflow in a Subway Tunnel with Natural Ventilation Ducts Using the Dynamic Layering Method

Cited by 70 publications

References 10 publications

Environmental and Health Effects of Ventilation in Subway Stations: A Literature Review

Environmental and Health Effects of Ventilation in Subway Stations: A Literature Review

Enhancing the piston effect in underground railway tunnels

Investigation of the effects of different parameters on the generated pressure waves inside the tunnels

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