Mathematical modeling and sensitive analysis of the train-induced unsteady airflow in subway tunnel

Zhang, Huan; Zhu, Chunguang; Liu, Minzhang; Zheng, Wandong; You, Shijun; Li, Bojia; Xue, Peng

doi:10.1016/j.jweia.2017.09.005

Cited by 59 publications

(14 citation statements)

References 32 publications

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“…The results showed that the cross-sectional shape of the tunnel does not affect the pressure wave, but the blockage ratio was related to the characteristics of the pressure wave. Zhang 24 and Cross 25 studied the influence of train speed, blockage ratio, tunnel features and train length, on the ventilation rate and piston wind. A sensitivity analysis showed that the blockage ratio had the greatest influence.…”

Section: Introductionmentioning

confidence: 99%

“…In most previous work, the blockage ratio was investigated in terms of the influence of pressure waves and aerodynamic drag. 22,24,25 This study focuses on the change in the friction drag and the effect of the blockage ratio on the boundary layer thickness, as well as the corresponding influence on the friction drag. First, the process of a train entering and operating in a metro train is simulated in the computational fluid dynamics (CFD) software STAR-CCM+ using an overset mesh based on the k-omega SST turbulence model.…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of the pressure and friction resistance of a high-speed subway train based on an overset mesh method

Liu

Guang

Zhou

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part F:

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The aerodynamic resistance induced by a high-speed metro train entering and operating in a tunnel with a speed of 120 km/h is simulated using a three-dimensional, compressible turbulence model. An overset mesh method is adopted to solve the moving boundary problem, and the flow field around the train is simulated with a k-omega SST turbulence model to obtain accurate stress values at the walls. The selected model is verified with experimental and numerical data from the literature. Then, numerical simulations are performed to analyse the formation mechanisms of the pressure and friction drags. The aerodynamic drag basically stabilizes after the expansion wave passes the train head. The results reveal that the variations in friction resistance are related to the direction of the Mach wave, and this trend differs from that observed for pressure resistance. Mach wave influences the velocity where it passes, and further influences the friction drag. Result shows that friction drag of the train increases when encounter with compression wave propagated from the front or expansion wave propagated from the back, and decreases otherwise. The effects of the blockage ratio on the maximum and average pressure and friction resistance values of each train section are evaluated based on fitting functions. The predicted aerodynamic drag varies with the blockage ratio and for each train section, and the results are summarized and compared with predictions and experimental data from the literature. The variations in tunnel resistance and the overall trend are in good agreement with the previous results. Therefore, the findings presented in this study may provide a reference for the design of high-speed subway tunnels.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the pressure and friction resistance of a high-speed subway train based on an overset mesh method

Liu

Guang

Zhou

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part F:

View full text Add to dashboard Cite

show abstract

“…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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“…For safety reasons, two tunnels connected with pressure relief pipes near the tunnel should be the first choice. When the train runs in a tunnel, the bypass tunnel can play a certain role of ventilation [29] and serve as a rescue channel in an emergency [30]. Therefore, it is necessary to study the effect of increasing bypass tunnels on pressure waves in the tunnel.…”

Section: Introductionmentioning

confidence: 99%

Model Test Research on Pressure Wave in the Subway Tunnel

Fang

Zhou

et al. 2020

Preprint

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The pressure wave is of crucial importance for subway development since it greatly influences the comfort while taking. As the subway lines are rapidly developing in the cities, the pressure wave in different subway tunnel constructures is urgently needed to be studied and receded. In this paper, a subway tunnel pressure wave experimental system was designed, constructed, and tested. The influence of train model head shape, train model speed, shaft number in the tunnel, and bypass number in the tunnel on the pressure wave amplitude were experimented with and analyzed. The results show that the train model head shapes significantly impact the amplitude of the initial compression wave in the tunnel. The blunter train model head generates a greater amplitude of the initial compression wave. When the train passes through a single-track tunnel, the maximum positive pressure amplitude of the pressure wave in the tunnel is at the first compression wave at the tunnel entrance. The maximum negative pressure value in the tunnel is at the superposition of the initial compression wave reflected from the first time and the train's body, which is related to the length of the train's body, tunnel length, train's speed, and sound speed. The shaft set in the tunnel decreases the amplitude of the initial compression wave in the tunnel space behind, but it will increase the pressure wave's amplitude reflected in the tunnel when the train passes through the shaft. After the bypass tunnel is added, the initial compression wave propagation in the tunnel behind the bypass tunnel is receded. Still, it also increases the negative pressure amplitude when the train passes.

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Mathematical modeling and sensitive analysis of the train-induced unsteady airflow in subway tunnel

Cited by 59 publications

References 32 publications

Numerical investigation of the pressure and friction resistance of a high-speed subway train based on an overset mesh method

Numerical investigation of the pressure and friction resistance of a high-speed subway train based on an overset mesh method

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

Model Test Research on Pressure Wave in the Subway Tunnel

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