Field measurements of the interior and exterior aerodynamic pressure induced by a metro train passing through a tunnel

Xiong, Xiaohui; Liang, Zhu; Zhang, Jie; Li, Aihua; Li, Xiaobai; Tang, Mingzan

doi:10.1016/j.scs.2019.101928

Cited by 41 publications

(14 citation statements)

References 23 publications

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“…This is mainly because the external pressure on the car at different positions is totally different when the train is running in the tunnel. In the moving direction of the train, the external pressure on the head car is positive relative to the internal pressure in the car [12], resulting in the increase of fresh air into the car through the fresh air valves. From the head car to the tail car, the external pressure decreases in turn and the surface of the tail car is under negative pressure which leads to the reduction of the fresh air rate and the serious deterioration of the air quality in the car.…”

Section: Co2 Concentration Distribution In Different Carsmentioning

confidence: 99%

Analysis of dynamic characteristics of CO₂ concentration in subway cars

Yang

Wang

2022

E3S Web Conf.

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The air environment in the subway car has a great impact on the comfort and health of passengers. In order to know the real air quality in the car when the train is running, this paper takes CO2 as an indicator and conducts a field test on Line 11 of Shanghai Metro to study and analyse the dynamic CO2 concentration and the fresh air rate in the subway car. The results show that the CO2 concentration increases from the head car to the tail car, and the fresh air volume decreases from the head car to the tail car is the reason for the large difference of CO2 concentration in different cars. The CO2 concentration in the car is greatly affected by the passenger load, and the maximum value of CO2 concentration in the morning peak can reach 2.3 times that of the normal hours. The background CO2 concentration has a certain influence on the CO2 concentration in the car, and the CO2 concentration in the underground line is higher than that in the elevated line in the same carriage. The CO2 concentration in subway cars of the underground line in the morning peak is significantly higher than 1500 ppm, which indicates that the dilution effects of the ventilation can’t meet the fresh air requirements in the morning peak. The research in this paper can provide a reference for the design of the ventilation system of subway trains and the environmental control in the car.

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Section: Co2 Concentration Distribution In Different Carsmentioning

confidence: 99%

Analysis of dynamic characteristics of CO₂ concentration in subway cars

Yang

Wang

2022

E3S Web Conf.

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“…The study of the pressure wave and aerodynamic load of the EMU train in the tunnel has great significance to the analysis of the traveling speed, tunnel passing capacity and stability of the EMU train. Xiong et al (2020) studied the aerodynamic effects caused by the tunnel when the train speed increases. And when the internal pressure fluctuation exceeds the limit, it will affect the comfort of passengers.…”

Section: Introductionmentioning

confidence: 99%

“…The magnitude of the internal pressure change of the train depends on the direction of travel. Moreover, when the train passes through the tunnel interval with a gap interval of 5.5m at a speed greater than 80km/h, it will cause passengers' ear discomfort [6]. Yuan et al (2019) analysed the aerodynamic characteristics of a quiet urban train passing through a tunnel based on sliding grid technology.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Behaviour Analysis of Emu Train Entering and Exiting Tunnels Using Aerodynamic Load Data

2021

IJOMAM

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To study the change of aerodynamic load pressure when the EMU (Electric Multiple Unit) enters and exits the tunnel, the corresponding aerodynamic equation is established. By analysing the development process of EMU trains under mechatronics, a research background for the air pressure problem caused by the speed increase of high-speed trains is displayed. Furthermore, the aerodynamic problems and related pressure waves in the tunnel of the training group are introduced. Based on the aerodynamic load data, the lateral vibration characteristics of the train are analysed. It is proposed that after the train enters the tunnel, the surrounding air generates pressure waves and expansion waves due to the restriction of the train surface and the tunnel wall. Subsequently, the Bernoulli equation is used to calculate the pressure values of the train under different running conditions in the tunnel. Finally, the ANSYS Fluent fluid calculation software is used to simulate the aerodynamics of the train tunnel of the EMU. The results show that, affected by space constraints and air compressibility, when the train enters the tunnel, the compression wave changes from three-dimensional to one-dimensional. After the head of the train enters the tunnel, the average pressure value at the cross-section of x=2D increases rapidly. At t=0.011 second, the average pressure of the cross-section increases slowly, and the rate of change reaches the maximum. At t=0.027 second, the average pressure of the cross-section reaches the maximum. When the train approaches the cross-section, the pressure value at the sampling point close to the train body changes much greater than the change rate of the other two sampling points. The simulation results show that the transverse force of the train in the tunnel is 0.45Kn. Therefore, when the train travels in the tunnel, it will be subject to more complicated aerodynamic load conditions. This study will provide references for studying the aerodynamics of high-speed trains passing through tunnels.

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“…Despite the fact that phenomenon of overpressures in tunnel is well defined in the European standards, as well as the test procedures required to certify a new train, some aspects need further investigation, as will be shown by experimental data presented in this work. Moreover, probably due to both organizational difficulties and high costs of full-scale tests, there is still a lack in the literature of full-scale data (some examples are reported in [18][19][20][21][22][23][24][25][26]) necessary to validate numerical codes that are required in the certification process and are used in train structural dimensioning. In this respect, after investigating the effects of various parameters on the measured pressure, a one-dimensional (1-D) code (TETUN, the 1-D code developed in the AeroTRAIN project to become a European reference) was extensively validated reproducing the numerous available experimental scenarios (single passages of different trains, two train crossing, different tests speed, different tunnel characteristics) and some important results are shown in this work.…”

Section: Introductionmentioning

confidence: 99%

Full-Scale Experimental Investigation of the Interaction between Trains and Tunnels

et al. 2020

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This works focuses on a series of experimental tests carried out to investigate overpressures in tunnels due to train crossings. Although the above-mentioned topic is well known and also defined in European standards, in the literature full-scale data are lacking, which are useful to validate the numerical codes required in the certification process and are used in train structural dimensioning. In this respect, an extensive full-scale experimental campaign was planned for observing as many test conditions as possible, such as single passages of different trains, two train crossing, different tests speed, and different tunnel characteristics. In detail, the understanding of the pressure wave generation and transmission is deeply enhanced by studying the pressure evolution both on board and at trackside, considering both single train passages or two trains crossings and having the possibility to compare aerodynamic loads on sealed and unsealed trains. Furthermore, the position of sensors, the speed of the train, and the initial conditions within the tunnel have been proven to be fundamental parameters for properly estimating the pressure loads on trains.

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Field measurements of the interior and exterior aerodynamic pressure induced by a metro train passing through a tunnel

Cited by 41 publications

References 23 publications

Analysis of dynamic characteristics of CO₂ concentration in subway cars

Analysis of dynamic characteristics of CO₂ concentration in subway cars

Dynamic Behaviour Analysis of Emu Train Entering and Exiting Tunnels Using Aerodynamic Load Data

Full-Scale Experimental Investigation of the Interaction between Trains and Tunnels

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Field measurements of the interior and exterior aerodynamic pressure induced by a metro train passing through a tunnel

Cited by 41 publications

References 23 publications

Analysis of dynamic characteristics of CO2 concentration in subway cars

Analysis of dynamic characteristics of CO2 concentration in subway cars

Dynamic Behaviour Analysis of Emu Train Entering and Exiting Tunnels Using Aerodynamic Load Data

Full-Scale Experimental Investigation of the Interaction between Trains and Tunnels

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Analysis of dynamic characteristics of CO₂ concentration in subway cars

Analysis of dynamic characteristics of CO₂ concentration in subway cars