A novel approach to the transient ventilation of road tunnels

Jang, Hong-Ming; Chen, Falin

doi:10.1016/s0167-6105(99)00135-x

Cited by 16 publications

(11 citation statements)

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“…The consequences of the distance of the smoke and the temperature are qualitatively evaluated from the current and temperature field. It is possible that the average values of different time and space steps, which are limited by the unified way of average calculation (Jang and Chen, 2000), could be miscalculated. With that, it is true that the risk of exposure to smoke can be understood as the moment when the smoke reaches the tunnel users.…”

Section: Parameters and Analysis Of Resultsmentioning

confidence: 99%

Application of CFD Method for Risk Assessment In Road Tunnels

Vidmar

Petelin

2007

Engineering Applications of Computational Fluid Mechanics

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The definition of the deterministic approach in safety analyses arises from the need to understand the conditions that emerge during a fire accident in a road tunnel. The key factor of the tunnel operations during a fire is ventilation, which during the initial phases of the fire has a strong impact on the evacuation of people and later on the access of the intervention units to the tunnel. The paper presents the use of the CFD (Computational Fluid Dynamics) model in tunnel safety assessment process. The set-up of the initial and boundary conditions and the requirement for grid density found from validation tests of an FDS (Fire Dynamics Simulator) are used to prepare three kinds of fire scenarios-20 MW, 50 MW and 100 MW, with different ventilation conditions: natural, semi-transverse, transverse and longitudinal ventilation. The observed variables, soot density and temperature, are presented in minutes time steps through the entire tunnel length. Comparing the obtained data in a table allows the analyses of the ventilation conditions for different heat releases from fires. The second step is to add additional criteria of human behaviour inside the tunnel (evacuation) and human endurance to the elevated gas concentrations and temperature. What comes out is a fully deterministic risk matrix that is based on the calculated data where the risk is ranged on five levels, from the least to a very dangerous level. The deterministic risk matrix represents the alternative to a probabilistic safety assessment methodology, wherein the fire risk is represented in detail and the CFD model results are physically correct.

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Section: Parameters and Analysis Of Resultsmentioning

confidence: 99%

Application of CFD Method for Risk Assessment In Road Tunnels

Vidmar

Petelin

2007

Engineering Applications of Computational Fluid Mechanics

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“…Assuming that the pressure gap between two portals of tunnels is zero, and traffic intensity remains stable in one control period, we can first use the original tunnel aerodynamic (2) to serve as the base for our system model [2,18,22,23]. We then re-write (2) into (3) in order to model the relationship between system input v j , disturbances v + , v − , K + , K − and state u (see (2) and 3)where N j is the number of jet fans inside the tunnel, A f is the section area of jet fan (m 2 ), k j is the pressure rise coefficient of fans, L is the tunnel length (m), c d is the average drag coefficient of the vehicle platoon and A v,m is the equivalent vehicle windward area (m 2 ), which is the weighted average of products of the windward area and the drag coefficient of all the vehicle types.…”

Section: Aerodynamic Modelmentioning

confidence: 99%

Adaptive fine pollutant discharge control for motor vehicles tunnels under traffic state transition

Tan¹,

Xia

Yang

et al. 2015

IET Intelligent Transport Systems

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“…F ∑ is the summation of the forces that affect the wind in its flow velocity inside the tunnel [15][16][17], which consist of following four elements: -t F : the traffic ventilation force by passing vehicles -j F : the equipment ventilation force by jet-fan operation -r F : the combination of the wall friction resistance and fluent loss at the entrance and exit -n F : the wind resistance by the natural wind outside the tunnel Eqs. (2) and (3) are used for simulations evaluating the suggested controller and comparing with conventional algorithms.…”

Section: Tunnel Ventilation Systemmentioning

confidence: 99%

Tunnel ventilation control via an actor-critic algorithm employing nonparametric policy gradients

2009

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The appropriate operation of a tunnel ventilation system provides drivers passing through the tunnel with comfortable and safe driving conditions. Tunnel ventilation involves maintaining CO pollutant concentration and VI (visibility index) under an adequate level with operating highly energy-consuming facilities such as jet-fans. Therefore, it is significant to have an efficient operating algorithm in aspects of a safe driving environment as well as saving energy. In this research, a reinforcement learning (RL) method based on the actor-critic architecture and nonparametric policy gradients is applied as the control algorithm. The two objectives listed above, maintaining an adequate level of pollutants and minimizing power consumption, are included into a reward formulation that is a performance index to be maximized in the RL methodology. In this paper, a nonparametric approach is adopted as a promising route to perform a rigorous gradient search in a function space of policies to improve the efficacy of the actor module. Extensive simulation studies performed with real data collected from an existing tunnel system confirm that with the suggested algorithm, the control purposes were well accomplished and improved when compared to a previously developed RLbased control algorithm.

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A novel approach to the transient ventilation of road tunnels

Cited by 16 publications

References 0 publications

Application of CFD Method for Risk Assessment In Road Tunnels

Application of CFD Method for Risk Assessment In Road Tunnels

Adaptive fine pollutant discharge control for motor vehicles tunnels under traffic state transition

Tunnel ventilation control via an actor-critic algorithm employing nonparametric policy gradients

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