A study of an optimal smoke control strategy for an Urban Traffic Link Tunnel fire

Statechart has been utilized as a visual formalism for the modeling of complex systems. It illuminates the features on describing properties of causality, concurrency and synchronization. The reachability structure is used to represented dynamic model by a Boolean function. In this paper, we try to describe State invariant method and equation function for hierarchical tree diagram. Finally, we used them to analyze the urban traffic control systems which are modeled by using Statecharts. Their formalism provides a concept of propositional logic for presenting control strategy.

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Pedestrian-Safety-Aware Traffic Light Control Strategy for Urban Traffic Congestion Alleviation

IEEE Transactions on Intelligent Transportation Systems ◽

10.1109/tits.2019.2955752 ◽

2019 ◽

pp. 1-16 ◽

Cited By ~ 2

Author(s):

Yi Zhang ◽

Yicheng Zhang ◽

Rong Su

Keyword(s):

Control Strategy ◽

Traffic Congestion ◽

Pedestrian Safety ◽

Urban Traffic ◽

Light Control ◽

Traffic Light ◽

Traffic Light Control

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Coordinate Signal Control in Urban Traffic of Two-Direction Green Wave Based on Genetic BP Neural Network

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.823.665 ◽

2013 ◽

Vol 823 ◽

pp. 665-668 ◽

Cited By ~ 1

Author(s):

Shao Jiao Lv ◽

Chun Gui Li ◽

Zhe Ming Li ◽

Qing Kai Zang

Keyword(s):

Neural Network ◽

Control Strategy ◽

Bp Neural Network ◽

Urban Traffic ◽

Signal Control ◽

Traffic Condition ◽

Real Time Traffic ◽

Coordinate Control ◽

Analytical Algorithm ◽

Trunk Road

To maximize the bandwidth of green wave of trunk road is a main issue in the research of signal control in urban traffic. However, the traditional analytical algorithmcan not be applied in actual traffic widely. A novel dynamic two-direction green wave coordinate control strategy was proposed to overcome the problem. By combining the genetic BP neural network with the traditional analytical algorithm, the urban traffic of two-direction was controlled coordinately online. Finally, an actual example was presented. It shows that not only the green wave bandwidth, the phase difference of each intersection and the critical cycle of trunk road were optimized according to real-time traffic flow, but also our algorithm can be used in different traffic condition by adjusting the parameters of the model.

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Combining diverse driving forces for smoke control in complex urban traffic link tunnels (UTLTs) using one-dimensional flow modelling

Sustainable Cities and Society ◽

10.1016/j.scs.2018.08.017 ◽

2018 ◽

Vol 43 ◽

pp. 265-274 ◽

Cited By ~ 5

Author(s):

Yingli Liu ◽

Dong Yang ◽

Yimin Xiao ◽

Shaohua Mao ◽

Manjiang Yang

Keyword(s):

Driving Forces ◽

Urban Traffic ◽

Smoke Control ◽

One Dimensional ◽

Flow Modelling ◽

Dimensional Flow

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On the Use of Solid Curtains Near Smoke Extraction Vents to Control Smoke Spread Resulting From Fire in Road Tunnels

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4048670 ◽

2020 ◽

Vol 13 (3) ◽

Author(s):

Taher Halawa

Keyword(s):

High Temperature ◽

Release Rate ◽

Control Strategy ◽

Smoke Control ◽

Smoke Spread ◽

Peak Heat Release Rate ◽

Road Tunnels ◽

Low Visibility ◽

Temperature Levels ◽

Fire Accidents

Abstract The effectiveness of the smoke control strategy plays an important role in increasing safety levels when fire accidents occur in road tunnels. This paper introduces clarifications about how the efficiency of smoke extraction control using solid curtains can be increased by placing smoke extraction vents close to the solid curtains. The effect of adding a solid curtain with different heights and at various positions relative to a smoke extraction vent was studied in this paper. A 14.3% increase in the vent flowrate occurs at the time corresponding to the fire peak heat release rate when the distance between the solid curtain and the vent is equivalent to 90% of the tunnel height and when the solid curtain height is equal to 16% of the tunnel height. High temperature and low visibility conditions occur near the solid curtain at the smoke-trapped area when the smoke curtain height exceeds 40% of the tunnel height. Using a solid curtain positioned far away from the vent with a distance equals to 90% of the tunnel height and with a height in the range from 16% to 30% of the tunnel height achieves the best results in terms of suppression of smoke spread and attaining acceptable visibility and temperature levels at the region where the smoke is trapped by the solid curtain.

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A Study on Ceiling Temperature Distribution and Critical Exhaust Volumetric Flow Rate in a Long-Distance Subway Tunnel Fire with a Two-Point Extraction Ventilation System

Energies ◽

10.3390/en12081411 ◽

2019 ◽

Vol 12 (8) ◽

pp. 1411 ◽

Cited By ~ 7

Author(s):

Peng Zhao ◽

Zhongyuan Yuan ◽

Yanping Yuan ◽

Nanyang Yu ◽

Tao Yu

Keyword(s):

Temperature Distribution ◽

Flow Rate ◽

Empirical Equation ◽

Ventilation System ◽

Volumetric Flow Rate ◽

Subway Tunnel ◽

Smoke Control ◽

Long Distance ◽

Tunnel Fire ◽

Ceiling Temperature

Smoke control is a crucial issue in a long-distance subway tunnel fire, and a two-point extraction ventilation system is an effective way to solve this problem, due to the characteristics of controlling the smoke in a limited area and removing high-temperature and toxic smoke in time. In this study, the ceiling temperature distribution and the critical exhaust volumetric flow rate to control the smoke in the zone between two extraction vents were investigated in a long-distance subway tunnel fire with a two-point extraction ventilation system. Experiments were carried out in a 1/20 reduced-scale tunnel model based on Froude modeling. Factors, including the heat release rate (HRR), the extraction vent length, the internal distance between two extraction vents and exhaust volumetric flow rate, were studied. Smoke temperature below the ceiling, exhaust volumetric flow rate and smoke spreading configurations were measured. The ceiling temperature distribution was analyzed. Meanwhile, an empirical equation was developed to predict the critical exhaust volumetric flow rate based on the one-dimensional theory, experimental phenomenon and the analysis of forces acting at the smoke underneath the extraction vent. The coefficients in the empirical equation were determined by experimental data. Compared with the experimental results, the developed empirical equation can predict the critical exhaust volumetric flow rate well. Research outcomes in this study will be beneficial to the design and application of two-point extraction ventilation system for a long-distance subway tunnel fire.

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The Study of the Confinement Velocity in the Longitudinal Ventilation Tunnel Fire

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.3665 ◽

2012 ◽

Vol 446-449 ◽

pp. 3665-3669

Author(s):

Ke Qing Sun ◽

Hui Yang

Keyword(s):

Characteristic Parameter ◽

Experimental Models ◽

Experimental Results ◽

Mixed Gas ◽

Control Effect ◽

Smoke Control ◽

Tunnel Fire ◽

Longitudinal Ventilation ◽

The Relationship ◽

Two Sides

For the situation that the smoke exhaust vents are located on both sides of the fire source, critical ventilation velocity is not appropriate to evaluate the smoke control effect. “Confinement velocity” is proposed as the characteristic parameter to study the longitudinal ventilation by O.Vauquelin in this situation. However, there have been few studies on confinement velocity. An experimental study was carried out on two reduced scale tunnel models. The main objective is to analysis the relationship between confinement velocity and fire heat release in this situation. Helium and air in different ratio was used as the smoke, and the "cold smoke" produced by smoke generator was put into the mixed gas in order to measure the length of smoke layer. The experimental models were based on the half tunnel as flow field at two sides of fire is symmetrical. The CFD model was created on the basis of the experiment, and the results were basically accord with the experimental results. It was shown from the experimental results that the critical point of the confinement velocity is between L / H = 2 to L / H = 4 in section 1, between L / H = 1 to L / H = 2 in section 2, rather than a fixed value; Two tunnel models had similar dimensionless confinement velocity, but the dimensionless total confinement velocity was different.

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