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smoke propagation characteristics and influencingfactors of high-temperature spiral tunnel fire

Transportation Safety and Environment 2022年第3期4卷 98-106页

作者： Yang Song Huibin Wang Chao Guo Sitong Pan Yan Wu PowerChina Roadbridge Group Co. LtdBeijing 100048China School of Mechanical Engineering Tongji UniversityShanghai 201804China.

A tunnel fire may cause great damage to people, vehicles, facilities and tunnel structures if it is not effectively controlled. Therefore,it is very important to clarify the smoke propagation characteristics and influencing factors that can help to accelerate the removal offire smoke and reduce casualties and property losses. In order to study the influence of slope, curvature radius and ambient temperatureon smoke propagation during the tunnel operation period, based on the high-temperature spiral tunnel in Midi village, YunnanProvince, the internal and external environmental parameters of the tunnel were measured on site and the numerical simulationmodel was established by using the simulation software FDS, and the control variablemethod was used to study the fire smoke propagationcharacteristics of the tunnel with different characteristics. The results show that: the influence of slope on smoke migrationvelocity is non-linear, the greater the slope is, the greater the change of smoke spreading speed is;the smaller the curvature radiusis, the greater the obstruction to smoke migration is, and the slower the smoke migration speed is;high temperature speeds up thesmoke exhaust rate in the tunnel but has less promotion of the fire smoke migration.

关键词： Tunnel engineering fire smoke numerical simulation slope curvature radius temperature

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Numerical investigation on fire-induced indoor and outdoor air pollutant dispersion in an idealized urban street canyon

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Building Simulation 2022年第4期15卷 597-614页

作者： Shengzhong Zhao Haoran Yang Chaorui Li Imad Obadi Fei Wang Wenjun Lei Tiantian Xu Miaocheng Weng School of Thermal Engineering Shandong Jianzhu UniversityJinanChina School of Architecture Design and PlanningThe University of SydneySydneyAustralia School of Civil Engineering Chongqing UniversityChongqingChina

fire-induced pollutant dispersion under the influence of buoyancy in urban street canyons has attracted wide attention given its adverse impact on human *** study analyzes the influences of fire source location and crossflowing wind(perpendicular to the canyon centerline)on indoor and outdoor air pollutant dispersion in an idealized urban street canyon by employing large eddy *** fire scenarios are defined according to the transverse location of the fire source:near the windward building(scenario 1),in the middle of the canyon(scenario 2),and near the leeward building(scenario 3).Results show that a re-entrainment phenomenon appears when the wind velocity reaches a critical value in scenarios 1 and 2,but it doesn't occur in scenario *** source location significantly influences the critical re-entrainment *** critical velocity in scenario 1 is approximate 1.2-1.5 m/s larger than that in scenario *** the heat release rate is large,the critical Fr numbers are less sensitive to changes in HRR,and remain approximately constant with values of 0.47(scenario 1)and 0.37(scenario 2).When the wind velocity is large,more compartments are expected to be affected in the upper floors in all of the three scenarios,and smoke is distributed in an inverted triangle within the *** indoor/outdoor temperature and pollutant concentrations are also *** findings can provide valuable information for both human and property safety in relation to urban street canyons and their surrounding buildings.

关键词： air pollutant dispersion fire smoke street canyon critical re-entrainment velocity fire source location

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An Early Forest fire Detection Method Based on Unmanned Aerial Vehicle Vision

An Early Forest Fire Detection Method Based on Unmanned Aeri...

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第30届中国控制与决策会议

作者： Sha Ma Youmin Zhang Jing Xin Yingmin Yi Ding Liu Han Liu Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing Xi’an University of Technology

Traditional forest fire detection methods based on flame are subject to detection delays due to the later appearrance of flame than smoke. When the flame is detected, the fire might have already been spread and out of ***, the objective of this paper is to study new fire detection method based on smoke. First a quadrotor unmanned aerial vehicle（UAV） is adopted to capture the fire video;then the collected video sequence will be processed by a series of preprocessing including filtering and image enhancement;finally a new significance detection algorithm is investigated for early and efficient smoke detection. Experimental results show that the algorithm can detect smoke effectively.

关键词： UAV vision fire smoke fire detection Significance detection algorithm

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