FULLTITLE

Effectsofambientpressureonsmokemovementpatternsinverticalshaftsintunnelfireswithnaturalventilationsystems

Keywords

ambientpressure,verticalshafts,plug-holing,boundary-layerseparation,high-altitudearea,naturalventilation

ABSTRACT

在隧道火灾中，排烟对生命安全和结构安全至关重要。烟气的运动方式会影响排烟效率，因此有必要确定自然通风的矿井内烟气的运动方式。然而，以往的研究主要集中在标准大气条件下，但在高海拔地区，环境压力降低会对烟的运动特性和温度分布产生影响。本文首先进行了理论分析，发现在低压条件下，由于热损失较小，烟速较高;此外，在火灾动力学模拟系统(FDS)上进行了数值模拟，研究了环境压力对自然通风系统下竖井火灾烟气运动规律的影响。结果表明，在环境压力降低的情况下，临界Richard数下降，而环境压力降低引起的烟温和烟速升高是临界Richard数下降的原因。希望本文的工作能为高海拔地区的隧道自然通风系统设计提供设计参考。

Smokeexhaustisofvitalimportanceforlifesafetyandstructuralsafetyinatunnelfire.Thesmokemovementpatterncouldaffectsmokeexhaustefficiency,soitisnecessarytodeterminethepatternsinshaftsintunnelfireswithnaturalventilationsystems.However,previousstudieshavefocusedonthisproblematstandardatmosphericconditions,buttheambientpressure,whichcouldhaveaneffectonsmokemovementcharacteristicsandtemperaturedistribution,decreasesinhigh-altitudeareas.First,theoreticalanalysisiscarriedouttofindthatthesmokevelocityishigherunderreducedpressureduetolowerheatloss.Inaddition,asetofnumericalsimulationsbasedonFireDynamicsSimulator(FDS)isconductedtoinvestigatetheeffectsofambientpressuresonsmokemovementpatternsinverticalshaftsintunnelfireswithnaturalventilationsystems.TheresultsshowthatthecriticalRichardnumberdeceasesunderreducedambientpressure,andthehighersmoketemperatureandvelocitycausedbylowerambientpressurearethereasonsforthedecreaseincriticalRi.Wehopethatourworkcanprovideadesignreferencefortunnelnaturalventilationsystemdesigninhigh-altitudeareas.

Authors

GuanfengYan1,2,MingnianWang1,2,LiYu1,2,RuyuDuan1,2,PengxiXia1,2

1.KeyLaboratoryofTransportationTunnelEngineering,MinistryofEducation,SouthwestJiaotongUniversity,Chengdu,China

2.SchoolofCivilEngineering,SouthwestJiaotongUniversity,Chengdu,China

YanG,WangM,YuL,DuanR,XiaP().Effectsofambientpressureonsmokemovementpatternsinverticalshaftsintunnelfireswithnaturalventilationsystems.BuildingSimulation,13:–.