1、 PDF外文：http:/ 中文 5018 字 出处： Applied Thermal Engineering, 2008, 28(5): 372-379 【原文】 Astudyonundergroundtunnelventilationforpistoneffectsinfluencedbydraughtreliefshaftinsubwaysystem Chi-JiLin,YewKhoyChuah,Chia-WeiLiu Abstract Thisisastudyonunderground
2、tunnelventilationforpistoneffectsinfluencedbydraughtreliefshaft.FieldmeasurementsoftransientairmovementinthedraughtreliefshaftforatypicalTaipeiundergroundsubwaystationweretakenunderwinterandsummerconditions.Ithasbeenfoundthattheairinthedraughtreliefshafthasamaximumof2m/s,andonaverageliesbetween0.7an
3、d1.1m/s.ThisstudydefinesanindexPE,for evaluatingtheefficiencyoftunnelventilationbypistoneffects.Thisindexcanbeusedto analyzethepistoneffectsduetodifferentshaftlengthandsectionalarea.Themeasurementresultsshowthatthetrainpistoneffectsareeffectiveonlyforcertainshaftlengthandoperatingconditions. T
4、hisstudyalsousedtheauthoritativeSEScomputerprogramtosimulatethepistoneffects.Thesimulationresultsforinflowandoutflowvelocityprofilearealmostconsistentwiththemeasurement.Theshaftsectionalareawasalsoinvestigatedandhasbeenfoundthatalargersectionalarearesultedinlargervolumeflowrate,butthepercentageincre
5、aseislessthanthepercentageincreaseinthesectionalarea.Thiswillresultinsmallerair velocityinshaftandlesseffectiveairexchangebetweenthetunnelandtheoutsideambient.Italsohasbeenfoundthatlengthofthedraughtreliefshaftismoresoanimportantdesignparameterforefficientairexchangebypistoneffectsforundergroundsubw
6、aysystems.It issuggestedherethatthedesignofthedraughtreliefshafthastoconsiderrequirementsincludingPE,pressurelossandnoise. Keywords:Draughtreliefshaft；Pistoneffect；Undergroundsubwaystation；Tunnelventilation 1. Introduction Intypicalsubwayenvironmentaldesignhandbooks,onecan
7、findequationsforcalculatingairvelocityandpressuredistributionforventilationshafts.However,theimportanceoftunnelventilationhasdrawnmanyrecentstudiesinenvironmentalcontrolforundergroundsubwaysystems.Popeetal.analyzedsomeinfluencingfactorsfordraughtreliefandairtemperatureinanundergroundmetrosystem.Itwa
8、sshownthatthedraughtreliefshaftswithacrosssectionalareaof20m2couldresultinacceptableairflows.Keetal.usedSES(subwayenvironmentalsimulationprogram)andCFDmethodstosimulatetheenvironmentalcontrolsystemforasubwaystationdesign.Itwasfoundthatthepistoneffectswereaffectedbythecrosssectionalareaandthelengthof
9、theshaft.MaidmentandMissendeninvestigatedthefeasibilityofusingundergroundwatercoolingsystemforsubwaystation.Thestudyshowedintheorythatthesystemcouldreducethetunnelairtemperaturebyapproximately6C.Ampofoetal.reviewedthethermalcomfortablefactorsforLondonundergroundrailwayenvironment.Acceptablethermalco
10、mfortcriteriaweredescribed.Ampofoetal.theninvestigatedtheheatloadusinganundergroundrailwaynetworkconcept,andproposedsomecoolingmethodstoreducethetunnelairtemperature.ARUPinvestigatedthedesignofamodernsubwayventilationsystemandfoundthattheventilationcapacityrequiredwasdeterminedtypicallybythefireemer
11、gencymode.HongandKimanalyzedenergyconservationforKoreansubwaystationsandfoundthatenergyconsumptionwasrelatedtothenumberofpassengersandtheoperationsofthefacilities.KimandKimanalyzedthetrain-inducedunsteady3-Dairflowbynumericalsimulation andalsoexperimentalmethods.Theyfoundabout13.7%15.9%differe
12、ncebetweencomputationandmeasurementforairvelocity.YuanandYouusedCFDsimulationtoevaluateandoptimizethevelocityandtemperaturedistributionforside-platformsubwaystation.Thebreadthwaysventilationwellpreventsthehotairspreadingontotheplatform. Subwayenvironmentaldesignhandbookdictatesthattheairvelocityfort
13、unnelventilationsystembedeterminedwiththefollowingequations: m C AvVv Qb (1) AV Qc Forairinflow, AvCm Ki Cp (2) A Cps Forairoutflow, AvCm Ko Cp1CHi (3) A CpsCHc where A tunnel
14、area(m2) Av reliefshaftarea(m2) Cm ratioofmassflowratethroughreliefshafttomassflowratethroughtunnel Cp upstreamreliefshaftheadloss Cps reliefshaftheadloss CHC couplinglossesrelatedtoconfigurationoftheinterfacebetweentunnelandreliefshaft CHi entrancelossatthebottom
15、ofreliefshaft Ki, Ko empiricalconstantsforinflowandoutflow Qb, Qc airflowvolumeratethroughreliefshaftandupstream(ordownstream)(m3/s) V airvelocityattunnel(m/s) Vv airvelocityatreliefshaft(m/s) Thespacegeometryofamodernsubwaystationistypicallycomplex.Thetrainoperationisaprimefactorforthepistoneffects.Thetrainmovementintunnelisahighlytransientairmovingproblem.Theaboveequationsareinsufficienttoanalyzethetransientairmovementinthetunnelandtheventilationshaft.TheenvironmentalcontrolandtheairmovementareanalyzedfrequentlyusingSES.
