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2.Conduction（导热）Thebestheat-insulatingsolidsowntheirinsulatingpropertiestotheairortoothergasescontainedincellswithinthematerial.（最好的隔热材料在空气和材料细胞中拥有自己的绝热性能。）Thesecellscausetheheattoflowthroughthesolidmaterialthroughalongtortuouspassage.（这些细胞使热量需要通过一个漫长曲折的通道才能流过这个坚实的固体。）Inaddition,theavailablecross-sectionalareaofthesolidmaterialismuchlessthantheprojectedarea.（另外，见识的固体材料可用的横截面面积比投影面你少得多。）Experimentalevidenceshowsthatmanysmallunicellularpocketsofgasaremuchmoreeffectivethanaseriesofconnectedcellshavingthesametotalvolumeingivinginsulatingvaluetoasubstance.（试验表明，一个物体在给定的总量上具有相同的绝热值上，许多小口袋气体单细胞比的一系列连通细胞更加有效）Theremaybeconsiderablevariationinthethermalconductivityofanygiveninsulatingmaterialbecausetheconductivitydependsonitsdensity,thesizeandnumberofitsaircells,anditsabsorbedmoisture.（在任何给定的绝热材料的导热系数方面有很大的差异，这是因为导热系数取决于它的密度，空气细胞的大小和数量，和它吸收的水蒸气。）3.NaturalConvection（自然对流）Considerheattransferbynaturalconvectionbetweenacoldfluidandahotsurface.（考虑到冷流体和热表面之间的自然对流换热。）Thefluidinimmediatecontactwiththesurfaceisheatedbyconduction,becomeslighterandrisesbecauseofthedifferenceindensityoftheadjacentfluid.（流体在表面直接接触通过传导加热，将变的更轻，也会上升，这是由于相邻流体的密度差异。）Themotionisresistedbytheviscosityofthefluid.（这种运动会被流体的粘度所抵制）Theheattransferisinfluencedby（传热的影响）:(1)gravitationalforceduetothermalexpansion,(2)viscousdragand(3)thermaldiffusion.（由于热力膨胀的引力，粘性阻力和热扩散。）Itmaybeexpectedtodependonthegravitationalaccelerationg,thecoefficientofthermalexpansionβ，thekinematicviscosityν(=μ/ρ),andthethermaldiffusivityα=(κ/ρcp).（这是可以预测的，这取决于引力加速度，g，热膨胀系数β，运动粘度ν(=μ/ρ)，和热扩散系数α=(κ/ρcp)。）Thesevariablescanbeexpressedintermsofdimensionlessnumber（这些热量可以早无量纲方面表示）:theNusseltnumber,Nu,isafunctionoftheproductofthePrandtlnumber,Pr,andGrashofnumber,Gr,which,whencombined,dependonthefluidproperties,thetemperaturedifferencebetweenthesurfaceandthefluid,∆t,andthecharacteristiclengthofthesurface,L.（努谢尔特数，Nu；普朗特数推导的函数，Pr，和格拉晓夫数；Gr，在混合条件下，取决于流动的特性，温差取决于流体和表面温度的不同，∆t；表面特征长度，L。）Theconstantcandexponentndependonthephysicalconfigurationandnatureofflow.（系数c和指数n取决于不同的物理构造和流动性质。）Naturalconvectioncanaffectthetransfercoefficientintheofweakforcedconvection.（自然对流可以影响现存在的微弱的受迫对流的传导系数。）Astheforcedconvectioneffect,i.e.,theReynoldsnumber,increases,the“mixedconvection”(superimposedforced-on-freeconvection)giveswaytothepureforcedconvectionregime.（对于受迫对流的影响，即雷诺数，增加，“混合对流”（加上自然对流影响的受迫对流）被单纯的受迫对流区域所替代。）Sincetheheattransfercoefficientinthemixedconvectionregionisoftenlargerthancalculatedbasedonthenaturalorforcedconvectionheattransfer.（由于在混合对流区域的传热系数往往大雨基于自然对流或受迫对流的换热计算结果。）Thereferencegivenbeforesummarizesnatural,mixed,andforcedconvectionregimesforverticalandhorizontaltubes.（在作出参考之前总结了纵向和横向管段的自然、混合和受迫对流区域。）Localconditionsinfluencethevaluesoftheconvectioncoefficientinamixedconvectionregime,butthereferencespermitlocatingthepertinentregimeandapproximatingtheconvectioncoefficient.（当地条件影响了在混合对流区域的对流系数的值，但是可引用当地区域相关允许值和近似得到对流换热系数。）6.FundamentalsofindustrialVentilation（工业通风的基础）Inessencethisboilsdowntoheattransferandmasstransferbetweentheincomingairandairthealreadywithinthebuilding.（从本质上讲，这归结于进入的空气和已经在建筑物内的空气的传热和传质。）Ifowingtoexcessiveinternalheatproductionthetemperatureoftheairinthebuildingtendstoexceedthespecifiednorms,coolerairisintroducedandmixedwiththeindoorair;thetemperatureoftheair(owningtoheattransfer)thenremainsatthenorm.（这是由于建筑物内部产热过多导致空气的温度往往超过规定的指标，引入冷的空气引入与室内空气混合（由于传热），使空气温度保持不变。）Ifharmfulgasesorvapoursarereleased,theirconcentrationisheldwithinspecifiedlimitsbydilutionwiththecleanincomingair.（如果有害挥发性气体被释放掉，它的浓度将会被在一定范围内通过引入室外清洁空气来稀释。）7.NaturalVentilationFieldsofApplication（自然通风的应用领域）Thetimehaslongpassedwhenitwasnecessarytodemonstratethebenefitsofnaturalventilationandjustifyitsapplication.Theproofsweresimpleandveryconvincing.（时间已经过去很久了当它有必要去表明自然通风的好处和证明它的可用性。）Theywerebasedoncomparisonsofmechanicalventilationandnaturalventilation.（这是基于自然通风和机械通风的比较。）Inhotshopswherealltheemphasiswaslaidonmechanicalventilation,andnaturalairchange,beingregardedasunimportant,wasnottakenintoaccountatall.（在热的车间里，所有的重点是机械通风，自然通风被认为是无足轻重的，没有被重视到的。）Itwasfoundinalltheteststhatthevolumeofnaturalairchangemanytimesexceededthevolumeofmechanicalventilation.（很多测试表明，自然通风的换气量几倍于机械通风的换气量。）Thisrevealedthenegligibleroleofgeneralmechanicalventilationdespiteitsheavyinstallationandrunningcosts.（这表明，全面的机械通风是不会估计到它的很大的装备和运行花费。）Mechanicalventilationinthesecaseswasbestusedasacorrectivetonaturalventilation,intheformofaircurtainsandlocalairsupplyorextraction.（在这些情况下，机械通风最好是自然通风的一个补救措施，以空气幕的形式和当地空气的供应和提取。）9.ComfortandDiscomfort（舒适与不舒适）Aparticularexampleistherangeeffect.（一个特别的例子这个范围的影响。）Whenanobserverexperiencesarangeofstimuliandisaskedtoratethemoncategoryscale,hetendstoratethembyputtingthestimulifromthemiddleoftherangeintothecentralcategoriesoftheratingscale.（当一个测试员经历了一定范围的刺激并且要求把他们分为不同类别范围的等级，他倾向于从评定列表范围的中间到中央类别投入的刺激来分类。）Thishasbeenclearlydemonstratedinexperimentsontheacceptabilityofnoise.（这已经清楚的表明对噪音的可接受性的实验。）Subjectsexposedtoarangeofsoundlevelstendtoplacetheboundarybetweenacceptableandunacceptablenoiseatthecentreoftherangeofnoisewhichtheyhavebeenexposed.（