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1、银 429铜 401 金 317 铝 237 铁 80 锡 67 铅 34.8 各种物质导热系数！ material conductivity K (W/m.K) diamond 钻石 2300 silver 银 429 cooper 铜 401 gold 金 317 aluminum 铝 237 各物质的导热系数 物质温度 导热系数物质温度 导热系数 亚麻布50 0.09落叶松木0 0.13 木屑50 0.05普通松木45 0.080.11 海砂 20 0.03杨木 100 0.1研碎软木20 0.04胶合板0 0.125 压缩软木 20 0.07纤维素 0 0.46 聚苯乙烯 100 0.
2、08丝 20 0.040.05 硫化橡胶50 0.220.29炉渣50 0.84 镍铝锰合金 0 32.7硬质胶 25 0.18 青铜 30 32153白桦木 30 0.15 殷钢 30 11橡木 20 0.17 康铜 30 20.9 雪松 0 0.095 黄铜 20 70183柏木 20 0.1 镍铬合金 20 12.3171普通冕玻璃 20 1 石棉0 0.160.37石英玻璃4 1.46 纸 12 0.060.13燧石玻璃 32 0.795 皮棉 4.1 0.03重燧石玻璃 12.5 0.78 矿渣棉 0 0.050.14精制玻璃 12 0.9 毡 0.04 汽油 12 0.11 蜡 0
3、.04凡士林 12 0.184 纸板0.14 “天然气”油12 0.14 皮革0.180.19甘油0 0.276 冰 2.22 煤油 100 0.12 新下的雪0.1蓖麻油500 0.18 填实了的雪 0.21橄榄油 0 0.165 瓷 1.05 已烷 0 0.152 石蜡油0.123二氯乙烷0.147 变压器油0.128 90%硫酸0.354 石油0.14醋酸18石蜡 0.12硝基苯 0.159 柴油机燃油 0.12 二硫化碳 0.144 沥青 0.699 甲醇 0.207 玄武岩2.177四氯化碳0.106 拌石水泥1.5三氯甲烷0.121 花岗石2.683.35氨气* 0.022 丙铜0
4、.177水蒸汽* 0.02350.025 苯 0.139重水蒸汽* 0.072 水 0.54空气* 0.024 聚苯板 0.04 木工板 0.1-0.2 重水 0.559硫化氢* 0.013 表2窗体材料导热系数 窗框材料钢材铝合金PVC PA松木 导热系数 58.2 203 0.16 0.23 0.17 表 3不同玻璃的传热系数 玻璃类型玻璃结构(m)传热系数 K-w/(m2-k) 单层玻璃6.2双层中空玻璃5x9x5 3.265x12x5 3.11 一层中空玻璃 5x9x5x9x5 2.22 o- 5x12x5x12x5 2.08Lhw-E 中空玻璃 5x12x5 1.71石墨比热 710
5、 J/(kgK)电导率0.061x10-6/(米欧姆)热导率129 W/(mKHeat transfer coefficientFrom Wikipedia, the free encyclopediaJump to: navigation, searchThe heat transfer coefficient, in thermodynamics and in mechanical and chemical engineering, is used in calculating the heat transfer, typically by convection or phase chan
6、ge between a fluid and a solid:where q = heat flow in input or lost heat flow , J/s = Wh = heat transfer coefficient, W/(m2K)A = heat transfer surface area, m2AT = difference in temperature between the solid surface and surrounding fluid area,KFrom the above equation, the heat transfer coefficient i
7、s the proportionality coefficient between the heat flux, that is heat flow per unit area, q/A, and the thermodynamic driving force for the flow of heat (i.e., the temperature difference, AT).The heat transfer coefficient has SI units in watts per squared meter -kelvin: W/(m2K).Heat transfer coeffici
8、ent is the inverse of thermal insulance. This is used for building materials (R-value) and for clothing insulation.There are numerous methods for calculating the heat transfer coefficient in different heat transfer modes, different fluids, flow regimes, and under different thermohydraulic conditions
9、. Often it can be estimated by dividing the thermal conductivity of the convection fluid by a length scale. The heat transfer coefficient is often calculated from the Nusselt number (a dimensionless number). There are also online calculatorsConvective Heat TransferHeat transfer between a solid and a
10、 moving fluid is called convection. This is a short tutorial about convective heat transferSponsored LinksHeat energy transferred between a surface and a moving fluid at different temperatures is known as convection.In reality this is a combination of diffusion and bulk motion of molecules. Near the
11、 surface the fluid velocity is low, and diffusion dominates. Away from the surface, bulk motion increase the influence and dominates.Convective heat transfer may take the form of eitherforced or assisted convectionnatural or free convectionForced or Assisted ConvectionForced convection occurs when a
12、 fluid flow is induced by an external force, such as a pump, fan or a mixer.Natural or Free ConvectionNatural convection is caused by buoyancy forces due to dens ity differences caused by temperature variations in the fluid. At heating the density change in the boundary layer will cause the fluid to
13、 rise and be replaced by cooler fluid that also will heat and rise. This continues phenomena is called free or natural convection.Boiling or condensing processes are also referred as a convective heat transfer processes.The heat transfer per unit surface through convection was first described by New
14、ton and the relation is known as the Newtons Law of Cooling.The equation for convection can be expressed as:q = hc A dT(1)whereq = heat transferred per unit time (W)A = heat transfer area of the surface (mo)hc= convective heat transfer coefficient of the process (W/m2K or W/m2oC)dT = temperature dif
15、ference between the surface and the bulk fluid (K or oC)Heat Transfer Coefficients - Units1 W/m2K = 0.85984 kcal/h m2 oC = 0.1761 Btu/ ft2 h oF1 Btu/ft2 h oF = 5.678 W/m2 K = 4.882 kcal/h m2 oC1 kcal/h m2 oC = 1.163 W/m2K = 0.205 Btu/ ft2 h oFConvective Heat Transfer CoefficientsThe convection heat
16、transfer coefficient - k - is dependent on the type of media, gas or liquid, the flow properties such as velocity, viscosity and other flow and temperature dependent properties.In general the convective heat transfer coefficient for some common fluids is within the ranges:Free Convection - Air : 5 - 25 (W/m2K)Free Convection - Water: 20 - 100 (W/m2K)Forced Convectio
