《Heat Pipe Technology》.ppt

发展及现状 1944年:通用发动机公司的R.S.Gaugler首先提出 了热管的工作原理,但是他的想法当时并没有被广泛的采纳利用。 1963年:美国的Los Alamos国家实验室的G.M.Grover重新独立发明了这种传热元件,并进行了性能测试实验,将这种传热元件正式命名为热管-heat pipe。 1965年:Cotter首次提出了较完整的热管理论。 70年代以来:热管技术飞速发展.我国也自70年代开始,开展了对热管的研究和应用。 热管特性 很高的导热性:比普通的金属导体高几个数量级。 优良的等温性:蒸汽处于饱和状态,从而保证了很小的温差,利用该特性来实现温度展平。 热流密度可变性:可以通过改变蒸发段和冷凝段的面积来很方便的调节热流密度。 热流方向的可逆性:由于其内部循环动力是毛细力,所以任意一端受热都可以成为蒸发段。 环境的适应性:热管的形状可以随热源和冷源的条件而变化,并可以将热源和冷源分隔在两个场所进行热交换。 传热极限 连续流动极限(Continuum flow limit) 冷冻启动极限(Frozen start up Limit) 黏性极限(Viscosity limit ) 声速极限(Sonic limit ) 携带极限(Entrainment limit ) 毛细极限(Capillary limit ) 冷凝极限(Condenser limit ) 沸腾极限(Boiling limit ) * Heat Pipe Technology and Applications 蒋爱华　 中南大学能源科学与工程学院 Definition Heat pipe structure Heat pipe features Operation principles Heat transport limit of a heat pipe Materials can be used to construct a heat pipe Selections of heat pipes Recent researches What is Heat Pipe? A traditional heat pipe is a hollow cylinder filled with a vaporizable liquid. A typical heat pipe consists of a vessel in which its inner walls are lined with a wick structure. The vessel is first vacuumed, then charged with a working fluid, and hermetically sealed. What is Heat Pipe? A heat pipe is a simple device with no moving parts that can transfer large quantities of heat over fairly large distances essentially at a constant temperature without requiring any power input. A heat pipe is basically a sealed slender tube containing a wick structure lined on the inner surface and a small amount of fluid such as water at the saturated state, as shown in figure of following page . Figure: Schematic and operation of a heat pipe Heat Pipe Structure A heat pipe is consisting of following three basic components: container the wick or capillary (no need for a gravity-heat pipe). the working fluid Gravity-heat pipe A gravity-heat pipe has a limit of inclination pitch (a elevation angle 15o ). Anti-gravity-heat pipe Anti-gravity-heat pipe 图 分离热管原理图 1.蒸发段,2.蒸汽上升管,3.冷凝