【作者】 王军；

【导师】 沈自求；

【作者基本信息】 大连理工大学 ， 化学工程， 2000， 博士

【摘要】 沸腾是取出热量十分有效的方法，一直受到传热界的关注。近年来，由于微电子设备、大型计算机等高新技术的迅速发展，需要在小体积内取出大量的热，因之池沸腾成为研究高热通量取出技术中的前沿课题。 沸腾传热速率较单相对流传热快的多.其主要原因是在沸腾泡核生长时，汽泡底部液体微层表面的液相汽化，带出潜热，形成了一个热阱使传热显著增强。这种由于形成热阱而使传热增强的作用。称为“界面汽化热阱效应”，可以由LDCT法与传热测定同时进行的实验方法加以分离。本文采用这一测定方法在一沸腾池中以0.005MK₃Fe（CN）₆十 0.005MK₄Fe（CN）₆十1MNaOH溶液为介质研究了核沸腾时的“汽化热阱”，测得了“界面汽化热阱效应”随热负荷的改变，并对实验中以LDCT测定获得的对流传热数据进行了分析与数据关联。 由于大型计算机和微电子设备等技术的迅速发展，高介电液体在微小放热壁面上的沸腾取出热量的研究受到深切关注。由于高介电液体对固体壁面的高润湿性，在沸腾开始时产生严重的温度偏异和沸腾滞后使放热壁面产生显著的温度波动，导致微电子元件产生噪音，严重地影响了元件的操作性能和使用寿命。本文进行了有关这方面问题的实验，并对文献发表的数据与结果以“界面汽化热阱”的概念作了分析和评述。 溶解气体对沸腾传热具有一定的影响。本文以增强“界面汽化热阱效应”的观点，对溶解气体解吸影响沸腾起始时的滞后作了分析，并以实验进行了研究。在实验中连续通入N₂ 气以保持沸腾液体中含有一定浓度的溶解气体，研究了其对沸腾传热的影响，并作了分析。 本文采用AEDT和HBS两种表面活性剂对沸腾滞后、“界面汽化热阱效应”的影响作了实验研究的探索。认为各种不同类型表面活性剂对沸腾传热的影响以及其作用机理是一个相当复杂的问题，有待进一步作深人的研究。 本文还在理论上对于单个汽泡动态变化过程的池核沸腾传热进肾了初步分析计算。计算结果表明，在汽泡的尘长阶段，壁面温度有明显地降低，这一阶段的时间很短。而在汽泡脱离后至新的汽泡重新生长，壁面温度较为缓慢的升高。 “界面汽化热陕效应”可以应用于其它一些类型的相变传热过程中。本文以互溶性冷剂在热液相中直接接触汽化冷却结晶为对象，应用“界面汽化热附”的概念对其汽化传热特点进行了分析。由于这种互溶性体系界面是不分明的，本文提出了“模糊界面”的概念，并按Hiebie的渗透模型作了初步的分析。更多还原

【Abstract】 Boiling is a heat transfer process with phase change in which a series process of the formation,growth and departure of a number of boiling vapor bubbles exists so that it includes various underlying phenomena. The interfacial vaporization heat sink coming with the evaporation of micro-liquid film at interface has the enhancement effect on boiling heat transfer. The mechanism of pool nucleate heat transfer and phenomena in its process are analyzed with the concept of interfacial vaporization heat sink in this present thesis. The method of LDCT and simultaneously measuring heat transfer is used to separate the effect of interfacial vaporization heat sink. The experimental results are given to show this effect in pool nucleate boiling.As fast development in new technology such as microelectronic device,pool boiling heat transfer is an attractive to the removing amount of heat from a heat transfer system with small volume because it has extremely high heat transfer coefficient. In recent years,pool boiling has come to the forefront of high-heat-flux thermal management research for many applications. The influence of hysteresis of boiling process on the operation of microelectronic components attracts many researcher’s attention. In this thesis,the mechanism of boiling hysteresis are analyzed in several aspects based on the formation of a boiling bubble nucleus and the concept of interfacial vaporization heat sinkDissolved gas may have the effect on the heat transfer in a nucleate boiling process. The experimental results of the effects of dissolved gas on boiling hysteresis and on the heat transfer are explained based on the concept of effect of interfacial vaporization heat sinkThe experiment is also conducted to investigate the effects on the boiling hysteresis and on the effect of inter facial vaporization heat sink of two water soluble surfactants (AEDT and HBS). The results show that we are still far from a systematic theory or explanation for the effect of surfactant additives on the boiling heat transfer. It seems that some more fundamental work should be done for this problem.The nucleate boiling heat transfer of formation < growth and departure of a single bubble is primarily analyzed,and the mathematical results with the numerical method are given to character the change in surface temperature during the evaporation of micro-liquid film.In a gas-lift loop apparatus,the experiment is conducted to study the heat transfer characteristic of alcohol drobble evaporating while rising in a column of the hot sucrose solution with high viscosity. The experimental results show that the evaporating heat transfer can be augmented by the effect of interfacial vaporization heat sink. At the bottom of the drobble,there is the vague interface on which sucrose nucleation takes place because of the opposite diffusions of alcohol and water.更多还原