导　　师： 徐明海

学科专业： 0807

授予学位： 博士

作　　者： ;

机构地区： 中国石油大学华东

摘　　要： 喷雾冷却具有换热能力高、冷却温差小、工质需求量小、没有沸腾滞后、没有接触热阻等优点，有望成为将来电子器件冷却的首选方式。光滑表面的研究表明喷雾冷却换热机理主要为强制对流、液膜蒸发、核态沸腾和“二次成核”。表面微结构化因增加了表面的凸起与凹槽，改善了表面液膜形态，为近几年来强化喷雾冷却换热的主要方向，已有一些初步研究成果，但理论和实验研究还很不充分，对强化换热机理缺乏认识。因此，本文采用实验研究、理论分析与数值模拟相结合的方法，对微槽表面喷雾冷却的换热特性进行了详细研究，主要研究内容及结果如下。 1．研究了喷雾特性对换热的影响。结果表明，雾滴速度、雾滴直径、雾滴数量通量共同影响喷雾冷却换热。换热强度随着雾滴速度、雾滴数量通量的增加而增强，但受雾滴直径的影响并不明显。喷雾体积通量（单位面积喷雾体积流量）是前述三个参量的组合，具有速度量纲，可作为表征换热特性的最佳参数，分析表明换热效果随体积通量的增加而增加。 2．研究了表面微结构特性对换热的影响。实验发现，所有微结构表面的换热均出现不同程度的增强，在槽深、槽横断面积相同的微结构表面中，直槽道更利于表面液膜顺畅流动，因此表现出更好的换热特性，在此基础上进一步研究了直槽表面结构参数（槽深、槽宽和槽间距）对换热的影响，得出了喷雾体积通量与最佳传热表面的对应关系，并结合雾滴受力分析对发生最优传热的原因进行了探讨。 3．研究了微结构表面的强化换热机理。结果显示，与光滑表面相比，微结构表面的对流换热和蒸发换热均增加，但两者各自增加的比例与喷雾体积通量有关。体积通量较小时，蒸发换热增加的比例更大，是强化换热的主要� Spray cooling technology has many advantages, such as higher heat transfer, smaller heattransfer temperature, less fluid inventory, smaller heat resistance and no hysteresis of boiling,which makes it become the best choice for cooling high heat flux electronics in the near future.Investigations for flat surface have demonstrated that heat transfer mechanisms of spraycooling include single phase convection, thin film evaporation, nucleate boiling andsecondary nucleation. Enhancement heat transfer of spray cooling is focusing onmicro-structured surfaces at present, but studies on this are not adequately, and mechanism ofenhancement of heat transfer is not well understood. In this paper, experimental study,theoretical analysis and numerical simulation are adopted to investigate the heat transfercharacteristics of spray cooling on micro-grooved surfaces. The main contents andconclusions are the following. 1. The influence of spray characteristics on heat transfer was investigated. Results showthat droplet velocity, droplet diameter and droplet number flux all affect the heat transfer. Heatflux increases with the increasing of droplet velocity and droplet number flux, while thedroplet diameter has small influence on heat flux. Spray volume flux is the best parameterwhich can be bused to distinguish heat transfer characteristics, because it not only possess thedimension of velocity, but also is a parameter combination of droplet velocity, dropletdiameter and droplet number flux. It is found that the bigger the spray volume flux is, thehigher the heat flux is. 2. The influence of surface structure on heat transfer was investigated. It is found that thestraight-grooved surface has the largest heat flux enhancement relative to the flat surface in allmicro-structured surfaces having the same groove depth and flow area, because the straightgroove is in favor of film flowing in it. On this basis, heat transfer was further studied underdifferent structure parameters /(groove depth, groove width and groove pitch/) of str

关 键 词： 喷雾冷却 微槽表面 换热特性 临界热流密度 无量纲关联式 模型

领　　域： [电子电信]