Fundamental Research for the Development of Compact Cooling Systems Corresponding to Ultra High Heat Generation Density by Optimization of Boiling and Evaporation Conditions

通过优化沸腾和蒸发条件开发对应超高生热密度的紧凑型冷却系统的基础研究

基本信息

批准号：
16360107
负责人：
OHTA Haruhiko
金额：
$ 8万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16360107/
关键词：
boiling critical heat flux narrow channel microlayer phase change self-wetting marangoni heat transfer センサー

项目摘要

In order to obtain the fundamental and general knowledge of boiling heat transfer in the high-performance cooling systems, a few experiments with different approaches were conducted.Transparent heating surface with multiple arrays of 88 thin film temperature sensors and micro-heaters was developed for the clarification of boiling heat transfer mechanisms, where the relation between local heat transfer coefficients and behaviors of liquid microlayer underneath attached vapor bubbles was investigated. Local surface temperature was controlled to keep constant by the feedback circuits, and a simple and ideal boundary condition on the heat transfer surface was realized. The local heat flux change characterized by the heat transfer enhancement due to the microlayer evaporation and the deterioration by the extending dry patches was detected corresponding to the observed liquid-vapor behaviors underneath a coalesced bubble.Experiments on pool boiling heat transfer were conducted by using the alcohol-aqueous solutions in order to confirm the increase in the critical heat flux due to the self-wetting effect. The heat transfer characteristics and critical heat flux were dependent on the alcohol concentration. The critical heat flux of alcohol-aqueous was observed higher than that of pure water. In addition, the thermal properties of binary mixtures and the phase equilibrium data were prepared for the data reduction.Flow boiling in a narrow channel is one of the most promising application forms for the actual high-performance cooling system. A devised structure of cooling system, which had a narrow main channel and an unheated auxiliary channel, was developed and the critical heat flux value was increased by more than twice by the liquid supply from an auxiliary channel.

为了获得高性能冷却系统中沸腾传热的基本知识和一般知识，进行了一些不同方法的实验。开发了具有多阵列88个薄膜温度传感器和微型加热器的透明加热表面。阐明沸腾传热机制，研究了局部传热系数与附着蒸汽气泡下方液体微层行为之间的关系。通过反馈电路控制局部表面温度保持恒定，实现了传热表面简单、理想的边界条件。局部热通量变化的特征是微层蒸发引起的传热增强和扩展的干燥斑块的恶化，这与观察到的聚结气泡下方的液-汽行为相对应。通过使用醇-水溶液，以确认由于自润湿效应而导致的临界热通量的增加。传热特性和临界热通量取决于酒精浓度。观察到醇-水的临界热通量高于纯水。此外，还准备了二元混合物的热性质和相平衡数据以进行数据简化。窄通道内的流动沸腾是实际高性能冷却系统最有前途的应用形式之一。开发了一种设计的冷却系统结构，该结构具有狭窄的主通道和未加热的辅助通道，并且通过辅助通道的供液使临界热通量值增加两倍以上。