A study of fundamental and application of high efficiency boiling and evaporation utilizing controlled liquid supply of ink-jet type

高度集成化的电子器件和热工设备的冷却，对体积小、效率高、性能好的冷却系统提出了强烈的要求。为了实现热流密度在几十MW/m^2以上的高热流密度冷却系统，并将其应用于蒸发器和冰箱，通过提供喷射型液体，控制液滴大小、撞击速度和液滴数，对新型过冷沸腾系统进行了系统的基础实验。在2006年的第一期研究中，通过改变供液速率，详细研究了减压条件下单个撞击射流和液滴的基本传热特性。传热表面采用400号砂纸进行处理。为了加强传热，日立公司的thermoexcel。附着在铜表面。2007年第二阶段研究了多喷嘴和纳米管焊接传热表面的沸腾性能。实验结果表明，即使供液率较低，也能获得足够高的换热，碳纳米管表面也表现出良好的换热性能，这与我们通常的认识是相反的。这些结果和想法成功地应用于图库巴AIST（先进工业科学技术研究所）的一项高科技研究项目中，开发了具有高性能的超小型吸收式冷却器。

In relation to the cooling of highly-integrated electronic devices and thermal equipments, cooling systems of small size with high efficient and high performance are strongly demanded. In order to realize the high heat flux cooling systems with the cooling performance over the heat flux of several tens MW/m^2 and apply the systems to the evaporators and refrigerators, systematic and fundamental experiment of subcooled boiling novel systems by supplying jet-type liquid and controlling the size of droplets, impinging velocity and number of the droplets. In the first research period of 2006, fundamental heat transfer characteristics of a single impinging jet and droplet were investigated in detail at reduced pressures by changing the rate of supply liquid. The heat transfer surface was finished by he sand paper of #400. In order to enhance the heat transfer, Thermo-excel of HITACH Ltd. Was attached onto the copper surface. In the second research period of 2007, boiling performance was studied for multiple jets and for nano-tube soldered heat transfer surface. As the results of those experiments, it is found that even if the liquid supply rate is low, sufficiently high heat transfer is able to be obtained and that car-bon-nanotube surface shows good heat transfer performance, contrary to the common knowledge. These results and ideas were successfully applied to the development of ultra-small-size absorption type cooler with high performance which was performed as a high-tech research project at AIST (Institute of Advanced Industrial Science and Technology), Tukuba.