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極微小伝熱面における超高熱流束下の沸騰現象に関する研究

微观传热表面超高热通量沸腾现象研究

基本信息

批准号：
02452126
负责人：
IIDA Yoshihiro
金额：
$ 3.71万
依托单位：
Yokohama National University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-02452126/
关键词：
Boiling Fluctuation Nucleation High Speed Heating Transient Boiling Bubble Nucleation Homogeneous Nucleation Heat Transfer Superheat Hmit 超高熱流束

项目摘要

An extremely small flat heater is formed on a quartz glass plate by spattering platinum on it. The size is O. 1mm in width, 0.25mm in length and 0.25x10^<-3>mm in thickness. Extremely higher temperature rise rate as well as extremely larger heat flux is attained by supplying a small electric power input to this test section in comparing with those in ordinary boiling experiments. The experimental apparatus is composed of the pulse generator, the high-speed power amplifier, the instrumentation part such as the storage oscilloscope, the observation part -such as the microscope and others. The most suitable system for this experiments is examined and fixed.A series of non-linear two-dimentional heat conduction simulation were conducted for evaluating the error of temperature measurements and for compensating it.Experiments with pure water at atmospheric pressure were carried out at first. The temperature rise rate of 0.7x10^8 K/s and the heat flux over 10^8 W/m^2 were attained by heating … More the test section pufsewisely. At a higher temperature rise condition a large number of bubble generation, about 10^<10> n/m^2 at the maximum, was observed. These buubbles generate on the heater by a single effort and grow uniformly. The authors named this peculiar configuration as the cavierwise bubble generation. Further, it was shown that the temperature at the beginning of bubble generation approached to the homogeneous nucleation temperature of water in accordance with the increase of temperature rise rate.Similar experiments were made for ethyl alcohol and toluen. The cavierwise bubble generation was also observed in these organic liquids and their temperatures at the beginning of bubble generation were shown to be almost equal to the respective homogeneous nucleation temperature. A series of theoretical calculation on the bubble number increase versus the lapse of time were made on the basis of the classical nucleation theory and it was shown that the experimental results were comparatively similar to the theoreticals. Thus, the bubble generation phenomenon represented by the cavierwise bubble generation was estimated to be due to the fluctuation nucleation. Less

在石英玻璃板上溅射铂，形成一个极小的扁平加热器。尺寸为宽0.1 mm，长0.25mm，厚0.25x10^<-3>mm。与普通沸腾实验相比，向该试验段提供较小的电力输入可获得极高的升温速率和极大的热流密度。实验装置由脉冲发生器、高速功率放大器、仪器部分（如存储示波器）、观察部分（如显微镜）等组成。研究并确定了最适合本实验的系统。为了对温度测量误差进行评估和补偿，进行了一系列非线性二维热传导模拟。首先进行了常压下的纯水实验。升温速率为0.7 × 10^8 K/s，热流密度大于10^8 W/m^2。在较高温升条件下，气泡生成量较大，最大时约为10^<10> n/m^2。这些气泡通过一次努力在加热器上产生并均匀生长。作者将这种奇特的结构命名为洞穴式气泡生成。结果表明，随着升温速率的增大，气泡产生开始时的温度逐渐趋近于水的均匀成核温度。对乙醇和甲苯也做了类似的实验。在这些有机液体中还观察到空洞方向的气泡生成，并且气泡生成开始时的温度几乎等于各自的均匀成核温度。在经典成核理论的基础上，对气泡数随时间的增加进行了一系列理论计算，实验结果与理论结果比较接近。由此估计，以腔向气泡生成为代表的气泡生成现象是由波动成核引起的。少