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A Study for Measurement of Thermophysical Properties using Thermal Fluctuations

利用热波动测量热物理性质的研究

基本信息

批准号：
04805022
负责人：
NAGASAKA Yuji
金额：
$ 1.34万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04805022/
关键词：
Thermophysical Properties Surface Tension Kinematic Viscosity Measurement Technique Thermal Fluctuations

项目摘要

The results obtained from the present research are summarized as follows.(1)In order to detect very weak scattered light from thermally excited surface wave (ripplon), we have developed an heterodyne detection apparatus using a grating having a100 mum period. By employing n-pentane as an sample liquid near room temperature, we found that the apparatus has enough ability to detect the signal from ripplon.(2)Through experimental considerations, we have found optimum conditions for the incident angel of laser beam on the liquid surface and the order of diffracted beam from the grating. It was confirmed that, in principle, we are able to calculate the surface tension and the kinematic viscosity from the power spectrum of ripplons.(3)As the first step towards measurement on high temperature melts, we have designed a trough for molten Si using BN.We also have designed a high temperature furnace system up to 1600 ﾟC by using an infrared imaging furnace.(4)In order obtain much stronger scattered light from ripplon, we have employed a 200 mum-optical grating. By using this grating, we were able to detect much better S/N ratio signals and the reproducibility was improved : surface tension (〕SY.+-.〔)0.4% and kinematic viscosity (〕SY.+-.〔)11%.(5)Due to the improvement of reproducibility, we were able to detect the change of surface tension as a function of time because of degradation of liquid surface.

本研究的结果总结如下：(1)为了探测热激发表面波（ripplon）发出的非常微弱的散射光，我们研制了一种使用周期为100 μ m的光栅的外差探测装置。以正戊烷为样品液，在接近室温的条件下，我们发现该装置有足够的能力检测来自ripplon的信号。(2)通过实验考虑，确定了激光入射液体表面的最佳角度和光栅衍射光束的顺序。结果表明，从理论上讲，我们可以通过波纹的功率谱计算出波纹的表面张力和运动粘度。(3)作为高温熔体测量的第一步，我们设计了一个用BN测量熔融硅的槽。我们还利用红外成像炉设计了高达1600℃的高温炉系统。(4)为了从ripplon中获得更强的散射光，我们采用了200 μ m的光栅。通过使用该光栅，我们能够检测到更好的信噪比信号，并提高了再现性：表面张力（]SY.+-.[）0.4%，运动粘度（]SY.+-.[）11%。(5)由于重现性的提高，我们能够检测到由于液体表面降解导致的表面张力随时间的变化。