沈降法による粒度分布測定に生ずる誤差 : 懸濁液の乱れの影響

概要

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Though photo-extinction sedimentometry is a very sensitive measuring method of size distribution, it has been recognized that this method brings some measuring error which is attributed to the instability of suspension. Kaye et al. has pointed out already that this instability is caused by the dropping of temperature at the liquid surface by evaporation. In this report, this instability phenomenon is analyzed quantitatively by using two types of photo-extinction sedimentometers. Four kinds of liquids were selected as dispersing media, each of which had different thermal properties. The starting time of instability was obtained experimentally, and the corresponding Rayleigh number (λ=P_r・G_r) was calculated with the aid of surface temperatures, which were obtained theoretically from the evaporation rate determined with the same cell. It can be concluded that the critical Rayleigh number is in the range of 3 000〜5 000, beyond which most probably instability in liquid suspension will occur.
社団法人日本材料学会の論文
1973-07-15