並列タイトル等低プラントル数流体のハーフゾーン液柱における熱毛管流の実験研究
タイトル（掲載誌）宇宙開発事業団技術報告: マランゴニ対流現象モデル研究:アニュアルレポート2002 = NASDA Technical Memorandum: Marangoni Convection Modeling Research: Annual Report April 1, 2002-March 31, 2003
一般注記The experimental study on thermocapillary convection of low Prandtl number fluid was carried out to understand transition behavior to oscillatory flow. The half-zone liquid bridge of molten tin was formed between hot and cold disks in high vacuum chamber (10(exp -5) Pa). The three radiation thermometers were used to measure the free surface temperature at a different azimuthal location at the same time. In addition, the temperature distribution at interface between liquid bridge and cold disk was measured by using very fine thermocouples to detect the transition point and to make clear the oscillation mode more precisely. It can be detected that the steady thermocapillary convection changes to oscillatory under certain condition. The observed phenomena of transition processes after the oscillatory onset were revealed by comparing to numerical result done by Imaishi et al. The effect of aspect ratio (L/r) on critical Marangoni number was investigated. The critical Marangoni number decreases with increasing aspect number. This behavior agrees with numerical simulation done by Imaishi et al. qualitatively except for region of smaller aspect ratio. The surface tension and its temperature coefficient were measured in the experimental chamber. A molten tin droplet was formed on an alpha-Al2O3 substrate in the evacuated experimental chamber. These analog photo images were transfer to digital images and the surface tension was calculated from the outlines of digital image, which was the sessile drop method. The value of surface tension and its temperature coefficient were 520 to 550 [mN/m] and 0.097 [mN/m/K]. The Fe-Ni/SB tracer particle has been developed for the visualization of the inner flow pattern of the Marangoni convection. Considering the traceability of the particle, high wettability and low reactivity with surrounding fluid, and high sphericity are required. Therefore, the multi-layer structure, which comprises Fe and Ni layers, was adopted. The plating techniques of both Fe and Ni layers were developed and the heat treatment technique to make the high sphericity particles was also developed. The test particle has already been manufactured and its reflectance of ultrasonic beam has been evaluated.
資料番号: AA0046980006
レポート番号: NASDA-TMR-030004E
一次資料へのリンクURLhttps://jaxa.repo.nii.ac.jp/?action=repository_action_common_download&item_id=42955&item_no=1&attribute_id=31&file_no=1
連携機関・データベース国立情報学研究所 : 学術機関リポジトリデータベース（IRDB）（機関リポジトリ）
提供元機関・データベース宇宙航空研究開発機構 : 宇宙航空研究開発機構リポジトリ