Mechanism of natural convection of water-or aqueous solution-fine particle suspension

水-或水溶液-细颗粒悬浮液的自然对流机理

• 批准号: 08650271
• 负责人: OKADA Masashi
• 金额: $ 1.41万
• 依托单位: Aoyama Gakuin University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650271/
• 关键词: Natural convection; Suspension; Heat transfer; Sedimentation; Stratification; Rectangular cell; Particle size distribution; Temperature distribution; 二重拡散対流; く形容器; 微粒子

Natural convection of water-or aqueous solution-fine particle (micro glass beads) suspension was investigated experimentally. Two kinds of experiments were carried out. In the experiment (1), a rectangular cell with 80mm width and 120mm height was used. Both the vertical walls were cold surfaces maintained at 10ﾟC and a central part of the bottom wall with 80mm width was heated. During the fall of particles, the suspension forms many layrs and the layrs vanish gradually. As the concentration of the solution increases, the sedimentation velocity in the case of saccharose aqueous solution, becomes slower but it becomes larger in the case of NaCl aqueous solution. When the concentration of NaCl aqueous soliton is larger than lwt%, the layrs do not appear.In the case of water-particle suspension, as the temperature difference between the hot and cold walls increases, the layrs vanish in shorter time.In the above experiments mean diameter of particles was 9.76mum and standard deviation was 3.62mum. When particles with a narrow distribution of particle size (2.04mum mean diameter and 0.52mum standard deviation) are dispersed in water, only two layrs can be observed. The interface of the two layrs goes down gradually and after then goes up quickly to the top of the suspension and vanishes.In the experiment (2), glass beads with 4.75mum mean diameter were dispersed in water in a rectangular cell with 40mm width and 160mm height. The temperature difference between the opposing vertical walls was kept at 10ﾟC.Several layrs were also observed. The falling velocities of the interfaces are constant and become slower as the initial concentration of particle increases. The lower interfaces have the larger falling velocities.

对水或水溶液-微细颗粒(玻璃微珠)悬浮液的自然对流进行了实验研究。进行了两种实验。在实验(1)中，使用了宽80 mm、高120 mm的矩形单元。两个竖壁都是冷表面，保持在10ﾟC，底壁中央部分80 mm宽的加热。在颗粒下落过程中，悬浮液形成多层，这些层逐渐消失。随着溶液浓度的增加，蔗糖水溶液的沉降速度变慢，而氯化钠水溶液的沉降速度变大。在水-颗粒悬浮液中，随着冷壁和热壁温差的增大，水层在较短的时间内消失，实验中颗粒的平均直径为9.76微米，标准差为3.62微米。当粒径分布较窄(平均直径2.04微米，标准差0.52微米)的颗粒分散在水中时，只能观察到两层。在实验(2)中，将平均直径为4.75um的玻璃微珠分散在宽40 mm、高160 mm的矩形水池中。相对竖壁之间的温差保持在10ﾟC，并观察到几层。界面的下降速度是恒定的，并且随着颗粒初始浓度的增加而变慢。界面越低，下降速度越大。

项目成果

Kazuya OYAMA,Chaedong KANG,and Masashi OKADA: "Natural convection of water-fine particle suspension in a rectangular cell" 35th National Heat Transfer Symposium of Japan. (to be published). (1998)

Kazuya OYAMA、Chaedong KANG、Masashi OKADA：“矩形池中水-细颗粒悬浮液的自然对流”，第 35 届日本全国传热研讨会。

Masashi OKADA,Kazuya OYAMA,and Chaedong KANG: "Natural convection of water-or aqueous solution-fine particle suspension in a rectangular cell" 11th International Heat Transfer Conference. (to be published). (1998)

Masashi OKADA、Kazuya OYAMA 和 Chaedong KANG：“矩形池中水-或水溶液-细颗粒悬浮液的自然对流”第 11 届国际传热会议。

大山 和也・美 採東・岡田 昌志: "矩形容器内における水・固体微粒子懸濁液の自然対流" 第35回日本伝熱シンポジウム講演論文集. (1998)

Kazuya Oyama、Teito Mi 和 Masashi Okada：“矩形容器中水/固体颗粒悬浮液的自然对流”第 35 届日本传热研讨会论文集（1998 年）。

Masashi OKADA,Masayoshi TATENO,Satoshi YANO,and Kazuya OYAMA: "Double diffusive convection of water-fine particle suspension heated and cooled from opposing vertical walls" 34th National Heat Transfer Symposium of Japan. Vol.1. 87-88 (1997)

Masashi OKADA、Masayoshi TATENO、Satoshi YANO 和 Kazuya OYAMA：“从相对的垂直壁加热和冷却的水细颗粒悬浮液的双重扩散对流”第 34 届日本全国传热研讨会。

岡田昌志 他3名: "垂直加熱・冷却壁による水-固体微粒子懸濁液の二重拡散対流" 第34回日本伝熱シンポジウム講演論文集. vol.1. 87-88 (1997)

Masashi Okada 等 3 人：“垂直加热/冷却壁的水-固体细颗粒悬浮液的双重扩散对流”第 34 届日本传热研讨会论文集第 1 卷（1997 年）。