凝固過程の動的挙動とその制御に関する研究

• Main Authors: 木村 繁男, Kimura Shigeo
• Format: Report
• Language: Japanese
• Published: 金沢大学工学部 2002
• Subjects: 凝固; 相変化; 非定常冷却温度; 熱伝達; 移動境界問題; 自然対流; 数値解析; 多孔質; Solidification; Phase Change; Unsteady Cooling Temerature; Heat Transfer; Moving Boundary; Natural Convection; Numerical Analysis; Porous Medium; Arctic
• Online Access: http://hdl.handle.net/2297/46873; https://kanazawa-u.repo.nii.ac.jp/?action=repository_uri&item_id=34824; https://kanazawa-u.repo.nii.ac.jp/?action=repository_action_common_download&item_id=34824&item_no=1&attribute_id=26&file_no=1

Solidification processes can be observed in a variety of fields of fields of engineering and geophysical phenomena. In metallurgy, for instance, the solidifying conditions of the melt determine the mechanical propertiesof the solid products. In semiconductor industry, integrated circuit devices require the large single crystals by high perfection, containing a uniformly distributed dopant. Geophysical problems also involve solidification processes, such as freezing sea water in arctic region, lake freezing and formation of igneous intrusives. In the present research we particularly concern with a possible way to control the location of solid liquid interface and the speed of advancing solid front. In order to achieve this goal it is needed to adjust the cooling temperature with time. From a point of view of fluid mechanics and heat transfer, a liquid to solid phase change involves a coupling of heat conduction in the solid layer as well as convecting process in the liquid layer. In cha pters 1 and 2, we develop both one-dimensional and two-dimensional models for a solidifying problem when a liquid body is cooled from the top boundary. The cooling temperature is varied periodically with time, and the bottom temperature is kept constant. The one-dimensional and two-dimensional models are formulated and solved numerically in general. But, it is also shown that an analytical solution is possible for a special case, where the Stefan number is small and the solid-liquid boundary movement is slow enough in comparison with the thermal diffusion in the solid layer. In chapter 3 we carry out a corresponding experiment with an insulated box containing distilled water. Both analytical and numerical predictions agree well with the experimental results regarding the solidifying front movement. In chapter 4 the study has been extended to solidification in a liquid-saturated porous medium. In chapters 5 and 6 we conduct a fundamental study on porous media convection and mixed convection in a vertical channel. Both analyzes ...