Three Dimensional Adaptive Phase Field Modeling of Dendritic Growth
博士 === 國立臺灣大學 === 化學工程學研究所 === 98 === In the solidification process, the properties of material can be controlled by the operating condition. It is important of understanding the mechanism and principle of solidification for us to choose the satisfied material can operation condition. At this study,...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2010
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| Online Access: | http://ndltd.ncl.edu.tw/handle/19982766975164800711 |
| Summary: | 博士 === 國立臺灣大學 === 化學工程學研究所 === 98 === In the solidification process, the properties of material can be controlled by the operating condition. It is important of understanding the mechanism and principle of solidification for us to choose the satisfied material can operation condition. At this study, the phase field model and finite volume method is used to simulate the solidification of a seed in the overcooling liquid. The problem can be solved by general personal computer with the use of adaptive mesh refinement code developed by our lab.
The solidification of dendrite is divided into three part in this study. The first part is the dendritic growth case without any convection. The dendritic growth is controlled by the initial overcooling and seed condition. The similarity of dendrite at several overcooling is successful to simulate by proper choose of rescaling. The difference caused by dimensionless large thermal boundary layer is also observed in our simulation.
The following part is about the dendritic growth under forced convection. The difference of flow effect between 2D and 3D is discussed followed by the effect of flow strength and initial condition.
The final part is the dendritic growth under natural convection. The Peclet number at several gravitational strengths and overcooling shows good comparison with classic theory in our simulation. The morphology also has the good agreement with the experiment observation. The difference between forced and natural convection is discussed by morphology and flow field comparison. The strength and orientation of gravity is also discussed in this study.
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