Mold Flow Simulation of Thin-Walled LED Heat Sinks
| Autor: | Yi-Tung Lu, 盧奕同 |
|---|---|
| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 In this paper, the filling analyses of vacuum die-casting of a thin-walled LED heat sink structure and the vacuum valve structure are simulated by FLOW-3D software. Two topics are analyzed and discussed in this study. First, numerical simulations for variety of molding conditions, including different parameters of thermal conductivity, vacuum pumping pressure, mold temperature, filling velocity, respectively, are conducted for the computational model of a thin-walled LED heat sink with a vacuum shut-off valve. Second, effects of several geometrical parameters, including thickness of LED heat sink, vacuum valve dimensions of T2, D1, D2, L1, L2, W, respectively, of the computational model of a thin-walled LED heat sink with a vacuum shut-off valve are explored. In these two topics, melts are set to liquid metal of Al 384.0 materials. The first topic of analysis mainly to investigate the effects of molding parameters based upon the same computational model of a thin-walled LED heat sink with a vacuum valve. The simulated results show if molding conditions are changed, different sizes of defects are appeared in castings; if vacuum pumping pressure is higher, the casting is also firmness, density prone to increase; if vacuum pumping pressure is too low, then pumping efficiency of mold cavity is low and it will be easy to form the casting porosity defects. For the second topic of analysis, molding conditions are hold constantly, and effects of different geometrical dimensions to quality of castings are simulated. T2 trigger mechanism can effectively operate, but too thin or too thick, it will affect the pumping time to different degrees of vacuum. Decreasing of gas residuals of castings for the vacuum pumping pressures of 760Torr, 200Torr, 100Torr to 10Torr, were 0.311%, 0.174%, 0.008%, respectively. However, the value is only 0.008% for the case of 100Torr to 10Torr. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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