| Summary: | 碩士 === 國立臺北科技大學 === 冷凍與低溫科技研究所 === 91 === Recently rapid advances in the development of high-density, large scale-integrated chips have led to numerous miniaturized electronic devices. This trend produces the increase of the resistance due to such reduction of the heat-dissipating path, and, consequently heat from such sophisticated electronic component is excessively generated. Unless high-power heat is effectively generated, the excessive heat generated within the electronic devices will rapidly degrade the performance of this sensitive system. Therefore, enhancing the convective cooling of chips is a primary concern in the study of electronic packaging.
The present work involves the numerical simulation of forced convective incompressible pulsating flow through porous media, and attendant heat transfer characteristics. A non-Darcian effects including the channel effects, solid boundary effects and inertial effects for the momentum equation was employed. The transport of energy equation was considered thermal dispersion and one-equation model. At the channel inlet, a pulsating flow , i.e. , is imposed with a strip heated element at a constant . Comprehensive time-dependent flow and temperature data are got and averaged in a periodic steady state over a cycle of pulsation. The analysis in flow behavior of the important nondimensional parameters, such as Reynolds numer,Re, particle diamater of porous media,dp Strouhal numer, St, pulsation amplitude, A, are also investigated. The results show that advance channel effect, resist the blowing effect and recirculation will enhance convective heat transfer. And Strouhal number, Reynolds number, particle diameter, and pulsation amplitude increase more, enhance heat transfer rate will increase more. The results indicate that thermal performances are enhanced by using pulsating flow and a porous block. But employed in a cooling high-power electronic devices must consider the pressure lose, and get the better effects in a thermal system.
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