Numerical Study on Heat Transfer Characteristics of Micro-Channel Heat Sink in Different Aspect Ratios using Nanofluids

• Main Authors: Szu-lin Liu, 劉思麟
• Other Authors: Chang-da Wen
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/59171572733907596570

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 97 === In this study, under forced convection and with fixed heating area, the heat transfer characteristics (channel temperature, heat flux, and Nusselt number) for nano-fluids with different concentrations used in different aspect ratios micro-channel heat sink are investigated. The examined nanofluid is and the control variables for numerical simulation are volume concentration and aspect ratio. The goal of this study is to find the optimal size of micro-channel heat sink with the best heat transfer performance. The results show that in the same channel size, nanofluids which have higher thermal conductivity than water can reduce the channel wall temperature near the inlet, increase the heat flux to fluid, and enhance convection. However, the increase of volume concentration will also raise the viscous force and cause larger pressure drop. With fixed channel width, to increase the channel aspect ratios can improve the effect of channel contraction and result in the decrease in pressure drop, the increase in mass flow rate, and the effective decrease in channel wall temperature and maximum temperature of heated surface as well. The overall thermal resistance will therefore decrease and better cooling performance can be achieved. In addition, the mass flow rate will increase with the increasing of the number of channel, channel width, and aspect ratio. Fluids can carry more heat and the overall thermal resistance will therefore pronouncedly decrease.