Title: Laminar heat transfer characteristics in entry region in micro-channels

Authors: Tiantian Zhang, Li Jia, Lixin Yang

Addresses: School of Mechanical and Electronic Control Engineering, Beijing Jiaotong University, Beijing 100044, China. ' School of Mechanical and Electronic Control Engineering, Beijing Jiaotong University, Beijing 100044, China. ' School of Mechanical and Electronic Control Engineering, Beijing Jiaotong University, Beijing 100044, China

Abstract: Heat transfer characteristics in entry region of microchannels are numerically investigated. It is found that the temperature gradient near the walls is very large. Thermal entry length in microchannels is much larger than that in conventional channels. Theoretical analysis is given to explain them. We found entrance effect is a key factor that results in the incompatible conclusion that is obtained in the available literatures. The explanation is given in details. Also the effects of Reynolds number, hydrodynamic diameter, length diameter ratio, height-to-width ratio and wall temperature on thermal entry length were analysed. The correlation among these parameters is established.

Keywords: microchannels; numerical simulation; thermal boundary layer; entrance effect; thermal entry length; laminar heat transfer; fluid flow; CFD; computational fluid dynamics.

DOI: 10.1504/PCFD.2010.033329

Progress in Computational Fluid Dynamics, An International Journal, 2010 Vol.10 No.3, pp.177 - 185

Available online: 25 May 2010 *

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