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Active and passive cooling are the two possible methods for removing heat. An active cooling system is the one that involves the use of energy as opposed to passive cooling that uses no energy. Passive cooling methods are cost effective and more reliable than active cooling due to the absence of moving parts. Microchannel heat sink is one of high-tech devices that have widely considered passive cooling methods especially for electronics cooling. In this paper, the use of passive cooling methods in microchannel heat sink is comprehensively discussed. This paper also present the effects of some important parameters such as the type of channel types, surface roughness, fluid additives, and Reynolds number on the rate of heat transfer in microchannel heat sink. Finally, the conclusions and important summaries were presented according to the data collected. [ABSTRACT FROM AUTHOR]

In this article, turbulent flow characteristic of nanofluids is thoroughly reviewed. Turbulent flows have unique characteristics and are preferred in many industrial applications. Therefore, this paper reviews different techniques used to enhance heat transfer using nanofluids within turbulent regime. This paper also presents the effects of some important parameters such as nanoparticle type, nanoparticles concentration, and Reynolds number on heat transfer rate. Studies on numerical techniques are also discussed. Finally, the conclusions and important summaries are presented according to the data collected. [ABSTRACT FROM AUTHOR]

This article deals with numerical analysis of two-dimensional viscous fluid in modified square duct. A rectangular obstacle with constant temperature at walls is placed inside it. Flow duct is depicted in Figs. 1 and 2. Influence of Prandtl number and geometry on heat transfer of working fluid is studied in two cases. Computation for the present model is made in commercial package ANSYS-Fluent. Calculations are carried at two different values of Reynolds numbers i.e., Re 40 and 200 for each of the cases. Liquid water (H 2 0) and Liquid Aniline (C 6 H 5 NH 2) are taken as working fluids. Stream functions, isotherms, vorticity, velocity and pressure profiles are examined. Graphical data for C f and Nu is presented to analyze the effect of Reynolds number and Prandtl number on heat transfer. Thermal boundary layers are discussed in each of the cases. It is shown that heat transfer has high dependance on Reynolds number and Prandtl number. Geometry of the problem has noticeable effect on heat transfer. [ABSTRACT FROM AUTHOR]