Conference Paper

Optimization of Microchannel Heat Sinks Using Entropy Generation Minimization Method

Department of Mechanical and Mechatronics Engineering, University of Waterloo, Ватерлоо, Ontario, Canada
DOI: 10.1109/STHERM.2006.1625210 Conference: Semiconductor Thermal Measurement and Management Symposium, 2006 IEEE Twenty-Second Annual IEEE
Source: IEEE Xplore

ABSTRACT

In this study, an entropy generation minimization (EGM) procedure is employed to optimize the overall performance of microchannel heat sinks. This allows the combined effects of thermal resistance and pressure drop to be assessed simultaneously as the heat sink interacts with the surrounding flow field. New general expressions for the entropy generation rate are developed by considering an appropriate control volume and applying mass, energy, and entropy balances. The effect of channel aspect ratio, fin spacing ratio, heat sink material, Knudsen numbers and accommodation coefficients on the entropy generation rate is investigated in the slip flow region. Analytical/empirical correlations are used for heat transfer and friction coefficients, where the characteristic length is used as the hydraulic diameter of the channel. A parametric study is also performed to show the effects of different design variables on the overall performance of microchannel heat sinks

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    • "This term, found in (2), can be determined with (10), where a relation is made between pressure drop due to load loss and to channel inlet and outlet, as a function of the average density of the fluid , of the average velocity of the fluid , of the Darcy friction factor , of the length or depth of the channel , of the hydraulic diameter , and of the relation given by , respectively[13]. "
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    ABSTRACT: This article describes the design of an optimal rectangular microchannel made of a high thermal conductive graphite (HTCG). For simulating the proposed microchannel heat sink, the total resistance model and the entropy generation minimization criterion were used. For solving the optimization problem, the unifi ed particle swarm optimization algorithm (UPSO), was used. Results showed a marked effect of using this high thermal conductor when compared to traditional materials, such as aluminum, and while using air and ammonia gas as the working fl uids. It is also reported the relative effect of the constriction, convective and fl uid thermal resistances on the overall equivalent thermal resistance. As a demonstrative example when changing the nature of the coolant, a titanium dioxide nanofl uid was selected. It was found that the Nusselt number is perceptibly lower, when the coolant is a nanofl uid and the material for the making of the microchannel is an HTCG.
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    • "In the literature, there has been a significant amount of research work published on the heat dissipation of heat sink through experimental [11]–[13], analytical [15], [16], and numerical studies [17]–[19]. Thermal characteristics of heat sinks under jet impingement can be experimentally studied with a good accuracy. "
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    • "Day after day, researchers realized that the basic capabilities of the microchannel heat sinks are not sufficient enough to perform effective cooling on the present ear ICs. Therefore, unlimited efforts were devoted to enhance the capabilities of the microchannel heat sinks using different structural material [3] [4] [5] [6], different channel geometries [7] [8] [9] [10] and different coolants [11] [12] [13]. The use of different materials and channel geometries have almost reached to their optimum stage, significant improvement in the overall performance of the microchannel heat sinks could not be achieved. "
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