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


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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    • "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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    ABSTRACT: Heat sinks are widely used for cooling electronic devices and systems. Their thermal performance is usually determined by the material, shape, and size of the heat sink. With the assistance of computational fluid dynamics (CFD) and surrogate-based optimization, heat sinks can be designed and optimized to achieve a high level of performance. In this paper, the design and optimization of a plate-fin-type heat sink cooled by impingement jet is presented. The flow and thermal fields are simulated using the CFD simulation; the thermal resistance of the heat sink is then estimated. A Kriging surrogate model is developed to approximate the objective function (thermal resistance) as a function of design variables. Surrogate-based optimization is implemented by adaptively adding infill points based on an integrated strategy of the minimum value, the maximum mean square error approach, and the expected improvement approaches. The results show the influence of design variables on the thermal resistance and give the optimal heat sink with lowest thermal resistance for given jet impingement conditions.
    IEEE Transactions on Components, Packaging, and Manufacturing Technology 03/2014; 4(3):429-437. DOI:10.1109/TCPMT.2013.2285812 · 1.18 Impact Factor
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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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    ABSTRACT: The present work focuses on analytical optimization of a rectangular microchannel heat sink using aqueous carbon nanotubes based nanofluid as coolant. The particles weight concentration used in this study is 0.01%. The density, the thermal conductivity and the rheological behavior of the nanofluid are experimentally investigated in order to evaluate the thermal resistance and the pumping power in microchannel under laminar flow. An analytical approach of optimization scheme was applied; it is compiled from a systematic thermal resistance model as an analysis method and the elitist non-dominated sorting genetic algorithm (NSGA2). The effects of the temperature, the channel aspect ratio, the channel wall ratio and the use of aqueous carbon nanotubes based nanofluid on the thermal resistance and the pumping power are investigated. The optimized results showed that use of the nanofluid as a working fluid reduce the total thermal resistance and can enhance significantly the thermal performances of the working fluid at high temperatures.
    Applied Thermal Engineering 01/2014; 62:492-499. DOI:10.1016/j.applthermaleng.2013.08.005 · 2.74 Impact Factor
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    • "However, the associated issues of the high pumping power demands [1] [2], leakage [3], and passage clogging [4] in the case of the nanofluids usage, have not been fully addressed. Air was used as an alternative coolant in many microchannel heat sink systems [5] [6] [7]. However, its poor heat removal capabilities [8] have limited its applications. "
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    ABSTRACT: In this paper, the optimization of the cooling performance of a rectangular microchannel heat sink is investigated with four different gaseous coolants; air, ammonia gas, dichlorodifluoromethane (R-12) and chlorofluoromethane (R-22). A systematic robust thermal resistance model together with a methodical pumping power calculation is used to formulate the objective functions, the thermal resistance and pumping power. The non-dominated sorting genetic algorithm (NSGA-II), a multi-objective algorithm, is applied in the optimization procedure. The optimized thermal resistances obtained are 0.178, 0.14, 0.08 and 0.133°K/W for the pumping powers of 6.4, 4, 22.4 and 16.5 W for air, ammonia gas, R-12 and R-22, respectively. These results show that among all the gaseous coolants investigated in the current study, ammonia gas exhibited balanced thermal and hydrodynamic performances. Due to the Montreal Protocol, the coolant R-12 is no longer produced while R-22 will eventually be phased out. The results from ammonia provide a strong motivation to conduct more investigations on the potential usage of this gaseous coolant in the electronic cooling industry.
    Procedia Engineering 01/2013; 56:337–343. DOI:10.1016/j.proeng.2013.03.128
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