Tailoring the fluid flow distribution in a parallel mini-channel heat sink under multiple-peak heat flux

Abstract Thermal performance of microchannel heat sink can be augmented by designing inlet/outlet manifolds such that fluid flow distribution is uniform across microchannels. In this work, the effect of inlet/outlet manifold configurations on the thermo-hydrodynamic performance of recharging microchannel heat sink (RMCHS) is investigated numerically. For this purpose branched, rectangular, trapezoidal, and triangular manifold configurations are considered. All the numerical simulations are performed for channel Reynolds number of 50–300 and constant heat flux of 10 W/cm2 applied on the substrate bottom surface of the RMCHS. The results reveal that branched manifold configuration shows uniform fluid flow distribution across all the microchannels of heat sink and also shows uniform temperature distribution on the substrate bottom surface of RMCHS. Branched manifold configuration reduces thermal resistance by 16% and enhances average Nusselt number by 9.5% compared to rectangular manifold configuration. However, branched manifold configuration shows higher pressure drop in spite of enhancements in thermal performance and flow distribution uniformity. Overall performance analysis indicates that RMCHS with branched manifold configuration can be advantageous for high heat flux removal applications if there is no restriction on pumping power requirement.

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Thermal Performance of Metal Foam Heat Sink With Pin Fins for Nonuniform Heat Flux Electronics Cooling

Journal of Electronic Packaging ◽

10.1115/1.4046756 ◽

2020 ◽

Vol 143 (1) ◽

Author(s):

Yongtong Li ◽

Liang Gong ◽

Minghai Xu ◽

Yogendra Joshi

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Heat Sink ◽

Heat Transfer Performance ◽

Metal Foam ◽

Electronics Cooling ◽

Flow Distribution ◽

Junction Temperature ◽

Transfer Performance ◽

Pin Fins

Abstract In this paper, a concept of metal foam heat sink with pin fins (MFPF heat sink) is proposed to improve the cooling performance of high-powered electronics with nonuniform heat flux. Numerical simulations are carried out to investigate the thermohydraulic performance of MFPF heat sink, and the metal foam (MF) heat sink and traditional pin fin (PF) heat sink are employed for comparison. The capability of MFPF heat sink in handling nonuniform heat flux is examined under different power levels. It indicates that the MFPF heat sink greatly enhances the heat transfer performance, due to the common effects of the improved flow distribution and enhanced overall effective thermal conductivity (ETC). Results also show that the MFPF heat sink promotes the improvement of the bottom wall temperature uniformity. Porosity has more pronounced effects on heat transfer performance of MFPF heat sink than pore density. A nonuniform distribution heat flux (15–80–15 W/cm2) can be successfully dissipated using the proposed MFPF heat sink with the junction temperature below 95 °C at Re of 500.

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Experimental Investigation on Fluid Flow in an Inclined Open Rectangular Microgrooves Heat Sink With Micro-PIV

Volume 4: Heat and Mass Transfer Under Extreme Conditions; Environmental Heat Transfer; Computational Heat Transfer; Visualization of Heat Transfer; Heat Transfer Education and Future Directions in Heat Transfer; Nuclear Energy ◽

10.1115/ht2013-17267 ◽

2013 ◽

Author(s):

Dong Yu ◽

Xuegong Hu ◽

Chaohong Guo ◽

Dawei Tang ◽

Fangyuan Sun ◽

...

Keyword(s):

Thin Film ◽

Heat Flux ◽

Fluid Flow ◽

Heat Sink ◽

Ccd Camera ◽

Micro Piv ◽

Corner Flow ◽

Meniscus Region ◽

The Right ◽

Flow Stage

The paper investigates the fluid flow in an inclined open rectangular microgrooves heat sink using LaVision-assembled micro-PIV system. The images of the accommodation stage and the corner flow stage at inclined 15 degrees angle with heat flux of 0.09W/cm2 were recorded by a CCD camera with the speed of 10 frames per second. The velocity profile at inclined 15 degrees angle with heat flux of 0.14W/cm2 was acquired by using the analyzing software DaVis 8.1. In accommodation stage, X-Y-Z scanning table was adjusted vertically and horizontally to investigate the velocity field of different focused planes. Results show that the experimental images of the accommodation stage and the corner flow stage verify the predictions proposed by Catton and Stroes that there exist accommodation stage and corner flow stage and no jump-like stage proposed by Nilson et al. Flow in microgroove driven by capillary force is very slow and the velocity is less than 1mm per second. In evaporating thin film region, from the left side to the right side of the microgroove, the velocity increases and velocity of the interface is the highest. In lower meniscus region, the velocity increases and then decreases.

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Numerical Evaluation of Clearance Requirements Around Obstructions in Finned Heat Sinks

Volume 1: Aerospace Heat Transfer; Computational Heat Transfer; Education; Environmental Heat Transfer; Fire and Combustion Systems; Gas Turbine Heat Transfer; Heat Transfer in Electronic Equipment; Heat Transfer in Energy Systems ◽

10.1115/ht2017-4715 ◽

2017 ◽

Author(s):

Steven Miner

Keyword(s):

Heat Transfer ◽

Fluid Flow ◽

Pressure Drop ◽

Temperature Rise ◽

Heat Sink ◽

Operating Temperature ◽

Flow Distribution ◽

Local Heat ◽

Heat Sinks ◽

Electronic Components

This study uses CFD to consider the effects of obstructions (bosses) on the fluid flow and heat transfer in finned heat sinks used for cooling electronic components. In particular, the effect of bosses, used for mounting components, on the fluid flow distribution and temperature distribution in the heat sink are evaluated. A typical heat sink has fins sandwiched between top and bottom plates, with electronic components mounted on the plates. The top and bottom plates spread the heat generated in the components to reduce the local heat flux. The fins substantially increase the heat transfer area, reducing the temperature rise from the coolant to the top and bottom plates. In this case a uniform distribution of flow across the heat sink can be achieved and there will be no localized hot spots. Ideally there are no protrusions into the finned portion of the heat sink which would cause disruptions in the uniform flow through the heat sink. However, a boss may be needed to bolt a component to the heat sink. The presence of the boss has three effects on the heat sink performance. The boss disrupts the flow in its immediate vicinity, increasing the thermal resistance. This will cause an increase in operating temperature at that location. In addition, the boss will change the flow distribution in the heat sink. Locations upstream and downstream of the boss may see reduced flow due to the obstruction, which in turn will cause an increase in operating temperature for these areas of the heat sink. Finally, the change in flow distribution may increase the pressure drop through the entire heat sink, increasing the power required to operate the system. The purpose of this study is to numerically evaluate the clearance requirements around circular bosses. Comparisons between an unobstructed heat sink and a heat sink with an obstruction are made for the maximum component temperature rise, the pressure drop and the flow distribution. Clearance ratios, diameter of the fin cut out to boss diameter, were varied from 1.1 to 3.3. The Reynolds number for the flow was varied from roughly 3000 to 70,000 based on the hydraulic diameter of flow passage.

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