Effects of longitudinal vortex generator pairs in transverse microchambers on thermal–hydraulic performances and entropy generation in an interrupted microchannel heat sink

This study applied the commercial software ANSYS CFD (FLUENT), for simulating the transient flow field and investigating the influence of each parameter of longitudinal vortex generators (LVGs) on the thermal flux of a plate-fin heat sink. Vortex generator was set in front of plate-fin heat sink and under the channel, which was in common-flow-down (CFD) and common-flow-up (CFU) conditions, which have the result of vortex generator of delta winglet pair (DWP). In this study the parameters were varied, such as the minimum transverse distance between winglet pair, the attack angle of the vortex generator, fins number, the fin height, and the distance between the vortex generator and plate-fin. The coolant fluid flew into the fin-to-fin channel and pushed the vortex from different geometry toward the bottom. This phenomenon took off the heat from the plate to enhance the heat transfer. The numerical results indicated that the LVGs located close to the plate-fin heat sink are zero with the attack angle being 30°, presenting optimal overall conditions.

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Effect of Magnetic Field on Entropy Generation in a Microchannel Heat Sink with Offset Fan Shaped

Entropy ◽

10.3390/e18010010 ◽

2015 ◽

Vol 18 (1) ◽

pp. 10 ◽

Cited By ~ 8

Author(s):

Mohammad Nasiri ◽

Mohammad Rashidi ◽

Giulio Lorenzini

Keyword(s):

Magnetic Field ◽

Entropy Generation ◽

Heat Sink ◽

Microchannel Heat Sink

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Constructal Optimization of Rectangular Microchannel Heat Sink with Porous Medium for Entropy Generation Minimization

Entropy ◽

10.3390/e23111528 ◽

2021 ◽

Vol 23 (11) ◽

pp. 1528

Author(s):

Wenlong Li ◽

Zhihui Xie ◽

Kun Xi ◽

Shaojun Xia ◽

Yanlin Ge

Keyword(s):

Heat Flux ◽

Aspect Ratio ◽

Entropy Generation ◽

Heat Sink ◽

Width Ratio ◽

Microchannel Heat Sink ◽

Rectangular Microchannel ◽

Entropy Generation Minimization ◽

Aspect Ratios ◽

Length Width

A model of rectangular microchannel heat sink (MCHS) with porous medium (PM) is developed. Aspect ratio of heat sink (HS) cell and length-width ratio of HS are optimized by numerical simulation method for entropy generation minimization (EGM) according to constructal theory. The effects of inlet Reynolds number (Re) of coolant, heat flux on bottom, porosity and volume proportion of PM on dimensionless entropy generation rate (DEGR) are analyzed. From the results, there are optimal aspect ratios to minimize DEGR. Given the initial condition, DEGR is 33.10% lower than its initial value after the aspect ratio is optimized. With the increase of Re, the optimal aspect ratio declines, and the minimum DEGR drops as well. DEGR gets larger and the optimal aspect ratio remains constant with the increasing of heat flux on bottom. For the different volume proportion of PM, the optimal aspect ratios are diverse, but the minimum DEGR almost stays unchanged. The twice minimized DEGR, which results from aspect ratio and length-width ratio optimized simultaneously, is 10.70% lower than the once minimized DEGR. For a rectangular bottom, a lower DEGR can be reached by choosing the proper direction of fluid flow.

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Parametric study of heat transfer performance including entropy generation of microchannel heat sink with fan cavity and different rib structure

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/09544089211043409 ◽

2021 ◽

pp. 095440892110434

Author(s):

K. Bala Subrahmanyam ◽

Aparesh Datta ◽

Pritam Das

Keyword(s):

Heat Transfer ◽

Entropy Generation ◽

Heat Sink ◽

Heat Transfer Performance ◽

Microchannel Heat Sink ◽

Transfer Performance ◽

Bulk Fluid ◽

Simultaneous Application ◽

Entropy Generation Number ◽

Generation Number

This numerical study investigates the simultaneous application of axial wall conduction effect and entropy generation minimization as two principles to identify heat transfer performance in a microchannel heat sink with fan cavity and ribs. In this conjugate analysis, three different materials for a microchannel heat sink considered are silicon, aluminium, and copper. In addition to the fan cavity (F), effects of different rib configurations arranged symmetrically inside the fan cavity, that is, backward triangle rib (FB), rectangular rib (FR), forward triangle rib (FF), and diamond rib (FD) with Reynolds numbers ranging from 136 to 588 are studied. The comparative study between silicon and copper in terms of local wall and bulk fluid temperatures, increment in solid wall to fluid thermal conductivity ratio within the range (247.07 < ksf < 669.44), local Nusselt number (Nu x), axial conduction number (M), and entropy generation number ( Ns, a) were furnished and examined. Structural optimization is performed on diamond rib configuration geometrical parameters to observe entropy generation number and wall conduction effects trend as thermal performance is greatly improved to 2.49, at the lowest Ns, a to 0.31 at Re 391.47, with copper in the back to back cavities case. However based on the numerical results, comparative importance of axial wall conduction effect consideration in the present design of microsink, silicon is showing best results in overcoming at Re 588.4, consistently in all optimization cases.

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