Pr > 1 unsteady thermal flows and heat transfer in a finned cavity with a uniform heat flux

Non-uniform heat fluxes are commonly observed in thermo-electronic devices that require distinct thermal management strategies for effective heat dissipation and robust performance. The limited research available on non-uniform heat fluxes focus mostly on microchannel heat sinks while the fundamental component, i.e. a single microchannel, has received restricted attention. In this work, an experimental setup for the analysis of variable axial heat flux is used to study the heat transfer in a single microchannel with fully developed flow under the effect of different heat flux profiles. Initially a hot spot at different locations, with a uniform background heat flux, is studied at different Reynolds numbers while varying the maximum heat fluxes in order to compute the heat transfer in relation to its dependent variables. Measurements of temperature, pressure, and flow rates at a different locations and magnitudes of hot spot heat fluxes are presented, followed by a detailed analysis of heat transfer characteristics of a single microchannel under non-uniform heating. Results showed that upstream hotspots have lower tube temperatures compared to downstream ones with equal amounts of heat fluxes. This finding can be of importance in enhancing microchannel heat sinks effectiveness in reducing maximum wall temperatures for the same amount of heat released, by redistributing spatially fluxes in a descending profile.

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An investigation of heat transfer characteristics of swirling flow in a 180° circular section bend with uniform heat flux

KSME International Journal ◽

10.1007/bf02982331 ◽

2003 ◽

Vol 17 (10) ◽

pp. 1520-1532 ◽

Cited By ~ 2

Author(s):

Tae-Hyun Chang

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Swirling Flow ◽

Uniform Heat Flux ◽

Heat Transfer Characteristics ◽

Circular Section ◽

Transfer Characteristics ◽

Uniform Heat

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Investigation on Convective Heat Transfer over a Rotating Disk with Bottom Wall Subjected to Uniform Heat Flux

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.249-250.443 ◽

2012 ◽

Vol 249-250 ◽

pp. 443-451

Author(s):

Jing Zhou Zhang ◽

Xiao Ming Tan ◽

Xing Dan Zhu

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Convective Heat Transfer ◽

Convective Heat ◽

Numerical Study ◽

Rotating Disk ◽

Outer Radius ◽

Bottom Wall ◽

Uniform Heat Flux ◽

Uniform Heat

A three-dimensional numerical study on the flow and heat transfer characteristics over a rotating disk with bottom wall subjected to uniform heat flux was conducted with the use of RNG k- turbulent model. And some experiments were also made for validation. The effects of rotating angular speed and pin configuration on the temperature maps and convective heat transfer characte-ristics on rotating surface are analyzed. As the increase of rotating velocity, the impingement of pumping jet on the centre of rotating disk became stronger and the transition from laminar to turbu-lent occurred at the outer radius of rotating disk, which resulted in heat transfer enhancement. The pins on the disk made the pumping action of a rotating disk weaker. Simultaneously, they also acted as disturbing elements to the cyclone flow near the rotating disk surface, which made the overall heat transfer to be enhanced. Under the same extend areas of different pins, needle pin has higher convective heat transfer capacity than the discrete ring pin.

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