Numerical investigation on heat transfer performance and flow characteristics in a rectangular air cooling channel (AR = 2) with ridged dimples

Air jet impingement is one of the effective cooling techniques employed in micro-electronic industry. To enhance the heat transfer performance, a cooling system with air jet impingement on a finned heat sink is evaluated via the computational fluid dynamics method. A two-dimensional confined slot air impinging on a finned flat plate is modeled. The numerical model is validated by comparison of the computed Nusselt number distribution on the impingement target with published experimental results. The flow characteristics and heat transfer performance of jet impingement on both of smooth and finned heat sinks are compared. It is observed that jet impingement over finned target plate improves the cooling performance significantly. A dimensionless heat transfer enhancement factor is introduced to quantify the effect of jet flow Reynolds number on the finned surface. The effect of rectangular fin dimensions on impingement heat transfer rate is discussed in order to optimize the cooling system. Also, the computed flow and thermal fields of the air impingement system are examined to explore the physical mechanisms for heat transfer enhancement.

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Entropy Generation and Heat Transfer Performance in Microchannel Cooling

Entropy ◽

10.3390/e21020191 ◽

2019 ◽

Vol 21 (2) ◽

pp. 191 ◽

Cited By ~ 5

Author(s):

Jundika Kurnia ◽

Desmond Lim ◽

Lianjun Chen ◽

Lishuai Jiang ◽

Agus Sasmito

Keyword(s):

Heat Transfer ◽

Entropy Generation ◽

Heat Transfer Performance ◽

Second Law Of Thermodynamics ◽

High Heat ◽

Heat Fluxes ◽

Transfer Performance ◽

Cooling Channel ◽

High Heat Transfer ◽

Microchannel Cooling

Owing to its relatively high heat transfer performance and simple configurations, liquid cooling remains the preferred choice for electronic cooling and other applications. In this cooling approach, channel design plays an important role in dictating the cooling performance of the heat sink. Most cooling channel studies evaluate the performance in view of the first thermodynamics aspect. This study is conducted to investigate flow behaviour and heat transfer performance of an incompressible fluid in a cooling channel with oblique fins with regards to first law and second law of thermodynamics. The effect of oblique fin angle and inlet Reynolds number are investigated. In addition, the performance of the cooling channels for different heat fluxes is evaluated. The results indicate that the oblique fin channel with 20° angle yields the highest figure of merit, especially at higher Re (250–1000). The entropy generation is found to be lowest for an oblique fin channel with 90° angle, which is about twice than that of a conventional parallel channel. Increasing Re decreases the entropy generation, while increasing heat flux increases the entropy generation.

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A Comparison on the Heat Transfer and Flow Characteristics of TiO2-Water Nanofluids Having Two Different Chemical Agents

ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels: Parts A and B ◽

10.1115/fedsm-icnmm2010-31020 ◽

2010 ◽

Author(s):

Weerapun Duangthongsuk ◽

Somchai Wongwises

Keyword(s):

Heat Transfer ◽

Heat Transfer Performance ◽

Volume Fraction ◽

Particle Volume Fraction ◽

Flow Characteristics ◽

Average Diameter ◽

Transfer Performance ◽

Particle Volume ◽

Tube Heat Exchanger ◽

Two Samples

Heat transfer performance and flow characteristics of aqueous TiO2 nanofluids with particle volume fraction of 0.2% flowing under turbulent flow regime are investigated. The test section is a 1.5 m long counter-flow double tube heat exchanger. Two different nanofluids are used as working fluids at the same concentration. Firstly, TiO2 nanoparticles with mean diameters of 21 nm mixed with small amount of CTAB (about 0.01%) named “SAM 1”. Secondly, VP Disp. W740x provided by DEGUSSA AG Company is used and called “SAM 2”. The latter mixture is composed of TiO2 nanoparticle with average diameter of 21 nm dispersed in water. The pH values of nanofluid SAM 1 and SAM 2 are 7.6 and 7.5, respectively. The heat transfer performance and friction characteristics of two samples of nanofluid were presented. In addition, the Nusselt numbers predicted from the published correlation for nanofluids are compared with the present experimental data.

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