scholarly journals Investigation on Heat Transfer Enhancement in Microchannel Using Al2O3/Water Nanofluids

2021 ◽  
Vol 2021 ◽  
pp. 1-9 ◽  
Author(s):  
Arunkumar Munimathan ◽  
T. Sathish ◽  
V. Mohanavel ◽  
Alagar Karthick ◽  
R. Madavan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
High Viscosity ◽  
Deionized Water ◽  
Transfer Performance ◽  
High Concentration ◽  
Rectangular Microchannel ◽  
Compact Size ◽  
Microchannel Cooling ◽  
Resistance Decrease

Nowadays, reducing heat generation in electronic devices while using microchannel cooling is used to solve this problem. Because the trend is globally marching toward the compact size, the component’s dimensions get smaller, but the warmth involved within the component increases. Studies of heat transfer rate are conducted to determine the effect of a fully heated microchannel conductor’s heat transfer performance. Experiments are performed using nanofluid Al2O3/water through a concentration percentage of 0.1% and 0.25% and deionized water through a microchannel conductor with 25 rectangular microchannel numbers with a dimension of ( 0.42 × 0.42 × 100 ) mm3. This present work deals with the effect of nanofluids and their concentration percentages. Finally, it concluded that better heat transfer performance was seen in nanofluids compared to deionized water. The reason is the high viscosity of nanofluid Al2O3/water due to these nanoparticles is deposited on the wall surface of the microchannel and outcomes trendy improvement in the heat transfer. Finally, a high concentration percentage of nanofluids revealed a practical improvement in the transfer of microchannel. As a result, 0.25% of the concentration percentage achieved a satisfactory result compared to the remaining fluids and almost 32.5% and 26% of thermal resistance decrease.

scholarly journals Entropy Generation and Heat Transfer Performance in Microchannel Cooling

Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 191 ◽  
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.

Numerical Investigation of a Crossflow Jet in a Rectangular Microchannel

2013 ◽  
Vol 284-287 ◽  
pp. 849-853
Author(s):  
Kok Cheong Wong
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Numerical Study ◽  
Three Dimensional ◽  
Horizontal Flow ◽  
Transfer Performance ◽  
Rectangular Microchannel ◽  
Transverse Jet ◽  
Nozzle Position ◽  
Jet Nozzle

The present numerical study is conducted in three dimensional to investigate the crossflow of an external round jet and a horizontal stream of microchannel flow. The results of heat transfer performance for the cases with and without transverse jet are compared. The patterns of different crossflow jet were analyzed to understand the flow and heat transfer characteristics. The effect of jet nozzle position on the heat transfer is investigated. Generally, the heat transfer performance increases with the jet Reynolds number. However, some cases of weak jet are found to cause lower heat transfer rate relative to the case without external jet. When vertical weak jet encounter strong horizontal flow, the horizontal flow is dominant that the jet cannot reach the microchannel bottom wall but imposes resistance to the horizontal flow. The investigation on the jet nozzle location shows that the jet nozzle location closer to the channel inlet gives better heat transfer performance.

Heat Transfer Enhancement in Micro-Domains Using Gas-Driven Liquid Film

2012 ◽  
Author(s):  
Farzad Houshmand ◽  
Yoav Peles ◽  
Michael Amitay
Keyword(s):  
Heat Transfer ◽  
Liquid Film ◽  
Gas Flow ◽  
Single Phase ◽  
Heat Transfer Performance ◽  
Main Stream ◽  
Transfer Performance ◽  
Rectangular Microchannel ◽  
Heated Area ◽  
The Impact

A liquid film has been introduced upstream of a heater in a microchannel with gas flow, and the impact on the heat transfer performance has been investigated. The shear force exerted by the gas flow on the gas-liquid interface drives the film and drags it downstream, onto the heated area. Distilled water was injected through a 350 μm circular hole in a main stream of Nitrogen in a 220 μm deep and 1.5 mm wide rectangular microchannel to enhance the heat transfer from a 1 mm × 1 mm heater. Average heat transfer coefficient was studied for different gas and liquid flow rates and compared with single-phase flow. Significant improvement in heat transfer performance was observed while the pressure drop in the channel was not increased dramatically.

scholarly journals Experimental Investigation on Pool Boiling Heat Transfer Performance Using Tungsten Oxide WO3 Nanomaterial-Based Water Nanofluids

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1922 ◽  
Author(s):  
Mohammed Saad Kamel ◽  
Ferenc Lezsovits
Keyword(s):  
Heat Transfer ◽  
Tungsten Oxide ◽  
Boiling Heat Transfer ◽  
Heat Transfer Performance ◽  
Volume Concentration ◽  
Pool Boiling ◽  
Deionized Water ◽  
Transfer Performance ◽  
Pool Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient

This study aims to experimentally investigate the pool boiling heat transfer coefficient behavior using tungsten oxide-based deionized water nanofluids and comparing them to deionized water as conventional fluid. The influence of different dilute volumetric concentrations (0.005%–0.05% Vol.) and applied heat fluxes were examined to see the effect of these parameters on the pool boiling heat transfer performance using nanofluids from a typical horizontal heated copper tube at atmospheric pressure conditions. Results demonstrated that the pool boiling heat transfer coefficient (PBHTC) for both deionized water and nanofluids increased with increasing the applied heat flux. The higher PBHTC enhancement ratio was 6.7% for a volume concentration of 0.01% Vol. at a low heat flux compared to the deionized water case. Moreover, the PBHTC for nanofluids was degraded compared to the deionized water case, and the maximum reduction ratio was about 15% for a volume concentration of 0.05% Vol. relative to the baseline case. The reduction in PBHTC was attributed to the deposition of tungsten oxide nanoflakes on the heating surface during the boiling process, which led to a decrease in the density of the nucleation sites.

Experimental Investigation of Single-Phase Microjet Array Impingement Cooling

2009 ◽  
Author(s):  
Eric A. Browne ◽  
Gregory J. Michna ◽  
Michael K. Jensen ◽  
Yoav Peles
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Single Phase ◽  
Heat Transfer Performance ◽  
Deionized Water ◽  
Transfer Performance ◽  
Transfer Coefficients ◽  
Impingement Cooling ◽  
Average Heat ◽  
Heat Transfer Coefficients

The heat transfer performance of two microjet arrays using degassed deionized water was investigated. The in-line jet arrays had a spacing of 250 μm, a standoff of 200 μm, and diameters of 54 and 112 μm. Average heat transfer coefficients were obtained for 150 < Red < 3300 and ranged from 80,000 to 414,000 W/m2-K. A heat flux of 1,110 W/cm2 was attained with 23 °C water and a surface temperature of 50 °C.

Experimental Investigation of Single-Phase Microjet Array Heat Transfer

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Eric A. Browne ◽  
Gregory J. Michna ◽  
Michael K. Jensen ◽  
Yoav Peles
Keyword(s):  
Heat Transfer ◽  
Single Phase ◽  
Heat Transfer Performance ◽  
Deionized Water ◽  
Transfer Performance ◽  
Transfer Coefficients ◽  
Number Range ◽  
Average Heat ◽  
Submerged Jet ◽  
Heat Transfer Coefficients

The heat transfer performance of two microjet arrays was investigated using degassed deionized water and air. The inline jet arrays had diameters of 54 μm and 112 μm, a spacing of 250 μm, a standoff of 200 μm (S/d=2.2 and 4.6, H/d=1.8 and 3.7), and jet-to-heater area ratios from 0.036 to 0.16. Average heat transfer coefficients with deionized water were obtained for 150≤Red≤3300 and ranged from 80,000 W/m2 K to 414,000 W/m2 K. A heat flux of 1110 W/cm2 was attained with 23°C inlet water and an average surface temperature of 50°C. The Reynolds number range for the same arrays with air was 300≤Red≤4900 with average heat transfer coefficients of 2500 W/m2 K to 15,000 W/m2 K. The effect of the Mach number on the area-averaged Nusselt number was found to be negligible. The data were compared with available correlations for submerged jet array heat transfer.

scholarly journals Heat Transfer Performance of R-1234ze(E) with the Effect of High-Viscosity POE Oil on Enhanced GEWA-B5H Tube

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2285
Author(s):  
Abhishek Kumar ◽  
Miao-Ru Chen ◽  
Jung-Hsien Wu ◽  
Kuo-Shu Hung ◽  
Li-Kang Su ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mass Fraction ◽  
Heat Transfer Performance ◽  
Saturation Temperature ◽  
Nucleate Boiling ◽  
High Viscosity ◽  
Heat Fluxes ◽  
Transfer Performance ◽  
Oil Viscosity ◽  
Low Viscosity

In this study, the heat transfer performance of high-viscosity polyol ester (POE) oil POEA-220 (220 cSt) with low-GWP (global warming potential) refrigerant R-1234ze(E) on enhanced GEWA-B5H tube was investigated at saturation temperatures of 10 °C, 0 °C, and −6 °C. The mass fraction of oil varied from 0.25% to 10%, and all the nucleate pool boiling data were measured at heat fluxes ranging from 10 kW/m2 to 90 kW/m2. The experimental results showed that the heat transfer performance of the R-1234ze(E)/POEA-220 mixtures were superior to the R-1234ze(E)/POEA-68 mixtures. At saturation temperatures of 0 °C and −6 °C, even a 10% mass fraction of the POEA-220 oil showed an enhancement in the HTC (heat transfer coefficient) compared to the pure refrigerant in the moderate heat flux range. On the other hand, for the R-1234ze(E)/POEA-68 mixtures, a 5% mass fraction of oil showed no enhancement in the HTC compared to pure refrigerant at the same saturation temperature. Moreover, at low saturation temperatures (0 °C and −6 °C), the enhancement in the HTC decreased with increasing mass fraction of low-viscosity oil POEA-68, whereas high-viscosity oil POEA-220 showed the highest enhancement in the HTC for a 5% mass fraction of oil at −6 °C saturation temperature compared to the pure refrigerant. The results indicate that for nucleate boiling, the effect of oil viscosity on heat transfer performance is negligible if it contains comparatively high thermal conductivity and low surface tension. In addition, the effect of surface aging on heat transfer performance for the GEAW-B5H tube with pure refrigerant was also reported.

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