Enhancement of heat transfer performance of water using nanoparticles

2018 ◽  
Author(s):  
N. A. M. Amran ◽  
H. Mohamed ◽  
P. Gunnasegaran ◽  
M. Satgunam ◽  
I. N. Ismail ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Enhancement Of Heat Transfer

Effects of Al2O3-Water Nanofluid and Angular Orientation on Entropy Generation and Convective Heat Transfer of an Elliptical Micro-Pin-Fin Heat Sink

2014 ◽  
Author(s):  
Husam Rajab ◽  
Da Yin ◽  
Hongbin Ma
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Volume Fraction ◽  
Al2o3 Nanoparticles ◽  
Transfer Performance ◽  
Enhancement Of Heat Transfer ◽  
Pin Fin ◽  
Prandtl Numbers

This paper presents an investigation of the effect of nanofluid on the heat transfer performance in an elliptical micro-pin-fin heat sink including the influence of entropy generation and pin orientation. The orientation angle of pins is decreased with the number of pins in the array with a 90 degree angle for the first pin and a 0 degree angle for the last pin. To study the flow and heat transfer behaviors in a micro-pin-fin heat sink, steady Navier-Stokes and energy equations were discretized using a finite volume approach and were solved iteratively. Deionized (DI) water was used as a base coolant fluid while aluminum oxide (Al2O3) nanoparticles were used in the present study with mean diameters of 41.6 nm. The results showed that (1) changing the angular orientation of pins can cause significant enhancement in heat transfer, (2) a significant enhancement of heat transfer can be attained in the system due to the suspension of Al2O3 nanoparticles in the base fluid in comparison with pure water, (3) enhancement of heat transfer is intensified with increasing volume fraction of nanoparticles and Reynolds and Prandtl numbers, (4) increasing volume fraction of nanoparticles, which is responsible for higher heat transfer performance, leads to a higher pressure drop, (5) using nanofluids as coolant can cause lower heat transfer entropy generation due to their high thermal properties, and (6) with increasing volume fraction and Reynolds and Prandtl numbers, overall entropy generation rate decreases.

Influence of Microscale Surface Modification on Impinging Flow Heat Transfer Performance

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
T. J. Taha ◽  
L. Lefferts ◽  
T. H. Van der Meer
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Heat Transfer Performance ◽  
Deposition Process ◽  
Silicon Sample ◽  
Transfer Performance ◽  
Surface Area Ratio ◽  
Enhancement Of Heat Transfer ◽  
Flow Heat ◽  
Impinging Flow

An experimental approach has been used to investigate the influence of a thin layer of carbon nanotubes (CNTs) on the convective heat transfer performance under impinging flow conditions. A successful synthesis of CNT layers was achieved using a thermal catalytic vapor deposition process (TCVD) on silicon sample substrates. Three different structural arrangements, with fully covered, inline, and staggered patterned layers of CNTs, were used to evaluate their heat transfer potential. Systematic surface characterizations were made using scanning electron microscope (SEM) and confocal microscopy. The external surface area ratio of fully covered, staggered, and inline arrangement was obtained to be 4.57, 2.80, and 2.89, respectively. The surface roughness of the fully covered, staggered, and inline arrangement was measured to be (Sa = 0.365 μm, Sq = 0.48 μm), (Sa = 0.969 μm, Sq = 1.291 μm), and (Sa = 1.668 μm, Sq = 1.957 μm), respectively. On average, heat transfer enhancements of 1.4% and − 2.1% were obtained for staggered and inline arrangement of the CNTs layer. This is attributed to the negligible improvement on the effective thermal resistance due to the small area coverage of the CNT layer. In contrast, the fully covered samples enhanced the heat transfer up to 20%. The deposited CNT layer plays a significant role in reducing the effective thermal resistance of the sample, which contributes to the enhancement of heat transfer.

Numerical Investigation of Array Impingement Heat Transfer on the Target With Advanced Pin Fins

2021 ◽  
Author(s):  
Tao Guo ◽  
Yun-Peng Ben ◽  
Yu-Chao Liu ◽  
Cun-Liang Liu ◽  
Hui-Ren Zhu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Hole Diameter ◽  
Transfer Performance ◽  
Target Plate ◽  
Enhancement Of Heat Transfer ◽  
Pin Fin ◽  
Plate Spacing ◽  
Impingement Heat Transfer ◽  
Pin Fins

Abstract The paper proposes a technique of using advanced pin fins on a target plate to improve the impingement heat transfer performance in an array impingement cooling system. The initial shape of the advanced pin fin is a frustum of a cone. In order to enhance heat transfer and reduce flow resistance, the upper and lower sharp edges of the frustum of a cone are rounded. There are arrays of film holes on the target plate, and the influence of the crossflow is not considered. The flow and heat transfer characteristics of the array impingement flat plate and advanced pin fin plate were studied by numerical simulation. During the numerical simulation, the Reynolds number was varied from 2000 to 19500, the jet-to-plate spacing Z/d from 3 to 6 (d = 0.50mm) and the jet hole diameter d is 0.50 mm, 0.75 mm and 1.00 mm respectively. The results show that the averaged Nusselt number values for the advanced pin fin target plate showed an increase ranging from 15% to 20% over those for the flat target plate, It is generally considered that the enhancement of heat transfer is mainly due to the enhancement of fluid disturbance by the pin fins. However, by changing the size of the pin fins, it is found that the enhancement of heat transfer is mainly caused by the increase of heat transfer area, and the influence of enhancing the disturbance is not significant. The pressure loss is little higher than that of the flat plate. The averaged Nusselt number values for the advanced pin fin target plate decreases with the increase of the jet-to-plate spacing, and increases with the increase of Reynolds number. At the same mass flow rate, the averaged heat transfer performance of the pin fin target plate decreases with the increase of jet hole diameter, and the results show that the averaged heat transfer performance of 0.5mm jet hole diameter is the best.

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