Wettability Effects on Heat Transfer

Choi, Chiwoong; Kim, Moo-Hwan

doi:10.5772/19512

Cited by 12 publications

(13 citation statements)

References 80 publications

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“…The wettability is an effective parameter for the heat transfer coefficient and the friction factor, especially for heat transfer to two-phase flow, and higher contact angle surfaces tend to decrease the heat transfer coefficient compared with the lower contact angle surfaces. 46 The initial equilibrium contact angle of the nanofluids was significantly affected by the nanoparticle sizes and concentrations. Nanofluid molecules tumble along the tube wall, similar to two solid surfaces sliding over one another, when the forces between the nanofluid and the tube wall molecules are not strong enough to overcome the shear forces at the wall.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

Experimental Investigation of Convective Heat Transfer Using Graphene Nanoplatelet Based Nanofluids under Turbulent Flow Conditions

Sadeghinezhad

Latibari

Mehrali

et al. 2014

Ind. Eng. Chem. Res.

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An experimental investigation was performed to evaluate the heat transfer characteristics and the pressure drop of a graphene nanoplatelet (GNP) nanofluid in a horizontal stainless steel tube that was subjected to a uniform heat flux at its outer surface. The thermal conductivity and viscosity of the GNP nanofluids at concentrations of 0.025, 0.05, 0.075, and 0.1 wt % were measured prior to the heat transfer experiments. The heat transfer and the pressure drop within the flowing base fluid (distilled water) were measured and compared with the corresponding data from the correlations. The data were satisfied within a 5% error and a 95% confidence level. The effects of the nanoparticle concentration and the heat flux on the enhancement of the heat transfer turbulent flow condition are presented. The convective heat transfer coefficient of the GNP nanofluid is higher than that of the base fluid by approximately 13–160%. Further, the heat transfer coefficient of the GNP nanofluid increased as the flow rate and the heat flux increased. However, the increase in the pressure drop ranged from 0.4% to 14.6%. Finally, an analysis of the thermal performance factor reveals that the GNP nanofluids at concentrations of 0.075 and 0.1 wt % could function as a good and alternative conventional working fluid in heat transfer applications.

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Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

Experimental Investigation of Convective Heat Transfer Using Graphene Nanoplatelet Based Nanofluids under Turbulent Flow Conditions

Sadeghinezhad

Latibari

Mehrali

et al. 2014

Ind. Eng. Chem. Res.

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“…However, this reaction is controlled by the molecular interaction between the different phases. 42 , 43 Other factors such as surface tension and surface energy are also determined by surface wettability. 44 …”

Section: Surface Propertiesmentioning

confidence: 99%

“…The weak solids like fluorocarbons and hydrocarbons have a low energy, where liquid molecules would take a very low energy to break them providing a complete or partial wetting depending on the liquid chosen. 42 , 45 …”

Section: Surface Propertiesmentioning

confidence: 99%

Impact of surface topography and coating on osteogenesis and bacterial attachment on titanium implants

et al. 2018

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Titanium (Ti) plays a predominant role as the material of choice in orthopaedic and dental implants. Despite the majority of Ti implants having long-term success, premature failure due to unsuccessful osseointegration leading to aseptic loosening is still too common. Recently, surface topography modification and biological/non-biological coatings have been integrated into orthopaedic/dental implants in order to mimic the surrounding biological environment as well as reduce the inflammation/infection that may occur. In this review, we summarize the impact of various Ti coatings on cell behaviour both in vivo and in vitro. First, we focus on the Ti surface properties and their effects on osteogenesis and then on bacterial adhesion and viability. We conclude from the current literature that surface modification of Ti implants can be generated that offer both osteoinductive and antimicrobial properties.

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“…The wettability of the surface has a great influence on heat exchange, because it influences the type of motion that is established between surface and fluid. The impact of wettability effect on heat transfer was studied in [10]. The effect of contact angle (or surface wettability) on the convective heat transfer coefficient in microchannels was studied in [11], while a correlation between the contact angle and the wetting properties is proposed in [12].…”

Section: State Of the Artmentioning

confidence: 99%

Use of Nanostructured Coating to Improve Heat Exchanger Efficiency

Bonanno

Raimondo

Pinelli

2019

Factories of the Future

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This work investigates the potential of surface nano-coatings on the heat transfer surface of heat exchangers, in order to improve their overall efficiency in terms of pressure drop and heat power exchanged. The work started from the consideration that, due to the increasingly strict international standards, the machines will be provided with optimized engines with new and improved devices to reduce the exhaust emissions (liquid cooled EGR valves, new catalytic converters and DPF systems) which reduce inevitably the space in the engine compartment. In this paper it is studied the feasibility of the coating processes and the adaptability of deposition techniques to the industrial production process of cross flow heat exchanger fins. The innovative exchanger performance, investigated using dedicated test rigs, shows that the results are influenced by the coating technology. 13.1 Scientific and Industrial Motivations Heat exchanger efficiency is one of the main concerns in trying to improve the overall efficiency of mobile off-road machines and industrial plants. Compact radiators play a fundamental role in temperature control of internal combustion engines (ICE) and hybrid drivelines. An improvement of this component could affect the global efficiency of the machine. Typically, the problem is studied from a geometrical point of view, using different production lines to make fins geometries dedicated to improve the heat exchange or to reduce the pressure drop. Heat exchanger optimization is needed to obtain smaller, lighter, but at the same time more efficient radiators.

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Wettability Effects on Heat Transfer

Cited by 12 publications

References 80 publications

Experimental Investigation of Convective Heat Transfer Using Graphene Nanoplatelet Based Nanofluids under Turbulent Flow Conditions

Experimental Investigation of Convective Heat Transfer Using Graphene Nanoplatelet Based Nanofluids under Turbulent Flow Conditions

Impact of surface topography and coating on osteogenesis and bacterial attachment on titanium implants

Use of Nanostructured Coating to Improve Heat Exchanger Efficiency

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