Convective heat transfer and pressure drop characteristics of graphene-water nanofluids in transitional flow

Demirkır, Çayan; Ertürk, Hakan

doi:10.1016/j.icheatmasstransfer.2020.105092

Cited by 33 publications

(22 citation statements)

References 44 publications

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“…Additionally, as seen in Figure 5 , the heat transfer coefficient was found to generally increase as the Reynolds number increased. This may be due to an increase in the amount of random particle motion [ 5 ]. The effects of base liquid, possible surfactant, concentration, and characteristics of nanoparticles (size, shape, and material) on thermal conductivity, viscosity and heat transfer coefficient were explained in detail in references [ 29 , 33 , 42 ].…”

Section: Resultsmentioning

confidence: 99%

“…The flow regime experienced by the nanofluid may significantly affect the heat transfer coefficient. Demirkir and Erturk [ 5 ] found that for a nanofluid traveling through a circular pipe, the heat transfer coefficient increases as the Reynolds number increases, concluding that the heat transfer coefficient increases as the flow regime becomes turbulent. This may be due to an increase in fluid random motion [ 42 ].…”

Section: Brief Review On Optimization Of Effects Of Nanoparticlesmentioning

confidence: 99%

“…Demirkir and Erturk [ 5 ] examined the characteristics of a graphene-water nanofluid in transitional flow for volume concentrations of 0.025%, 0.1%, and 0.2%. The nanofluid was pumped through a 2.1 m long copper pipe with an inner diameter of 6 mm and exposed to a constant heat flux.…”

Section: Brief Review On Optimization Of Effects Of Nanoparticlesmentioning

confidence: 99%

“… Convective heat transfer coefficient with respect to Reynolds Number over the laminar and turbulent flow regimes for various water-based nanofluids: 0.9% Ag at 48 °C [ 43 ], 0.2% Graphene with constant heat flux [ 5 ], 15 nm SiO 2 [ 44 ]. …”

Section: Figurementioning

confidence: 99%

“…Additionally, the solid particles may cause increased mixing and higher turbulence in the fluid, leading to improved energy transfer between fluid layers. It was also found that modifying the concentration [ 2 ], shape [ 2 ], size [ 3 , 4 ], and flow regime [ 5 ] of a nanofluid may affect the heat transfer coefficient.…”

Section: Introductionmentioning

confidence: 99%

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Heat Transfer Enhancement in the Microscale: Optimization of Fluid Flow

et al. 2022

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The focus of this paper is to investigate the effects of the addition of a connector between two serial microchannels. The idea of adding connector at the inlet of microchannels to enhance the random motion of molecules or nanoparticles in low Reynolds numbers was developed in our research group for the first time. It was experimentally determined that the shape of a connector between two microchannels has a significant impact on the enhancement of the random motion of molecules or nanoparticles. Consequently, the heat transfer coefficient is improved inside the second microchannel. The connector is large enough to refresh the memory of the fluid before entering the second channel, causing a higher maximum heat transfer coefficient in the second channel. It was also observed that the heat transfer coefficient can be increased at the end of the channel when the outlet temperature is relatively high. This may be explained by the fact that as temperature increases, the fluid viscosity tends to decrease, which generally drives an increase in the local random motion of base fluid molecules and nanoparticles. This causes an increase in the microchannel heat transfer coefficient. It was found that the addition of nanoparticles significantly modified the impact of the connector on the microchannel heat transfer coefficient. In addition, the effects of changing the Reynolds number and the shape of the connector were investigated through use of computational fluid dynamics (CFD) calculations. It was found that both factors have an important impact on the variation of velocity and enhancement of random motion of molecules and consequently significantly affect the heat transfer coefficient.

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Section: Resultsmentioning

confidence: 99%

Section: Brief Review On Optimization Of Effects Of Nanoparticlesmentioning

confidence: 99%

Section: Brief Review On Optimization Of Effects Of Nanoparticlesmentioning

confidence: 99%

Section: Figurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Heat Transfer Enhancement in the Microscale: Optimization of Fluid Flow

et al. 2022

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Effects of Key Parameters on Nanofluid Thermal Performance in Heat Exchangers

2023

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Nanofluids are utilized in cooling equipment such as heat exchangers and renewable energies such as solar cells as heat transfer fluid. The techniques for nanofluid stability enhancement and stability evaluations, such as zeta potential, electron microscopy, and photographic techniques for sedimentation, are reviewed as well as some recent achievements in nanofluid stabilization and research on the parameters affecting the thermal properties of nanofluids. Finally, the applications of nanofluids in cooling devices are described. Increased heat transfer, reduced heat transfer time and size of heat exchangers, and finally higher energy and heat efficiency could be the most significant achievements. The parameters affecting the thermal conductivity of nanofluids include concentration, temperature, particle fluid, type of base fluid, and nanoparticles.

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