Surface wettability change during pool boiling of nanofluids and its effect on critical heat flux

Kim, Sung Joong; Bang, In Cheol; Buongiorno, Jacopo; Hu, Lin‐Wen

doi:10.1016/j.ijheatmasstransfer.2007.02.002

Cited by 748 publications

(398 citation statements)

References 19 publications

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“…A result of such a structure force is that nanofluids could exhibit a good spreading capability in confined spaces. Such forces have been observed (i) to be able to change the macroscopic contact angle of a liquid droplet [64][65][66] , (ii) to stabilise liquid films 67 , and (iii) to lift an oil droplet from a wall in an aqueous solution 36,[68][69][70][71][72] As shown by 36 , the SDP could be important for mobilising individual oil droplets. However as suggested earlier, the droplet form of oil was unlikely in the current experiments.…”

Section: The Structural Disjoining Pressure Effectmentioning

confidence: 99%

Nanoparticle-Assisted Water-Flooding in Berea Sandstones

Azmi

Raza

et al. 2016

Energy Fuels

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ABSRACT:The use of nanoparticles (NP) to improve reservoir characterisation or to enhance oil recovery (EOR) has recently received intensive interest; however there are still many un-resolved questions. This work reports a systematic study of the effect of rutile TiO 2 nanoparticle-assisted brine flooding. Rutile ellipsoid TiO 2 nanoparticles were synthesised and stabilised by tri-sodium citrate dehydrate for brine flooding of water-wet Berea sandstone cores. Careful characterisation of the rock samples and nanomaterials before and after the flooding was conducted, and the relative contributions to the modified flooding results from the stabiliser and the nanoparticles of different concentrations were examined. The oil recovery performance was evaluated both at break-through (BT) point and at the end of flooding (~3.2 pore volumes). Nanoparticle migration behavior was also investigated in order to understand the potential mechanisms for oil recovery. The results showed that both nanoparticle transport rate and EOR effect were strongly dependent on the particle concentration. The oil recovery efficiency at the BT point was found to increase at low nanoparticle concentrations but decrease at higher values. A maximum 33% increase of the recovery factor was observed at the BT point for a TiO 2 concentration of 20 ppm, but higher nanoparticle concentrations usually had higher ultimate recovery factors. The presence of oil phase was found to accelerate the particle migration though the core. The discussion of various mechanisms suggested that the improvement in the mobility ratio, possible wettability change and log-jamming effect were responsible for the observed phenomena.

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Section: The Structural Disjoining Pressure Effectmentioning

confidence: 99%

Nanoparticle-Assisted Water-Flooding in Berea Sandstones

Azmi

Raza

et al. 2016

Energy Fuels

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“…According to common consensus by researchers [7][8][9][10][11][12], this nanoparticle deposition layer is the primary mechanism for CHF enhancement, as it changes the porosity and the hydrophilicity of the surface, altering the dynamics of the three phase interface at the heater surface.  Most of the studies report significant CHF enhancement (up to 200%) with nanofluids compared to water [5][6][7][8][9][10][11][12][13][14][15][16][17][18].  Even relatively low concentrations (<1% by volume) of nanoparticles are capable to enhance CHF.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of transient critical heat flux of water-based zinc–oxide nanofluids

Sharma

Buongiorno

McKrell

et al. 2013

International Journal of Heat and Mass Transfer

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Pool boiling experiments were conducted for sandblasted stainless steel (grade 316) plate heaters submerged in deionized (DI) water and water-based zinc-oxide nanofluid, for transient heat flux conditions with power through the heaters increasing quadratically with time. Heat flux in the experiments was increased from zero to CHF in short time frames of 1, 10 and 100 s. Consistent with previous studies, transient CHF for DI water was higher than steady state CHF, and CHF increased with decreasing duration of the transient. Additionally, it was observed that for nanofluid tests, a porous and hydrophilic nanoparticle layer started to deposit on the heater surface in short time frames of 10 and 100 s, and this layer was responsible for the enhanced CHF compared to DI water. However, for the 1 s tests, nanoparticle deposition did not occur and consequently the CHF was not enhanced. Finally, experiments with heaters pre-coated with nanoparticles were performed and it was found that CHF was enhanced for all transient durations down to 1 s, establishing firmly that the CHF enhancement occurs due to surface modifications by the deposited nanoparticles, and not by nanoparticles suspended in solution. Keywords

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“…The temperature gradient for the central rake is calculated by linear regression of temperature measurements at junctions j 1 , j 2 , j 3 and j 4 , and for the outer rakes by a temperature differential. The local wall temperatures are then calculated as follows:…”

Section: Methodsmentioning

confidence: 99%

“…Some studies have found that seeding water with a small concentration of alumina, zirconia, or silica nanoparticles enhances the thermal conductivity of the fluid, while also altering the surface wettability by roughening, thereby nearly doubling CHF [3,4]; however, the boiling heat transfer coefficient was reduced due to the deposition of an insulating nanoparticulate layer. Other studies report CHF values nearly triple those with pure water when alumina nanoparticles were included [5], and up to 60% higher than for pure water when silica nanoparticles were introduced [6], but with negligible change in the heat transfer coefficient.…”

Section: Introductionmentioning

confidence: 99%

“…White et al [8] studied boiling of water with zinc oxide nanoparticles to explain these contrasting characteristics. The heat transfer coefficient increased initially due to enhanced thermal properties of the nanofluid; however, after deposition of a nanoparticle layer that completely covered the surface at higher concentrations, the heat transfer coefficient was decreased due to the suppression of bubble nucleation and release from the surface by the suspended nanoparticles (as in [3,4]). …”

Section: Introductionmentioning

confidence: 99%

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Effect of particle size on surface-coating enhancement of pool boiling heat transfer

Sarangi

Weibel

Garimella

2015

International Journal of Heat and Mass Transfer

126

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The enhancement of pool boiling heat transfer by copper-particle surface coatings is experimentally investigated, using the wetting dielectric fluid FC-72. In one technique, loose copper particles are placed on a heated copper surface to provide additional vapor nucleation sites in the cavities formed at particlesurface and particle-particle contact points, thereby enhancing boiling performance over a polished surface. This 'free-particle' technique is benchmarked against the more traditional technique of sintering a fixed layer of copper particles to the surface to enhance boiling heat transfer performance. The effect of particle size on the heat transfer performance is studied for particle diameters ranging from 45 µm to 1000 µm at a constant coating layer thickness-to-particle diameter ratio of approximately 4. The parametric trends in the boiling curve and the critical heat flux are compared between the two techniques, and the dominant boiling mechanisms influencing these trends are compared and contrasted. High-speed visualizations are performed to qualitatively assess the boiling patterns and bubble departure size/distribution, and thus corroborate the trends observed in the boiling curves. The measured wall superheat is significantly lower with a sintered coating compared to the free-particle layer for any given particle size and heat flux. Performance trends with respect to particle size, however, are remarkably similar for both enhancement techniques, and an optimum particle size of ~100 µm is identified for both free particles and sintered coatings. The free-particle technique is shown to offer a straightforward method to screen the boiling enhancement trends expected from different particulate layer compositions that are intended to be subsequently fabricated by sintering.

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Surface wettability change during pool boiling of nanofluids and its effect on critical heat flux

Cited by 748 publications

References 19 publications

Nanoparticle-Assisted Water-Flooding in Berea Sandstones

Nanoparticle-Assisted Water-Flooding in Berea Sandstones

Experimental investigation of transient critical heat flux of water-based zinc–oxide nanofluids

Effect of particle size on surface-coating enhancement of pool boiling heat transfer

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