Enhancing the bubble collapse energy using the electrohydrodynamic force

Taleghani, Mohammad Hassan; Khodadadi, Sajad; Maddahian, Reza; Mokhtari‐Dizaji, Manijhe

doi:10.1063/5.0146491

Cited by 7 publications

(3 citation statements)

References 78 publications

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“…In contrast, the regular jet has a speed of the order of 80 m s −1 that increases slowly with γ . The micro-jet shape and velocity are dependent on the particular flow conditions, where acoustic (Rosselló et al 2018) and electric fields (Taleghani et al 2023), bubble interaction (Han et al 2015), and the presence of more than one boundary have been reported to affect the velocity.…”

Section: Introductionmentioning

confidence: 99%

Jetting enhancement from wall-proximal cavitation bubbles by a distant wall

Zeng,

Zhang,

Tan

et al. 2024

J. Fluid Mech.

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An additional distant wall is known to highly alter the jetting scenarios of wall-proximal bubbles. Here, we combine high-speed photography and axisymmetric volume of fluid (VoF) simulations to quantitatively describe its role in enhancing the micro-jet dynamics within the directed jet regime (Zeng et al., J. Fluid Mech., vol. 896, 2020, A28). Upon a favourable agreement on the bubble and micro-jet dynamics, both experimental and simulation results indicate that the micro-jet velocity increases dramatically as $\eta$ decreases, where $\eta =H/R_{max}$ is the distance between two walls $H$ normalized by the maximum bubble radius $R_{max}$ . The mechanism is related to the collapsing flow, which is constrained by the distant wall into a reverse stagnation-point flow that builds up pressure near the bubble's top surface and accelerates it into micro-jets. We further derive an equation expressing the micro-jet velocity $U_{jet}=87.94\gamma ^{0.5}(1+(1/3)(\eta -\lambda ^{1.2})^{-2})$ , where ${\gamma =d/R_{max}}$ is the stand-off distance to the proximal wall with $d$ the distance between the initial bubble centre and the wall, $\lambda =R_{y,m}/R_{max}$ with $R_{y,m}$ the distance between the top surface and the proximal wall at the bubble's maximum expansion. Viscosity has a minimal impact on the jet velocity for small $\gamma$ , where the pressure buildup is predominantly influenced by geometry.

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Section: Introductionmentioning

confidence: 99%

Jetting enhancement from wall-proximal cavitation bubbles by a distant wall

Zeng,

Zhang,

Tan

et al. 2024

J. Fluid Mech.

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“…Much research in boiling has been aimed at developing and enhancing the geometry of a particular surface to increase nucleation, reduce the surface superheat temperature, and delay the CHF [11][12][13][14][15]. A large number of methods are proposed, which are divided into active methods [16][17][18][19] and passive methods [20][21][22]. Passive methods include rough surfaces [23], porous and hydrophilic surfaces [24,25], nanoparticle addition to the base fluid [26][27][28], and surface expansion and using fins [29,30].…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study of Heat Transfer in Pool Boiling to Investigate the Effect of Surface Roughness on Critical Heat Flux

Ali

2024

ChemEngineering

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Utilizing pool boiling as a cooling method holds significant importance within power plant industries due to its ability to effectively manage temperature differentials amidst high heat flux conditions. This study delves into the impact of surface modifications on the pool boiling process by conducting experiments on four distinct boiling surfaces under various conditions. An experimental setup tailored for this investigation is meticulously designed and implemented. The primary objective is to discern the optimal surface configuration capable of efficiently absorbing maximum heat flux while minimizing temperature differentials. In addition, this study scrutinizes bubble dynamics, pivotal in nucleation processes. Notably, surfaces polished unidirectionally (ROD), exhibiting lower roughness, demonstrate superior performance in critical heat flux (CHF) compared to surfaces with circular roughness (RCD). Moreover, the integration of bubble liquid separation methodology along with the introduction of a bubble micro-layer yields a microchannel surface. Remarkably, this modification results in a noteworthy enhancement of 131% in CHF and a substantial 211% increase in the heat transfer coefficient (HTC) without resorting to particle incorporation onto the surface. This indicates promising avenues for enhancing cooling efficiency through surface engineering without additional additives.

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“…They observed nanofluid had a higher critical heat flux than critical heat flux of boiling, and the highest CHF was related to ferrofluid and was 2.6 times higher than pure water. This is because of the accumulation of nanoparticles on the surface and increased surface wettability [31].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Effects of Grooves in Fe2O4/Water Nanofluid Pool Boiling

Rashid,

Ali,

Zorah

et al. 2024

Fluids

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In this study, we systematically explored how changing groove surfaces of iron oxide/water nanofluid could affect the pool boiling heat transfer. We aimed to investigate the effect of three types of grooves, namely rectangular, circular, and triangular, on the boiling heat transfer. The goal was to improve heat transfer performance by consciously changing surface structure. Comparative analyses were conducted with deionized water to provide valuable insights. Notably, the heat transfer coefficient (HTC) exhibited a significant increase in the presence of grooves. For deionized water, the HTC rose by 91.7% and 48.7% on circular and rectangular grooved surfaces, respectively. Surprisingly, the triangular-grooved surface showed a decrease of 32.9% in HTC compared to the flat surface. On the other hand, the performance of the nanofluid displayed intriguing trends. The HTC for the nanofluid diminished by 89.2% and 22.3% on rectangular and triangular grooved surfaces, while the circular-grooved surface exhibited a notable 41.2% increase in HTC. These results underscore the complex interplay between groove geometry, fluid properties, and heat transfer enhancement in nanofluid-based boiling. Hence, we thoroughly examine the underlying mechanisms and elements influencing these observed patterns in this research. The results provide important insights for further developments in this area by shedding light on how surface changes and groove geometry may greatly affect heat transfer in nanofluid-based pool boiling systems.

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Enhancing the bubble collapse energy using the electrohydrodynamic force

Cited by 7 publications

References 78 publications

Jetting enhancement from wall-proximal cavitation bubbles by a distant wall

Jetting enhancement from wall-proximal cavitation bubbles by a distant wall

An Experimental Study of Heat Transfer in Pool Boiling to Investigate the Effect of Surface Roughness on Critical Heat Flux

Experimental Investigation of the Effects of Grooves in Fe2O4/Water Nanofluid Pool Boiling

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