Experimental investigation on heat transfer and flow patterns of pulsating heat pipe assisted by ultrasonic cavitation

Zhang, Dongwei; Guan, Jian; He, Zhuantao; Shen, Chao; Cao, Hongliang

doi:10.1016/j.ijheatmasstransfer.2021.122187

Cited by 25 publications

(4 citation statements)

References 18 publications

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“…It was found that the thermal convection induced by nanoparticles was increased by 11.37% coupled with ultrasonic vibration. By visualization experiments, Zhang et al 18 found that the addition of ultrasonic waves generated a large number of small bubbles in the evaporation section of the pulsating heat pipe, which could accelerate the amplitude and speed of the cycle oscillation of the working fluid in the pipe as well as enhance the heat-transfer performance. The cavitation effect plays a key role in inhibiting the aggregation and deposition of nanoparticles in the collapse of cavitation bubbles.…”

Section: ■ Introductionmentioning

confidence: 99%

Near-Wall Cavitation Effect: A Molecular Dynamics Study

Zhang,

Guan,

et al. 2023

Langmuir

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Cavitation has been the subject of abundant studies, but the internal mechanism of cavitation is less well known. In this article, a microlevel near-wall model was established by using LAMMPS to present the process of cavitation effect. The results of molecular dynamics simulation revealed the fluctuation process of the liquid near the wall with the change in pressure. Molecular dynamics was also used to evaluate the void volume fraction and density distribution of the system. The results exhibited that the cavitation process can be divided into two stages: the initial cavitation stage and the rapid growth stage. Based on these results, the effects of wettability and initial system temperature on the near-wall cavitation effect were demonstrated. The results indicated that the hydrophobic near-wall forms a gas layer to weaken the density fluctuation, while the hydrophilic wall is opposite. Increasing the temperature could positively affect molecular motion and cavitation. This work provides a theoretical basis for further exploration of the cavitation effect.

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Section: ■ Introductionmentioning

confidence: 99%

Near-Wall Cavitation Effect: A Molecular Dynamics Study

Zhang,

Guan,

et al. 2023

Langmuir

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“…The MD simulation method, combined with momentum mirroring, shares parallels with the principle of ultrasonic cavitation’s bubble collapse. Ultrasonic cavitation refers to the rapid formation, growth, and subsequent collapse of microbubbles in liquids due to ultrasonic wave action . Within the MD simulation, shock waves induce bubble collapse, enabling the study of its progression.…”

Section: Introductionmentioning

confidence: 99%

“…Ultrasonic cavitation refers to the rapid formation, growth, and subsequent collapse of microbubbles in liquids due to ultrasonic wave action. 11 Within the MD simulation, shock waves induce bubble collapse, enabling the study of its progression. Adhikari et al 12,13 and Santo et al 14 investigated the detailed mechanism of shock wave-induced bubble collapse on lipid bilayers using various shock velocities and bubble radii.…”

Section: ■ Introductionmentioning

confidence: 99%

Effect of Shock-Wave-Mediated Collapse on Nanobubble Characteristics

Xu,

Zhao,

Wang

et al. 2023

Langmuir

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To enhance the comprehension of the cavitation mechanism and explore its practical use in industrial production, this study developed models involving oxygen, varying bubble radii, and bubble quantities. This study uses molecular dynamics simulations coupled with the momentum mirror method to examine the collapse characteristics of bubbles during ultrasonic cavitation. The investigation uncovers patterns in the fluctuation of the maximum local density of water molecules, released pressure, and temperature. The findings demonstrate that, when oxygen-containing bubbles collapse at identical radii, the local density is notably higher and diminishes more rapidly. Moreover, the changes in the shape exhibit greater regularity. During the bubble collapse, a depression forms on the bubble's surface, coinciding with a notable surge in local density around the depression. As bubble radii and quantities increase, so does the local density along with a concurrent rise in the maximum pressure. Intriguingly, the model demonstrates the lowest pressure at Z = 35 Å accompanied by the emergence of a small crescent-shaped region with a reduced density. Throughout the pressure ascension phase, the rate of the maximum pressure change escalates with an increase in the number of bubbles. Conversely, during the pressure descent phase, the rate of the maximum pressure change diminishes with a growing number of bubbles. However, it is important to note that the maximum pressure does not exhibit a direct correlation with the number of bubbles. Ultimately, this study provides valuable technical guidance and a theoretical foundation for the integration of ultrasonic cavitation in industrial production processes.

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“…Acoustic cavitation was also used to improve the performance of CPU water-cooling systems [16]. The authors of [15][16][17][18][19] agreed that using cavitation to reduce the boundary layer in heat exchangers effectively enhances heat transfer. These studies have shown that using bubbles in fluids could be suitable for intensifying heat transfer processes.…”

Section: Introductionmentioning

confidence: 99%

Review of Micro- and Nanobubble Technologies: Advancements in Theory and Applications and Perspectives on Adsorption Cooling and Desalination Systems

Lasek,

Krzywanski,

Skrobek

et al. 2023

Energies

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Adsorption refrigerators are a compelling ecological alternative to compressor refrigerators; global warming forces us to constantly look for alternative sources of energy and cold. Cold production in adsorption chillers is based on the use of heat generated by other processes running in the company. Waste heat from production processes, which has, until now, been irretrievably lost, is a potential source of energy for generating cold via an adsorption unit producing chilled water. Cooling optimizes the use of the heating network in summer and can lead to increased electricity production while reducing heat supply losses. Thus far, attempts to implement adsorption refrigerators for widespread use have not been successful as a result of the low efficiency of these devices; this is directly related to the poor heat and mass transfer conditions in the beds and heat exchangers of adsorption refrigerators. The solutions used so far, such as new working pairs, glued beds or modifications to the structure or cycle length, are still not strong enough for these devices. Therefore, it is necessary to look for new solutions. Using micro- and nanobubbles as media to increase mass and heat transfer in refrigerators is an innovative and pioneering solution. Thus, this document describes the most important features of micro- and nanobubble technology applications in adsorption refrigerators. This article is an introduction and a basis for the implementation of further research, consolidating the existing literature as a review.

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Experimental investigation on heat transfer and flow patterns of pulsating heat pipe assisted by ultrasonic cavitation

Cited by 25 publications

References 18 publications

Near-Wall Cavitation Effect: A Molecular Dynamics Study

Near-Wall Cavitation Effect: A Molecular Dynamics Study

Effect of Shock-Wave-Mediated Collapse on Nanobubble Characteristics

Review of Micro- and Nanobubble Technologies: Advancements in Theory and Applications and Perspectives on Adsorption Cooling and Desalination Systems

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