Non-intrusive diagnostics of differentially-heated two-component immiscible fluid layer with phase change

Kumar, Amit; Hinduja, Chirag; Srivastava, Atul

doi:10.1016/j.icheatmasstransfer.2022.106513

Cited by 3 publications

(2 citation statements)

References 19 publications

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“…MATLAB program is utilized to calculate the bubble's equivalent diameter using the aforementioned equations. The uncertainties associated with the data and the calculated heat flux are listed in Table 1 and the properties of DCM were taken from previous works by the authors [15].…”

Section: Methodsmentioning

confidence: 99%

Experimental Investigation of Boiling Characteristics of High Volatile Fluids under Varying Heat Flux Levels

Kumar,

Shahdhaar,

Srivastava

2024

Proceedings of the 9th World Congress on Momentum, Heat and Mass Transfer

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In recent years, there have been significant advances in the field of supercomputers and data centers, resulting in the generation of high heat flux levels. To effectively cool such high heat flux equipment, boiling immersion cooling has emerged as a promising solution. In the quest to enhance the heat transfer performance of nucleate boiling through passive means, this research focuses on exploring the boiling behavior of one of the high volatile fluids, namely dichloromethane (DCM). To investigate the nucleate boiling phenomenon of DCM, pool boiling experiments were conducted within a closed vessel at atmospheric pressure. Three distinct levels of heat flux were applied (58, 76, and 95 kW/m 2 ) to observe its impact on bubble dynamics. The experimental setup employed high-speed rainbow schlieren deflectometry to simultaneously map the dynamics of vapor bubbles while varying the heat flux levels. The results obtained from the experiments demonstrated a strong correlation between heat flux and various bubble characteristics. Specifically, the bubble mechanism, including bubble departure frequency, bubble diameter, waiting time, and forces acting on bubble, exhibited notable changes in response to variations in heat flux levels. By studying the bubble dynamics, it was observed that as the heat flux increased, the frequency at which bubbles departed from the heated surface decreased. Additionally, the bubble diameter was found to increase at higher heat flux levels. Furthermore, the waiting time, representing the duration between bubble departure and the subsequent bubble formation, as well as the various forces acting on bubble were also seen to be strongly influenced by the applied heat flux.

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Section: Methodsmentioning

confidence: 99%

Experimental Investigation of Boiling Characteristics of High Volatile Fluids under Varying Heat Flux Levels

Kumar,

Shahdhaar,

Srivastava

2024

Proceedings of the 9th World Congress on Momentum, Heat and Mass Transfer

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“…However, it is important to note that the temperature field of the subsurface is transient and has a significant temperature gradient over time during ISTD. This may lead to deviations from theoretical analysis of co-boiling under thermal equilibrium conditions, particularly in instances of rapid heating or when there is a substantial temperature difference between the solid matrix and fluid. ,− Regarding heat transfer during boiling, researchers have conducted numerous studies to explore heat and mass transfer in boiling of immiscible fluids toward thermal management of electronic devices. , − A series of theoretical studies on the boiling and heat transfer of immiscible liquids have also been conducted, ,− including the evolution of the vapor layer and the formation rate and diameter of bubbles. These works focus on bubble behaviors, heat flux density, and heat transfer coefficient toward the application of equipment cooling but lack attention to temperature field variations as well as NAPL removal rates.…”

Section: Introductionmentioning

confidence: 99%

Understanding of Co-boiling between Organic Contaminants and Water during Thermal Remediation: Effects of Nonequilibrium Heat and Mass Transport

Xu,

Hu,

Qian

et al. 2023

Environ. Sci. Technol.

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In situ thermal desorption (ISTD) provides an efficient solution to remediation of soil and groundwater contaminated with nonaqueous phase liquids (NAPLs). Establishing a relationship between the subsurface temperature rise and NAPL removal is significant to reduce energy consumption of ISTD. However, the co-boiling phenomenon between NAPL and water poses a great challenge in developing this relationship due to the nonequilibrium heat and mass transport effects. We performed a systematic experimental investigation into the local temperature rise patterns at different distances from a NAPL pool and under different degrees of superheat by selecting four representative NAPLs (i.e., trichloroethylene, tetrachlorethylene, n-hexane, and noctane) according to their density and boiling point relative to water. The patterns of temperature rise indicated that the underground temperature field can be divided into three zones: the zone of local thermal equilibrium, the nonequilibrium zone affected by co-boiling, and the zone unaffected by co-boiling. We developed a pattern-recognition-based approach, which considers the effects of local heat and mass transport to establish a qualitative correlation between the temperature rise and NAPL removal. Our results give deeper insights into the understanding of subsurface temperatures in ISTD practice, which can serve as the guideline for more accurate and sustainable remediation.

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Coupled bubble dynamics and interaction mechanisms of adjacently nucleated vapor bubbles under subcooled pool boiling regime

2023

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The present work investigates the plausible modes of interaction between two adjacently located vapor bubbles growing on high wettability surface during subcooled nucleate pool boiling. The study becomes important as the phenomenon of bubble interaction has a significant impact on the resulting bubble dynamic parameters as well as on microlayer dynamics of the respective vapor bubbles. As against the symmetric growth of microlayer in the case of isolated pool boiling, microlayers of mutually interacting vapor bubbles no longer remain symmetric and tend to deplete relatively faster, thereby influencing the resulting wall heat transfer rates. Toward this, the microlayers and dynamics of adjacently located interacting vapor bubbles have been mapped in a simultaneous manner using thin-film interferometry and high-speed rainbow schlieren deflectometry as a function of varying subcooling levels. Results of the experiments revealed that parameters such as non-dimensional spacing between the two vapor bubbles, supplied heat flux, and degree of subcooling have a strong impact on the mechanism of bubbles' interaction, which, in turn, influence the bubble departure frequency, bubble diameter, and microlayer dynamics. Three dominant modes of bubble interaction, hydrodynamic interaction (HI), thermal interaction (TI), and coalescence (C), were identified as a function of the level of subcooling. Quantification of the experimental data showed that the equivalent diameter of the vapor bubble increases with an increase in the level of heat flux, while it decreases with an increase in the subcooling level. Additionally, the secondary nucleation affects the liftoff time and movement of the primary bubble and can hydrodynamically deplete the microlayer of the first bubble even when the bubbles are far apart, with the depletion rates showing a strong dependence on the growth rate and location of the secondary nucleation.

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Non-intrusive diagnostics of differentially-heated two-component immiscible fluid layer with phase change

Cited by 3 publications

References 19 publications

Experimental Investigation of Boiling Characteristics of High Volatile Fluids under Varying Heat Flux Levels

Experimental Investigation of Boiling Characteristics of High Volatile Fluids under Varying Heat Flux Levels

Understanding of Co-boiling between Organic Contaminants and Water during Thermal Remediation: Effects of Nonequilibrium Heat and Mass Transport

Coupled bubble dynamics and interaction mechanisms of adjacently nucleated vapor bubbles under subcooled pool boiling regime

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