Measurement of heat transfer coefficients for steam condensation on a vertical 21.5-mm-O.D. tube in the presence of air

Kim, Un-Ki; Yoo, Ji-Woong; Jang, Yeong-Jun; Lee, Yeon-Gun

doi:10.1080/00223131.2020.1736200

Cited by 21 publications

(2 citation statements)

References 17 publications

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“…It is shown that, on average, a 40.2% higher mass of water is collected on the dynamic SLIPS than on the nonactuated SLIPS. From the condensate mass accumulation rate calculated from Figure (f), we used the mass collection method as a means to measure heat flux indirectly. − To calculate the heat flux of dynamic SLIPSs, the mass increasing rate is multiplied by the latent heat of condensation for water (2.26 MJ/kg) and normalized by the condensing surface area (17.35 cm 2 ) of the device. Therefore, the heat flux of the dynamic SLIPS ( q ″ E ) for the 12 kV AC with D = 1/3 is 1.35 kW/m 2 , while the heat flux of the nonactuated SLIPS ( q ″ 0 ) is 0.96 kW/m 2 .…”

Section: Resultsmentioning

confidence: 99%

Enhanced Condensation on Liquid-Infused Nanoporous Surfaces by Vibration-Assisted Droplet Sweeping

Cha

Chen

et al. 2020

ACS Nano

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Condensation is a universal phenomenon that occurs in nature and industry. Previous studies have used superhydrophobicity and liquid infusion to enable superior liquid repellency due to reduced contact angle hysteresis. However, small condensate droplets remain immobile on condensing surfaces until they grow to the departing size at which the body force can overcome the contact line pinning force. Hence, condensation heat transfer is limited by these remaining droplets that act as thermal barriers. To break these limitations, we introduce vibrational actuation to a slippery liquid-infused nanoporous surface (SLIPS) and show enhanced droplet mobility, controllable condensate repellency, and more efficient heat transfer compared to static SLIPSs. We demonstrate 39% smaller departing droplet size and 8× faster droplet departing speeds on the dynamic vibrating SLIPS compared to the nonactuated SLIPS. To understand the implications of these behaviors on heat transfer, we investigate the condensate area coverage and droplet distribution to verify enhanced dewetting on dynamic vibrating SLIPSs. Using well-validated heat transfer models, we demonstrate enhanced condensation heat transfer on dynamic SLIPSs due to the higher population of smaller condensate droplets (<100 μm). In addition to condensation heat transfer, we also show that vibrating SLIPSs can enhance droplet collection. This work utilizes the synergistic combination of surface chemistry and mechanical actuation to realize enhanced droplet mobility and heat transfer in an electrically controllable and switchable manner.

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Section: Resultsmentioning

confidence: 99%

Enhanced Condensation on Liquid-Infused Nanoporous Surfaces by Vibration-Assisted Droplet Sweeping

Cha

Chen

et al. 2020

ACS Nano

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“…Nevertheless, Lee et al [116] have discovered that the length of the condenser tube can have a substantial effect on condensation heat transfer under natural convection, as evidenced by their prior research. It has been highlighted that notable variations in the collected data can arise across different facilities, primarily attributed to In a study conducted by Kim et al [120], an investigation was undertaken to explore the impact of tube diameter on the HTC during condensation. They found that reducing the tube diameter from 40 mm to 21.5 mm resulted in an average increase of 62% in condensation HTC across a range of air mass fractions from 0.1 to 0.8.…”

Section: Separate Effect Experimentsmentioning

confidence: 99%

Steam Condensation Heat Transfer in the Presence of Noncondensable Gases (NCGs) in Nuclear Power Plants (NPPs): A Comprehensive Review of Fundamentals, Current Status, and Prospects for Future Research

Albdour,

Addad,

Alyammahi

et al. 2024

International Journal of Energy Research

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Efficient steam condensation is crucial for safe nuclear power plant (NPP) operations, preventing pressure buildup, overheating, and the release of radioactive materials. However, the presence of noncondensable gases (NCGs), such as air, nitrogen, hydrogen, or helium, can hinder the condensation process by creating a thermal resistance layer that impedes steam diffusion and condensation on the system’s surface. Maximizing the efficiency of steam condensation requires a thorough grasp of the fundamental processes, theories, advancements, and technical hurdles. Therefore, this work thoroughly addresses these needs, with a particular emphasis on addressing the challenges posed by NCGs by dividing the work into four thematic areas. The first theme relates to a comprehensive examination of pure steam condensation phenomena, which includes an exploration of familiar condensation scenarios and various film condensation types. The second theme examines condensation in the presence of NCGs, their mixture properties, and related theories and modelling of heat and mass transfer. The third theme investigates condensation in NPP by exploring passive cooling systems and condensation phenomena under both natural and forced convection conditions during nuclear accidents, the origin of NCGs in NPP and their transportation aspects. This is followed by experimental work related to condensation scenarios and scale. Finally, the last theme looks upon the recent advancements in computational fluid dynamics (CFD) modelling of wall condensation, system analysis codes coupling with CFD, and the implementation of machine learning (ML) for predicting the condensation HTC. By bridging the gap between fundamental knowledge and practical applications, the four thematic areas presented in this work are aimed at providing a comprehensive foundation for researchers and experts in the field of steam condensation when NCGs are involved. The ultimate objective is to bolster the safety and efficacy of NPP operations by understanding the heat and mass transfer mechanisms while mitigating the risk of catastrophic events.

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Derivation of a Condensation Heat Transfer Model for Light Water Reactor Applications Using Machine Learning Techniques

Albdour,

Addad,

Afgan

2024

Lecture Notes in Mechanical Engineering

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Measurement of heat transfer coefficients for steam condensation on a vertical 21.5-mm-O.D. tube in the presence of air

Cited by 21 publications

References 17 publications

Enhanced Condensation on Liquid-Infused Nanoporous Surfaces by Vibration-Assisted Droplet Sweeping

Enhanced Condensation on Liquid-Infused Nanoporous Surfaces by Vibration-Assisted Droplet Sweeping

Steam Condensation Heat Transfer in the Presence of Noncondensable Gases (NCGs) in Nuclear Power Plants (NPPs): A Comprehensive Review of Fundamentals, Current Status, and Prospects for Future Research

Derivation of a Condensation Heat Transfer Model for Light Water Reactor Applications Using Machine Learning Techniques

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