Modeling of heat and mass transfer for dropwise condensation of moist air and the experimental validation

Zheng, Shao-Fei; Eimann, Ferdinand; Philipp, Christian; Fieback, Tobias; Groß, Ulrich

doi:10.1016/j.ijheatmasstransfer.2017.12.059

Cited by 67 publications

(40 citation statements)

References 34 publications

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“…Based on the mass and energy conservation, 20 methodology for estimation of mass loss rate can be explored by the heat absorbed and released by the surface in burning of PMMA plate as shown in Figure 5. The heat transfers in the burning include the heat of radiation and convection from the flame to surface of PMMA, the reradiation from PMMA surface to the surrounding environment, the radiation from surrounding to PMMA surface, and the missed conduction from insulation board to the air.…”

Section: Resultsmentioning

confidence: 99%

“…According to the definition of mean flame height which is that mean flame height is the distance above the fire source where the intermittency has declined to 0.5, 19 mean flame height for a certain period of time can be obtained through the data. Besides, the corresponding flame thickness is defined as the distance between the outer edge of the flame surface of the vertical PMMA plate and the wall surface which can be obtained using the data in the study by Zheng et al 20 In order to guarantee the accuracy of experiment, the experiments were repeated three times in this study.…”

Section: Methodsmentioning

confidence: 99%

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Effects of equivalent diameter on vertical PMMA combustion in natural convection environment

et al. 2020

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Summary A series of combustion experiments of polymethyl methacrylate (PMMA) plates with two shapes, three thicknesses, and different sizes was performed to investigate the effects of equivalent diameter on combustion characteristics of vertical PMMA in a natural convection environment. Two digital video cameras were used to record the burning process. The temporal variation of mass was recorded by an electronic balance. The influence of equivalent diameter on mass loss rate and flame height was then analyzed theoretically. Convection and radiation heat transfer were calculated and modeled in the theoretical analysis and compared to experiment. The result shows that the theoretical prediction of mass loss rate for each equivalent diameter is in good agreement with the experimental measurements. In addition, the relationship between flame height and heat release rate was analyzed using dimensionless analysis method. It was found that the flame height for vertical PMMA burning in a nature convection environment is dominated by heat release rate and equivalent diameter.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Effects of equivalent diameter on vertical PMMA combustion in natural convection environment

et al. 2020

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“…established a numerical simulation, which was validated against experimental results. [ 143 ] The mechanism of droplet growth was characterized through the heat and mass transfer process from the freestream vapor to the cold substrate where condensation occurred. As the nucleation and subsequent droplet growth process spanned multiple length scales, the approach presented a description for the Knudsen layer to handle the transition between the continuum and kinetic limit.…”

Section: Effects Of Noncondensable Gas During Condensationmentioning

confidence: 99%

Implementing Superhydrophobic Surfaces within Various Condensation Environments: A Review

Singh

Zhang

Stafford

et al. 2020

Adv Materials Inter

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Steam condensation is omnipresent, and inevitable in many industrial processes. A classic example is seen within condensers that are used to liquify various gasses. In consequence, water‐vapor is eventually deposited upon the exterior of heat pipes that passively cool the gas to form a thin film of liquid. This macroscopic film is responsible for the degradation of heat transfer efficiencies. Liquid repellent surfaces can microscopically manipulate the hydrodynamics of formulating condensate to transition toward dropwise/jumping‐droplet condensation. This effect will save operating and maintenance costs of steam condensers within power‐plants, subsequently reducing emissions, operating power, and fuel consumption. However, the challenges associated with the stabilization of dropwise/jumping‐droplet condensation, especially at large subcooling temperatures and high supersaturation ratios, have prohibited the use of liquid repellent surfaces. This review aims to discuss recent improvements and understanding of dropwise/jumping‐droplet condensation surfaces on superhydrophobic surfaces. Numerous examples shall be included, showing experimental and numerical studies of various innovative properties of superhydrophobic structures. In addition, various fabrication techniques of superhydrophobic surfaces that are applicable within industrial systems are discussed. These topics are consolidated to provide guidelines for future research into dropwise/jumping‐droplet condensation on liquid repellent surfaces.

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“…ðÞ Nr ðÞ dr (11) where q d is the heat flux through an individual droplet and N is the droplet size distribution on the surface. Subsequently, corresponding modifications of dropwise condensation heat transfer model to include more accurate expressions for the heat transfer through an individual droplet [35,[39][40][41][42][43][44][45][46][47][48] and droplet size distribution [14,33,39,43,46,[49][50][51] are developed, for example, the conduction resistance of the liquid droplet, the thermal resistance of a hydrophobic coating, mass transfer on the liquid-vapor interface, and the effect of interface curvature.…”

Section: Basics Of Dropwise Condensationmentioning

confidence: 99%

Advances in Dropwise Condensation: Dancing Droplets

Wen¹,

Ma²

2020

21st Century Surface Science - A Handbook

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Vapor condensation is a ubiquitous phase change phenomenon in nature, as well as widely exploited in various industrial applications such as power generation, water treatment and harvesting, heating and cooling, environmental control, and thermal management of electronics. Condensation performance is highly dependent on the interfacial transport and its enhancement promises considerable savings in energy and resources. Recent advances in micro/nano-fabrication and surface chemistry modification techniques have not only enabled exciting interfacial phenomenon and condensation enhancement but also furthered the fundamental understanding of interfacial wetting and transport. In this chapter, we present an overview of dropwise condensation heat transfer with a focus on improving droplet behaviors through surface design and modification. We briefly summarize the basics of interfacial wetting and droplet dynamics in condensation process, discuss the underlying mechanisms of droplet manipulation for condensation enhancement, and introduce some emerging works to illustrate the power of surface modification. Finally, we conclude this chapter by providing the perspectives for future surface design in the field of condensation enhancement.

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Modeling of heat and mass transfer for dropwise condensation of moist air and the experimental validation

Cited by 67 publications

References 34 publications

Effects of equivalent diameter on vertical PMMA combustion in natural convection environment

Effects of equivalent diameter on vertical PMMA combustion in natural convection environment

Implementing Superhydrophobic Surfaces within Various Condensation Environments: A Review

Advances in Dropwise Condensation: Dancing Droplets

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