Computational fluid dynamics investigation of dropwise condensation heat transfer through a single droplet on Wenzel structures

Mohammadpour, Loghman; Moghadasi, Hesam; Saffari, Hamid

doi:10.1016/j.icheatmasstransfer.2023.106853

Cited by 2 publications

(1 citation statement)

References 38 publications

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“…This is strongly associated with the hydrophilic and hydrophobic surface wetting modes. Droplets on hydrophilic surfaces exhibit an infiltrating Wenzel state [30], where the droplet edges are pinned to the surface and difficult to spread, so the external groove structure has a strong influence on the apparent contact angle. On the other hand, the droplets on hydrophobic surfaces show a suspended Cassie state, in which the droplets are constrained by the solid boundary in a relatively small way.…”

Section: Wettabilitymentioning

confidence: 99%

Experimental Study on the Condensation Heat Transfer on a Wettability-Interval Grooved Surface

Ren,

Gao,

et al. 2023

Applied Sciences

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To provide further insight into humid air condensation on hybrid surfaces, an experiment was conducted to visually investigate the condensation process on wettability-interval grooved surfaces, which had hydrophobic ridges and hydrophilic grooves. The droplet dynamic behavior and heat transfer performance of condensation on a wettability-interval grooved surface were explored and compared with four other functional surfaces, including the plain hydrophilic surface, plain hydrophobic surface, hydrophilic grooved surface, and hydrophobic grooved surface. The presence of hydrophobic ridges perpendicular to the groove direction and hydrophilic grooves allowed for the exclusion and easy spreading of droplets, respectively. Compared with the other four functional surfaces, the coupling phenomena during condensation, i.e., the spontaneous suction and directional drainage via hydrophilic grooves, were only found on the wettability-interval grooved surface. These could not only remove condensate quickly but also suppress the formation of the flooded liquid film, which was beneficial to the enhancement of heat transfer performance. It was proven by the experimental results that at subcooling 12 K, the condensation heat flux on the wettability-interval grooved surface reached 1280 W/m2, which was 1.25 times that of the plain hydrophobic surface (1030 W/m2), and 15% higher than that of the hydrophobic grooved surface (1110 W/m2). This indicated that the wettability-interval microgrooves could effectively enhance humid air condensation heat transfer performance.

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Section: Wettabilitymentioning

confidence: 99%

Experimental Study on the Condensation Heat Transfer on a Wettability-Interval Grooved Surface

Ren,

Gao,

et al. 2023

Applied Sciences

View full text Add to dashboard Cite

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Prediction of Condensation in the Heat Exchangers of Engine Intake Systems according to External Environmental and Operating Conditions

Ju,

Chung,

Lee

et al. 2023

International Journal of Energy Research

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Low-pressure exhaust gas recirculation (LP-EGR) systems are applied to diesel engines because they reduce nitrogen oxide emission by lowering the internal temperature of the cylinder by mixing the oxides with intake air. However, low-temperature ambient conditions include a large amount of vapor in the mixed gas flowing into the intercooler; when heat is exchanged, the water vapor condenses and is adsorbed on the surface of the intercooler fin to form a liquid film. Condensation occurs as the thermal resistance between the vapor and solid surface increases with the thickness of the liquid film and causing a corrosion due to condensation of the surface. In this study, the amount of condensation was predicted through calculations based on thermodynamic studies. Factors that can cause condensation inside the intercooler (fuel, air, and LP-EGR) were selected as variables. A mathematical formula was established to predict the convergence form of condensation or the amount of condensation over time at various temperature and relative humidity conditions. The formula predicted the condensation amount in the intercooler of the diesel engine, compared it to the actual amount of condensation in the test evaluation with an error of less than 4%. Additionally, because the formula can predict the amount of condensation by changing the heat exchange area of the intercooler, the application range of the formula was expanded to predict the condensation in the intercoolers of gasoline vehicles with different heat exchange areas and fuel types. The condensation error was within 2%, indicating a high consistency. Validation of the formula predicts a reliable amount of condensation under various operating and ambient temperature conditions, which means that both the time and cost of the test evaluation require the determination of the cause before solving the actual condensation problem.

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Computational fluid dynamics investigation of dropwise condensation heat transfer through a single droplet on Wenzel structures

Cited by 2 publications

References 38 publications

Experimental Study on the Condensation Heat Transfer on a Wettability-Interval Grooved Surface

Experimental Study on the Condensation Heat Transfer on a Wettability-Interval Grooved Surface

Prediction of Condensation in the Heat Exchangers of Engine Intake Systems according to External Environmental and Operating Conditions

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