Year-end Sale % OFF 
Abstract
A new heat-transfer model for dropwise condensation with non-condensable gas (NCG) is developed, which can be used in the design and calculations of a dehumidifier in humidification–dehumidification technology. A single-droplet heat-transfer model is established via the rounded analysis of all the contributing thermal resistances based on the diffusion-layer theory. Combined with the drop size distribution, the heat flux of dropwise condensation with NCG is determined, and the error between the predicted results and previous experimental data is found to be within ±20%. The effects of different parameters on the heat transfer of dropwise condensation with NCG are investigated, and the results indicate that there is an optimal contact angle to maximize the heat flux, which depends on the NCG content. The thickness of the coating layer has little effect on the heat flux at a given thermal conductivity of the coating layer, indicating that the dropwise condensation effect can be improved by increasing the thickness of the coating layer, neglecting the heat-transfer deterioration due to the additional thermal resistance during dropwise condensation with NCG.
Highlights
Extracting fresh water from seawater and brackish water is an alternative method to obtain clean water
According to the diffusion-layer theory, the temperature difference caused by the diffusion layer between the moist air bulk and the surface of the droplet can be regarded as a thermal resistance, which can be used to replace the vapor–liquid interfacial resistance scitation.org/journal/adv in describing the heat transfer of a single droplet under dropwise condensation with non-condensable gas (NCG)
The results show that the minimum droplet radius decreases gradually with the increase in the NCG content and subcooling, which is conducive to the formation of the initial droplet
Summary
Extracting fresh water from seawater and brackish water is an alternative method to obtain clean water. According to the homogeneous nucleation theory and heat-transfer model of a single droplet, the effect of the NCG on the heat-transfer performance of dropwise condensation was investigated quantitatively. Luo et al. established a single droplet evaporation and condensation model to quantitatively describe the process on a solid surface in the presence of NCG, which considered the effects of the solid surface They divided the outside of the droplet into two regions according to the ratio of the mean free path of the vapor–gas mixture to the distance between the vapor molecules and the droplet surface. A single-droplet heat-transfer model for various radii based on the model of Kim and Kim in which the effect of the diffusion layer is taken into account is developed to describe all the contributing thermal resistances. The new model is more applicable than the classical model without NCG and is more accurate at high NCG contents, i.e., in the humidity range of HDH systems
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
