<p>Condensation is one of the most effective ways of transferring heat and it is widely used in power generation units, refrigeration and air-conditioning system, water desalination systems, petroleum industry, chemical production plant, etc. Condensation heat transfer depends on many factors including surface material, surface morphology, degree of sub-cooling, characteristics of the fluid used, presence of impurities, etc. Among different properties, surface modification is an easy and effective way to enhance the condensation heat transfer behavior. Condensation behavior on coated, hydrophilic, hydrophobic, sine shaped groove, etc has already been researched comprehensively but the effect of wedge shaped groove (Mimic to leaf vein structure) on copper plate is yet to be explored. Surfaces of some plants and animals have natural ability to harvest water from the environment in an effective and efficient way. In this research, it is tried to mimic the leaf vein structure (Wedge shaped groove) on copper plate and then carried out condensation heat transfer experiment. Due to fabrication of wedge shaped groove on copper plate, contact angle and droplet parameters like droplet size, droplet frequency, droplet growth rate, droplet coalescence rate, droplet drainage rate, etc are affected. Condensation heat transfer behavior like condensation heat transfer co-efficient, contact angle, droplet diameter, droplet growth rate, droplet frequency, sliding velocity of condensate, etc have been studied for both plain copper plate and wedge shaped groove copper plate in this article. Due to fabrication of leaf vein structure on copper plate it is observed that active nucleation site of droplets has increased and coalescence of droplets was also suppressed, so smaller diameter droplets enhanced dropwise condensation. This smaller diameter droplets slided faster in wedge shaped copper plate compared to plain copper plate. Thus the condensate drainage is made faster in modified plates and this accelerated condensate drainage enhanced the condensation behavior of wedge shaped copper plate. A comparative study of droplet parameters and condensation heat transfer parameters have also been shown in this article. It is observed from the droplet nucleation process, coalescence rate and droplet drainage process that dropwise condensation is more stable in case of wedge shaped groove copper plate compared to plain copper plate thus the surface modification is effective in condensation process of copper plate like nature. Results obtained from this condensation heat transfer experiment shows that heat transfer co-efficient of wedge shaped groove copper plate is 30-40% greater compared to plain copper plate. Plausible reason of this enhancement has been broadly discussed in this paper.</p>

Effect of Leaf Vein Structure on Condensation Behavior of Vertical Copper Plate: An Experimental Approach

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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