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Evaluation of the thermal performance of dropwise condensation from a semi-solid lubricant impregnated vertical condenser tube
  • Rajkumar. M.,
  • Jyothish Abraham,
  • Venugopal G
Rajkumar. M.
Rajiv Gandhi Institute of Technology Department of Mechanical Engineering

Corresponding Author:[email protected]

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Jyothish Abraham
College of Engineering Trivandrum Department of Mechanical Engineering
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Venugopal G
St Thomas College of Engineering
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Abstract

The quest for augmenting dropwise condensation heat transfer performance has been the driving force behind the exploration of innovative techniques and approaches to fulfil the desired objective. Recent literature in condensation heat transfer unveils that dropwise condensation heat transfer improvements from Slippery Liquid Infused Porous Surfaces (SLIPSs) was central to the study of several researchers because these surfaces have shown excellent droplet mobility due to extremely low adhesion between the condensing liquid and the lubricant infused surface, thereby, promote dropwise condensation. As part of supplementing current research on SLIPSs, for the first time, the present study explores the potential of a semi-solid lubricant impregnated porous surface in enhancing the condensation heat transfer performance of a vertical condenser tube. The results of experiments conducted over a wide range of subcooling (5°C ≤ ΔT ≤ 65°C) in a saturated steam environment signify that Copper tubes with semi-solid lubricant impregnated porous surfaces are potential candidates for enhancing dropwise condensation heat transfer coefficient when compared to an untreated vertical Copper condenser tube. The highest enhancement is found to be 280% at a subcooling of 40°C. Also, the semi-solid lubricant impregnated porous surfaces are proficient in sustaining dropwise condensation for a time period of 72 hours without any degradation in the heat transfer performance. The method devised here for fabricating the semi-solid lubricant impregnated surfaces is simple, less expensive, and less time-consuming compared to the techniques reported earlier for fabricating the SLIPSs. Additionally, in this work an approach based on numerical optimization by a stochastic global optimization technique, namely, Genetic Algorithm, is proposed to retrieve the coefficients and the exponent in the mathematical expression of overall resistance, which in turn is used to compute the tube-side dropwise convection heat transfer coefficient.