scholarly journals Dropwise condensation induced on chromium ion implanted aluminum surface

2019 ◽  
Vol 51 (1) ◽  
pp. 84-94 ◽  
Author(s):  
Kiwook Kim ◽  
Youngjin Lee ◽  
Ji Hwan Jeong
Keyword(s):  
Aluminum Surface ◽  
Dropwise Condensation ◽  
Chromium Ion ◽  
Ion Implanted

Dropwise Condensation Heat Transfer on Plasma-Ion-Implanted Small Horizontal Tube Bundles

2010 ◽  
Vol 31 (10) ◽  
pp. 821-828 ◽  
Author(s):  
Ali Bani Kananeh ◽  
Michael Heinrich Rausch ◽  
Alfred Leipertz ◽  
Andreas Paul Fröba
Keyword(s):  
Heat Transfer ◽  
Horizontal Tube ◽  
Condensation Heat Transfer ◽  
Dropwise Condensation ◽  
Tube Bundles ◽  
Ion Implanted

Mechanism of Dropwise Condensation on Ion Implanted Metallic Surfaces

2010 ◽  
Author(s):  
Michael H. Rausch ◽  
Alfred Leipertz ◽  
Andreas P. Fro¨ba
Keyword(s):  
Ambient Air ◽  
Contact Angles ◽  
Dropwise Condensation ◽  
Free Energies ◽  
Metallic Surfaces ◽  
Short Term ◽  
Microscopic Mechanism ◽  
Theoretical Approaches ◽  
Modified Surfaces ◽  
Ion Implanted

In this work a model for the mechanism of dropwise condensation on ion implanted metallic surfaces is proposed. Considering experimental results for respective surfaces, the model is based on droplet nucleation and growth on preferably wetted, elevated precipitates, resulting in short-term steam entrapment after droplet coalescence. According to wetting theory this transition state yields increased macroscopic contact angles enabling dropwise condensation. Open condensation phenomena like enlarging dropwise condensation areas in spite of increasing condensation rate become comprehensible by our approach. Furthermore, the model points out that contact angles and surface free energies measured under ambient air conditions are not usable for predicting the condensation form of steam on the modified surfaces. Although the suggested microscopic mechanism cannot be directly proved by experiment, its capability of explaining experimental observations colliding with previous theoretical approaches supports its validity. The results also reveal that dropwise condensation of steam can originate from microscopically different mechanisms.

scholarly journals Droplet sweeping to enhance heat transfer during dropwise condensation

2021 ◽  
Vol 2116 (1) ◽  
pp. 012013
Author(s):  
M Tancon ◽  
M Mirafiori ◽  
S Bortolin ◽  
A Martucci ◽  
D Del Col
Keyword(s):  
Heat Transfer ◽  
Sol Gel ◽  
Saturation Temperature ◽  
Copper Surface ◽  
Aluminum Surface ◽  
Transfer Model ◽  
Dropwise Condensation ◽  
Transfer Coefficients ◽  
Vapor Velocity ◽  
Heat Transfer Coefficients

Abstract It is well known that dropwise condensation (DWC) can achieve heat transfer coefficients (HTCs) up to 5-8 times higher as compared to filmwise condensation (FWC). The interaction between the condensing fluid and the surface defines the condensation mode. Coatings that present low surface energy and high droplet mobility are a solution to promote DWC instead of FWC on metallic substrates. In the present paper, the effect of vapor velocity during DWC has been investigated over a sol-gel coated aluminum surface and a graphene oxide coated copper surface. Heat transfer coefficients and droplets departing radii have been measured at constant saturation temperature and heat flux, with average vapor velocity ranging between 3 m s−1 and 11 m s−1. A recent method developed by the present authors to account for the effect of vapor velocity on the droplet departing radius is here presented. The results of the proposed method, when coupled with the Miljkovic et al. [1] heat transfer model, are compared against experimental data.

On the Characteristics of Ion Implanted Metallic Surfaces Inducing Dropwise Condensation of Steam

Langmuir ◽  
2010 ◽  
Vol 26 (8) ◽  
pp. 5971-5975 ◽  
Author(s):  
Michael H. Rausch ◽  
Alfred Leipertz ◽  
Andreas P. Fröba
Keyword(s):  
Dropwise Condensation ◽  
Metallic Surfaces ◽  
Ion Implanted
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