Hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating

The impingement of ethanol droplet train on the heated titanium substrates without or with the titanium oxide nanotube coating has been experimentally investigated in close view. The coating makes the substrate with high wettability. Four distinct but steady hydrodynamic patterns are observed on bot...

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Main Authors: Shen, Suping, Tong, Wei, Duan, Fei
Other Authors: Singapore Centre for 3D Printing
Format: Article
Language:English
Published: 2021
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Online Access:https://hdl.handle.net/10356/145908
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1459082021-01-16T20:11:15Z Hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating Shen, Suping Tong, Wei Duan, Fei Singapore Centre for 3D Printing Engineering Droplet Train Impingement Nanotube Coating The impingement of ethanol droplet train on the heated titanium substrates without or with the titanium oxide nanotube coating has been experimentally investigated in close view. The coating makes the substrate with high wettability. Four distinct but steady hydrodynamic patterns are observed on both two surfaces, namely, liquid aggregation and crown periphery instability; sub-droplet splashing and crown periphery instability; splashing and stable crown; and splashing with stable angle. However, the more wetting nanotube coated substrates push the transition between the patterns to a higher temperature. The quantitatively analysis of spreading length, diameter and height of crown and stable splashing angle further proved the transitions between the hydrodynamic patterns on the two titanium surfaces. The instability at the crown periphery may result from the low surface tension of the working fluids in first and second patterns, while the crown becomes stable on the third pattern. In the fourth pattern, a sharp shift of the splashing angle from decreasing to increasing is found at the surface temperature of 323 ∘C and 404 ∘C for the bare titanium surface and the nanotube coated surface, respectively. The shift could be attributed to the emergence of Leidenfrost effect. It is found that the Leidenfrost point at the droplet train impingement on the nanotube coated surface has been remarkably delayed. Accepted version 2021-01-14T02:58:15Z 2021-01-14T02:58:15Z 2020 Journal Article Shen, S., Tong, W., & Duan, F. (2020). Hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating. International Journal of Heat and Mass Transfer, 0017-9310 https://hdl.handle.net/10356/145908 10.1016/j.ijheatmasstransfer.2020.120409 2-s2.0-85090358829 163 120409 en International Journal of Heat and Mass Transfer © 2020 Elsevier Ltd. All rights reserved. This paper was published in International Journal of Heat and Mass Transfer and is made available with permission of Elsevier Ltd. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering
Droplet Train Impingement
Nanotube Coating
spellingShingle Engineering
Droplet Train Impingement
Nanotube Coating
Shen, Suping
Tong, Wei
Duan, Fei
Hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating
description The impingement of ethanol droplet train on the heated titanium substrates without or with the titanium oxide nanotube coating has been experimentally investigated in close view. The coating makes the substrate with high wettability. Four distinct but steady hydrodynamic patterns are observed on both two surfaces, namely, liquid aggregation and crown periphery instability; sub-droplet splashing and crown periphery instability; splashing and stable crown; and splashing with stable angle. However, the more wetting nanotube coated substrates push the transition between the patterns to a higher temperature. The quantitatively analysis of spreading length, diameter and height of crown and stable splashing angle further proved the transitions between the hydrodynamic patterns on the two titanium surfaces. The instability at the crown periphery may result from the low surface tension of the working fluids in first and second patterns, while the crown becomes stable on the third pattern. In the fourth pattern, a sharp shift of the splashing angle from decreasing to increasing is found at the surface temperature of 323 ∘C and 404 ∘C for the bare titanium surface and the nanotube coated surface, respectively. The shift could be attributed to the emergence of Leidenfrost effect. It is found that the Leidenfrost point at the droplet train impingement on the nanotube coated surface has been remarkably delayed.
author2 Singapore Centre for 3D Printing
author_facet Singapore Centre for 3D Printing
Shen, Suping
Tong, Wei
Duan, Fei
format Article
author Shen, Suping
Tong, Wei
Duan, Fei
author_sort Shen, Suping
title Hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating
title_short Hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating
title_full Hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating
title_fullStr Hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating
title_full_unstemmed Hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating
title_sort hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating
publishDate 2021
url https://hdl.handle.net/10356/145908
_version_ 1690658279430029312