Intricate Evaporation Dynamics in Different Multi-Droplet Configurations

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Main Authors: A., Hari Govindha, Balusamy, Saravanan, Banerjee, Sayak, Sahu, Kirti Chandra
Format: Preprint
Published: 2024
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author A., Hari Govindha
Balusamy, Saravanan
Banerjee, Sayak
Sahu, Kirti Chandra
author_facet A., Hari Govindha
Balusamy, Saravanan
Banerjee, Sayak
Sahu, Kirti Chandra
contents We experimentally investigate the evaporation dynamics of an array of sessile droplets arranged in different configurations. Utilizing a customized goniometer, we capture side and top view profiles to monitor the evolution of height, spread, contact angle, and volume of the droplets. Our results reveal that the lifetime of a droplet array surpasses that of an isolated droplet, attributed to the shielding effect induced by neighbouring droplets, which elevates the local vapour concentration, thereby reducing the evaporation rate. We found that lifetime increases as droplet separation distance decreases at a fixed configuration and substrate temperature. It is observed that the lifetimes increase with the number of droplets. We observe a decrease in lifetimes, following a power law trend with increasing substrate temperature, with the shielding effect diminishing at higher substrate temperatures due to natural convective effects. We also observe a generalised behavior for the centrally placed droplet across various separation distances and substrate temperatures. This arises from different droplet configurations and substrate temperatures, which modify the local vapour concentration around the droplets without significantly impacting the contact line dynamics. Additionally, the experimental results are compared with a diffusion-based theoretical model that incorporates the evaporative cooling effect to predict the lifetime of the central droplet within the array. We observe that the theoretical model satisfactorily predicts the lifetime of the droplet at room temperature. However, for high-temperature cases, the model slightly overpredicts the evaporative lifetimes.
format Preprint
id arxiv_https___arxiv_org_abs_2408_06649
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Intricate Evaporation Dynamics in Different Multi-Droplet Configurations
A., Hari Govindha
Balusamy, Saravanan
Banerjee, Sayak
Sahu, Kirti Chandra
Fluid Dynamics
We experimentally investigate the evaporation dynamics of an array of sessile droplets arranged in different configurations. Utilizing a customized goniometer, we capture side and top view profiles to monitor the evolution of height, spread, contact angle, and volume of the droplets. Our results reveal that the lifetime of a droplet array surpasses that of an isolated droplet, attributed to the shielding effect induced by neighbouring droplets, which elevates the local vapour concentration, thereby reducing the evaporation rate. We found that lifetime increases as droplet separation distance decreases at a fixed configuration and substrate temperature. It is observed that the lifetimes increase with the number of droplets. We observe a decrease in lifetimes, following a power law trend with increasing substrate temperature, with the shielding effect diminishing at higher substrate temperatures due to natural convective effects. We also observe a generalised behavior for the centrally placed droplet across various separation distances and substrate temperatures. This arises from different droplet configurations and substrate temperatures, which modify the local vapour concentration around the droplets without significantly impacting the contact line dynamics. Additionally, the experimental results are compared with a diffusion-based theoretical model that incorporates the evaporative cooling effect to predict the lifetime of the central droplet within the array. We observe that the theoretical model satisfactorily predicts the lifetime of the droplet at room temperature. However, for high-temperature cases, the model slightly overpredicts the evaporative lifetimes.
title Intricate Evaporation Dynamics in Different Multi-Droplet Configurations
topic Fluid Dynamics
url https://arxiv.org/abs/2408.06649