Determining Contact Angle and Spreading Velocity of a Droplet Impacted Hot Solid Surface

Abstract:

Spray cooling is a method to lower the solid surface temperature by splashing droplets. The evaporation of droplet will take the heat from solid surface. One of the factors that contributes to the evaporation rate and droplet spreads on the surface is the wettability of fluid on surface. Contact angle is a parameter in categorizing the wettability of fluid at a solid surface. Many methods have been developed to measure the contact angle on solid surface. This paper will explain how to measure the contact angle by analyzing the image taken when droplet fluid attached to a surface. The method use MATLAB codes as tools for processing image and compute the result. There are four steps in processing an image of droplet on a surface: convert image to binary image, detect the boundary of the surface, determine the correlation of x-y pixel, and take the tangent of a line at the outer point of contact between fluid and surface. Validation is taken by comparing the result with “standard image” with various resolutions. This method also explains droplet dynamics when impacting a hot surface.

• Periodical: Applied Mechanics and Materials (Volume 771)
• Pages: 183-186
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.771.183
• Online since: July 2015
• Authors: Windy Hermawan Mitrakusuma*, Deendarlianto Deendarlianto, Samsul Kamal, Indarto Indarto, M. Nuryadi, Rudi Rustandi
• Keywords: Contact Angle, Droplet Spreading, Image Processing, Wettability

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