Volume-independent contact angle prediction

Abstract

The contact angle of droplets attracts attention as one of the relevant thermophysical properties describing the wettability behaviour of the fluids. The contact angle depends on the surface characteristics such as surface type and roughness as well as on the liquid type and surrounding atmosphere. This study aims to correct the error in the coefficient of the theoretical model developed for droplet shape prediction by Vafaei and Podowski [1]. The corrected model is also rearranged by non-dimensional numbers. The contact angle and the shape of water droplets for different volumes and surface types are predicted by the rearranged model and validated by experimental results. Contact angles have been over-estimated compared to experimental results because of measurement errors in geometrical parameters. It is found that the contact angle model is too sensitive to geometrical parameters. Moreover, the contact angle is found to be independent of the volume.