Analytical consideration of liquid droplet impingement on solid surfaces

Area of Science:

• Fluid dynamics
• Surface science
• Thermodynamics

Background:

• Accurate prediction of droplet impingement is vital for industrial applications such as spray-cooling and combustion.
• Existing theoretical models for droplet spreading diameter have limitations in their applicability.
• Understanding droplet behavior on surfaces impacts heat removal and energy consumption estimations.

Purpose of the Study:

• To develop a novel analytical model for predicting the maximum spreading diameter of a droplet impinging on a solid surface.
• To incorporate adhesion energy in both horizontal and vertical directions at the contact line into the model.
• To validate the model against experimental data across a wide range of conditions.

Main Methods:

• Development of an analytical model based on the principle of energy conservation.
• Inclusion of adhesion energy at the contact line in both horizontal and vertical orientations.
• Experimental validation using various Newtonian liquids, droplet sizes (micro- to millimetre), and solid surfaces.

Main Results:

• The developed model accurately predicts the maximum spreading diameter (βm) for diverse droplet-surface interactions.
• The model successfully determines the transition between capillary and viscous regimes.
• Theoretical relations for observed scaling laws in droplet impingement were derived.

Conclusions:

• The new energy conservation-based model provides a robust framework for predicting droplet impingement spreading.
• The model's accuracy across various conditions validates its utility for industrial applications.
• This work advances the theoretical understanding of droplet dynamics on solid surfaces.