Curvature Dependence of the Mass Accommodation Coefficient

Area of Science:

• Physical Chemistry
• Fluid Dynamics
• Materials Science

Background:

• The mass accommodation coefficient governs molecular transport at liquid-vapor interfaces, critical for condensation.
• Experimental determination of this coefficient is challenging.
• Its applicability to curved interfaces of small droplets remains unclear.

Purpose of the Study:

• To compute equilibrium mass accommodation coefficients for small droplets using molecular dynamics.
• To investigate the influence of temperature, droplet size, and curvature on the coefficient.
• To determine if a universal relationship exists for the mass accommodation coefficient.

Main Methods:

• Employing molecular dynamics simulations.
• Simulating various fluids including Lennard-Jones and Buckingham fluids, benzene, butane, methane, methanol, and water.
• Calculating equilibrium mass accommodation coefficients at different temperatures and droplet sizes.

Main Results:

• The mass accommodation coefficient increases with droplet size, reaching a plateau.
• A decrease in the mass accommodation coefficient was observed with increasing temperature.
• The curvature dependence of the accommodation coefficient collapses into a universal scaled curve.

Conclusions:

• The mass accommodation coefficient exhibits size and temperature dependencies.
• A universal scaling law for the accommodation coefficient's curvature dependence was established.
• Findings provide insights into molecular transport at curved interfaces, relevant for droplet condensation.