Nanoscale surface effects on heterogeneous vapor bubble nucleation.

Area of Science:

• Thermodynamics
• Fluid Dynamics
• Materials Science

Background:

• Vapor bubble nucleation on surfaces is crucial for thermal management and turbomachinery.
• Classical Nucleation Theory (CNT) explains wettability effects on smooth surfaces.
• The role of nanoscale roughness and wettability in nucleation is less understood.

Purpose of the Study:

• To investigate the influence of nanoscale surface roughness and wettability on vapor bubble nucleation.
• To determine if Classical Nucleation Theory (CNT) applies to rough surfaces.
• To explore the role of surface cavities in nucleation.

Main Methods:

• Molecular dynamics simulations were employed.
• The study focused on the interplay between surface geometry, wettability, and nucleation.
• Simulations analyzed cavity behavior at varying temperatures.

Main Results:

• CNT accurately describes wettability effects on nucleation, even for rough surfaces.
• Surface cavities can initiate nucleation without trapped gases via spontaneous dewetting.
• Nucleation enhancement by cavities depends on wettability and geometry (dewetting vs. rewetting).

Conclusions:

• Surface cavities significantly influence bubble nucleation, especially on lyophobic surfaces.
• Dewetting of cavities enhances nucleation, while rewetting on lyophilic surfaces neutralizes this effect.
• Findings offer guidance for designing surfaces to control bubble nucleation in engineering applications.