Computational study of state equation effect on single acoustic cavitation bubble's phenomenon

Area of Science:

• Physical Chemistry
• Chemical Engineering
• Acoustics

Background:

• Acoustic cavitation bubbles involve complex gas dynamics and chemical kinetics.
• The choice of state equation significantly influences bubble evolution models.
• Understanding these effects is crucial for accurate simulation of cavitation phenomena.

Purpose of the Study:

• To compare the impact of the ideal gas equation versus the Van der Waals equation on acoustic cavitation bubble dynamics.
• To quantify the differences in pressure, temperature, and chemical product formation between the two models.
• To assess the influence of frequency and acoustic amplitude on these discrepancies.

Main Methods:

• Development and comparison of two numerical models for single acoustic cavitation bubble oscillation.
• Model 1: Utilizes the ideal gas equation of state.
• Model 2: Utilizes the Van der Waals equation of state, accounting for real gas effects.

Main Results:

• Bubble dynamics show minimal differences, but pressure and temperature ranges increase significantly with the Van der Waals model.
• Chemical product yields approximately double when using the Van der Waals equation compared to the ideal gas model.
• Differences are more pronounced at low frequencies and high acoustic amplitudes, with Van der Waals increasing free radicals at high frequencies.

Conclusions:

• The Van der Waals equation provides a more accurate representation of gas behavior in acoustic cavitation compared to the ideal gas equation.
• Real gas effects substantially enhance temperature, pressure, and chemical product formation, particularly free radicals.
• Model selection is critical, with potential relative differences up to 60% for temperature and 100% for pressure and free radicals.