Numerical study of real gas effects during bubble collapse using a disequilibrium multiphase model.

Area of Science:

• Computational fluid dynamics
• Thermodynamics
• Multiphase flow

Background:

• Accurate modeling of gas-liquid flows is crucial for many engineering applications.
• Existing models often rely on ideal gas assumptions, which may not capture real fluid behavior under extreme conditions.

Purpose of the Study:

• To develop and validate an explicit density-based solver for inviscid, immiscible gas-liquid flows.
• To investigate the impact of real gas equations of state on gaseous bubble collapse dynamics.
• To improve the numerical estimation of equilibrium pressure in multiphase computational cells.

Main Methods:

• Coupling an Euler equations solver with real-fluid thermodynamic equations of state.
• Generalizing a 6-equation disequilibrium method for multiphase pressure estimation.
• Implementing an iterative numerical procedure for non-linear real gas properties.
• Calibrating the model with shock tube data up to 5000 K and 28 GPa.

Main Results:

• The real gas model predicts a significant temperature reduction during bubble collapse (up to 41% space-averaged, 50% locally) compared to the ideal gas approximation.
• The choice of equation of state strongly influences predicted maximum temperatures.
• The numerical method successfully handles co-existing gas and liquid phases while conserving energy.

Conclusions:

• Real gas effects are critical for accurately predicting temperatures during gas-liquid flow phenomena like bubble collapse.
• The developed solver provides a more realistic simulation of extreme thermodynamic conditions in multiphase flows.
• This work advances computational methods for non-ideal fluid dynamics.