Contents

• Abstract and Acknowledgments
• 1. Introduction
• 2. Background
• 3. Microgravity Experiments on Polymer Spheres
• 4. Theory
• 4.1 One-Fluid Mixture Submodel
• 4.1.1 Mass Balance
• 4.1.2 Momentum Equations
• 4.1.3 Energy Equation
• 4.1.4 Effective Thermal Conductivity
• 4.2 Bubble Submodel
• 4.2.1 Bubble Nucleation
• 4.2.2 Bubble Growth
• 4.2.3 Bubble Migration
• 4.2.4 Bubble Bursting
• 4.2.5 Bubble Coalescence
• 5 Computational Approach
• 5.1 Geometry
• 5.2 Mass Balances
• 5.3 Bubble Growth
• 5.4 Bubble Migration
• 5.5 Bubble Bursting and Coalescence
• 5.6 Gas Distribution Within Elements
• 5.7 Bubble Nucleation
• 5.8 Effective Material Properties
• 5.9 Component Velocities
• 5.10 Energy Equation
• 5.11 Convergence
• 6 Results
• 6.1 PMMA Base Case: Instantaneous Escape of Gases
• 6.2 Bubble Generation
• 6.3 Bursting Effects
• 6.4 Nucleation Effects
• 6.5 Bubbles in Polypropylene (PP)
• 7 Conclusions
• References
• Appendix A - Temperature Equation Derivation
• Appendix B - The Finite Element Method