Design of Thermal Initial and Boundary Conditions to Control the Expansion of Water-Based Phase-Change Materials in Low Gravity

ABSTRACT

A passive carrier employing water-based phase-change materials is designed to return temperature-critical payloads from the International Space Station. These materials expand by 9% when frozen, which can cause rupture of freezers and/or an inability to fit inside the carrier. To solve this problem a method is devised that decouples the thermodynamic and physical expansion characteristics. Solutions are found simultaneously to the two independent problems by coupling them through pressure. The final numerical models are used to devise a freezing method to ensure desirable final shapes. Finally, ground-based experiments are conducted, adding validity to the model and freezing method.