Abstract: Systems and methods for thermal transport in space for cryogenic propellant storage tank chilldown are described. In order to maximize the storage tank chilldown thermal efficiency for the least amount of required cryogen consumption, the embodiments relate to quenching heat transfer concepts that can include the combination of cryogenic spray quenching cooling, thermal insulator thin-film coating on the tank inner surface, and spray flow pulsing. The boiling heat transfer physics that supports the concepts are described. The completed flight experiments successfully demonstrated the feasibility of the concepts and discovered that spray cooling can be an efficient cooling method for the tank chilldown in microgravity. In microgravity, the data shows that the chilldown thermal efficiency can reach 30% with a thermal insulator coating alone. Further thermal efficiencies can be made up to 50% with flow pulsing.

Abstract: Various methods and systems are provided for cryogenic heat transfer by nanoporous surfaces. In one embodiment, among others, a system includes a cryogenic fluid in a flow path of the system; and a system component in the flow path that includes a nanoporous surface layer in contact with the cryogenic fluid. In another embodiment, a method includes providing a cryogenic fluid; and initiating chilldown of a cryogenic system by directing the cryogenic fluid across a nanoporous surface layer disposed on a surface of a system component.

Abstract: Various methods and systems are provided for cryogenic heat transfer by nanoporous surfaces. In one embodiment, among others, a system includes a cryogenic fluid in a flow path of the system; and a system component in the flow path that includes a nanoporous surface layer in contact with the cryogenic fluid. In another embodiment, a method includes providing a cryogenic fluid; and initiating chilldown of a cryogenic system by directing the cryogenic fluid across a nanoporous surface layer disposed on a surface of a system component.