Steady boiling and transient quenching of cryogenic fluids: new experiments to enable advanced propellant tank design and operations planning

Abstract

Cryogenic fluid management and storage are key to future space missions. Engineers need accurate tools to design efficient processes and lightweight components for cryogenic fluid management (CFM) to help enable the next generation of space exploration missions. A common and critical element of CFM is the need to chill down a warm tank, fill it with liquid cryogen, and maintain liquid cryogen over extended periods until it is used or transferred. The major processes that govern the design requirements for this process are transient and often simulated using lumped-node calculation models. Pool boiling is a key phenomenon that must be modeled in a way that is accurate and compatible with these lumped-node thermal design tools. Creare and Case Western Reserve University (CWRU) are developing data and correlations for pool boiling that will support the design of efficient propellant management systems. These data and methods improve on existing technology because: (1) they are based solely on measurements of cryogenic boiling, (2) they fully account for physical differences between steady boiling and quenching, and (3) their accuracy is equal to or better than state of the art correlations across all fluids and boiling regimes. Creare is responsible for design and operation of the test facility, while CWRU is responsible for assessment of the existing literature and development of the improved correlations.

We have designed and built an experimental facility designed for gathering heat transfer data under both steady boiling and transient quenching conditions using key cryogenic propellants. We have used this facility to measure boiling curves for liquid nitrogen, liquid argon, and liquid methane over a range of pressures and orientations in both steady and transient configurations, gathering a total of 445 new steady-state data points and 5,180 new transient-quenching data points. The test matrix was selected to fill gaps in the existing literature data. We also measured boiling curves using a second test article constructed from a much thinner wall to show the impact of wall thickness on heat transfer performance and boiling regime transitions. We analyze trends in data to identify conditions when the differences between steady and transient boiling modes must be considered. This work enables formulation of new pool boiling / quenching heat transfer correlations to support design of CFM systems and procedures.