Reduced Gravity Experiments to Measure Cryogenic Two-Phase Heat Transfer Coefficients for Future In-Space Transfer Systems

The Reduced Gravity Experiments to Measure Cryogenic Two-Phase Heat Transfer Coefficients for Future In-Space Transfer Systems will develop highly accurate models for the prediction of flow boiling rates. Specifically, the demonstration’s objective is to obtain the first microgravity steady state cryogenic heat transfer coefficient (HTC) data. It will also measure HTC during parabolic flight as a function of gravity level, mass flux, and other geometrical and flow parameters.Data collected will inform new steady state HTC models for microgravity that improve predictive capabilities for in-space propellant transfer systems. 

Problem Statement Highly accurate flow boiling models are required to predict a spacecraft’s propellant consumption and determine the maximum allowable heating rates of the fluid. Currently, no cryogenic flow boiling data exists in the microgravity steady state.

Technology Maturation The cryogenic steady state flow boiling data collected will be used to develop new heat transfer coefficient correlations. The data will improve the technology’s predictive capabilities, bringing it to TRL 5.

Summary of Flight Test
2022-06-27 Our test rig is undoubtedly a new national asset, capable of providing critically needed cryogenic heat transfer data in microgravity, which are crucial for design and performance analysis of important NASA space applications such as Low Earth Orbit (LEO) fuel depot and Nuclear Thermal Propulsion. Another dual-use benefit of our work is better understanding of flow boiling in tubes, through which PU-BTPFL investigators successful achieved electric vehicle ultra-fast charging in less than 5 minutes, a world record that eclipses all advanced charging technologies in use today.
2022-11-02 Purdue University Boiling and Two-Phase Flow Laboratory (PU- BTPFL) and NASA Glenn successfully operated cryogenic flow boiling experiments in parabolic flight, acquiring nucleate boiling datapoints and three full boiling curves comprised of 420 steady state heat transfer datapoints along with video recordings of flow regime transitions and interfacial behavior in microgravity. Cryogenic steady-state flow boiling has never been measured in microgravity before, giving this flight campaign extraordinary novelty and ability to acquire two phase flow physics and heat transfer knowhow essential to NASA’s near-future space applications such as Low Earth Orbit (LEO) fuel depot and Nuclear Thermal Propulsion. Results from this project will optimize the design factors of space fuel transfer system by providing accurate understanding of propellant’s two-phase flow and heat transfer behaviors. Ultimately, the enhanced design of fuel transfer system will economize the entire process of space missions. Another dual-use benefit of our work is better understanding of flow boiling in tubes, through which PU-BTPFL investigators successful achieved electric vehicle ultra-fast charging in less than 5 minutes, a world record that eclipses all advanced charging technologies in use today.
2023-12-04 & 2024-03-05 Purdue's BTPFL and NASA Glenn have successfully conducted groundbreaking cryogenic flow boiling experiments during parabolic flights, collecting crucial heat transfer data points under Lunar, Martian, and Microgravity conditions. This pioneering effort marks the first-ever steady-state testing of cryogenic flow boiling in such extreme gravitational environments, providing unprecedented insights into cryogenic two-phase heat transfer and flow physics. The results of this experiment hold immense value for NASA's forthcoming space architectures, including LEO fuel depots and Nuclear Thermal Propulsion technology. By optimizing the design factors of space fuel transfer systems, based on accurate understanding of cryogenic propellant's two-phase flow and heat transfer behaviors, this research promises to significantly enhance mission efficiency and economize space exploration endeavors. Additionally, the project's findings contribute to a better understanding of flow boiling in tubes, paving the way for breakthroughs such as electric vehicle ultra-fast charging, achieved in less than 5 minutes, setting a new world record.

Highly accurate, data-anchored models for cryogenic flow boiling rates can be used to design and analyze in-space propellant transfer systems. Improved propellant system models reduce unnecessary propellant costs and load and also optimize system efficiency.This would benefit NASA missions and the commercial space industry.

Future Customers
•NASA missions like Artemis, particularly for lunar and Martian ascent and descent stages
•In-space cryogenic fuel depots
•Nuclear thermal propulsion systems
•In-space commercial transfer systems

This is early/mid-stage (TRL 6) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.

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