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Completed TRL 6 (started at 4, targeting 6)
The Transport Properties of Fluids for Exploration demonstration seeks to measure heat transfer rates in low gravity and to develop accurate thermal diffusivity values of commonly used fluids in space. To do this, researchers have created unique methodologies that require only a non-timed heat pulse and subsequent temperature measurements in the heated fluid. A suborbital flight test will evaluate the hardware’s performance in a space environment using water and liquid metal as the device’s test fluids.
Problem Statement Thermal transport of fluids on the Earth, under terrestrial gravity, occurs due to both conductive transport and convective transport. Convective heat transport dominates for most process or situations on earth. Convection leads to more efficient heat transport, thus in a gravitational field heat energy is transferred at a higher rate than by conduction alone. In low-gravity environments, without convection, heat transfer will be lower, and heat transfer rates inferred from terrestrial measurements cannot be assumed to be valid in a low-gravity environment. Thus, it is important, to confidently understand and model the low-gravity process, to have accurate values of the thermal diffusivity of fluids common to low-gravity environments, or for materials that mimic fluids used in low-gravity environments.
Technology Maturation The flight test will validate the applicability of the hardware to future low-gravity missions to support exploration initiatives. The hardware will be tested by determining the thermal diffusivity of water and Galinstan. Water is a fluid used in multiple process in spacecraft, while Galinstan represents an analog to possible heat transfer fluids, such a liquid ammonia, or other liquid metals. The current hardware is at TRL 4-5. At the completion of this project, the TRL will be 6-7.
Summary of Flight Test
2022-09-12 This experiment was to use the test fluid, the liquid metal Galinstan, to establish the utility of using lowercost, commercial suborbital vehicles to determine the conductive only component of heat transport in liquids. The experiment was also to verify the applicability of a simple experimental method for these measurements.
2023-12-19 The Transport Properties of Fluids for Exploration measured the thermal diffusivity of the liquid metal galinstan over 180 seconds of low-gravity. Galinstan is used for heat transfer in nuclear reactors and in flexible electronic circuit. Further data analysis will provide numerical values for use in these and other industrial and scientific applications.
• High fidelity: Collects thermal diffusivity data that is unaffected by convection
• Predictive: Enables development of models for heat transfer processes in space
• Accurate: Produces more accurate heat transfer measurements than ground-based models
Future Customers
• Heat transfer system designs, particularly those that use water or liquid metal
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