Development of the Thermal Interface Between the Dragonfly Mass Spectrometer and the DrACO Sample Delivery Carousel
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Peter Barfknecht↗
Engineering topics
Franklin L. Robinson
Publications and source records attributed to Franklin L. Robinson.
Switchable Wettability for Condensation Heat Transfer
Condensation proceeds as dropwise or filmwise depending on the wettability of the condensing surface. These two modes of condensation have disparate heat transfer coefficients, with dropwise often exceeding filmwise. This work reports a surface with switchable superhydrophilic to hydrophobic wetting behavior that can exhibit both modes of condensation. Relative to the highly-wetting state which yields filmwise condensation, the non-wetting state exhibits dropwise condensation and twice the heat transfer coefficient. Relevance to thermal management is additionally discussed.
Heat transfer↗
Flow Boiling in Microgap Coolers - Suborbital Flight Results
Flow Boiling in Microgap Coolers (FBMC) is a thermal management technique that provides embedded, on-site heat removal for power dense electronic components and systems. The dielectric coolant undergoes liquid-to-vapor phase change as it passes through channels integrated within or between devices. By facilitating direct contact between the coolant and heat-generating devices and relying on phase change, the system provides tight temperature control, hot spot mitigation, very high heat transfer coefficients, and low pumping power. Ground tests demonstrated removal of high heat fluxes (up to 500 kW/m2), very high coefficients of performance (up to 40 W of heat transferred per W of pumping power), and consistent performance across five evaporator orientations under the appropriate conditions. As a follow-on study and to better assess the role of gravity on such two-phase systems, the FBMC payload was developed and flown twice aboard the Blue Origin New Shepard space vehicle in January and May 2019. Each flight exposed the payload to weightlessness (150 seconds below 0.01 g) and shorter periods of high-g during ascent (up to 3 g) and descent (up to 5 g). The flow boiling performance was consistent independent of the acceleration levels, which provides confidence that such systems will provide consistent performance when tested on the ground, orbiting or traveling through weightlessness, and operating on the surface of the Moon, Mars, and other planetary bodies. Details of the flight results, payload development, flight environment, and planned future testing will be presented.
Flow boiling↗
Development of the Thermal Interface Between the Dragonfly Mass Spectrometer and the DrACO Sample Delivery Carousel
Icy celestial bodies are an exciting new frontier for surface exploration and in-situ sampling and analysis. These destinations are inherently cryogenic in nature, and each body presents unique challenges related to thermal design. The Dragonfly mission to Titan is one such example. One of the most important requirements of a sampling system is to preserve the integrity of the surface material. The interface between the Dragonfly Mass Spectrometer (DraMS) and the Drill for Acquisition of Complex Organics (DrACO) is complicated by several competing requirements. Development of this interface has required the use of new enabling technologies such as 3D printing to achieve a successful design. This overview of the DraMS Cryogenic subsystem will show how the design meets all the requirements of the interface and preserves integrity of Titan surface samples.
Peter W. Barfknecht↗