Browsing by Author "Alexander, Dennis"
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Item Continued Laser Processed Condensing Heat Exchanger Technology Development(48th International Conference on Environmental Systems, 2018-07-08) Hansen, Scott; Castro-Wallace, Sarah; Hamilton, Tanner; Zuhlke, Craig; Alexander, Dennis; Fischer, BillThe reliance on non-permanent coatings in Condensing Heat Exchanger (CHX) designs is a significant technical issue to be solved before long-duration spaceflight can occur. Therefore, high reliability CHXs have been identified by the Evolvable Mars Campaign (EMC) as critical technologies needed to move beyond low earth orbit. In continued pursuit of Laser Processed Condensing Heat Exchanger (LP-CHX) development, a sub-scale LP-CHX coupon was designed and constructed. For construction of this coupon, numerous manufacturing methods were developed. These include development of unique laser processing methods of silver finned surfaces of various thicknesses, laser welding of silver, and unique brazing operations. Additionally, microbial growth testing and long duration condensing is reported in this paper. These studies conclude that silver laser processed surfaces significantly reduce microbial growth and increase the number silver ions found in condensate water.Item Laser Processed Condensing Heat Exchanger Technology Development(47th International Conference on Environmental Systems, 2017-07-16) Hansen, Scott; Wright, Sarah; Wallace, Sarah; Hamilton, Tanner; Alexander, Dennis; Zuhlke, Craig; Sanders, JohnThe reliance on non-permanent coatings in Condensing Heat Exchanger (CHX) designs is a significant technical issue to be solved before long-duration spaceflight can occur. Therefore, high reliability CHXs have been identified by the Evolvable Mars Campaign (EMC) as critical technologies needed to move beyond low earth orbit. The Functionalized Condensing Heat Exchanger project aims to solve these problems through the use of femtosecond laser processed surfaces, which have unique wetting properties and potentially anti-microbial growth properties. These surfaces were investigated to identify if they would be suitable candidates for a replacement CHX surface. Among the areas researched in this project include microbial growth testing, siloxane testing in which functionalized surfaces were exposed to an air stream of siloxanes, and condensation testing in which functionalized surfaces were condensed upon.