Thin Film Measurement Assessment of the VPCAR Water Recovery System in Partial and Microgravity
2007-01-3039
07/09/2007
- Event
- Content
- The Vapor Phase Catalytic Ammonia Removal (VPCAR) system is being developed to recycle water for future NASA Exploration Missions [1,2,3,4,5]. Reduced gravity testing of the VPCAR System has been initiated to identify any potential problems with microgravity operation. Two microgravity testing campaigns have been conducted on NASA's C-9B Reduced Gravity Aircraft. These tests focused on the fluid dynamics of the unit's Wiped-Film Rotating Disk (WFRD) evaporator.The experiments used a simplified system to study the process of forming a thin film on a rotating disk. The configuration simulates the application of feed in the VPCAR's WFRD evaporator. The first round of aircraft testing, which was completed in early 2006, indicated that a problem with microgravity operation of the WFRD existed. It was shown that in reduced gravity the VPCAR wiper did not produce a uniform thin film [6]. The film was thicker near the axis of rotation where centrifugal forces are small. A thickening of this film could have a negative effect on the heat transfer coefficient of the evaporator and could result in higher than expected specific power consumption during microgravity operation.In the second round of microgravity tests a potential solution to this problem was tested. This test demonstrated that mounting the feed wiper slightly higher than the axis of rotation of the WFRD disk produced a uniform thin film. This paper presents the results of this reduced gravity testing.
- Pages
- 11
- Citation
- Hall, N., Niederhaus, C., Mackey, J., Litwiller, E. et al., "Thin Film Measurement Assessment of the VPCAR Water Recovery System in Partial and Microgravity," SAE Technical Paper 2007-01-3039, 2007, https://doi.org/10.4271/2007-01-3039.