The Zero Boil-Off Tank (ZBOT) experiment was operated onboard the International Space Station (ISS) in the Microgravity Science Glovebox (MSG). ZBOT is a small-scale simulant-fluid experiment that will be used to obtain valuable microgravity empirical data for cryogenic storage tank pressure control design and archival science data for model validation. It will be used to build a science base for future space storage tank engineering efforts by elucidating the roles of the various interacting transport and phase change phenomena that impact tank pressurization and pressure control in variable gravity. The project science team will develop, validate, and verify two-phase Computational Fluid Dynamics (CFD) models for tank pressure control that can be used to aid the future scale-up tank design. ZBOT will show the feasibility of a Zero-Boil-Off (ZBO) pressure control scheme for microgravity and variable gravity applications by examining the effect of forced mixing of the bulk liquid on destratification and pressure reduction in a ventless dewar.
Control variables for ZBOT include tank liquid fill levels, heater powers, vacuum jacket temperature, initial fluid temperature and jet speed and temperature. Diagnostics include temperatures and pressure measurements, white light imaging and Digital Particle Image Velocimetry (DPIV) for flow visualization and velocity measurements.
ZBOT was delivered to the ISS aboard Orbital Cygnus flight OA-7, which launched on April 18, 2017. The ZBOT system was installed in the MSG by Astronaut Joe Acaba on September 19 & 20. System thermal and fluid characterizations started on September 24 and actual test runs began on October 1. All data and images were downloaded to the ground prior to removal of the hardware from the MSG and stowage, which occurred on December 1, 2018.
The ZBOT flight hardware was returned to earth on SpaceX flight SPX-13 in January 2018 and delivered to GRC. Post-flight activities were conducted, including several additional runs of 1g DPIV tests and preparation of the hardware for use on the ZBOT-Noncondensables (NC) project.
The relevance/impact of ZBOT will be to reduce propellant launch mass (cost) and decrease risks for future space missions by aiding the development of dynamic pressure control schemes for long-term storage of cryogenic fluids. ZBOT will also increase design reliability by providing archival data for benchmarking and improving CFD models/codes used by the Cryogenic Fluids Management Community and the Aerospace Companies for future (ground-tested-only) tank designs.More »
|Organizations Performing Work||Role||Type||Location|
|Glenn Research Center (GRC)||Lead Organization||NASA Center||Cleveland, OH|
|Case Western Reserve University||Supporting Organization||Academic||Cleveland, OH|
|USRA||Supporting Organization||Industry||Huntsville, AL|
|ZIN Technologies Inc.||Supporting Organization||Industry||Middleburg Hts, OH|
During ZBOT operations, 104 test points were completed: 31 at the 70% tank fill level, 19 at 80%, 38 at 90% and 16 DPIV at 90%.
Key science observations from ZBOT:
Of the 104 test points conducted, 37 tests were selected for numerical modeling:
The Principal Investigator has stated that substantial (i.e. complete) success had been met for the ZBOT experiment.
Presentations of the ZBOT experiment's microgravity results to NASA programs, aerospace companies & national/international conferences:
1.Webex Presentation to NASA AES Lunar Lander Management (Suzuki Nantel and Greg Chavers) on April 5th 2018
2.Presentation to NASA NESC Cryogenics Technical Discipline Team Meeting, Kennedy Space Center, April 26th 2018
3.Webex Presentation to NASA STMD Chief Engineer, Deputy Principal Technologist and eCryo Management, NASA GRC, June 15th 2018
4.Webex Presentation to Blue Origin, May 3rd 2018
5.Webex Presentation to Southwest Research Institute, Dec 14 2017
6.Conference Presentation/Paper at the 65th JANNAF Joint Propulsion Meeting, Long Beach, California, May 23rd 2018
7.Conference Presentation/Paper at the 54th AIAA/SAE/ASEE Joint Propulsion Conference, Cincinnati, OH, June 10th 2018
8.Two Recorded Webcast Lectures NASA NESC Academy, Part 1 (July 2018) & Part 2 (Sept 2018)
9.Conference Presentation/Paper at the 69th International Astronautical Congress, Bremen, Germany, October 2nd 2018
10. Conference Presentation/Paper at 34th Annual Meeting of ASGSR, Washington DC, November 3rd 2018More »