ZBOT Short Overview Presentation
• ZBOT research will aid the design of long-term storage
systems for cryogenic fluids. Simulated by Perfluoro-normal-Pentane (P-n-P).
• Obtain 1-g and microgravity two-phase flow data for
pressure control through mixing and active cooling.
• Verify and validate a Computational Fluid Dynamics
(CFD) model for cryogenic storage in 1g and microgravity.
• Use data and CFD model to assess and optimize cryogenic
liquid storage design concepts.
• Reduces launch mass and decreases risks through enabling
design concepts for long-term storage of cryogenic fluids.
• Cost effective and reliable cryogenic storage for
both life support and propulsion systems satisfying the requirements for long term mission scenarios from Moon to Mars and beyond.
• Ground phase: develop ground-based experiment and
obtain 1-g data for tank pressurization and pressure control.
• Flight phase: develop ISS experiment and obtain microgravity
data for tank pressurization and pressure control.
• Develop a state-of-the art two-phase CFD model for
tank pressurization and pressure control.
• Validate and Verify (V&V) the CFD model with
microgravity and 1g data.
• Use the validated CFD model and empirical correlations
derived from the 1g and microgravity data for scale-up tank design.
The following general steps are taken to prepare the tank before each test run in order to ensure that the tests are all started from a common initial state:
• Set the jet temperature to the desired initial fluid
• Set jet flow rate so that fluid will be well mixed.
• Continue to run the jet until:
• All thermal gradients have sufficiently decayed
(i.e. until all thermistor temperatures are within +/- 0.25 oC of each
• All thermistors are within +/- 0.25oC of the desired
• Turn on the heater power supply and set desired
• Configure the data acquisition system to record
1. Self-Pressurization Tests: Isolate test cell from
mixing/cooling loop by valving off the jet inlet and the tank outlet.
At time = 0, turn on the heater and record measurements. After a prescribed
pressurization time, turn off the heaters and go back to step #1 to
prep the tank for the next run.
2. Mixing Tests: Set desired jet speed. At time = 0,
turn on the heaters allowing the tank to pressurize for a specified
time period. After the pressurization time has elapsed, turn on the
jet and continue to run until either the maximum allowable mixing time
has elapsed or the tank pressure has returned to the initial pressure
for this particular experimental run. Turn off the heaters and jet
and go back to step #1 to prep the tank for the next run.
3. Subcooled Jet Cooling/Mixing Tests: Specify heater
power, jet inlet temperature and jet speed. Specify whether jet will
be active during the entire run or whether an initial pressurization
will occur. For mixing throughout, at time = 0, turn on the jet and
heaters. After a specified elapsed time, turn off the jet and the heaters
and return to step #1. For an initial pressurization, at time = 0,
turn on the heaters allowing the system to pressurize. After the pressurization
time as elapsed turn on the jet. Continue until either the maximum
allowable mixing time has elapsed or the tank pressure has decayed
to the initial pressure. Turn off jet and heaters and return to step
• Tank Pressure
• Heat Powers
• Temperature at all locations (inside and outside)
• Ullage position
• Inlet Jet Temperature
• Tank Outlet Temperature
• Jet Flow Rate
• Gravitational Acceleration Data
• Velocity Field Visualization-PIV
Contacts at NASA Glenn Research
Project Manager: William Sheredy, NASA GRC
Project Scientist: Dr. David Plachta , NASA GRC
Principal Investigator: Dr. Mohammad Kassemi, NCSER/GRC
Co-Investigator: Dr. David Chato, NASA GRC