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| UT - Utah State University |
http://www.mrt.usu.edu-a.googlepages.com/home |
| Proposal
ID: 2010-2501 |
Flight Week: June 17-26, 2010 |
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FUNBOE
Follow-Up Nucleate Boiling On-flight Experiment
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As humans explore further into space, thermal management systems will require greater robustness, efficiency, and reliability. Nucleate boiling is a well-known and heavily researched mode of boiling and would be ideal for thermal management systems due to its associated high heat transfer rates. However, nucleate boiling dynamics in microgravity are not well understood due to the fact that previous experiments have produced contradictory results. Without buoyancy as the dominant force, the fluid dynamics are heavily dependent on system characteristics such as working fluid, degrees of subcooling, heat flux, and surface geometry; therefore, the resulting dynamics of one system cannot readily be used to determine the dynamics of another.
The proposed study follows up on a previous experiment flown onboard Space Shuttle Endeavor (STS-108) as part of the Utah State University (USU) Get Away Special (GAS) team’s previous outreach efforts motivated by the former NASA GAS Program. After student analysis of the initial nucleate boiling experiment developed by Box Elder High School and the GAS team, it was determined that a follow-up experiment was needed that incorporates better thermal monitoring and higher resolution video recording (Koeln, 2009). This was absent from the previous experiment. Following the previous outreach pattern, FUNBOE is meant to involve K-12 students and GAS team members from a variety of disciplines in studying the effects of system characteristics on nucleate boiling behavior in microgravity. Multiple fluid chambers incorporating different heating element geometries and power inputs (resulting in different heat fluxes) will determine which system characteristics correlate to improved heat transfer. Experiments performed in microgravity and on earth will be compared to determine if nucleate boiling is an effective means of heat transfer in microgravity. Increased understanding of system characteristics of nucleate boiling, like heat flux and surface geometry, will allow accurate models to be developed.
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| WA - University of Washington |
http://students.washington.edu/mjw48/AstroDawgs.html |
| Proposal
ID: 2010-2472 |
Flight Week: June 17-26, 2010 |
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Rotational Damping of Slosh in Microgravity |
From Apollo 11 to NEAR, fluid sloshing within partially filled propellant tanks has plagued countless space missions. One solution is a rotating fluid tank which uses centripetal acceleration to force liquids to the outside of the container and maintain a stable gas column in the center. Consequently, this results in a predictable center of gravity of the tank and the contained liquid. In 2006, however, SpaceX lost a Falcon 1 rocket to a case of rotational forces gone awry. As the rocket's first stage detached, there was an impact between the interstage and the second stage, inducing oscillations and a small rotation of the second stage. As the propellants drained, the angular velocity of the rocket increased due to conservation of angular momentum. It began to spin so fast that the propellants could not be extracted, thereby halting thrust and rendering the vehicle unable to reach its orbit. Clearly, merely rotating a propellant tank is insufficient.
Inspired by this failure, University of Washington students have designed the Rotational Damping of Slosh in Microgravity mechanism, RDSM, which consists of a tapered tank, having a larger diameter at its base than at its top. This design provides a consistent centripetal acceleration which both stabilizes the liquid's center of gravity and draws the fluid toward a common collection point for extraction. Currently, propellant tanks utilize ring baffles to attenuate slosh disturbances. With a tapered rotating design, standard ring baffles would defeat the purpose of the tapering; therefore, the ring baffles will be replaced by a corkscrew shape to provide additional damping capabilities whilst drawing fluid to the base of the tank. Since there is only a specific amount of power available in a spacecraft, and angular velocity is a monotonic function of power, it is the goal of this experiment to confirm the effectiveness of the RDSM design in mitigating fluid slosh, and to determine the minimum amount of rotation necessary to create a reasonable amount of slosh damping.
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| WI - University of Wisconsin @ Madison |
http://zerogravity.rso.wisc.edu/index.html |
| Proposal
ID: 2010-2503 |
Flight Week: June 17-26, 2010 |
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The Influence of Frequency on the Performance of Ultrasonic Enhancement of Liquid Convection Cooling in Variable Gravity |
Ultrasonic liquid cooling has been shown to be an effective method for cooling surfaces in a variety of applications on Earth. By tracking changes in the heat transfer coefficient, this experiment will determine how gravity affects ultrasonic cooling. In addition, this experiment will investigate how changing the ultrasonic frequency can mitigate any possible changes that gravity causes. Results from this experiment will help determine the usefulness of ultrasonic liquid cooling in space applications as an efficient alternative to current cooling methods.
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| WV - West Virginia University |
http://www2.cemr.wvu.edu/~wwwzerog |
| Proposal
ID: 2010-2486 |
Flight Week: June 17-26, 2010 |
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Controlling Fuel Sloshing Through the Use of a Ferromagnetic Solvent Manipulated via an Electromagnetic Field |
Propellant sloshing in microgravity occurs when a force is applied to a fuel container during launch, maneuvering, or docking. The resulting sloshing motion of the liquid can alter the trajectory of the spacecraft which may cause mission delays or failure. These effects are amplified in microgravity because the fluid sloshing is prolonged due to the lack of gravitational forces. Therefore, controlling this fluid sloshing behavior is essential for accurate spacecraft navigation. The proposed experiment studies the feasibility of controlling sloshing in microgravity using a ferromagnetic fluid (ferrofluid) and an electromagnetic field. The magnetic field effects induced on the ferrofluid emulate an effective body force as a substitute for the lacking gravitational force that will help to confine the fluid, alter any sloshing frequencies, and provide damping of such a system.
The use of a magnetic field is expected to help confine the ferrofluid in its desired position and to increase damping of any resulting sloshing motion under microgravity conditions. The ferrofluid EFH1, commercially manufactured by Ferrotec Inc., is currently being considered for use in testing due to the availability of literature identifying its fluid properties. A stepper motor, connected to one cylindrical and one two-dimensional test tank by linkages, will induce sloshing by setting the tanks into oscillatory motion. Once significant sloshing is apparent, the motor will be stopped and the resulting effect of the magnetic field on the ferrofluid will be recorded. Fluid level measurements of the liquid free surface will be correlated to the sloshing motion. Various methods of data collection will be used to gather both quantitative and qualitative data. The data collected will be used to analyze the effects of the electromagnetic field upon the ferrofluids sloshing behavior under microgravity conditions.
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