Microgravity Research Division Weekly Highlights – Week Ending (7/14/2000)

Microgravity Research Division

Weekly Highlights – Week Ending (7/14/2000)

Indicates item is appropriate for the HQ senior staff meetings

and may appear on the MRPO Web site:

http://microgravity.msfc.nasa.gov

FLUID PHYSICS PI GIVES KEYNOTE AT EUROFOAM 2000: Fluid physics PI Prof. D. Durian (UCLA) gave a keynote lecture at the EuroFoam 2000 EuroConference on Foams, Emulsions and Applications 4 – 8 June 2000 Delft University of Technology Delft, the Netherlands in the session “Microgravity and solid foams” . The title of his Keynote Lecture was “Jamming in foams: vanishing elasticity vs liquid fraction, shear rate and forced counterflow rate. Prof. Durian also gave another talk “Vanishing elasticity for wet foams equivalence with emulsions and role of polydispersity”. Prof. Durian is a flight definition PI for the experiment entitled “Foam Optics and Mechanics (FOAM)”. This experiment is to be conducted on the International Space Station.

The conference information is at: http://www.eurofoam2000.tudelft.nl/

NASA GLENN FLUID PHYSICIST AWARDED EXCEPTIONAL SERVICE MEDAL: Richard B. Rogers of NASA Glenn Research Center’s Microgravity Fluid Physics Branch was awarded NASA’s Exceptional Service Medal during the Honor Awards Ceremony held on July 13, 2000 at NASA Glenn. Mr. Rogers was recognized “for pioneering work in and contributions to the Microgravity Fluid Physics Program at NASA Glenn Research Center in the area of morphology and rheology of colloids”. He was co-investigator for the

highly successful Colloidal Disorder Order Transition (CDOT) Glovebox Investigation conducted during USML-2. Gen. John R. Dailey (retired) Director of National Air and Space Museum presented the award.

EDUCATION and OUTREACH

POTENTIAL EDUCATION COLLABORATION WITH TEXAS INSTRUMENTS: As a result of meeting with Texas Instruments (TI) educational division representatives at the National Council of Teachers of Mathematics conference in Chicago this year, a potential collaboration between NASA’s Microgravity Research Program and TI is under consideration. Catherine Lowney, Texas Instruments (TI) European new product development manager, based in Paris, France, met with Dan Woodard in Huntsville, AL on June 27. Texas Instruments is aggressively growing their educational product line, branching out to include science and mathematics educational curriculum supplements that utilize their calculators. TI is interested in partnering with NASA’s Microgravity Research Program Office (MRPO) to develop a joint mathematics and science curriculum product that utilizes the TI line of classroom calculators.

SOLICITED PAPER PUBLISHED IN AEROSPACE AMERICA: A solicited paper entitled “A Solid Case for Processing in Microgravity” by Dr. Richard Grugel, Marshall Space Flight Center, was published in the June 2000 issue of Aerospace America. The paper introduces accessing a low-gravity environment and the benefits that can be gained from conducting controlled solidification experiments of metals and alloys therein.

SUCCESSFUL SUBORBITAL ROCKET LAUNCH: A Microgravity Research payload, the Extensional Rheology Experiment (ERE) was successfully launched aboard a suborbital rocket from the White Sands Missile Range (WSMR) on July 6, 2000. Following recovery, a preliminary assessment was performed which determined that the experiment generally performed as planned. The hardware has been returned to the project team at Glenn Research Center for further review, and additional information from that activity, as well as initial findings from the Principle Investigator, Gareth McKinley, Massachusetts Institute of Technology (MIT), will be provided by the end of July.

MICROGRAVITY RESEARCH PAYLOAD ADDED TO STS-107: During the July 6, 2000 Shuttle Payload Requirements Control Board (PRCB),held at the Johnson Space Center (JSC), several changes were made to the STS-107 shuttle mission. The launch date was moved by one month to June 14, 2001. The Triana payload was removed from the STS-107 manifest. A Microgravity Research Program (MRP) payload, the Critical Viscosity of Xenon (CVX-2) payload was officially added to the STS-107 payload complement. The CVX-2 will be mounted on a Get Away Special (GAS) cross bay bridge assembly called FREESTAR. Another MRP payload named Collisions Into Dust Experiment (COLLIDE-2) is an alternate payload for the STS-107 mission.

JSC CALL FOR THE R2 MISSION MRPO PAYLOADS: The Microgravity Research Program and the Space Product Development Program Research Mission number 2 (R2) payload candidate lists were provided to the Johnson Space Center (JSC) R2 mission management personnel. It is anticipated that the JSC mission management team will submit the research candidate payload lists to Spacehab Inc. in the very near future. After Spacehab receives the data, they will begin to perform a total mission complement assessment and report back to NASA their findings. The R2 launch date, originally planned for November 2001, was moved to April 2002 during the Flight Assignment Working Group (FAWG) meeting held during the week of July 3.

MISTE PI DESCRIBES CROSSOVER BEHAVIOR OF THE HEAT CAPACITY AND SUSCEPTIBILITY NEAR THE 3HE CRITICAL POINT: Marty Barmatz of JPL, MISTE Principal Investigator, presented an invited paper titled “Thermodynamic Measurements near the Liquid-Gas Critical Point of 3He” at the 2000 International Symposium on Quantum Fluids and Solids. This talk, co-authored by Inseob Hahn, F. Zhong, M. A. Anisimov and V. A. Agayan, was part of a Microgravity session. The talk described the objectives of the MISTE flight experiment now being developed to fly in the Low Temperature Microgravity Physics Facility (LTMPF) on the International Space Station. The MISTE flight experiment plans to perform measurements in the asymptotic region very near the critical point. Recent ground-based measurements of the heat capacity and isothermal susceptibility, obtained along the critical isochore in the crossover region farther away from the critical point, were also presented. These measurements were analyzed using a new parametric crossover equation of state and a field theoretical renormalization group calculation based on a f4 model. Both models provided a good fit to these data. A paper was submitted to the QFS 2000 Proceedings that will be published in the Journal of Low Temperature Physics.

DYNAMX TEAM ACTIVE AT QFS MEETING: The Critical Dynamics in Microgravity (DYNAMX) Group at the University of New Mexico presented one invited talk and three posters at the Quantum Fluids and Solids Conference in Minneapolis in June, 2000. PI Robert Duncan gave an overview of the new science discovered by DYNAMX during the ground-phase research, and described the open questions that can only be resolved in microgravity. Dmitri Sergatskov presented two posters, one on the development of a new type of PdMn thermometer for use at low-temperatures, and the other on a new cell construction technology. Alex Babkin presented a poster on a revolutionary miniature cryogenic valve with a mass of less than 1.5 grams.

ACOUSTICALLY FORCED CONDENSED PHASE FUEL COMBUSTION: The objective of this investigation, led by Prof. O. Smith of UCLA, is to characterize burning rates of condensed phase fuels in relatively weak acoustically forced convective flows. This work is significant in that weak convective flow fields present in spacecraft, due to motions such as that of fans, can increase the microgravity burning rate of condensed phase fuels in comparison to the more commonly studied quiescent conditions, and hence, should prove valuable in analysis of spacecraft fire hazards. The results of recent drop tower experiments at NASA Glenn demonstrate that the burning rate constant increases during acoustic excitation, by as much as 18% for these experiments, consistent with the normal gravity experiments. It is also found that the sound pressure levels, which are somewhat higher than those suggested in the original proposal, do not appear to lead to measurable distortion of the droplet shape. Droplet burning in an imposed acoustic field has been modeled with a one-dimensional code using detailed chemistry, valid in the vicinity of the stagnation point. Burning at sound pressure levels up to 140 dB was simulated, and it was found that burning rates were enhanced at higher sound pressure levels, consistent with previous normal as well as microgravity studies. At a constant sound pressure level, the average burning rate is seen to reach a maximum at frequencies in the range 200-400 Hz, then the augmentation in burning rate decreases at higher frequencies consistent with previous studies.

COMBUSTION OF INDIVIDUAL BUBBLES AND SUBMERGED GAS JETS IN LIQUID FUELS: The objective of this investigation, led by Prof. D. Rosner of Yale University, is to study a mode of liquid fuel combustion that is associated with the consumption of one/more near-spherical oxidizer vapor bubbles. Because of the large density difference between the liquid fuel and the vapor, even for transparent fuels with large surface tensions, such studies are not readily done in a ground-based laboratory due to gravitationally-induced bubble distortion or bubble breakaway and buoyant rise through the liquid. Moreover, because the total diffusion-controlled combustion time will scale with the square of the initial bubble diameter, while the ignition time will scale linearly, there is an incentive to study rather large bubbles to minimize the inevitable effects of asymmetric ignition transients. This unexplored “inverse” mode of liquid fuel combustion should guide the design of future “submerged gas jet combustors” for ground-based synthesis-oriented chemical industry (e.g., when the liquid “fuel” (feedstock) is difficult to “atomize” due to high effective viscosity and/or “chemical aggressiveness”). The PI’s team confirmed that it is possible to select an appropriate combination of gaseous fuel/oxidizer/diluent composition, bubble size, and liquid properties (viscosity and surface tension) to deliberately ‘couple’ the required combustion time with the natural “breathing time” of the ignited bubble, thereby inducing large amplitude oscillations and enhanced gas/liquid contacting. A simple, yet rational theory to predict the combustion time and associated overpressures in such spherical “mini-fluid bomb” situations is developed. Family of H2-O2-CO2 mixtures, which meet the ‘resonance condition’, is chosen as the combustible mixture. Here the CO2 would play the role of both the diluent (required to keep the raise in pressure within safe limits) and the solute whose rate of dissolution from the nonlinearly oscillating bubble could be experimentally monitored.

FLUID PHYSICS:

NEW ELECTRO-HYDRODYNAMIC INDUCTION PUMP: Successful assessment of optimum electrode designs for the EHD induction pump was carried out experimentally at Texas A&M University by Prof. Seyed-Yagoobi and his team. The EHD pump does not involve any moving parts and offers high reliability and long life. It can be used to augment the performance of passive thermal management devices in space. Three different designs (three-needle , pin-head needle, and hollow tube designs for the high voltage electrodes) were explored on the two static apparatuses. The pressure generated with these electrodes were measured as a function of applied voltage. The hollow tube high voltage electrode was shown to be the best design with over 1,000 Pa pressure generated at 20 kV with R-123 fluid. An EHD induction pump (based on the hollow tube high voltage electrode) was designed by Texas A&M University and provided to NASA Goddard where it was fabricated. The two-phase apparatus at Goddard was modified and the EHD induction pump was installed in the liquid return line (following the condenser section) of the apparatus. Preliminary tests were conducted by the Goddard and Texas A&M groups recently. The pump successfully/effectively circulated the test fluid (R-123). Prof. Seyed-Yagoogi and his team is in the process of defining a flight experiment “EHD Driven Heat Transfer Experiment “.

FUNDAMENTAL PHYSICS:

FUNDAMENTAL PHYSICS INVESTIGATOR TALKS AT FRENCH MEETINGS: Randy Hulet of Rice University attended two meetings in France where he described his NASA-sponsored work with laser-cooled lithium atoms. At the Summer School on Fundamental Physics and Trapped Particles at Les Houches, Francehe he presented a talk titled “Quantum Degeneracy in Lithium Gases.” Also, at the European

Center on Atomic Physics Workshop on Attractive Condensates in Lyon, France he discussed “Bose-Einstein Condensation in Attractive Atoms — Review.”

MATERIALS SCIENCE:

ARTICLES PUBLISHED IN JOURNAL OF CRYSTAL GROWTH: Dr. Witold Palosz (USRA) recently had two articles published in the Journal of Crystal Growth: “Physical Vapor Transport of Lead Telluride” (vol. 216, pp. 273-282, 2000) and “Thermochemical Model and Experimental Studies on Physical Vapor Transport of Lead Telluride-Selenide” (vol. 216, pp. 283-292, 2000). The co-authors of the second article were H. A. Alexander (Glenn Research Center) and K. Grasza (Polish Academy of Sciences, Warsaw). Thermochemical conditions and limitations of the growth processes were analyzed theoretically and verified experimentally. A critical effect of different material preparation procedures on the growth conditions, particularly the growth rate, was investigated and scrutinized. Conditions for growing homogeneous ternary crystals were determined.

PAPER PRESENTED AT AMERICAN SOCIETY OF MECHANICAL ENGINEERS SYMPOSIA ON THERMOPHYSICAL PROPERTIES: Dr. Jan Rogers (MSFC) presented a paper, entitled “The Electrostatic Levitation Facility at NASA’s Marshall Space Flight Center,” at the Society’s 14th Symposia on Thermophysical Properties, Special Sessions on Subsecond Thermocphysics in Boulder, CO, June 25-30, 2000. Co-authors of the paper included R. W. Hyers, L. Savage, M.B. Robinson (MSFC), and T J. Rathz, University of Alabama, Huntsville (UAH).

UPCOMING EVENTS

Additional meetings and symposia can be found at: http://microgravity.grc.nasa.gov/ugml/ugmltext.htm

July 17 – 19, 2000, 33rd COSPAR Scientific Assembly, Warsaw, Poland http://www.copernicus.org/COSPAR/COSPAR.html

July 20, 2000, MRT/PMR Telecon (10am-2pm Central Time)

July 25 – 26, 2000, Workshop on Research Needs in Space Thermal Systems and Processes for Human Exploration of Space, Sheraton Airport Hotel, 5300, Riverside Drive,Cleveland, OH, http://microgravity.grc.nasa.gov/6712/thermal/workshop.html

August 7-25, 2000, Quantum Vortex Dynamics and Superfluid Turbulence, Isaac Newton Institute in Cambridge, England

August 9-11, 2000, Fifth Microgravity Fluid Physics and Transport Phenomena Conference, Cleveland, OH, http://www.ncmr.org/events/fluids2000.html