NASA/TM—2002-212009 IAC–02–T.4.02 The NASA Microgravity Fluid Physics Program—Knowledge for Use on Earth and Future Space Missions Fred J. Kohl and Bhim S. Singh Glenn Research Center, Cleveland, Ohio J. Iwan Alexander National Center for Microgravity Research, Cleveland, Ohio Nancy J. Shaw, Myron E. Hill, and Frank G. Gati Glenn Research Center, Cleveland, Ohio December 2002 The NASA STI Program Office . in Profile Since its founding, NASA has been dedicated to • CONFERENCE PUBLICATION. Collected the advancement of aeronautics and space papers from scientific and technical science. The NASA Scientific and Technical conferences, symposia, seminars, or other Information (STI) Program Office plays a key part meetings sponsored or cosponsored by in helping NASA maintain this important role. NASA. The NASA STI Program Office is operated by • SPECIAL PUBLICATION. Scientific, Langley Research Center, the Lead Center for technical, or historical information from NASA’s scientific and technical information. The NASA programs, projects, and missions, NASA STI Program Office provides access to the often concerned with subjects having NASA STI Database, the largest collection of substantial public interest. aeronautical and space science STI in the world. The Program Office is also NASA’s institutional • TECHNICAL TRANSLATION. English- mechanism for disseminating the results of its language translations of foreign scientific research and development activities. These results and technical material pertinent to NASA’s are published by NASA in the NASA STI Report mission. Series, which includes the following report types: Specialized services that complement the STI • TECHNICAL PUBLICATION. Reports of Program Office’s diverse offerings include completed research or a major significant creating custom thesauri, building customized phase of research that present the results of databases, organizing and publishing research NASA programs and include extensive data results . even providing videos. or theoretical analysis. Includes compilations of significant scientific and technical data and For more information about the NASA STI information deemed to be of continuing Program Office, see the following: reference value. NASA’s counterpart of peer- reviewed formal professional papers but • Access the NASA STI Program Home Page has less stringent limitations on manuscript at http://www.sti.nasa.gov length and extent of graphic presentations. • E-mail your question via the Internet to • TECHNICAL MEMORANDUM. Scientific [email protected] and technical findings that are preliminary or of specialized interest, e.g., quick release • Fax your question to the NASA Access reports, working papers, and bibliographies Help Desk at 301–621–0134 that contain minimal annotation. Does not contain extensive analysis. • Telephone the NASA Access Help Desk at 301–621–0390 • CONTRACTOR REPORT. Scientific and technical findings by NASA-sponsored • Write to: contractors and grantees. NASA Access Help Desk NASA Center for AeroSpace Information 7121 Standard Drive Hanover, MD 21076 NASA/TM—2002-212009 IAC–02–T.4.02 The NASA Microgravity Fluid Physics Program—Knowledge for Use on Earth and Future Space Missions Fred J. Kohl and Bhim S. Singh Glenn Research Center, Cleveland, Ohio J. Iwan Alexander National Center for Microgravity Research, Cleveland, Ohio Nancy J. Shaw, Myron E. Hill, and Frank G. Gati Glenn Research Center, Cleveland, Ohio Prepared for the 53rd International Astronautical Congress cosponsored by the International Astronautical Federation (IAF), the International Academy of Astronautics (IAA), and the International Institute of Space Law (IISL) Houston, Texas, October 10–19, 2002 National Aeronautics and Space Administration Glenn Research Center December 2002 Available from NASA Center for Aerospace Information National Technical Information Service 7121 Standard Drive 5285 Port Royal Road Hanover, MD 21076 Springfield, VA 22100 Available electronically at http://gltrs.grc.nasa.gov THE NASA MICROGRAVITY FLUID PHYSICS PROGRAM—KNOWLEDGE FOR USE ON EARTH AND FUTURE SPACE MISSIONS Fred J. Kohl and Bhim S. Singh National Aeronautics and Space Administration Glenn Research Center Cleveland, Ohio 44135 J. Iwan Alexander National Center for Microgravity Research Cleveland, Ohio 44106 Nancy J. Shaw, Myron E. Hill, and Frank G. Gati National Aeronautics and Space Administration Glenn Research Center Cleveland, Ohio 44135 ABSTRACT INTRODUCTION Building on over four decades of research and Many of the biological, environmental, and technology development related to the behavior of industrial processes required to support life take fluids in low gravity environments, the current place in the fluid phase. Fluid motion accounts NASA Microgravity Fluid Physics Program for most transport and mixing in natural and continues the quest for knowledge to further industrial processes as well as in living organisms. understand and design better fluids systems for use A detailed understanding of fluid dynamics over a on earth and in space. The purpose of the Fluid broad range of length and time scales is essential Physics Program is to support the goals of NASA's for progress in many emerging research areas of Biological and Physical Research Enterprise which physical and biological sciences. The low-gravity seeks to exploit the space environment to conduct environment of space offers a unique opportunity research and to develop commercial opportunities, for the study of fluid physics and transport while building the vital knowledge base needed to phenomena, as the nearly weightless conditions enable efficient and effective systems for allow researchers to observe and control fluid protecting and sustaining humans during extended phenomena in ways that are not possible on Earth. space flights. In addition, detailed knowledge of fluid flows is essential for the design of practical space systems There are currently five major research areas in the for propulsion, power, and life support. Microgravity Fluid Physics Program: complex fluids, multiphase flows and phase change, NASA's Office of Biological and Physical interfacial phenomena, biofluid mechanics, and Research (OBPR) seeks to exploit the space dynamics and instabilities. Numerous environment to conduct research and to develop investigations into these areas are being conducted commercial opportunities, while building the vital in both ground-based laboratories and facilities and knowledge base needed to enable efficient and in the flight experiments program. Most of the effective systems for protecting and sustaining future NASA-sponsored fluid physics and transport humans during extended space flights.1 OBPR phenomena studies will be carried out on the addresses the two fundamental challenges International Space Station in the Fluids Integrated associated with human space flight: 1) Rack, in the Microgravity Science Glovebox, in understanding nature's forces in space; and 2) EXPRESS racks, and in other facilities provided by understanding the human experience in space. international partners. This paper will present an The specific thrusts of the OBPR Physical Sciences overview of the near- and long-term visions for Research Division Program in fluid physics are to NASA's Microgravity Fluid Physics Research conduct peer-reviewed research based on scientific Program and brief descriptions of hardware value that exploits the advantages of the systems planned to achieve this research. microgravity environment of space and research NASA/TM—2002-212009 1 based on applications that are relevant to future the bubble, causing rewetting of the heater surface. human and robotic space exploration.2 Thus the These results also indicated the potential for NASA Microgravity Fluid Physics Program quasisteady nucleate pool boiling in long-term provides a significant component of the foundation microgravity, with certain combinations of heat for the broad range of diverse NASA OBPR- flux and bulk liquid subcooling. These simple sponsored research activities. experiments provided evidence that nucleate pool boiling may be achievable in a microgravity Previous experiments conducted on the ground and environment. in low-earth orbit over the past four decades have yielded rich results that have provided valuable Ground-based researchers have recently reported insights into fundamental fluid behavior that apply the first-ever experimental observation of to both terrestrial and space environments.3–8 Many Marangoni-Bénard long-wavelength instability in results were unexpected or could not have been investigations using very thin liquid layers where observed in Earth-based laboratories. For example, the effect of gravity is negligible.12,13 The short- in the Physics of Colloids in Space (PCS) wavelength Bénard instability results in formation experiment on the International Space Station of well-known hexagonal cells. Although this long- (ISS), de-mixing of the colloid-polymer critical wavelength instability was predicted 35 years ago, point sample could be studied over four decades of it had not been observed. Researchers have also length scale, from one micron to one centimeter, as developed a numerical simulation whose results are this sample phase-separated into two phases.9 Such in qualitative agreement with experimental behavior cannot be observed in this type of sample observations. This instability could become the on Earth because sedimentation would cause the primary one in a microgravity environment. colloids to fall to the