Microgravity Flame Balls in Space: Combustion Research by Paul D. Ronney

1. Space travel and space research Paul D. Ronney Dept. of Aerospace & Mechanical Engineering University of Southern California Los Angeles, CA 90089-1453 USA Presented at Jhong-Li High School, 3 October 2005 http://ronney.usc.edu

2. University of Southern California • Established 125 years ago this week! • …jointly by a Catholic, a Protestant and a Jew - USC has always been a multi-ethnic, multi-cultural, coeducational university • Today: 32,000 students, 3000 faculty • 2 main campuses: University Park and Health Sciences • USC Trojans football team ranked #1 in USA last 2 years

3. USC Viterbi School of Engineering • Naming gift by Andrew & Erma Viterbi • Andrew Viterbi: co-founder of Qualcomm, co-inventor of CDMA • 1900 undergraduates, 3300 graduate students, 165 faculty, 30 degree options • $135 million external research funding • Distance Education Network (DEN): 900 students in 28 M.S. degree programs; 171 MS degrees awarded in 2005 • More info: http://viterbi.usc.edu

4. Paul Ronney • B.S. Mechanical Engineering, UC Berkeley • M.S. Aeronautics, Caltech • Ph.D. in Aeronautics & Astronautics, MIT • Postdocs: NASA Glenn, Cleveland; US Naval Research Lab, Washington DC • Assistant Professor, Princeton University • Associate/Full Professor, USC • Research interests • Microscale combustion and power generation (10/4, INER; 10/5 NCKU) • Microgravity combustion and fluid mechanics (10/4, NCU) • Turbulent combustion (10/7, NTHU) • Internal combustion engines • Ignition, flammability, extinction limits of flames (10/3, NCU) • Flame spread over solid fuel beds • Biophysics and biofilms (10/6, NCKU)

5. Paul Ronney

7. What is gravity? • 4 forces of nature • Gravity force • Electromagnetic force • Strong nuclear force • Weak nuclear force • Gravity is the attractive force between any two objects • Gravity is the most constant feature of our lives • Aristotle's "laws" of nature: heavier objects fall faster than lighter objects • Galileo Galilei proved this wrong!

8. Gravity on the planets and the moon Earth 1 g Moon 1/6 g Mars 1/3 g Jupiter 2.5 g Saturn 1.1 g

9. What happens when there is no gravity? • “Microgravity” (µg) • Simple example - candle flame • Hot gases don’t rise - flame shape and burning rate are different 1g µg

10. Why study microgravity? Material science Earth-grown crystal: defects in structure Space-grown crystal: nearly perfect structure

11. Biotechnology

12. Fundamental physics Einstein predicted that space-time is warped by gravity Satellite experiment to test Einstein’s prediction more accurately than is possible on earth

13. How do we remove gravity? - free-fall Japan Microgravity Center - Kamisunagawa, Hokkaido Largest microgravity facility on earth

14. JAMIC drop shaft

15. Aircraft flying special paths

16. Orbiting spacecraft

17. International Space Station

18. Example of microgravity research - “FLAME BALLS” • Predicted by Russian physicist Yakov B. Zeldovich in 1944, but no experimental evidence until ….

19. Flame balls - history • Ronney (1990): flame balls accidentally discovered in very weak hydrogen-air mixtures in drop-tower experiment

20. Flame balls - history • Results confirmed in aircraft flights, but aircraft vibrations problematic

21. Implementation of space experiment • Need space experiment - long duration, high quality µg • Structure Of Flame Balls At Low Lewis-number (SOFBALL) • 2 NASA Space Shuttle missions (April 4 - 8, 1997, July 1 - 16, 1997)

22. Implementation of space experiment • Combustion Module-1 (CM-1) facility • 15 different mixtures burned

23. Experimental apparatus • Combustion vessel • Spark ignition system • Video cameras • Temperature, pressure, heat transfer

24. Flame balls - practical importance • Fire safety in manned spacecraft - space shuttle and International Space Station • Flame ball - simplest possible flame - test combustion models • Improved understanding of combustion of weak mixtures - can provide better fuel efficiency & lower pollutant emission, but better scientific understanding needed

25. Practical importance

26. Flame balls in space • Stable for more than 500 seconds (!) • Weakest flames ever burned (1 – 2 Watts/ball) (birthday candle ≈ 50 Watts) 4.0% H2-air, 223 sec elapsed time 4.9% H2- 9.8% O2 - 85.3% CO2, 500 sec 6.6% H2- 13.2% O2 - 79.2% SF6, 500 sec

27. Astronaut Janice Voss with Zel’dovich’s watch

28. Re-flight on STS-107 / Columbia mission • SOFBALL mission re-flown on STS-107 / Columbia’s last flight to obtain additional scientific results • Much of experimental data obtained despite loss of Columbia and crew by “downlinking” data to the ground during the mission

29. Crew operations

30. Thanks Dave, Ilan, KC and Mike!

31. …and the rest!

32. Space flight training • 2 types of training • Orbiter-related • Launch & entry • Living in space • Photography, videography • Payload related • Science background • Procedures and schedules • Performing experiments • On-orbit repair • Not like “The Right Stuff” now - STRAIGHTFORWARD • Toughest part - TRAVEL • Best parts • Doing experiments when no one can predict what will happen • Looking out the window

33. Space flight training • 3 types of astronauts • Pilots • Responsible for launch, landing and on-orbit operation of Space Shuttle • Chosen by NASA Astronaut selection board • Almost all are military pilots • Mission specialists • Responsible for payload operations - science experiments, spacewalks, etc. • Chosen by NASA Astronaut selection board • Payload specialists • Chosen because of need for a particular scientific / engineering / political expertise not available in regular astronaut corps • Chosen by scientists with experiments on flight, or by political will • Not present on most flights • Examples: PDR, John Glenn, Ilan Ramon (1st Israeli astronaut)

34. Space flight training • Classroom training - Shuttle equipment &operations, communications, emergency procedures, photography, …

35. Space flight training • Living in space

36. Space flight training • Space walk (EVA)

37. Space flight training • Flight training

38. Perspective on space flight training

39. Earth Observations Tifernine Sand Dunes, Algeria

40. Earth Observations Guadalupe Island, Mexico

41. Earth Observations Deforestation in Brazil

42. Earth Observations Red Sea and Sinai Peninsula

43. Earth Observations Dead Sea - Israel

44. Earth Observations Hurricane Elena, September 1985

45. Earth Observations Tibet - Himalayas

46. Earth Observations Taiwan

47. Thanks to… • Jhong-Li High School • Combustion Institute (Bernard Lewis Lectureship travel award) • NASA