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Conbustion And Convection In Microgravity

Conbustion And Convection In Microgravity. Naiara Barrado Izagirre EHU-UPV. Authors: Javier Rodríguez, Naiara Barrado, Daniel Fernández de Castillo, Leire Del Campo, Manuel J. Tello. Index. What do we know about a candle in microgravity? Experiment Objectives. Experiment Description.

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Conbustion And Convection In Microgravity

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  1. Conbustion And Convection In Microgravity Naiara Barrado Izagirre EHU-UPV Authors: Javier Rodríguez, Naiara Barrado, Daniel Fernández de Castillo, Leire Del Campo, Manuel J. Tello

  2. Index • What do we know about a candle in microgravity? • Experiment Objectives. • Experiment Description. • Technical support. • Outreach. Naiara Barrado Izagirre EHU-UPV Aalborg´05

  3. Althogh it may raise an eyebrow, the candle hides a complex physics behind. What Do We Know About A Candle? • COMBUSTION: • The flame of a candle  a non-propagating pure difusion flame. • Many interesting results around flame: • Estructure • Size chemistry and transport feature • Colour • Shape aerodynamic feature • Differences under normal gravity or microgravity. Naiara Barrado Izagirre EHU-UPV Aalborg´05

  4. Candle under normal gravity Candle under microgravity conditions • Tear-drop-like. • Yelow. • Hemi spherical. • Dim blue. If anyone thinks about bringing a candle to the space in order to light up, it has been proved that he is wrong: The candle doesn’t light in microgravity!!!!

  5. Why these tear-drop-like form? Naiara Barrado Izagirre EHU-UPV Aalborg´05

  6. CONVECTION CURRENTS: Currents into the melted wax (in the top of the candle). Produced by temperature gradients between the flame base and the candle border. • Very important in order to avoid a very quickly candle meltingthe well base is an isothermal surface where the wax is contained. Naiara Barrado Izagirre EHU-UPV Aalborg´05

  7. Experimet Objectives The following experiment are proposed: • Convection currents. • Behavior of the flame in presence of an electrical field. • Variation of the oxigen concentration. Naiara Barrado Izagirre EHU-UPV Aalborg´05

  8. CONVECTIONCURRENTS: Study of the convection currents using sketchers. We were able to observe fluctuations in the currents under gravity conditions. Sketchers will follow the convection currents. Thermocouples: Allow registering the temperature changes at different points of the melted wax. Flame Hot focus Thermocouples Convection currents followed by sketchers Isothermal surface Experiment Description I 1) Naiara Barrado Izagirre EHU-UPV Aalborg´05

  9. FLAME SHAPE IN AN ELECTRICAL FIELD: Study of the flame shape in an electrostatic field. Ifluence of the electrical field is due to the presence of some charged particles in the flame (soot). Plane capacitor Experiment Description II 2) Naiara Barrado Izagirre EHU-UPV Aalborg´05

  10. Experiment Description III 3) OXIGEN CONCENTRATION: • Study the convection currents and the flame shape with and without electrical field changing the oxygen concentration. • Variation of oxygen will be made using a little oxygen container coupled to the boxes*. Naiara Barrado Izagirre EHU-UPV Aalborg´05

  11. Technical support I • Candles located in apropiate polycarbonate boxes (not flammable). Naiara Barrado Izagirre EHU-UPV Aalborg´05

  12. Location at the rack. Four cameras operating in the visible and ultraviolet. Horizontal compensation mechanical system: Allows to maintain the melted wax surface in the same position during the parabolic flight. Cameras Technical support II Naiara Barrado Izagirre EHU-UPV Aalborg´05

  13. Candles of different characteristics will be used : • diameter • length • type of wick • etc… • To see the influence of all these parameters in: • flame shape • colour and dimensions • soot formation • oxygen combustion Naiara Barrado Izagirre EHU-UPV Aalborg´05

  14. Outreach • Experiments have scientific, technological and educational objectives: • Scientific: Writing an article. • Tehnological: Application on candle production. • Educational:Divulgation DVD. Naiara Barrado Izagirre EHU-UPV Aalborg´05

  15. Bilbliography • J. Wisniak, “Candle: A light into the past”, Indian Journal of Chemical Technology 7 (2001) 319-326. • D.L. Dietrich, H.D. Ross, Y. Shu, P. Chang, J.S. Tien, “Candle flames in non-buoyant atmospheres”, Combustion Science & Technology 156 (200) 1-24. • X. Q. Zhang, W.F. Du, M.G. Wei, W.J. Kong, Y.Hua, “A study of candle flame in microgravity” (to be published). • Some internet pages. Naiara Barrado Izagirre EHU-UPV Aalborg´05

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