Conbustion And Convection In Microgravity

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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
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Index

• What do we know about a candle in microgravity?
• Experiment Objectives.
• Experiment Description.
• Technical support.
• Outreach.

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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

?aerodynamic feature

• Shape

• Differences under normal gravity or
  microgravity.

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• 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 doesnt light in
microgravity!!!!

• Candle under microgravity conditions

• Candle under normal gravity

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Why these tear-drop-like form?
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• 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.

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Experimet Objectives

• The following experiment are proposed
• Convection currents.
• Behavior of the flame in presence of an
  electrical field.
• Variation of the oxigen concentration.

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Experiment Description I

• CONVECTION CURRENTS
• 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.

1)
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Experiment Description II
2)

• 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).

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Experiment Description III

• 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.

3)
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Technical support I

• Candles located in apropiate polycarbonate boxes
  (not flammable).

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Technical support II

• Horizontal compensation mechanical system
• Allows to maintain the melted wax surface in the
  same position during the parabolic flight.

• Location at the rack.
• Four cameras operating in the visible and
  ultraviolet.

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• 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

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Outreach

• Experiments have scientific, technological and
  educational objectives
• Scientific Writing an article.
• Tehnological Application on candle production.
• Educational Divulgation DVD.

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Bilbliography

1. J. Wisniak, Candle A light into the past,
   Indian Journal of Chemical Technology 7 (2001)
   319-326.
2. 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.
3. X. Q. Zhang, W.F. Du, M.G. Wei, W.J. Kong, Y.Hua,
   A study of candle flame in microgravity (to be
   published).
4. Some internet pages.