Setting Fire to CIS or Small Scale Combustion Chamber and Instrumentation

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Setting Fire to CIS- or- Small Scale Combustion
Chamber and Instrumentation

• Dave Pogorzala
• Bob Kremens, PhD, Advisor
• Center For Imaging Science
• Rochester Institute of Technology
• 05.10.02

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overview

• history
• project goals
• research methods
• results
• conclusions / future work

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history

• the Forest Fire Imaging Experimental System
  (FIRES)
• team traveled to the Fire Sciences Lab (FSL) in
  Missoula,
• Montana during the summer of 01.
• there they used a large combustion chamber to
  image several
• fires with the ASD, an IR Radiation Pyrometer,
  and a
• visible / IR camera

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project goals

• we want to be able to image fire at any time
• construct a small-scale, self standing
  combustion chamber
• - what features from the FSL facility are needed?
• allow the chamber to be tailored to other
  specific uses
• - Adam and Jims project
• work to be done this summer
• test the chamber
• - does it hold up to a full-fledged fire?
• - will the instruments be able to image the fire?

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combustion chamber facility at the FSL
Smoke hood
Burn surface
Bryce
Instruments
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project goals

• find fires emissivity
• emissivity- the ratio of the radiance emitted by
  an object
• at a certain temperature to the radiance by a
  perfect
• blackbody at that same temperature
• - We definitely need, at a minimum, the
  emissivity
• and temperature profiles of the flames to model
  a
• fire with DIRSIG
• - Bob Kremens
• - come to a conclusive value that could be
  published

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research methods chamber design

• initial design was simplified
• research was done on flume dynamics
• no need for smoke hood and fan
• - burn surface can be simulated with
• an outdoor grill
• - camera ports were made square
• - easier to modify their size

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research methods data acquisition

• both instruments had to be interfaced with the
  computer
• developed thermocouple data logging program in VB
• used preexisting program with the pyrometer

thermocouple pyrometer
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experimental setup
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combustion chamber facility at CIS
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research methods calculating the emissivity

• the Steffan-Boltzmann Law

calculated emissivity
Flux (W/cm2) e a T4
thermocouples
pyrometer
unfortunately, it was not this easy
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research methods calculating the emissivity

• both instruments yielded temperature data
• - thermocouples measured actual temperature of
  the flame
• - pyrometer interpreted detected radiance as
  temperature
• assuming an emissivity of 1.0
• emissivity was found using a look up table

but it still wasnt this easy
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research methods calculating the emissivity

• the pyrometers rise time coefficient is lt 1 sec
• the thermocouples rise time is 45sec
• in order to correlate the two sets of data, a
  Fourier analysis
• had to be done on the pyrometer data
• - frequencies above 1/45 cyc/sec were removed
• resulting pyrometer data was more stable

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temperature vs. time
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research methods calculating the emissivity

• temperature was read from the new pyrometer data
  ( )
• this was used to find the fires radiance e1.0
  ( )
• this radiance was found at the fires actual
  temp ( )
• the union of the pyrometers radiance and the
  thermocouples
• temperature yielded the emissivity ( )

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results

• a set of 12 individual samples in time gave an
  average
• emissivity of 0.265
• H. P. Telisin (1973) measured emissivity under
  various
• weather and fuel conditions, resulting in a
  range of 0.1 0.58

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conclusions / future work

• this figure of 0.265 can be trusted, but will be
  verified by
• additional testing this summer
• add up to 5 more thermocouples to simultaneously
  monitor
• the fire in various locations
• - do temperature variations give different
  emissivities?
• collect data on different species of wood
• - different chemical compositions could yield
• their own emissivities
• automate the LUT process in IDL

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acknowledgments

• Bob Kremens, PhD
• Don Latham
• Project Leader, Fire Sciences Lab, Missoula, MT
• Al Simone
• Telisin, H. P. 1973, Flame radiation as a
  mechanism of fire spread in forests,
• In Heat Transfer in Flames, Vol. 2. (N.H. Afgan
  and J.M. Beer, eds.), 441-449.
• John Wiley, New York