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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. overview:. history project goals research methods results conclusions / future work.

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Setting fire to cis or small scale combustion chamber and instrumentation

SettingFireto 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


overview:

  • history

  • project goals

  • research methods

  • results

  • conclusions / future work


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


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 Jim’s 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?


combustion chamber facility at the FSL

Smoke hood

Burn surface

Bryce

Instruments


project goals:

  • find fire’s 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


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


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

thermocouplepyrometer




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


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 wasn’t this easy


research methods: calculating the emissivity

  • the pyrometer’s rise time coefficient is < 1 sec

  • the thermocouple’s 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”



research methods: calculating the emissivity

  • temperature was read from the new pyrometer data ( )

  • this was used to find the fire’s radiance; e=1.0 ( )

  • this radiance was found at the fire’s actual temp ( )

  • the union of the pyrometer’s radiance and the thermocouple’s

  • temperature yielded the emissivity ( )


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


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


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


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