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. 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


Setting fire to cis or small scale combustion chamber and instrumentation

overview:

  • history

  • project goals

  • research methods

  • results

  • conclusions / future work


Setting fire to cis or small scale combustion chamber and instrumentation

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


Setting fire to cis or small scale combustion chamber and instrumentation

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?


Setting fire to cis or small scale combustion chamber and instrumentation

combustion chamber facility at the FSL

Smoke hood

Burn surface

Bryce

Instruments


Setting fire to cis or small scale combustion chamber and instrumentation

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


Setting fire to cis or small scale combustion chamber and instrumentation

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


Setting fire to cis or small scale combustion chamber and instrumentation

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


Setting fire to cis or small scale combustion chamber and instrumentation

experimental setup


Setting fire to cis or small scale combustion chamber and instrumentation

combustion chamber facility at CIS


Setting fire to cis or small scale combustion chamber and instrumentation

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


Setting fire to cis or small scale combustion chamber and instrumentation

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


Setting fire to cis or small scale combustion chamber and instrumentation

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”


Setting fire to cis or small scale combustion chamber and instrumentation

temperature vs. time


Setting fire to cis or small scale combustion chamber and instrumentation

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 ( )


Setting fire to cis or small scale combustion chamber and instrumentation

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


Setting fire to cis or small scale combustion chamber and instrumentation

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


Setting fire to cis or small scale combustion chamber and instrumentation

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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