setting fire to cis - or- small scale combustion chamber and instrumentation dave pogorzala bob...
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SettingSetting FireFire to CISto CIS- or- - or-
Small Scale Combustion Chamber Small Scale Combustion Chamber and Instrumentationand Instrumentation
Dave PogorzalaDave Pogorzala
Bob Kremens, PhD, AdvisorBob Kremens, PhD, Advisor
Center For Imaging ScienceCenter For Imaging Science
Rochester Institute of TechnologyRochester Institute of Technology
05.10.0205.10.02
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
• history
• project goals
• research methods
• results
• conclusions / future work
overview:
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
• 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
history:
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
• 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?
project goals:
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
combustion chamber facility at the FSL
Burn surfaceBurn surface
Smoke hoodSmoke hood
InstrumentsInstruments
BryceBryce
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
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
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
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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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
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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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
experimental setup
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
combustion chamber facility at CIS
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
Flux (W/cm2) = * * T4
pyrometer thermocouples
calculatedemissivity
research methods: calculating the emissivity
unfortunately, it was not this easy
• the Steffan-Boltzmann Law
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
• 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
research methods: calculating the emissivity
but it still wasn’t this easy
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
• 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
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
temperature vs. time
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
• temperature was read from the new pyrometer data ( )
• this was used to find the fire’s radiance; =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 ( )
research methods: calculating the emissivity
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
• 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
results:
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
• 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
conclusions / future work:
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Digital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing LaboratoryDigital Imaging and Remote Sensing Laboratory
• 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
acknowledgments: