Thin-filament pyrometry

TFP image in diluted methane flame. Filament spacing is about 10 mm.

Thin-filament pyrometry (TFP) is an optical method used to measure temperatures. It involves the placement of a thin filament in a hot gas stream. Radiative emissions from the filament can be correlated with filament temperature. Filaments are typically silicon carbide (SiC) fibers with a diameter of 15 micrometres. Temperatures of about 800–2500 K can be measured.

History

TFP in flames was first used by Vilimpoc et al. (1988).^[1] More recently, this was demonstrated by Pitts (1996),^[2] Blevins et al. (1999),^[3] and Maun et al. (2007).^[4]

Technique

The typical TFP apparatus consists of a flame or other hot gas stream, a filament, and a camera.

Advantages

TFP has several advantages, including the ability to simultaneously measure temperatures along a line and minimal intrusiveness. Most other forms of pyrometry are not capable of providing gas-phase temperatures.

Drawbacks

Calibration is required. Calibration typically is performed with a thermocouple. Both thermocouples and filaments require corrections in estimating gas temperatures from probe temperatures. Also, filaments are fragile and typically break after about an hour in a flame.

Applications

The primary application is to combustion and fire research.

References

^ Vilimpoc, V.; Goss, L. P.; Sarka, B. (1988). "Spatial temperature-profile measurements by the thin-filament-pyrometry technique". Applied Optics. 13 (2): 93–95. doi:10.1364/OL.13.000093.
^ Pitts, W. M. (1996). "Thin-filament pyrometry in flickering laminar diffusion flames". Proceedings of the Combustion Institute. 26: 1171–1179.
^ Bevins, L. G.; Refro, M. W.; Lyle, K. H.; Laurendeau, N. M.; Gore, J. P. (1999). "Experimental study of temperature and CH radical location in partially premixed CH₄/air coflow flames". Combustion and Flame. 118: 684–696. doi:10.1016/S0010-2180(99)00023-1.
^ Maun, J. D.; Sunderland, P. B.; Urban, D. L. (2007). "Thin-filament pyrometry with a digital still camera". Applied Optics. 46 (4): 483–488. doi:10.1364/AO.46.000483. hdl:1903/3602.

[1] Vilimpoc, V.; Goss, L. P.; Sarka, B. (1988). "Spatial temperature-profile measurements by the thin-filament-pyrometry technique". Applied Optics. 13 (2): 93–95. doi:10.1364/OL.13.000093.

[2] Pitts, W. M. (1996). "Thin-filament pyrometry in flickering laminar diffusion flames". Proceedings of the Combustion Institute. 26: 1171–1179.

[3] Bevins, L. G.; Refro, M. W.; Lyle, K. H.; Laurendeau, N. M.; Gore, J. P. (1999). "Experimental study of temperature and CH radical location in partially premixed CH₄/air coflow flames". Combustion and Flame. 118: 684–696. doi:10.1016/S0010-2180(99)00023-1.

[4] Maun, J. D.; Sunderland, P. B.; Urban, D. L. (2007). "Thin-filament pyrometry with a digital still camera". Applied Optics. 46 (4): 483–488. doi:10.1364/AO.46.000483. hdl:1903/3602.

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