Thin filament pyrometry

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.

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

History

TFP was first used by V. Vilimpoc and L.P. Goss (1988). A recent paper using TFP is Maun et al. (2007).

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.

See also

• ASTM Subcommittee E20.02 on Radiation Thermometry

References

• L.G. Blevins, M.W. Renfro, K.H. Lyle, N.M. Laurendeau, J.P. Gore, Experimental study of temperature and CH radical location in partially premixed CH₄/air coflow flames , Combustion and Flame 118 (4) 684-696 (1999).
• J.D. Maun, Thin-Filament Pyrometry With a Digital Still Camera, M.S. Thesis, University of Maryland (2006).
• J.D. Maun, Peter B. Sunderland, D.L. Urban, Applied Optics, 46:483-488 (2007).
• W.M. Pitts, Proceedings of the Combustion Institute 26:1171-1179 (1996).
• V. Vilimpoc, L.P. Goss, Proceedings of the Combustion Institute 22:1907-1914 (1988).