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 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.

See also

• ASTM Subcommittee E20.02 on Radiation Thermometry