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.

History
TFP in flames was first used by Vilimpoc et al. (1988). More recently, this was demonstrated by Pitts (1996), Blevins et al. (1999), and 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.