The Evolving Temperature Field in a 1 m Methanol Pool Fire

Thin filament pyrometry is used to measure the time-varying temperature field in a 1 m methanol pool fire. A digital camera with optical filters and zoom lens recorded the emission intensity of an array of 12 microm Silicon-Carbide filaments oriented horizontally at various heights across the steadily burning pool fire. A 50 microm diameter thermocouple measured the temperature at locations corresponding to the filament positions. A correlation was developed between the local probability density functions of the thermocouple time series measurements corrected for radiation and thermal inertia effects and the camera grayscale pixel intensity of the filaments. A regression analysis yields the local mean temperature and its variance. The time series of the temperature field is transformed into average values during consecutive phases of the fire's puffing cycle, providing quantitative insight into the complex and dynamic structure of a turbulent fire.