Thin Filament Pyrometry Field Measurements in a Medium-Scale Pool Fire

Area of Science:

• Fire Science
• Optical Diagnostics
• Thermometry

Background:

• Pool fires pose significant risks, necessitating accurate temperature field characterization.
• Existing methods for measuring dynamic fire temperatures are often limited in spatial or temporal resolution.
• Understanding transient temperature variations is crucial for fire safety and modeling.

Purpose of the Study:

• To develop and validate a novel thin filament pyrometry technique for measuring time-varying temperature fields in pool fires.
• To assess the spatial and temporal resolution, and uncertainty of the developed pyrometry method.
• To analyze the dynamic structure and cyclic behavior of a medium-scale methanol pool fire.

Main Methods:

• Utilized a digital camera with optical filters to record emission intensity from Silicon-Carbide filaments (14 µm diameter).
• Correlated filament pixel intensity with radiation-corrected thermocouple measurements (50 µm diameter) for temperature calibration.
• Employed statistical analysis and time-series transformation to characterize the temperature field and fire dynamics.

Main Results:

• The thin filament pyrometry method achieved temperature measurements from 1150 K to 1900 K.
• Achieved spatial resolution of 160 µm and temporal resolution of 0.033 s, with an uncertainty of ~150 K.
• Revealed the cyclic nature of the pool fire, determining its dominant puffing frequency and analyzing temperature variations during different fire phases.

Conclusions:

• Thin filament pyrometry is a viable technique for high-resolution, time-varying temperature measurements in pool fires.
• The study provides valuable data on the dynamic structure and transient temperature fields of methanol pool fires.
• The developed method offers improved characterization of fire behavior for safety and research applications.