Thin-filament pyrometry with a digital still camera

A novel thin-filament pyrometer is presented. It involves a consumer-grade color digital still camera with 6 megapixels and 12 bits per color plane. SiC fibers were used and scanning-electron microscopy found them to be uniform with diameters of 13.9 μm. Measurements were performed in a methane-air coflowing laminar jet diffusion flame with a luminosity length of 72 mm. Calibration of the pyrometer was accomplished with B-type thermocouples. The pyrometry measurements yielded gas temperatures in the range of 1400-2200 K with an estimated uncertainty of ±60 K, a relative temperature resolution of ±0.215 K, a spatial resolution of 42 μm, and a temporal resolution of 0.66 ms. Fiber aging for 10 min had no effect on the results. Soot deposition was less problematic for the pyrometer than for the thermocouple.