Imaging Measurements of Soot Temperature and Volume Fraction in Flames

摘要

New diagnostics are presented that use a digital camera to measure full-field soot temperatures and soot volume fractions in axisymmetric flames. The camera was a Nikon D700 with 12 megapixels and 14 bit depth in each color plane, and was modified by removing the infrared and anti-aliasing filters. The flame considered here was an 88 mm long ethylene/air coflowing laminar jet diffusion flame on a round 11.1 mm burner. Soot temperatures were measured using ratio pyrometry at 450, 650, and 900 nm and deconvolution. These had a range of 1500 - 1850 K, spatial and temporal resolutions of 23 μm and 20 ms, and an estimated uncertainty of ±50 K. Soot volume fractions were measured using laser extinction at 632.8 nm and deconvolution. These had a range of 0.2 - 10 ppm, spatial and temporal resolutions of 34 μm and 167 ms, and an estimated uncertainty of ±10%. The diagnostics were calibrated with a blackbody furnace. The present measurements agree with past measurements in this flame using traversing optics and probes, but they avoid the long test times and other complications of such traditional methods.