Low Cost Image Processing of Bunsen Flame Photography for Estimation of Flame Speeds

Abstract

ABSTRACTThe need for measuring laminar flame speeds for various fuels and blends is crucial for determining flame stabilization characteristics and design parameters for practical burner configurations. Various methodologies have been used over the years to estimate laminar flame speeds with axisymmetric Bunsen flames being one of the oldest and “simplest” techniques. Nonetheless, the cost of the instrumentation to measure laminar flame speeds with minimum experimental uncertainties remains noticeably high. The present work describes a low-cost flame speed estimation methodology and investigates its efficacy for methane and propane-air mixtures at different equivalence ratios. Flame propagation speeds with respect to the unburned gas were evaluated using both the cone angle and the surface area measurement methods. The experimental approach involves an automated image processing procedure that numerically processes plain photographic images of the flames and estimates the Bunsen cone borders, the cone angle, and the surface area in a straightforward manner. Those values are then used to extract the flame speed. Thus, it can be considered as an integrated experimental and numerical processing methodology that affords flame speed estimation, with reasonable accuracy, for a variety of gaseous fuel-oxidizer mixtures, relevant to industrial burner applications.