Towards a method of estimating out-of-plane effects on measurements of turbulent flame dynamics

Turbulent flames are highly three-dimensional and while planar measurement techniques for studying these flames are widely used, the interpretation of two-dimensional flame data can suffer from three-dimensional, out-of-plane effects. In this study, a methodology to statistically estimate three-dimensional effects on flame propagation measured from planar high-speed measurements is presented. This methodology uses a theoretical approach to estimate the out-of-plane motion effects on flame propagation and probabilistic modeling to separate this effect from measured experimental data. The methodology is applied to the consumption speeds of reactant pockets in a rectangular Bunsen flame experiment. Simultaneous s-PIV and OH-PLIF measurements are performed to track the behavior of reactant pockets and obtain their consumption rates. A univariate mixture model is used to model the experimental data and a distribution reflecting the out-of-plane motion contribution of the consumption speed is obtained by modeling three-dimensional pockets and convecting them through a plane based on the measured pocket edges and out-of-plane velocities. A Markov-chain Monte Carlo approach is used to separate the two distributions and uncertainties are estimated in the experimental consumption speed data. Finally, we discuss the applicability of this approach to experimental measurements. (C) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.