Evaluation of a novel measurement method for the laminar burning speed in laminar lifted iron dust flames

In this study, a method adapted from gas-phase combustion is presented to determine the local laminar burning velocities of iron dust flames. This method is also applicable for non-stationary flames, which presents a notable advantage for metal dust flames, as temporally stationary flames remain a challenge for practical reasons. This approach relies on the simultaneous measurement of flame contours, preheat zones, and gas velocities. These parameters were determined in two dimensions by processing multiplane particle image velocimetry measurements. For the investigations, lifted iron dust flames were selected in which the oxygen volume fraction of 30 and 40 vol% and the particle size distribution with a fixed median diameter were varied. Statistical and systematic errors were estimated. Notably, this analysis also underscores the necessity of simultaneous gas and particle velocity measurements, especially for larger particle fractions, which poses a challenge for future experimental research.