Oscillation characterization of volatile combustion of single coal particles with multi-species optical diagnostic techniques

This paper investigated the oscillation characterization of volatile combustion of single coal particles using high-speed OH-PLIF and CH* chemiluminescence, meanwhile advanced data-driven algorithm as post-processing. The measurement region of in-situ 500 Hz OH-PLIF system was set to 53mm × 35 mm with a spatial resolution of ~23 µm per pixel, which was used to capture the continuous and whole volatile combustion process of single particle in a group of pulverized coal particles (SPGCP). A high-volatiles bituminous coal (30 wt%) burned at a gas temperature of 1700 K with oxygen mole fractions in the range of 10%–30%. The morphology of volatile flame and dynamic evolution was obtained. Dynamic mode decomposition (DMD) method can provide a new insight into combustion oscillation of pulverized coal. The oscillation frequency characteristics of pulverized coal flame were captured, and the red-shift phenomenon of dominant frequency with the increase of oxygen concentration was found. The particle aggregation might lead the low-frequency oscillation of pulverized coal combustion. On the contrary, individual or separated particle combustion could generate larger oscillation frequency.