High-precision 2D surface phosphor thermometry at kHz-rates during flame-wall interaction in narrow passages

This work demonstrates high-speed 2D wall temperature measurements occurring during flame-wall interaction (FWI) within a narrow channel. Such are essential to understand transient heat transfer and flame behavior micro-combustors designated engine crevices. Wall is measured using the phosphor Bismuth-doped Scandium vanadate (ScVO4:Bi3+). ScVO4:Bi3+ exhibits short phosphorescence lifetime (2 microseconds at room temperature), enabling kHz measurement rates. also high sensitivity, which yields single-shot precision less than 0.5 K range of 295 - 335 K. A frequency-doubled Ti:Sapphire laser emitting light 400 nm used excite ScVO4:Bi3+, 22 x mm2 region with 380 micrometer spatial resolution. Phosphor thermometry CH* imaging combined 1 measure spatiotemporal dynamics (Twall) 2 mm crevice passage in fixed volume chamber designed for studies. Measurements describe Twall signatures associated FWI events, including unique features wrinkled fronts. For our operating conditions, cusps consistently exhibit temperatures 5 20 lower crest regions. The most extreme difference seen large cusp formation, where local cooling noticeable trough cusp. feature may be caused by intrinsic flame-flow instabilities, locally temporally cool wall.