Measurement of particle velocity fields in a strong self-luminous high-speed erosion simulation environment

Due to ultra-high flow speed, extreme total temperature and intense self-luminescence of typical particle erosion environments such as in the arc heater, it is difficult to measure the particle velocity field accurately. To address the measurement requirements of particle velocity fields in ‌hypersonic vehicle nose‌ and ‌engine throat erosion, ‌this paper developed a particle image velocimetry (PIV) technique based on high-temperature and strong self-luminescence particles. A narrowband filter was used to achieve spectral separation of particle scattered light, greatly suppressing the self-luminescence generated by the high-temperature airflow of the arc heater, thus images with high signal-to-noise ratio were obtained under high-speed flow. ‌Implementing this technique‌, PIV measurements were conducted on Al₂O₃ particles (the average particle size of 20 μm) and graphite particles (the average particle size of 50 μm) ‌across‌ total temperature ranges of 2150–3570 K. ‌The results revealed that‌: 1) ‌For identical particle materials‌, increased total enthalpy significantly enhanced particle exit velocities, ‌with‌ Al₂O₃ particles reaching peak average velocities of 1302 m/s (2150 K), 1421 m/s (2770 K), and 1527 m/s (3570 K); 2) ‌Despite their larger size‌, graphite particles achieved higher peak velocity (1539 m/s) ‌attributed to‌ their lower density; 3) ‌Spatial analysis demonstrated near-normal distribution of axial velocity components along the radial (x) direction; 4) ‌Notably‌, distinct low-speed shear boundaries (35.5–45 mm span) were observed ‌at the jet periphery‌, ‌resulting from‌ free atmospheric interaction with arc-heater exhaust flows. ‌Comprehensive comparison‌ of particle velocity and vorticity distributions ‌under varied inflow conditions‌ elucidates jet boundary characteristics, ‌providing quantitative experimental support‌ for ‌precision evaluation‌ of particle erosion mechanisms.