Particle Temperature and Velocity Measurements by Two-Wavelength Streak Imaging

Abstract

Abstract A two-wavelength particle imaging sensor has been developed to measure temperature and velocity of individual particles in most thermal spray devices. The sensor provides continuous updates to particle condition profiles, histograms and correlation’s. The software locates particle streaks, determines the intensity ratio and dimensions of each streak, and calculates the particle temperature and velocity. Many forms of advanced materials processing technologies, such as thermal spray, spray-forming and atomization have considerable need of process control sensor technology. These measurements provide the basis for application of the sensor to many of these processes. Particle temperature and velocity measurements of plasma-sprayed ceramic powder were obtained using the sensor. The average temperature varied from 2800 K to 3000 K as the current to the plasma was increased from 700 amps to 900 amps. The average velocity varied from 85 m/s to 99 m/s over the same range. These results compare favorably with similar measurements, reported in the literature. With its full-stream field of view, the vision-based particle sensor can be applied to control strategies for the purpose of providing stable particle temperatures and velocities over long duration plasma spray processes.