HIGH-SPEED, 2-WAVELENGTH RADIATION THERMOMETRY OF SINGLE MICROPARTICLES DURING CO2-LASER HEATING

A high speed, two-wavelength radiation thermometer that is capable of monitoring surface temperatures of 50-150 mum diameter particles in th e 600-2000 K range and at heating rates of up to 10(6) K/s, characteri stic of pulverized coal combustion, was designed and constructed. To m eet the above characteristics, special attention was paid to detector wavelength range and speed, detection electronics and optical system a lignment. The thermometer was calibrated using an in-house constructed , black cavity radiation source. Spherocarb model particles, which hav e more uniform size, physical properties and emissivity than coal part icles, were used to demonstrate the level of short term reproducibilit y attainable. Consistent, reproducible temperature-time profiles obtai ned for particles from different coals indicate that non-grey body eff ects do not dominate these measurements.