Simultaneous in Situ Measurement of the Size, Temperature and Velocity of Particles in a Combustion Environment

摘要

An in situ method for measuring simultaneously the size, temperature and velocity of pulverized fuel particles is described. Particle size is obtained by imaging a moving, incandescent particle onto a coded aperture and observing the transmitted light. A specially designed aperture yields a double-pulse signal in response to a passing particle. The ratio of the heights of the two pulses yields a measure of particle size that is independent of temperature, emissivity and refractive index. Particle temperature is obtained simultaneously by measuring the transmitted light in two wavelength bands and applying ratio (two-color) pyrometry to these signals. Velocity is measured from the same signals by transit timing. The system is operated as a single particle counter to generate the joint distribution of particle size, temperature and velocity. Since this method uses optical imaging, it is limited to applications where the particle size range of primary interest is 10 mu m or larger, and the number density does not exceed 10 exp 4 /cm exp 3 . In addition to this constraint, the minimum particle size and temperature that can be measured is determined by shot noise in the optical detection process. The system is evaluated in a flow reactor using size-classified pulverized fuel particles. 9 references, 4 figures, 4 tables. (ERA citation 09:032633)