Laser diffraction method measurements of particle-gas dispersion effects in a coaxial jet

Particle concentration and particle size distributions have been measured for two-phase (solid/air) turbulent coaxial jets using the laser diffraction method (LDM) and a tomography data transform technique. Effects of velocity ratio, particle loading ratio, and particle size on the dispersions of gas and particles were determined. Experimental results show that the gas disperses much more rapidly than the particles and particle dispersion decreases with increasing in particle size. Increasing velocity ratio significantly increases gas dispersion, while effects of other variables are less significant. The mean particle size at the jet edge is about 15–20% smaller than that at the jet centerline. The turbulent Schmidt number Sc_p for two-phase turbulent coaxial jets ranges from 1.4 to 1.5.