Recent developments in nonintrusive measuring techniques for particle velocity and size measurements

Laser techniques for local particle velocity and size measurements in flows are presented and discussed. The laser doppler anemometer utilizing the Doppler shift of light scattered on small particles in a flow for velocity measurements is the basis of the presented techniques. Furthermore phase Doppler anemometry based on the spatial properties of the Doppler shift and shadow Doppler velocimetry utilizing the shadow image of particle for size measurements are briefly discussed. Experimental results illustrating the use of the techniques are presented. These comprise particle velocity measurements in a sudden expansion liquid solid flow as well as in a model of a beater wheel mill. PDA measurements of the size distribution of droplets produced by a nebulizer ar also presented.