LDA-MEASUREMENTS OF DISPERSED GAS-PARTICLE FLOW IN A PLANE, TWO -DIMENSIONAL CONFINED JET

Abstract

The present paper concerns the motion of particles in turbulent flow and in particular the details of the fluid and particle velocity field in a plane twodimensional particulate jet flow emerging centrically into a plane two-imensional upward facing duct flow of air. Laser-Doppler anemometry was employed to map out the flow yielding local mean velocity distributions for both, the upward gas flow and the particle motion as well as local information of the rms-value of the turbulence velocity fluctuations of both phases. The particle size was known in the experiments. This permitted a combined amplitude/visibility signal discrimination to be employed to separate the particle and fluid velocity information in the laser-Doppler signals. A counting procedure was employed to determine the local volume fraction of the particles.The flow was studied under several inlet flow conditions. The dispersion of particles from the jet was studied extensively scanning the flow field downstream of the particle jet inlet. Several flow settings of the two outer and the inner inlet channels were investigated and laser Doppler measurements were supplemented by wall pressure recordings. The complete set of data provides a basis for flow predictions yielding computer programs in which experimental findings, on turbulent particulate flows are stored. Such programs can afterwards be successfully employed to study details of particle erosion near walls, flow of liquid sprays, combustion of pulverized coal etc.