PARTICLE-TURBULENCE INTERACTIONS IN THE TURBULENT BOUNDARY-LAYER FOR CROSS-FLOW OVER A TUBE

The turbulent fluid and particle interaction in the turbulent boundary layer for cross flow over a tube was studied experimentally. A phase Doppler anemometer (PDA) was used to measure the mean and fluctuation velocities of both phases. Two size ranges of particles (30-60 mu m an d 80-150 mu m) at certain concentrations were used to investigate the effect of the particle size on the mean velocity profiles and turbulen t intensity levels. The measurements clearly demonstrated that the lar ger particles damped the fluid turbulence. For the smaller particles, this damping effect was less noticeable. The measurement further showe d a delay in the separation point for two-phase turbulent cross flow o ver a tube. (C) 1997 Elsevier Science S.A.