Application Of Phase Doppler Particle Anemometer For Studying Turbulent Gas-Particle Flows At Tsinghua University

摘要

The phase Doppler particle anemometer (PDPA) made by both Aerometrcis Inc. and Dantec Inc. are used to measure the time-averaged gas and particle velocities, RMS values of gas and particle fluctuation velocities, gas-particle velocity correlations, gas turbulence modification and particle concentration for turbulent swirling and non-swirling gas-particle flows and also gas-particle flows with combustion in the Laboratory of Two-phase Flows and Combustion, Department of Engineering Mechanics, Tsinghua University. For strongly swirling gas-particle flows with swirl numbers greater than unity (s(velence)1.5 and s(velence)2.1), it is found that their gas-particle flow behavior is different among each other and is different from that for weakly swirling flows. For example, there are no central reverse flows and there are enlarged solid-body rotation zones for swirling flows with s(velence)1.5. The behavior of swirling gas-particle flows depends on the swirl number and the flow configuration For sudden-expansion gas-particle flows it is found that the gas-particle velocity correlation has the distribution similar to that of gas and particle RMS fluctuation velocities and its magnitude is smaller than that of both gas and particle RMS fluctuation velocities. For turbulence modification in sudden-expansion flows it is found that the separating flows increase the gas-turbulence enhancement tendency in comparison with the pipe flows. For combusting gas-particle flows it is found that combustion reduces the velocity slip between the gas and particle phases.