Flow Visualization and Laser Measurement on Particle Modulation to Gas-Phase Turbulence

Article type: Research Article

Authors: Cui, J. L. | Zhang, H. Q. | Wang, B. | Rong, Y. | Wang, X. L.

Affiliations: Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China

Abstract: Particle modulation to turbulence is investigated experimentally by means of PDPA, PIV and flow visualization for a gas-particle two-phase jet flow. Large particles can enhance the small-scale vortex, so that gas-phase turbulence intensity is increased, while small particles may delay the rolling up of the gas vortex, so that gas-phase turbulence intensity is attenuated. The critical particle size range for such different effects is between 150 μm and 200 μm, corresponding to the Stokes number is between 88 and 157 under the present flow conditions. The PIV results show small particles can retain the gas-phase vortex structure, while large particles can break large vortex structure. The particle Stokes number is not the only judgment standard whether particles enhance or attenuate gas-phase turbulence. The CTI (Change of Turbulence Intensity) number can mark off particle modulation on turbulence in two-phase flow, but more studies are needed.

Keywords: Two-phase jet, PDPA, PIV, Flow visualization, Turbulence modulation

Journal: Journal of Visualization, vol. 9, no. 3, pp. 339-345, 2006