Movement of Small Spheres in a Plane Mixing Layer

• Published in: JSME international journal. Ser. 2, Fluids engineering, heat transfer, power, combustion, thermophysical properties Vol. 35; no. 4; pp. 519 - 528
• Main Authors: KOBAYASHI, Hironobu, MASUTANI, Stephen M., AZUHATA, Shigeru, MORITA, Shigeki
• Format: Journal Article
• Language: English
• Published: Tokyo The Japan Society of Mechanical Engineers 01.01.1992; Japan Society of Mechanical Engineers
• Subjects: Applied sciences; Coherent Structures; Dispersions; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Flow Visualization; Large-Scale Vortex; Laser doppler velocimeters; LDV; Mathematical models; Mixing; Multiphase Flow; Particle Dispersion; Particles (particulate matter); Plane Mixing Layer; Spheres; Theoretical studies. Data and constants. Metering; Thermodynamics, mechanics etc. For energy applications; Turbulence; Velocity measurement; Vortex flow; Gas particle flow; Two phase flow; Shear flow; Particle motion; Doppler laser anemometer; Pulverized coal; Flow velocity; Mixing layer
• ISSN: 0914-8817
• DOI: 10.1299/jsmeb1988.35.4_519

Experiments were performed in a two-phase, two free-stream plane mixing layer to study the behavior of heavy spheres in an intermittent shear flow. Particles with three different diameters were employed in these experiments. Comparisons between data on streamwise and transverse components of particle and gas velocities are presented. These data, as well as flow visualization images, suggest that the ratio of the particle time constant τp and the large-scale eddy turnover time plays an important role in the cross-stream transport of a heavy dispersed phase. When the τp/τ was approximately on the order of 1, heavy particles began to move with gas flow. There exists movement of heavy spheres back toward the particle feed stream. The transverse component of large-particle turbulent velocity, vp', in the interior of the layer was observed to be significantly smaller than the corresponding streamwise component, up' <v'2>/<u'2> of the particle reaches an asymptotic value, 0.2, around the high-speed side of the mixing layer.