Particle Dispersion in a Plane Mixing Layer with Streamwise Pressure Gradient

• Published in: JSME international journal. Ser. 2, Fluids engineering, heat transfer, power, combustion, thermophysical properties Vol. 35; no. 1; pp. 29 - 37
• Main Authors: KOBAYASHI, Hironobu, MASUTANI, Stephen M., AZUHATA, Shigeru, MORITA, Shigeki
• Format: Journal Article
• Language: English
• Published: Tokyo The Japan Society of Mechanical Engineers 1992; Japan Society of Mechanical Engineers
• Subjects: Applied sciences; Coherent Structures; Combustion of solid fuels; Combustion. Flame; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Flow Visualization; Large Scale Vortex; LDV; Multiphase Flow; Particle Dispersion; Plane Mixing Layer; Pressure Gradient; Theoretical studies. Data and constants. Metering; Turbulence; Gas particle flow; Turbulence; Shear flow; Doppler laser anemometer; Pulverized coal; Flow velocity; Combustion; Pressure gradient; Mixing layer
• ISSN: 0914-8817
• DOI: 10.1299/jsmeb1988.35.1_29

Experiments were performed in a two-phase (gas-solid), plane mixing layer to study the behavior of heavy particles in an intermittent shear flow. The high-speed stream inlet velocity was fixed at 10.5m/s and the inlet velocity ratio was 0.377. The low-speed stream was seeded with 30- and 50-μm-diameter particles. Particle and gas velocity statistics were obtained in flows subjected to accelerating, neutral, and adverse pressure gradients. These data support the proposal that particle dispersion is strongly affected by the large-scale vortical structures of the mixing layer. The streamwise pressure gradient effects particle dispersion through changes induced in the behavior of these vortices. In these experiments, lateral transport was favored in the flow in the contraction where the mixing layer expands into the particle feedstream. The relative insensitivity of particle turbulent velocities to pressure gradient may be attributed to the independence of the Stokes number and d/dX. Particle inertia and the anisotropy of the gas turbulence structure result in large differences in streamwise and transverse particle velocity fluctuations. Particle inertia may also account for the observed dependence of particle lag on the streamwise pressure gradient.