Journal of Flow Visualization and Image Processing

ISSN for PRINT: 1065-3090

For Online Access

Best Paper Award Selection - Editorial Board Site

2004, Volume11

Issue 1

88 pages

DOI: 10.1615/JFlowVisImageProc.v11.i1

Issue price - $154.00

Ku-Ho Su
Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2125, USA

Wen-Jei Yang
Department of Mechanical Engineering and Applied Mechanics, University of Michigan, Ann Arbor, Michigan 48109, U.S.A.

Jr-Ming Miao
Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2125, USA

The present study employs an air—water cold model to simulate a gas-stirred ladle system with throughflow in a novel steel—making process. The bubble boundary layer is formed by the injection of air through a nozzle installed on an unheated vertical wall into a recirculating flow. Flow visualization by means of direct photography of the two-phase flow region is performed while the depth of the nozzle and the rate of air injection are varied. The bubble boundary-layer thickness is determined which is the distance from the surface to a locus separating the single-phase core in the recirculating flow from the bubble boundary. Both the growth rate and the local average ascending velocity of bubbles in the boundary layer are also measured and their empirical formulas are derived. In addition, five dimensionless parameters governing bubble growth are identified as gas Reynolds number, viscosity ratio, buoyancy number, Weber number, and Froude number. An empirical equation is derived to correlate the experimental data for the bubble boundary-layer thickness. It is disclosed that for all gas injection rates, each bubble boundary layer resembles the hydrodynamic boundary in natural convection over a heated vertical plate.

DOI: 10.1615/JFlowVisImageProc.v11.i1.20 Download article, 14 pages

Article price - $35.00

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