Visualization of flow characteristics in a 2-D bubble column and three-phase fluidized bed

Journal Article · Sat May 01 00:00:00 EDT 1993 · AIChE Journal (American Institute of Chemical Engineers); (United States)

DOI:https://doi.org/10.1002/aic.690390502· OSTI ID:6345242

Tzeng, J W; Chen, R C; Fan, L S ^[1]

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1. Ohio State Univ., Columbus (United States)

Macroscopic flow structures of gas-liquid and gas-liquid-solid fluidization systems are studied through flow visualization using a two-dimensional column under various operating conditions. The gas distributor in the column comprises multiple injectors which are individually regulated to generate desired gas flow rates, bubble injection frequencies, and bubble sizes. Colored bed particles and neutrally buoyant particles as solid and liquid tracers, respectively, are used for flow visualization through video photography. In a gas-liquid system operated under liquid-batch conditions, bubble streams injected near both sidewalls are observed to migrate toward be vertical axis, and vortices appear along the sidewalls when gas velocity exceeds 4-6 mm/s. A considerable amount of liquid descends along the sidewalls in a vortical flow pattern. The gross circulation pattern occurring at high gas velocities is associated closely with induced liquid or liquid-solid flows resulting from rising bubbles and bubble wakes. When the gross circulation occurs, four flow regions can be distinguished. The formation of and mechanism for gross circulations can be interpreted in part based on two simplified flow conditions involving single bubbles rising in a stationary liquid and single chains of bubbles injected in a batch liquid. The effects of particle size, inlet liquid velocity and gas flow distribution on the macroscopic flow structure are also examined.

• OSTI ID: 6345242
• Journal Information: AIChE Journal (American Institute of Chemical Engineers); (United States), Journal Name: AIChE Journal (American Institute of Chemical Engineers); (United States) Vol. 39:5; ISSN AICEAC; ISSN 0001-1541
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320303 -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Equipment & Processes
42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
BUBBLES
CAMERAS
EXTRACTION APPARATUSES
EXTRACTION COLUMNS
FLOW RATE
FLOW VISUALIZATION
FLOWMETERS
FLUID FLOW
FLUID MECHANICS
FLUIDIZED BEDS
GAS FLOW
LIQUID FLOW
MEASURING INSTRUMENTS
MECHANICS
METERS
MORPHOLOGY
MULTIPHASE FLOW
PARTICLE SIZE
SEPARATION EQUIPMENT
SIZE
SOLIDS FLOW
TWO-DIMENSIONAL CALCULATIONS
VORTICES