Instantaneous pressure and heat transfer in pulse-stabilized fluidization

Book · Tue Dec 31 04:00:00 EST 1996

OSTI ID:504596

Beasley, D E; Postle, M C ^[1]; Pence, D V ^[2]

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1. Clemson Univ., SC (United States). Dept. of Mechanical Engineering
2. Univ. of Rhode Island, Kingston, RI (United States). Dept. of Mechanical Engineering and Applied Mechanics

A hybrid combustor concept that couples a pulsed combustor with an atmospheric bubbling fluidized bed was developed by Manufacturing Technology Conversion International, Inc. (MTCI, Inc.) and licensed to Thermo-Chem, Inc. This Pulsed Atmospheric Fluidized Bed technology has technical advantages in energy efficiency and emissions and is currently in pilot scale demonstration on the campus of Clemson University. The present study examines the effect of an opposing oscillatory flow on the pressure and overall heat transfer in a bubbling gas-fluidized bed. This opposing flow models the flow in the tailpipe of a pulsed combustor. Pressure measurements at the wall and on a submerged horizontal cylinder clearly indicate that the bed hydrodynamics are significantly altered by the opposing secondary flow. Under operating conditions of low secondary flow rates and pulse frequencies, the dominant frequency of the pressure fluctuations measured in the bed shifts from the natural, unforced response of the bed to the imposed frequency. For higher fluidization and secondary flow rates both the natural and forced response of the bed are present. Overall and time-averaged local heat transfer measurements from a submerged horizontal cylinder clearly indicate that the heat transfer rates are significantly altered by the opposing secondary flow. The most dramatic increases in heat transfer, on the order of 12%, were identified with operating conditions with low primary and secondary flow rates and pulse frequencies near the natural frequency of the bed. The local heat transfer was most significantly altered at the stagnation point. A modified form of the Strouhal number is shown to effectively describe the effect of pulse stabilization on overall heat transfer.

• OSTI ID: 504596
• Report Number(s): CONF-960954--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ATMOSPHERIC PRESSURE
DESIGN
EXPERIMENTAL DATA
FLOW MODELS
FLUIDIZED-BED COMBUSTORS
HEAT TRANSFER
HYBRID SYSTEMS
PRESSURE MEASUREMENT
PULSE COMBUSTORS