Overall and average local heat transfer from a horizontal cylinder in a gas-fluidized bed with an opposing oscillatory flow

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:442622

Pence, D V ^[1]; Beasley, D E ^[2]

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

The Pulsed Atmospheric Fluidized Bed Combustor (PAFBC), a hybrid combustor concept that couples a pulsed combustor with an atmospheric bubbling fluidized bed, has technical advantages in energy efficiency and emissions. The present study examines fundamental aspects of heat transfer in this hybrid combustor by measuring the effect of an opposing oscillatory flow on the overall and time-averaged local heat transfer in a laboratory scale bubbling gas-fluidized bed. This opposing secondary flow consisted of a steady mean component and an oscillating component thereby modeling the flow in the tailpipe of a pulsed combustor. Data were acquired for a monodisperse distribution of particles with a mean diameter of 345 {micro}m and total fluidization ratios ranging from 1.1 through 2.7. Overall and time-averaged local heat flux measurements from the surface of a submerged horizontal cylinder show that heat transfer characteristics are significantly altered by an opposing oscillatory flow. Increases in overall heat transfer on the order of 12% were identified for operating conditions with low primary and secondary flow rates and low pulse frequencies. These enhancements were identified to be a consequence of significant localized enhancements. The fundamental trends and magnitude of the particle Nusselt number are effectively characterized by a modified form of the Strouhal number.

• OSTI ID: 442622
• Report Number(s): CONF-961105--; ISBN 0-7918-1521-8
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
AIR POLLUTION ABATEMENT
ATMOSPHERIC PRESSURE
COAL FINES
ENERGY EFFICIENCY
FLUIDIZED-BED COMBUSTORS
HEAT TRANSFER
HYBRID SYSTEMS
PULSE COMBUSTORS