Header menu link for other important links
X
Heat transfer at a long electrically-simulated water wall in a circulating fluidised bed
Ajit Kumar Kolar
Published in
2009
Pages: 350 - 356
Abstract
In the present work, heat transfer measurements are reported in a 100mm square, 5.5 m tall, cold CFB. The test section is a 19 mm OD electrically heated heat transfer tube, 4.64 m tall (covering more than 80% of the CFB height), sandwiched between two equally tall dummy tubes of 19mm OD, thus simulating a water wall geometry, forming one wall of the CFB. Narrow cut sand particles of mean diameters 156, 256, and 362 micrometers, and a wide cut sample of mean diameter 265 micrometer were used as the bed material. The superficial gas velocity ranged from 4.2 to 8.2 m/s, and the solids recycle flux varied from 17 to 110 kg/m2s. Local heat transfer coefficient at the simulated water wall varies, as expected from a low value at the top of the riser to a high value at the bottom, with an interesting increasing and decreasing trend in between. The average heat transfer coefficients were compared with those available in open literature. Correlations for average heat transfer coefficient are presented, both in terms of an average suspension density and also in terms of important nondimensional numbers, namely, Froude number, relative solids flux and velocity ratio. Comparisons are also made with predictions of relevant heat transfer models. Based on the present fifty-five experimental data points, the following correlation was presented with a correlation coefficient of 0.862 and maximum error is ±15 %.
About the journal
JournalProceedings of the 20th International Conference on Fluidized Bed Combustion
Open AccessNo
Concepts (29)
  •  related image
    BED MATERIALS
  •  related image
    CFB
  •  related image
    CIRCULATING FLUIDISED BED
  •  related image
    Correlation coefficient
  •  related image
    DUMMY TUBES
  •  related image
    Experimental data
  •  related image
    Heat transfer correlation
  •  related image
    Heat transfer measurements
  •  related image
    HEAT TRANSFER MODEL
  •  related image
    In-between
  •  related image
    Local heat transfer coefficient
  •  related image
    Maximum error
  •  related image
    Mean diameter
  •  related image
    Nondimensional
  •  related image
    SAND PARTICLES
  •  related image
    SOLIDS FLUX
  •  related image
    SUPERFICIAL GAS VELOCITIES
  •  related image
    SUSPENSION DENSITIES
  •  related image
    Test sections
  •  related image
    Velocity ratio
  •  related image
    WATER WALL
  •  related image
    Fluidization
  •  related image
    Fluidized beds
  •  related image
    Heat exchangers
  •  related image
    Heat transfer coefficients
  •  related image
    Micrometers
  •  related image
    Statistical tests
  •  related image
    Suspensions (fluids)
  •  related image
    Fluidized bed combustion