Emissivity of an inhomogeneous fluidized bed

Borodulya, V. A.; Kovenskii, V. I.

doi:10.1007/bf00835053

Cited by 3 publications

(3 citation statements)

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“…where * is the fraction of the heat exchange surface in contact with bubbles in the maximum inhomogeneity of the bed ( *"0·614) (Borodulya and Kovenskii, 1984). The parameter is a function of the Reynolds and Archimedes numbers, given by…”

Section: Determination Of Heat Transfer Coefficientsmentioning

confidence: 99%

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Heat transfer to a horizontal tube bundle located in the freeboard of a bubbling fluidized bed combustor

Hafez

El-Mahallawy

Sharobeem

et al. 1997

Int. J. Energy Res.

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SUMMARYThe characteristics of heat transfer from bubbling gas-fired fluidized bed to a horizontal staggered water-tube bundle located in the freeboard region is experimentally investigated. The purpose is to demonstrate the effect of bed temperature on the coefficients of heat transfer by the different modes to each of the four rows of the bundle, which experiences heat transfer by convection from flue gases, luminous radiation from bed material and non-luminous radiation from gases. The bed temperature itself is varied and controlled through the fuel-air mass ratio. Sixteen runs have been conducted with bed temperature ranging from 1114 to 1429 K, resulting in an overall heat transfer coefficient in the range 74·0-105·0 W m\ K\ for the first row and 58·0-65·0 W m\ K\ for the last. An overall convective heat transfer coefficient from gases, and possible carried over sand particles, to the bundle is formulated.

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Section: Determination Of Heat Transfer Coefficientsmentioning

confidence: 99%

“…The degree of blackness of the surface of an isothermal inhomogeneous fluidized bed, , is determined from the following formula (Borodulya and Kovenskii, 1984):…”

Section: Determination Of Heat Transfer Coefficientsmentioning

confidence: 99%

Heat transfer to a horizontal tube bundle located in the freeboard of a bubbling fluidized bed combustor

Hafez

El-Mahallawy

Sharobeem

et al. 1997

Int. J. Energy Res.

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“…The emissivity contents of the fluidized bed (gas-solids), e b , which is the case of the freeboard space, may be obtained as [10] e b = e p 0.31…”

Section: (C) the Radiation Componentmentioning

confidence: 99%

Theoretical Consideration Of Complex Heat Transfer In The Freeboard Region Above The Fluidized Bed

Teplitsky,

Borodulya,

Hassoun

et al.

1999 Annual Conference Proceedings

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This paper discusses the scope and studies based on a complex heat transfer process in a fluidized bed. The heat transfer process occurring in the freeboard region above the bed exert a great influence on the thermal region in the whole apparatus containing a fluidized bed. This region occupies up to 90% of the working volume of the configuration. For this reason, the information of regularity of the heat transfer in the freeboard region above the bed with the heat transfer surface becomes very important in very large size equipment. It should be noted that the regularities of the heat transfer in this region are much more complicated than those in the fluidized bed itself. This circumstance apparently is due to the fact that the space above the bed is essentially nonhomogeneous in the vertical direction. The aerodynamic non-homogeneity is caused by nonuniform concentration of the particulates. This in turn results in thermal nonhomogeneity. The variation of particulate concentration from about 10 -3 to 10 3 kg/m 3 leads to corresponding strong changes in the transfer properties of the system. This essentially complicates the research of the regularities of heat transfer to the surface in the space above the bed.

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2002

Fundamentals and Technology of Combustion

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Emissivity of an inhomogeneous fluidized bed

Cited by 3 publications

References 2 publications

Heat transfer to a horizontal tube bundle located in the freeboard of a bubbling fluidized bed combustor

Heat transfer to a horizontal tube bundle located in the freeboard of a bubbling fluidized bed combustor

Theoretical Consideration Of Complex Heat Transfer In The Freeboard Region Above The Fluidized Bed

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