An analytical-empirical model to predict heat transfer coefficients in circulating fluidized bed combustors

1995 ◽  
Vol 30 (6) ◽  
pp. 377-383 ◽  
Author(s):  
M. R. Golriz ◽  
B. Sundén
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Empirical Model ◽  
Circulating Fluidized Bed ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

HEAT TRANSFER COEFFICIENTS FOR TUBES SUBMERGED IN CIRCULATING FLUIDIZED BED

1991 ◽  
Vol 4 (4) ◽  
pp. 343-353 ◽  
Author(s):  
Suisheng Dou ◽  
Blaine Herb ◽  
Kemal Tuzla ◽  
John C. Chen
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Measurement of Heat Transfer in a 465t/h Circulating Fluidized Bed Boiler

2005 ◽  
Author(s):  
Yu Wang ◽  
Junfu Lu ◽  
Hairui Yang ◽  
Xinmu Zhao ◽  
Guangxi Yue
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Bulk Density ◽  
Fluidized Bed ◽  
Thermal Boundary Layer ◽  
Circulating Fluidized Bed ◽  
Transfer Coefficients ◽  
Cfb Boiler ◽  
Heat Transfer Coefficients ◽  
Solid Bulk

The study of heat transfer and thermal boundary layer in the combustor of a circulating fluidized bed (CFB) is important to the boiler design and operation. Both heat transfer coefficient between the solid-gas flow and the water-wall and the thickness of thermal boundary layer are key data to determine the amount and layout of the tube walls in a CFB furnace. A series of experiments was conducted on a 465t/h commercial CFB boiler, which operated at bed temperature between 850 and 900°C, and at superficial gas velocity between 5.2 to 5.9m/s. Local bed to water wall heat transfer coefficients and temperature profiles near the wall were measured at a set of test ports at different heights of the sidewall. In the same time, the local solid bulk density near the wall was also measured. Special tools such as heat flux probe, solid bulk density sampling probe and temperature probe were developed for the experiments and their structures were introduced. The experimental results were compared with the data from previous studies. Theoretical analysis of the factors that play important role in heat transfer in a CFB boiler was also performed. The relationship between heat transfer and thermal boundary layer was also discussed. Furthermore, a simple model correlating the local heat transfer coefficients with bulk density was developed.

scholarly journals Heat transfer in fluidized and fixed beds of adsorption chillers

2019 ◽  
Vol 128 ◽  
pp. 01003 ◽  
Author(s):  
Jaroslaw Krzywanski ◽  
Karolina Grabowska ◽  
Marcin Sosnowski ◽  
Anna Zylka ◽  
Anna Kulakowska ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Fluidized Bed ◽  
Fluidized Beds ◽  
Fixed Bed ◽  
Wall Heat Transfer ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Innovative Idea ◽  
Fixed Beds

An innovative idea, shown in the paper constitutes in the use of the fluidized bed of sorbent, instead of the conventional, fixed-bed, commonly used in the adsorption chillers. Bed–to–wall heat transfer coefficients for fixed and fluidized beds of adsorbent are determined. Sorbent particles diameters and velocities of fluidizing gas are discussed in the study. The calculations confirmed, that the bed–to–wall heat transfer coefficient in the fluidized bed of adsorbent is muchhigher than that in a conventional bed.

Fluidized Bed Solar Collector

1988 ◽  
Vol 110 (4) ◽  
pp. 321-326 ◽  
Author(s):  
L. R. Glicksman ◽  
J. Azzola ◽  
J. Modlin
Keyword(s):  
Heat Transfer ◽  
Power Consumption ◽  
Fluidized Bed ◽  
Solar Collector ◽  
Effective Conductivity ◽  
Thermal Design ◽  
Low Density ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Order Of Magnitude

An air fluidized bed, contained in the wall cavity of an exterior building wall, forms the basis of a new solar collector design which is simpler than a water-cooled collector and has a thermal performance superior to that of an air-cooled collector. The fluidized bed serves as an intermediate heat transfer medium between a solar flux absorbed on the external building surface and a liquid thermal transfer loop. Fluidized beds yield heat-transfer coefficients an order of magnitude higher than single phase air flow. Low density particles are used in the bed to minimize power consumption. When defluidized, the bed acts as a good thermal insulator. Recent experimental results are presented for the heat-transfer coefficients of the immersed tubes, bounding walls, the effective conductivity of the bed, and the overall full-scale thermal design efficiency for various low density materials. Structural and power consumption performance is examined as well. An integrated fluidized bed solar collector design is proposed and compared with representative water and air collector designs.

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