Comparison of solid phase closure models in Eulerian-Eulerian simulations of a circulating fluidized bed riser

The riser tube solar receiver of a circulating fluidized bed solid particle absorption solar thermal energy system was numerically modeled for analyzing hydrodynamic and heat transfer behaviors of the solid particles in the riser. Hydrodynamics of the model is validated by comparing radial distribution of void fractions with an experimental study. For the heat transfer from the opaque walls of the receiver that is heated to high temperatures by the solar rays concentrated by the heliostat field, a simple fractional model is used in which radiative transfer is neglected and total heat flux is distributed to phases according to the instantaneous volume fractions at the boundary cells. MFIX: Multiphase Flow with Interphase eXchanges code of NETL is used with a 2.5D Eulerian-Eulerian computational model for transient simulations. The 2.5D grid is a combination of planar cells and cylindrical cells with the determined optimum fraction of planar cells of 0.15. For the solar receiver riser, transient and time averaged results of void fraction and gas and solid phase temperature distributions were numerically obtained and analyzed.

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Turbulence structure of the solid phase in transition region of a circulating fluidized bed

Chemical Engineering Science ◽

10.1016/s0009-2509(99)00370-x ◽

2000 ◽

Vol 55 (4) ◽

pp. 839-847 ◽

Cited By ~ 17

Author(s):

Haosheng Zhou ◽

Jidong Lu ◽

Liang Lin

Keyword(s):

Fluidized Bed ◽

Transition Region ◽

Circulating Fluidized Bed ◽

Solid Phase ◽

Turbulence Structure

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Heat Transfer Investigation of the Circulating Fluidized Bed Evaporator for Concentrating Pineapple Juice

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.614-615.272 ◽

2012 ◽

Vol 614-615 ◽

pp. 272-276

Author(s):

Zhen Ling Fu ◽

Li Li Zhang ◽

Yan Bin Shi

Keyword(s):

Heat Transfer ◽

Flow Regime ◽

Fluidized Bed ◽

Circulating Fluidized Bed ◽

Solid Phase ◽

Engineering Technology ◽

Pineapple Juice ◽

Corrugated Tube ◽

Turbulent Flow Regime ◽

Experimental Values

Vapor-liquid-solid phase change is a common phenomenon in nature and engineering technology. In this paper, the three-phase circulating fluidized bed evaporator was applied to concentrate Pineapple juice according to the structure and characteristics of it. Inert particles, as fluidizing medium, are put in the heating tube, increased the turbulence of the fluid, destroyed the boundary layer, and strengthened the convection, it had a good antifouling and descaling performance. Based on the experimental values derived from the circulating fluidized bed heat transfer experiments, the heat transfer experimental correlations of corrugated-tube in laminar flow regime and turbulent flow regime were obtained.The results show that the experimental value was in good agreement with the theoretical value.

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Numerical Research Of Influence Of Disperse Composition On Characteristics Of Combustion Of Coal-Fired Circulating Fluidized Bed

Siberian Journal of Physics ◽

10.54362/1818-7919-2016-11-3-53-61 ◽

2016 ◽

Vol 11 (3) ◽

pp. 53-61

Author(s):

Vladimir Salomatov ◽

Andrey Gil ◽

Aleksandr Starchenko ◽

Roman Arkhipov

Keyword(s):

Fluidized Bed ◽

Circulating Fluidized Bed ◽

Solid Phase ◽

Radiation Heat Transfer ◽

Solid Particles ◽

Fluidised Bed ◽

Two Phase ◽

Chemical Reaction Kinetics ◽

Characteristic Features ◽

Ignition And Combustion

The peculiarity of mathematical modeling of the circulating fluidized bed (CFB) is that the solid phase (fuel and ash particles) is always a polydispersed medium. The paper constructed a mathematical model of gas dynamics, heat and mass transfer and combustion in the furnace volume of CFB steam generator with a highly concentrated content of the dispersed phase in relation to the investigation of processes in aerothermochemical CFB furnace. Taking into account: the turbulent structure of the two-phase flow, radiation heat transfer in a dusty environment, the chemical reaction kinetics of ignition and combustion, the effects of the power and thermal interactions between the particles and the particles with the wall. A model of such an environment has been chosen phenomenological model of interpenetrating continua Rahmatulina HA. The characteristic features of CFB technology are: firstly organized circulation of solid particles; Second, the repeated return unburned coarse fractions in the fluidised bed. As a result, during the low-temperature burn-in CFB increased almost two orders of magnitude compared with torch mode, allowing you to burn the most difficult fuels in the energy sector. Numerical analysis of data showed that the best results on the effects of polydisperse composition for fuel combustion characteristics in CFB process provides a particle size distribution in which a small fraction predominates.

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