Numerical Simulation of Uprising Gas-Solid Particle Flow in Circulating Fluidised Bed

Abstract

Concentration of solid particles of ash and inert material present in the combustion chamber of a circulating fluidised-bed boiler is very high, giving rise to some disadvantages. At the same time, the required temperature level in the combustion chamber is guaranteed by circulation of solid particles. In this work numerical simulation of gas-solid particle flow has been performed in the frame of a two-fluid model, namely the Eulerian approach for the dispersed phase, for conditions of the circulating fluidised bed, ranging from moderate to high mass ratios of the flow. An incorporated original model of closure of transport equations of the dispersed phase permitted to account the interparticle collisions which might be indispensable to proper numerical simulation of the process in the circulating fluidised bed under discussion. The results of this work would help to improve the processes occurring in the combustion chamber of the circulating fluidised-bed boiler.

Numerical Simulation of Uprising Turbulent Flow by 2d Rans for Fluidized-Bed Conditions

“…Comparing the results with our previous work "Numerical simulation of uprising gas-solid particle flow in circulating fluidized bed" [2], in which theoretical initial data was used, the following remarkable facts can be noticed:…”

“…This article is a sequel to the previous reference: "Numerical simulation of uprising gas-solid particle flow in circulating fluidized bed" [2]. In that work the flow of gas-solid particles in conditions of CFB was studied, taking into account the amount of heat that must be separated from the combustor by the sensible heat of solid ash particles.…”

“…The previous numerical simulations were performed using the two-phase turbulent boundary layer (TBL) approach [2]. This implies that the diffusive source terms were retained only in one direction, namely in the transverse one, and the magnitude of the average transverse velocity components of the gas-and dispersed phases was much less than that of the longitudinal components of the corresponding velocities of gaseous and dispersed phases.…”

Mathematical Model of Two-Phase Flows Loaded With Light and Heavy Particles to Analyze CFB Processes

“…The previous numerical simulations have been performed using the twophase turbulent boundary layer (TBL) approach [2]. This approach implies that the diffusive source terms were retained only in one direction, namely in the transverse one, and magnitudes of the average transverse velocity components of the gaseous and dispersed phases were much less than those of the longitudinal components of the corresponding velocities of gaseous and dispersed phases.…”

“…In comparison with our previous article, in calculations the following practical initial data [2] were used: The present research is a continuation of our previous numerical study of processes occurring in CFB using the two-fluid (Euler-Euler) approach describing the behavior of solid particles as a continuous co-existing solid phase. Along with this the 2D RANS modeling with the use of finite (control) volume method [5] is currently applied to avoid common assump-tions of TBL approximation.…”