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Computational Science, Engineering & Technology Series
ISSN 17593158 CSETS: 8
ENGINEERING COMPUTATIONAL TECHNOLOGY Edited by: B.H.V. Topping, Z. Bittnar
Chapter 11
Equilibrium EulerEuler Modelling of Pulverized Coal Combustion A.C. Benim
Department of Mechanical and Process Engineering, Düsseldorf University of Applied Sciences, Germany A.C. Benim, "Equilibrium EulerEuler Modelling of Pulverized Coal Combustion", in B.H.V. Topping, Z. Bittnar, (Editors), "Engineering Computational Technology", SaxeCoburg Publications, Stirlingshire, UK, Chapter 11, pp 251269, 2002. doi:10.4203/csets.8.11
Keywords: pulverized coal combustion, twophase flow, equilibrium EulerEuler vs. EulerLagrange modelling.
Summary
This paper demonstrates the application of an equilibrium EulerEuler model of
twophase flow for modelling pulverized coal combustion. The stateofthe art twophase
flow models, being used for pulverized coal flames are majorly based on an
EulerLagrange description. An alternative approach is the equilibrium EulerEuler
description of the twophase flow. The latter offers the advantage of being
potentially more economical due to the reduced number of momentum and energy
transport equations and the missing problem of interphase coupling. The present
paper shows that the equilibrium EulerEuler model is able to deliver results with a
similar degree of accuracy compared to the EulerLagrange model for the
investigated configurations. This designates the equilibrium EulerEuler model as a
potentially attractive alternative especially for largescale industrial applications.
In the modelling, we assume that gas and solid phases behave as interpenetrating continua and can both be described using an Eulerian frame of reference. The additional assumption introduced here is that the phases are in fluid dynamical and thermodynamical equilibrium. This assumption simplifies the problem in such a way that only a single set of momentum and energy transport equations needs to be solved, where the particle phase appears as a "component" of the "mixture". What remains is a convenient description of the relevant transport equations of the mixture, which is discussed in the full paper. Results for a twodimensional flame have been compared with experiments and predictions of other authors using an EulerLagrange approach. This comparison indicates that the degree of accuracy obtained by the present model is comparable to that of the principally more expensive EulerLagrange modelling. The reduced computer costs by the present approach become important, especially for large scale applications. An application of the model to a large utility boiler is also demonstrated. purchase the fulltext of this chapter (price £20)
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