Despite high levels of emissions that are dangerous to human and ecosystem health, pulverized coal will continue to be the main fuel for the generation of electricity for some time to come . Computational fluid dynamics (CFD) has become a very powerful tool for the simulation of coal combustion processes and in the design of a coal combustor with low levels of emissions.
CFD study of sudden-expanding coal combustor was performed by a team of researchers, led by Prof. WEI xiaolin, at the Key Laboratory of Environmental Mechanics, Institute of Mechanics, CAS. The Euler-Euler (E-E) and Euler-Lagrange (E-L) models designed for the same chemical mechanism of heterogeneous reactions were used to predict the performance of a typical sudden-expanding coal combustor. The results showed that the current E-E model underestimated the coal burnout rate because the particle temperature fluctuation on char combustion is not adequately considered. A comparison of the E-E and E-L simulations showed the underestimation of heterogeneous chemical reaction rates by the E-E model. Compared with E-L model E-E model greatly saves computational time, but in E-E model the effect of turbulence on heterogeneous chemical reactions of particles must be carefully considered. This paper indicates that in order to promote the accuracy of E-E simulation, a reasonable coal combustion sub-model which takes into account the particle temperature fluctuation on char combustion is essentially required.
The research entitled “CFD study of a sudden-expanding coal combustor using Euler-Euler and Euler-Lagrange models” has been published in FUEL, 2010, 89(12), 3643-3649, DOI: 10.1016/j.fuel.2010.07.038
Fig. Ratio of heterogeneous reaction rate obtained by the E–L model to that used in the E–E model.