In this study, 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. This paper was published as: Zhang Y, Wei XL, Liu DY. CFD study of a sudden-expanding coal combustor using Euler-Euler and Euler-Lagrange models.FUEL, 89(12):3643-3649(2010)