ANALYSIS OF MULTIDIMENSIONAL MODELS OF MONOLITH CATALYSTS FOR HYBRID COMBUSTORS

Distributed parameter models of the single channel of a monolith combu stor have been derived from progressively simplified assumptions. Simu lation results are compared to assess the importance of the different physicochcmical phenomena occurring in the combustor and to identify t he simplest adequate model. For typical operating conditions of the hy brid combustor (gas and wall temperature not exceeding 1,073 and 1,273 K, respectively, high flow rate and pressure, natural gas as fuel), t he results show that variations of gas properties have to be considere d while homogeneous combustion can be neglected. Assumption of the app roximate radial profile of axial velocity with invariant parabolic sha pe, rather than the rigorous solution of momentum balance and the cont inuity equation, provides accurate results. Moreover, for simulation o f ceramic monoliths, backward heat transmission by wall conduction can be neglected with a substantial saving of computational labor.