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.