A physical model for simulating combustion systems in laminar flow reactors has been developed. The model is one-dimensional and includes transport phenomena. It is derived from conservation equations and thermodynamic relations. The present model is an extension of zero-dimensional models which were proposed by others. It enables one to accurately interpret the chemical time. A numerical program, LIOR, has been developed for solving the governing equations. It has been coupled with both CHEMKIN, an advanced package designed to facilitate simulations of elementary chemical reactions, and with TRANSPORT, a package capable of evaluating the transport property coefficients. The numerical code has been validated via the simulation of ethane (C2H6) combustion. The results were compared to available experimental results. Good agreement was evident. The model has been used to examine methane (CH4) and ethane combustion in a synthetic atmosphere system where nitrogen is replaced as a diluent with carbon dioxide. Special attention is given to the role of the detailed chemistry in the problem using a scheme containing about 100 elementary reactions. Examination of a set of model problems show that under such conditions, where there is a large concentration of carbon dioxide, the chemistry effects are very important. The typical area of application of this work is sub-sea vehicles and other closed-environment machines. The model also served a study aimed at elucidating the oxidation mechanism of the energy enriched fuel, deborane (B2H6) The results obtained can provide the basis for further investigation of this mechanism.