Abstract:
Parametric studies of combustion in radiation dominated heat transfer with a cyclic flow reversal of mixture is investigated and described in the thesis. In this combustion system, an extremely low-heat-content gas flows into the porous medium, where the flow direction reverses regularly. Use control valve to recirculate mixture pass through theqay that the exhaust gas has passed and use porous medium to be an intermediate to exchange heat between the mixture and the exhaust gas, the mixture is efficiently preheated prior to combustion. Mathematical model of the combustion system is formulated and solved by a numerical method. Attention was focused on the influence of the dominating parameters, i.e., flow velocity, half period, heating value or equivalence ratio, and optical thickness, on the formation of temperature profiles in the porous body. Results show that the maximum temperature is independent of half period and optical thickness but increases in proportion to the logarithm of Reynolds number and the heating value. Furthermore the flammable limit was extended to the extremely low equivalence ratio of 0.029 and the maximum temperature is about 7.5 times higher than the theoretical maximum temperature of an ordinary flame in free space. The model was validated by comparing the theoretical results with the experiments. The theoretical results agree well with the experimental ones.