Document Type : Research Article
Department of Mechanical Engineering, University of Kashan, Kashan, Iran
Combustion in porous media is an effective method to minimize dissipations and save energy. It enhances the efficiency of the system while reducing environmental pollution. The conditions for the formation of a steady-state submerged flame in a ceramic (SiC) porous medium were investigated at four firing rates. The results were obtained on a ceramic foam with a cross section area of 63.6 cm2 and pore density of either 10 or 30 ppi. The reactants were air and natural gas with various equivalence ratios. In this experimental study, eight thermocouples were mounted on the burner walls along its axis in order to track the flame position, and the results were presented as temperature profiles of the porous wall. It was observed that the formation of submerged flame depends on firing rate and equivalence ratio. The stability limit of submerged flame (the range between surface flame and flash back limits) is reduced by increasing the firing rate. Results show that the maximum temperature takes place near the interface of the two layers. Also, it was observed that when the mixture velocity is low, the stability limit extends. Finally, the ranges of equivalence ratio and mixture velocity for the formation of submerged flame are presented at various firing rates.