Introducing a novel spiral-channel combustion chamber and experimentally investigating the effect of nitrogen dilution on non-premixed micro methane-oxygen flame by spectroscopy method

In this study, the experimental investigation of oxygen-methane combustion has been done by investigating the effect of nitrogen dilution in a novel spiral-channel combustion chamber along with the recovery of thermal energy of the products.  The methane-oxygen non-premixed flame by a fixed equivalence ratio of 1.69, with nitrogen dilution percentages of 0%, 5%, 10%, and 18%, has been investigated with the spectroscopy method. The chamber is made of aluminum and created as a spiral-form channel to aid heat recovery. In this chamber, the combustion gases then pass a path parallel to the inlet flow, causing the inlet gases to be preheated. Also, oxygen is diluted and mixed with nitrogen before entering the chamber. Based on the results, by increasing of the diluent ratio the reduction of the H2O* radical radiation spectrum has been observed, where indicates complete combustion. In general, with the increase of the dilution ratio, the flame length increases, and in 5% and 10% dilution states, the best temperature distribution uniformity, and the completion of the combustion reaction chain are observed.