Heat Transfer Characteristic for Premixed Flame Jet from Swirl Chamber

Abstract

The objective of this research is to study flame structure and heat transfer characteristics for the premixed flame jet from the swirling chamber. In this study, LPG and air was utilized as gas fuel and oxidizer for a premixed flame. The equivalence ratios () of LPG and air were considered at 0.8, 1.0, and 1.2 under a Reynolds number Re = 4,000. The swirl flame was generated by double tangential inlets in cylindrical chamber.  The diameter of chamber was fixed at D = 20 mm and the hydraulic diameter of the inlet was D_h = 5 mm. In this study, the effect of chamber geometry on flame structure was investigated by varying the chamber from H = 2.2D_h to 7.0D_h. The structures and temperature of the free flame jet was recorded with camera and measured with a thermocouple. The heat transfer rate of impinging flame jet was also measured at distance from chamber outlet to flame impingement surface varying from L = 4D_h to 10D_h. The results show that the maximum of flame temperature occurs at =1.2. Impinging flame jet for case of chamber height at H = 4.6D_h and impingement distance at L = 4D_h give the highest heat transfer for all equivalence ratios due to the reaction zone of combustion reached to approach near the heat transfer surface.