EXPERIMENTAL INVESTIGATION OF THE EFFECTS OF PREHEATING ON THE FLAME STABILITY OF NATURAL GAS-AIR PREMIXTURE OF A FLAT FLAME MICRO COMBUSTOR FOR ULTRA MICRO GAS TURBINE

摘要

A small scale flat flame combustor which enables the utilization of different flame holders was developed in order to investigate the effects of preheating the reactants on the flame stability limit, the pressure drop across the flame holder and the usability of different materials as flame holders. Alumina ceramic porous plates, sintered stainless steel and perforated plates were used as flame holders within a 46 mm quartz walled micro combustor. The range of the average pore size of the porous plates and the sintered stainless steel plates are between 100μm and 580 μm with an average porosity of 43～54% and thickness of 1mm to 4 mm. The perforated plate had a hole diameter of 1 mm and the distance between the hole centers was 2 mm. The flame stability limits of natural gas air mixture obtained at room temperature and 600 K were compared. The results showed that preheating the reactants widened the flame stability limit substantially. In addition, the exhaust gas concentrations of O_2, CO_2 and CO as a function of air/fuel ratio at constant air mass flow rate of 0.38 g/s were presented.