AUTOIGNITION OF GASEOUS FUEL-AIR MIXTURES NEAR A HOT SURFACE

摘要

An experimental investigation of the hot surface autoignition temperatures for methane, natural gas, propane, and butane mixtures with air was conducted. A stainless steel cartridge heater was installed, with the exposed surface pointing downwards, within a thermally insulating ceramic plate, and heated up to 1000°C in an enclosed volume of flammable fuel/air atmosphere. Exposed surface temperatures that caused autoignition in mixtures of varying stoichiometry were determined by slowly heating up the cartridge heater until combustion occurred. The measured hot surface temperatures, representing the most favourable conditions for ignition to occur near an exposed stainless steel surface, were found to be approximately 1.5-1.75 times higher than the reported minimum autoignition temperatures determined by standard test methods. These observations were used to validate a CFD based chemical kinetics modelling method. This validated model could form the basis of a predictive tool for general use.