Characteristics of Ignition of Combustible Mixture with Platinum Catalyst

Abstract

In order to investigate the effects of equivalence ratio and total pressure on hot catalytic surface ignition, experimental and numerical studies were conducted. A platinum sphere of 1.5 mm diameter was used as the catalyst. Premixed gases contained hydrogen, oxygen and nitrogen. The mole fraction of nitrogen was 75% in all cases. Surface temperature of the platinum catalyst was measured by a thermocouple. A photodiode was used to detect the ignition. In this paper, ignition temperature was defined as the output of the thermocouple at which ignition occurred. When total pressure decreased, ignition temperature increased and the effect of equivalence ratio changed. This seems to be caused by the difference in diffusion characteristics of dominant species.