Effect of catalyst size on flameless combustion's hysteresis characteristics of air-gas mixtures with combustible gas's impurities

Abstract

Analytical models of heat and mass transfer's hysteresis and combustion kinetics of combustible gas impurities on a metal catalyst particle (wire) in the presence of only one onesided reaction are proposed. The analysis is carried out taking into account thermal diffusion and depending on the catalyst's size and the gas-air mixture's temperature. The dependences of platinum wire's temperature on hydrogen-air mixture's temperature at various wire diameters are presented. Decrease in the wire's diameter under unchanged other conditions leads to a decrease in the hysteresis region and its further degradation. The method used for analytical determination of hysteretic regions and degradation points, which lies in representing the desired dependences of operating parameters in a parametric form (parameter is catalyst's temperature). Analytical dependence (spinodal) gas-air mixture's temperature on catalyst's diameter was found that describes all critical points, including degradation points.The value of the diameter's and temperature's wire catalyst, the mixture's temperature, which correspond to critical condition’s degradation, were obtained in explicit form.