A Tentative Modeling Study of the Effect of Wall Reactions on Oxidation Phenomena

This paper gives details of a tentative modeling study that investigates the inhibiting effect of internal reactor walls treated with acid or metal oxides on low-temperature autoignition phenomena. Reactions that depend on the type of reactor wall coating have been considered for HO2 and RO2 radicals and H2O2 with estimated rate constants. These heterogeneous reactions have been incorporated into a homogeneous comprehensive n-butane oxidation mechanism. Simulations have been performed with spatial uniformity assumed, in order to assess the effect of the wall reactions on autoignition delay times and on a pressure−ambient temperature (p−Ta) ignition diagram. Experimental comparisons show that the main trends are qualitatively captured well by the model. Simulation results show an importance of RO2 wall reactions at temperatures below 750 K that control the minimum autoignition temperature. HO2 radical and H2O2 related wall reactions have an important effect at temperatures above 650 K and influence the min...