Spark ignition of propane-air mixtures near the minimum ignition energy: Part II. A model development

Abstract

A model is developed to simulate the kernel growth observed in the exprimental study of Part I. Kernel growth, described as a two-step process, initially involves a blast wave over a negligible short time followed by a diffusive growth with an electrical input power. The diffusive growth is formulated by an integral approach involving temperature dependent overall reaction kinetics and electrode heat loss. The model predicts the kernel growth reasonably well with the measured spark power input. It predicts both ignition and nonignition kernel growth. The existence of a critical radius is also demonstrated. In addition, dimensional analyses are given to clarify the physical aspects of the critical radius and the characteristic radius of the blast wave.