Jet Fuel Ignition Delay Times and Modeling: Studies at High Pressures and Low Temperatures in a Shock Tube

Abstract

New ignition time data for purely gaseous fuel-air mixtures have been obtained in a heated shock tube for Jet-A/air mixtures at high pressures and low temperatures. These experimental conditions are typical of many engines, and hence it is important to study the characteristics of ignition times under such conditions. Driver-gas tailoring methods were utilized to enable measurement of long ignition times at low temperatures. Ignition times were measured using sidewall-mounted piezo-electric transducers and confirmed at the same location with OH* emission (306 nm) measurements. Initial reflected shock conditions spanned the following ranges: temperatures of 715 to 1220 K, pressures of 18 to 51 atm, and at an equivalence ratio of 1.0. The experimental results were compared with model calculations of ignition times using the mechanism of Ranzi et al. (2006), applied to a jet fuel surrogate composition proposed by Violi et al. (2002). This mechanism along with the surrogate mixture gave good agreement at high temperatures (above 1000K), but failed to predict the low temperature behavior of data.