Shock Tube Ignition Delay Times and Modeling of Jet Fuel Mixtures

Abstract

Ignition delay times were measured for stoichiometric jet fuel mixtures (Jet-A and JP-8) in air behind reflected shock waves in a heated shock tube. Reflected shock conditions spanned the following ranges: temperature 875 to 1220 K, pressure 18 to 36 atm, and an equivalence ratio of 1.0. Ignition times were measured using sidewall-mounted piezo-electric transducers and confirmed at the same location with OH* emission measurements at 306 nm. The shock tube and mixing assembly were heated to 100 and 125 C, respectively, to prevent condensation of the lower vapor pressure/higher boiling point components of the fuel. The Jet-A/JP-8 results have very low scatter and are in excellent agreement with the limited previous shock tube measurements. To the best of our knowledge, we report the first shock tube ignition time data for JP-8. Although JP-8 composition is slightly different from Jet-A, their ignition times are in close agreement. The experimental results were compared with model calculations of ignition time using the models of Ranzi et al. (2005) and Zhang et al. (2005), applied to a jet fuel surrogate composition proposed by Violi et al. (2002).