Temporally resolved, two-line fluorescence imaging of NO temperature in a transverse jet in a supersonic cross flow

Abstract

Temporally resolved temperature imaging of a fuel jet in a hot, nonoxidizing supersonic cross flow is described. The temperature measurements are obtained with two lasers and two intensified cameras, with a two-line ratio of planar laser-induced fluorescence from nitric oxide, seeded either in the jet or in both the jet and the cross flow. Diagnostic issues related to the application of the two-line technique in high-speed combustion flows are addressed and include temperature sensitivity, transition selection, measurement resolution, fluorescence lifetime, temporal resolution, and intensifier and camera dynamicrange limitations. Single-shot and frame-averaged side-view temperature images of the flow field are presented, and the measurement uncertainties, which are dominated by photon statistical noise and pulse-to-pulse laser fluctuations, are discussed.