Planar measurements of instantaneous species and temperature distributions in reacting flows - A novel approach to ground testing instrumentation

Abstract

This paper describes the technique and instrumentation for the simultaneous acquisition of the instantaneous distribution of temperature and the OH radical in high temperature reacting flowfields. The technique is based on Planar Laser-Induced Fluorescence (PLIF). Tunable, pulsed radiation derived from two Nd:YAG-pumped dye laser systems is focused by a common cylindrical telescope across a plane in the flow. The cylindrical telescope transforms the beams into twin sheets which are adjusted to overlap in space but are separated in time by approximately 1 s . The laser wavelengths are tuned to two isolated absorption lines of OH and the resulting fluorescence is imaged onto two intensified CCDarray camera systems. The ratio of the two images is used to infer gas-phase temperature while one of the images is used for OH number density. The resulting images constitute instantaneous, two-dimensional measurements of the distribution of temperature and an important reactive intermediate in the flowfield plane.