Fluorescence Lifetime Imaging: An Approach for Fuel Equivalence Ratio Imaging

Abstract

This paper describes dopants, apparatus, and procedures which can be used for planar laser-induced fluorescence (PLIF) imaging of the fuel/oxygen equivalence ratio, the most important mixture parameter in combustion studies. The lifetime imaging techniques described here provide data beyond the data available from conventional intensity imaging, and should allow the equivalence ratio to be determined in real time in a two-dimensional slice of a fuel spray. Lifetime imaging methods require the sequential gating of two 2-D detectors during the fluorescence decay. Proof-of-concept experiments indicate that lifetimes ranging from 5 to 50 ns can be imaged with good accuracy. The requirements for fluorescent dopants and considerations for use under flame conditions are also discussed.