In-situ soot particle sensing in an aero-engine exhaust plume

This paper reports the use of a fiber-laser to produce spatially resolved images of the distribution of absorbing particles in the exhaust plume of a modified helicopter gas turbine engine. In-situ sensing of soot particles by Laser-Induced Incandescence (LII) is demonstrated using fiber-lasers with higher power, longer pulse duration, and higher pulse repetition rates than conventional LII. The sensitivity of the method is illustrated by the detection of ambient absorbing particles prior to engine running. With a running engine images are obtained in 0.01s. The demonstration of LII using fiberlasers is a first step in the development of a new model for long-pulsed LII.