Laser induced incandescence for soot concentration measurements in turbine engine exhausts

Abstract

To address the need for monitoring soot emanating from aircraft engines, a measurement system employing laserinduced incandescence (LII) has been developed and was successfully tested.* The † instrument ‡ instantaneously § images* * up † † to a 1-m chord of an exhaust plume with a spatial resolution of 5.1 cm, and is capable of providing measurements of soot concentration down to 0.02 mg/m 3. The system is completely non-intrusive and thus can be used to complement extractive sampling methods. Our efforts show how the LII method has matured to a level where it is ready for the harsh environment of an engine test cell. This paper describes the design and implementation of an LII system for soot concentration measurements in a full-scale, ground-based engine test, and presents results from such a test.

Optical control and diagnostics sensors for gas turbine machinery

“…Furthermore, monitoring of gas turbine emissions can be accomplished with optical techniques. For instance, the soot mass output emitted from a gas turbine has been measured with Laser-induced Incandescence (LII) 4 whereas metal debris in the exhaust due to wear can be measured with laserinduced breakdown spectroscopy (LIBS).…”

Optical Waveguiding and Applied Photonics

“…We propose a denoising process of interfence fringes produced by a laser in a thermovelocimetric chamber for soot detection and measurements (Jenkins et al 2002). A laser He-Ne, it is used in a qualitative manner to determine soot topography during diffusion flame-vortex interactions.…”

Development of sensing system for carbonaceous particles using LIBS combined with LII temporal analytical technique

“…He was able to relate the time dependence of the interference to laser particulate heating. Melton and many other researchers developed his work [9,10]. In this report, the LII technique was based on these earlier experiments and the LII decay simulation model was based on one of the most detailed studies provided by H.A.…”