Endoscopic System to Measure Droplet Size and Velocity in Turbine Engine Augmentors

In response to an Air Force requirement for a high temperature endoscope to measure fuel spray in a turbine engine augmentor, MetroLaser proposes an endoscopic system that will be capable of measuring droplet size from 10 to 1000 microns and velocity from 3 m/s to 300 m/s. The endoscopic tubes will fit inside high temperature sheaths developed at AEDC that keep the inside temperature at 200ºF or cooler. The diameter of the endoscopes will be 0.5" and will extend to about 20". The system will include a traversing mechanism to probe different regions of the augmentor and, thus, obtain the distribution of droplet size and velocity. The proposed work is based on a SBIR Phase I feasibility study, where the ability to measure droplet size with an endoscope was successfully demonstrated. The Phase I system, which included a receiving endoscope, a pulse laser and a CCD camera, was used to measure droplets with an index of refraction of 1.4 (like kerosene) from 10 to 150 microns with great accuracy. The proposed Phase II work will consist of developing, delivering, and field testing, in an actual jet engine augmentor, a complete high temperature spray measurement system.