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

This is a proposal to develop and demonstrate the feasibility of an endoscopic system to measure droplet size and velocity distributions in high temperature sprays of turbine engine augmentors. We propose a technique that would measure with high interferometric precision the size distribution of spray droplets over an entire plane using a pulsed laser and CCD cameras. Double-pulsing the laser would yield velocity maps using PIV. The proposed droplet sizing technique derives the size measurement from intensity independent features of the scattered light and is immune to changes in the laser intensity, signal blocking, and the laser intensity profile. A special receiving endoscope would be developed during Phase I and incorporated into a breadboard measurement system. The endoscope would be designed and developed to be compatible with high temperature probes developed at AEDC. The feasibility of the proposed technique would be demonstrated in a series of controlled experiments using known-size particles from about 3 ƒYm to 200 ƒYm in diameter under known flow velocity conditions. The Phase I work would consist of modeling to optimize system parameters and experimental work to demonstrate system performance.