Burning aluminized propellants eject reacting molten aluminum drops with a broad size distribution. Prior to this work, in situ measurement of the drop size statistics and other quantitative flow properties was complicated by the narrow depth-of-focus of microscopic videography. Here, digital in-line holography (DIH) is demonstrated for quantitative volumetric imaging of the propellant plume. For the first time, to the best of our knowledge, in-focus features, including burning surfaces, drop morphologies, and reaction zones, are automatically measured through a depth spanning many millimeters. By quantifying all drops within the line of sight, DIH provides an order of magnitude increase in the effective data rate compared to traditional imaging. This enables rapid quantification of the drop size distribution with limited experimental repetition.
© 2014 Optical Society of America
Original Manuscript: June 10, 2014
Revised Manuscript: July 25, 2014
Manuscript Accepted: July 28, 2014
Published: August 22, 2014
Daniel R. Guildenbecher, Marcia A. Cooper, Walter Gill, Howard Lee Stauffacher, Michael S. Oliver, and Thomas W. Grasser, "Quantitative, three-dimensional imaging of aluminum drop combustion in solid propellant plumes via digital in-line holography," Opt. Lett. 39, 5126-5129 (2014)