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Proceedings Paper

Automatic particle sizing from rocket motor holograms
Author(s): John P. Powers; David W. Netzer
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Paper Abstract

Solid-propellant rocket fuels frequently have spherical aluminum pellets added to improve combustion efficiency and to improve thrust performance. In order to model the combustion process, information is required about the size of the particles as they lift off of the propellant surface. We have used optical pulsed-laser holography to record an approximate 2.5 cm X 2.5 cm X 2.5 cm volume at the propellant surface in a test rocket motor. A pulsed ruby laser, combined with a laser line filter to remove the flame light, records the hologram. A diffuser is used to remove the phase gradients introduced by the thermal effects in the flame. The scene is reconstructed with a krypton laser, viewed with an optical microscope, and captured on videotape. The recorded scene is digitized and analyzed with digital image processing techniques on a personal computer equipped with a video memory board and an image processing subroutine library. The image processing techniques developed reduce the speckle in the scene, apply a threshold to differentiate the particles from the background, and locate and size the particles. Statistical analysis of the sizing results provides a histogram representation of the particles size distribution. Particle resolution down to 10 micrometers has been achieved with this technique.

Paper Details

Date Published: 1 May 1992
PDF: 10 pages
Proc. SPIE 1667, Practical Holography VI, (1 May 1992); doi: 10.1117/12.59628
Show Author Affiliations
John P. Powers, Naval Postgraduate School (United States)
David W. Netzer, Naval Postgraduate School (United States)

Published in SPIE Proceedings Vol. 1667:
Practical Holography VI
Stephen A. Benton, Editor(s)

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