Light deviation based optical techniques applied to solid propellant combustion

Abstract

The Investigation in Combustion of Energetic Materials (InCoME) program is aimed at validating the numerical simulation of composite propellant combustion using nonintrusive optical techniques. The Focusing Schlieren Technique (FST) was selected; it allows catching light deviation from a thin vertical planar section centered above the propellant combustion surface. The optical system is described in the paper. Signi¦cant results are presented showing the capabilities of this technique when applied to solid propellant combustion in terms of studying §ame structure, §ame propagation, and particle tracking.

Quantitative, three-dimensional imaging of aluminum drop combustion in solid propellant plumes via digital in-line holography

“…4 with traditional high-magnification imaging, such as those in Fig. 1 and [6][7][8], indicates that DIH reconstructs the critical features of aluminum drop combustion, but with the added advantage of numerical refocusing. In Figs.…”

“…Many experimental investigations of aluminum droplet behavior in propellant plumes have been performed [4][5][6][7][8][9]. Optical techniques for measuring molten aluminum sizes and/or velocities have included point-wise phase Doppler anemometry [4], line-of-sight laser diffraction [5], videography [6], shadowgraphy [7], Schlieren [8], and holography [9].…”

“…Optical techniques for measuring molten aluminum sizes and/or velocities have included point-wise phase Doppler anemometry [4], line-of-sight laser diffraction [5], videography [6], shadowgraphy [7], Schlieren [8], and holography [9]. Among these techniques, imagingbased methods (videography, shadowgraphy, Schlieren, and holography) are particularly advantageous because images allow for differentiation of reacting aluminum drops from other particulates and provide insight into the flow physics.…”

Digital In-Line Holography of Condensed-Phase Particles in Solid Rocket Motor Plume

“…A lot of experimental research has been conducted on the characteristics of CCPs in plumes, such as the mechanical collection and optical measurement method [6][7][8][9][10][11]. The traditional particle collection method can reveal the particle size distribution of the condensed phase particles; however it modifies the flow field structure and particle state, resulting in a different actual plume state.…”

Optical measurements in multiphase combustion

“…Also, they are limited to small interrogation regions (about 1 mm in length) dictated by the focused laser beam geometry. To capture twodimensional information, imaging diagnostics including backlit videography [97], shadowgraphy [67] and schlieren [20] are widely used to capture the temporal and spatial evolution of multiphase combustion. Cauty et al [20] investigated a focusing schlieren technique (FST) to capture solid propellant flame structure, flame propagation, and individual particles near the burning surface.…”