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Combustion – Progress in optical diagnostics

A new optical method for the observation and measurement of the combustion of aluminum particles in solid propellant engines.

Focused Schlieren photography has been used to validate the combustion models for aluminum particles in solid propellant engines used for missiles and launchers.
Schlieren photography is based on the deviation, due to refraction index gradients, of rays from a source of light. Its focused variant allows for the viewing of a zone of very low depth of field , similar to a laser section.

Evolution of an aluminum particle in combustion leaving the surface of a solid propellant on four images taken at 1 ms intervals.