IGNITION PROCESSES AND FLAME SPREADING IN A GRANULAR SOLID PROPELLANT BED
Open Access
- Author:
- Colletti, Alexander E.
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- None
- Committee Members:
- Kenneth K Kuo, Thesis Advisor/Co-Advisor
Kenneth K Kuo, Thesis Advisor/Co-Advisor - Keywords:
- granular bed
flame spreading
interior ballistics
solid propellant - Abstract:
- Understanding the detailed ignition, flame spreading, and combustion processes inside of a granular solid propellant bed is vital for accurate internal ballistic modeling and development of weapon systems. To characterize these items, a modular test chamber was designed, fabricated, and utilized to analyze ignition processes in axial, radial, and azimuthal directions. A percussion primer and black powder igniter jet were fired into a bed of an inert material which simulates the geometric properties of the live granular propellant to characterize its penetration. These particles were analyzed with energy dispersive X-ray spectroscopy (EDS) to confirm that the condensed phase species contain potassium species as predicted by equilibrium analyses. Three correlations were found which describe the region affected in the granular bed by condensed phase products of the igniter jet including: axial depth of penetration, maximum radial penetration, and the volume of the coated region. They are related by: the Reynolds number based on the jet diameter, the ratio of pressure in the igniter jet to the ambient, and the ratio of bed particle diameter to orifice diameter. Through the use of high-speed photography, photodetectors, and pressure transducers igniter jet penetration into the granular bed was examined in terms of its influence on flame spreading behavior. The igniter jet is shown to fully penetrate the bed, over approximately 1 ms, before any major granular bed combustion was measured through pressure time traces, high-speed photography, or photodetector signals. Tests performed with high-speed photodetectors, sensitive to either the visible and infrared spectrum, show that the relative spread between the hot gaseous front and the flame front can be determined utilizing this windowed test chamber. The axial fronts were separated by an average of 0.15 ms at 4000 to 6000 psia.