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Record Details

Record 11 of 109
SEM Characterization of Extinguished Grains from Plasma-Ignited M30 Charges
Author and Affiliation:
Kinkennon, A.(Army Research Lab., Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD United States)
Birk, A.(Army Research Lab., Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD United States)
DelGuercio, M.(Army Research Lab., Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD United States)
Kaste, P.(Army Research Lab., Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD United States)
Lieb, R.(Army Research Lab., Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD United States)
Newberry, J.(Army Research Lab., Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD United States)
Pesce-Rodriguez, R.(Army Research Lab., Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD United States)
Schroeder, M.(Army Research Lab., Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD United States)
Abstract: M30 propellant grains that had been ignited in interrupted closed bomb experiments were characterize by scanning electron microscopy (SEM). Previous chemical analysis of extinguished grains had given no indications of plasma-propellant chemical interactions that could explain the increased burning rates that had been previously observed in full-pressure closed bomb experiments. (This does not mean that there is no unique chemistry occurring with plasma ignition. It may occur very early in the ignition event and then become obscured by the burning chemistry.) In this work, SEM was used to look at grain morphologies to determine if there were increases in the surface areas of the plasma-ignited grains which would contribute to the apparent increase in the burning rate. Charges were made using 30 propellant grains (approximately 32 grams) stacked in two tiers and in two concentric circles around a plastic straw. Each grain was notched so that, when the grains were expelled from the bomb during extinguishment, it could be determined in which tier and which circle each grain was originally packed. Charges were ignited in a closed bomb by either a nickel wire/Mylar-capillary plasma or black powder. The bomb contained a blowout disk that ruptured when the pressure reached 35 MPa, and the propellant was vented into a collection chamber packed with polyurethane foam. SEM analysis of the grains fired with a conventional black powder igniter showed no signs of unusual burning characteristics. The surfaces seemed to be evenly burned on the exteriors of the grains and in the perforations. Grains that had been subjected to plasma ignition, however, had pits, gouges, chasms, and cracks in the surfaces. The sides of the grains closest to the plasma had the greatest amount of damage, but even surfaces facing the outer wall of the bomb had small pits. The perforations contained gouges and abnormally burned regions (wormholes) that extended into the web. The SEM photos indicated that a grain from the top tier, which was farther away from the plasma ignition source, sustained more plasma-induced damage to the perforations and the web than did the grains on the bottom tier.
Publication Date: May 01, 2000
Document ID:
20000116529
(Acquired Dec 08, 2000)
Subject Category: PROPELLANTS AND FUELS
Document Type: Conference Paper
Publication Information: JANNAF 29th Propellant Development and Characterization Subcommittee Meeting; 345-363; (CPIA-Publ-697)
Meeting Information: Propellant Development and Characterization; 29th; 8-12 May 2000; Cocoa Beach, FL; United States
Meeting Sponsor: Department of the Army; Washington, DC United States
Department of the Navy; Washington, DC United States
Department of the Air Force; Washington, DC United States
NASA; Washington, DC United States
Financial Sponsor: Army Research Lab.; Weapons and Materials Research Directorate; Aberdeen Proving Ground, MD United States
Organization Source: Army Research Lab.; Weapons and Materials Research Directorate; Aberdeen Proving Ground, MD United States
Description: In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: COMBUSTION; DAMAGE; EXPLOSIVES; IGNITION; PLASMAS (PHYSICS); PROPELLANT GRAINS; PROPELLANTS; CHARACTERIZATION; SCANNING ELECTRON MICROSCOPY; SURFACE CRACKS; BURNING RATE; PLASMA INTERACTIONS; POLYURETHANE FOAM
Availability Source: CPIA, 10630 Little Patuxent Pkwy., Suite 202, Columbia, MD 21044-3264
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