Flamespreading in Granular Solid Propellant: Initial Results
Abstract
This study is an experimental investigation into fundamental aspects of ignition and flamespreading in compacted granular solid propellant. The 76- mm-diameter dual-chamber laboratory apparatus was designed as a closed-volume simulator with an ignition source at one end to generate a gas-phase planar wave. Diagnostics include wall-mounted pressure gages to monitor the time- history of the pressure field, and fast-response. Type S thermocouples mounted in special hollow steel holders. Concern about adequacy of the thermocouple response time in this transient flow field is addressed by comparing data from 1-mil-, and 3-mil-diameter thermocouples. The simulator is loaded with two granular solid propellants: the triple-base M30A1 and the LOVA nitramine composite M43. Under certain conditions, the granular bed of 'insensitive' M43 ignites more readily than the granular bed of M30A1, which emphasizes an important concept: Time to ignition is determined by competition between the 'flow residence time' and the 'characteristic time for chemical reaction.' For M43, chamber diagnostics indicate pressure of 2-3 MPa and gas-phase temperatures in the range of 800-1,200 K before combustion runs away. These conditions are compatible with speculation that 'dark zone' flame chemistry is controlling delayed ignition in LOVA propellant.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1994
- Accession Number
- ADA284245
Entities
People
- Douglas E. Kooker
- Lang-mann Chang
- Stephen L. Howard
Organizations
- United States Army Research Laboratory