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Initiation of combustion in the thermally choked ram acceleratorThe methodology for initiating stable combustion in a ram accelerator operating in the thermally choked mode is presented in this paper. The ram accelerator is a high velocity ramjet-in-tube projectile launcher whose principle of operation is similar to that of an airbreathing ramjet. The subcaliber projectile travels supersonically through a stationary tube filled with a premixed combustible gas mixture. In the thermally choked propulsion mode subsonic combustion takes place behind the base of the projectile and leads to thermal choking, which stabilizes a normal shock system on the projectile, thus producing forward thrust. Projectiles with masses in the 45-90 g range have been accelerated to velocities up to 2650 m/sec in a 38 mm bore, 16 m long accelerator tube. Operation of the ram accelerator is started by injecting the projectile into the accelerator tube at velocities in the 700 - 1300 m/sec range by means of a conventional gas gun. A specially designed obturator, which seals the bore of the gun during this initial acceleration, enters the ram accelerator together with the projectile. The interaction of the obturator with the propellant gas ignites the gas mixture and establishes stable combustion behind the projectile.
Document ID
19930061504
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Bruckner, A. P.
(NASA Ames Research Center Moffett Field, CA, United States)
Burnham, E. A.
(NASA Ames Research Center Moffett Field, CA, United States)
Knowlen, C.
(NASA Ames Research Center Moffett Field, CA, United States)
Hertzberg, A.
(Washington Univ. Seattle, United States)
Bogdanoff, D. W.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1992
Publication Information
Publication: In: Shock waves; Proceedings of the 18th International Symposium, Sendai, Japan, July 21-26, 1991. Vol. 1 (A93-45451 19-34)
Publisher: Springer-Verlag
Subject Category
Ground Support Systems And Facilities (Space)
Accession Number
93A45501
Distribution Limits
Public
Copyright
Other

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