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Nonequilibrium in a low power arcjet nozzleEmission spectroscopy measurements were made of the plasma flow inside the nozzle of a 1 kW class arcjet thruster. The thruster propellant was a hydrogen-nitrogen mixture used to simulate fully decomposed hydrazine. The 0.25 mm diameter holes were drilled into the diverging section of the tungsten thruster nozzle to provide optical access to the internal flow. Atomic electron excitation, vibrational, and rotational temperatures were determined for the expanding plasma using relative line intensity techniques. The atomic excitation temperatures decreased from 18,000K at a location 3 mm downstream of the constrictor to 9,000K at a location 9 mm from the constrictor, while the molecular vibrational and rotational temperatures decreased from 6,500K to 2,500K and from 8,000K to 3,000K, respectively, between the same locations. The electron density measured using hydrogen H line Stark broadening decreased from about 10(exp 15) cm(-3) to about 2 times 10(exp 14) cm(-3) during the expansion. The results show that the plasma is highly nonequilibrium throughout the nozzle, with most relaxation times equal or exceeding the particle residence time.
Document ID
19910017901
Document Type
Conference Paper
Authors
Zube, Dieter M. (Stuttgart Univ. (Germany F.R.)., United States)
Myers, Roger M. (Sverdrup Technology, Inc., Brook Park OH., United States)
Date Acquired
September 6, 2013
Publication Date
July 1, 1991
Subject Category
SPACECRAFT PROPULSION AND POWER
Report/Patent Number
E-6427
AIAA PAPER 91-2113
NASA-CR-187166
NAS 1.26:187166
Meeting Information
Joint Propulsion Conference(Sacramento, CA)
Funding Number(s)
CONTRACT_GRANT: NAS3-25266
PROJECT: RTOP 506-42-31
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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