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Unsteady 1-D thrust modeling with EOS effects for ram accelerator experiments at different bores

Knowlen, C.; Bauer, P.; Bengherbia, T.; Yao, Yufeng; Bruckner, A. P.; Giraud, M.


C. Knowlen

P. Bauer

T. Bengherbia

Yufeng Yao
Professor in Aerospace Engineering

A. P. Bruckner

M. Giraud


Advances made to the unsteady, one-dimensional (1-D) modeling of the thermally choked ram accelerator thrust-Mach number characteristics include the use of real-gas equations of state to account for the compressibility effects of the combustion products. Equations of state based on generalized empirical and theoretical considerations are incorporated into a 1-D computer code to predict the combustion end state equilibrium conditions when the propellant starts out a relatively high fill pressure (>2.5 MPa) and the projectile acceleration exceeds 100 km/s2. The objective of this work is to improve the unsteady 1-D model as a useful tool to predict the thrust of the thermally choked ram accelerator propulsive mode by utilizing key results from the more computationally intensive 2-D or 3-D simulations. New thrust-Mach number calculations compared with experimental data from 25-mm, 30-mm, 38-mm, 90-mm, and 120-mm-bore experiments are generally in good agreement until the point where enhanced accelerations are observed, presumably due to projectile material combustion. The results of this investigation indicate the need for more research on ram accelerator flow fields and the role projectile material may play in the combustion process.


Knowlen, C., Bauer, P., Bengherbia, T., Yao, Y., Bruckner, A. P., & Giraud, M. (2018). Unsteady 1-D thrust modeling with EOS effects for ram accelerator experiments at different bores.

Journal Article Type Article
Acceptance Date Jan 1, 2018
Online Publication Date Jan 1, 2018
Publication Date Jan 31, 2018
Journal Aerotecnica Missili & Spazio
Print ISSN 0365-7442
Peer Reviewed Peer Reviewed
Volume 97
Issue 1
Pages 19-26
Publisher URL
Additional Information Additional Information : The final publication is available at Springer via


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