Title: Equations of state implementation for 1-D modelling of performance in ram accelerator thermally choked propulsion mode

Authors: Pascal Bauer; Tarek Bengherbia; Carl Knowlen; Adam Bruckner; Yufeng Yao; Marc Giraud

Addresses: Lab. PPRIME, ENSMA, Rue C. Ader, 86960 Futuroscope CDX, France ' Lab. PPRIME, ENSMA, Rue C. Ader, 86960 Futuroscope CDX, France ' University of Washington, Seattle, WA 98195, USA ' University of Washington, Seattle, WA 98195, USA ' University of the West of England, Department of Engineering Design and Mathematics, Bristol BS16 1QY, UK ' Exobal Consulting, Saint-Louis la Chaussée, 68300, France

Abstract: This paper presents advancement on one-dimensional (1-D) unsteady modelling of a ram accelerator (RAMAC) in the sub-detonative velocity regime by including real-gas equations of state (EoS) in order to account for the compressibility effects of the combustion products. Several equations of state based on generalised empirical and theoretical considerations are incorporated into a 1-D computer code TARAM. The objective of this work is to provide the best available formulations in order to improve the unsteady 1-D model and make the TARAM code a useful tool to predict the performance of the RAMAC in the sub-detonative velocity regime, without having to resort to more complicated 2-D or 3-D computational schemes. The calculations are validated against experimental data from 38-mm and 90-mm-bore facilities and good agreements have been achieved. Yet, the results demonstrate the need for further CFD studies involving the scale effect.

Keywords: detonation; equations of state; EoS; ram accelerator; RAMAC; propulsion; scale effects; thermally choked mode; 1D modelling; sub-detonative velocity; compressibility effects; combustion products; unsteady models; shock-induced combustion; projectile velocity; supersonic speed; gaseous combustible mixtures; computational fluid dynamics; CFD.

DOI: 10.1504/IJESMS.2015.068650

International Journal of Engineering Systems Modelling and Simulation, 2015 Vol.7 No.2, pp.71 - 79

Received: 09 Dec 2013
Accepted: 22 Dec 2013
Published online: 08 Apr 2015 *

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