Laboratoire de Combustion et de Détonique (CNRS), ENSMA Poitiers, BP 109, 86960 Futuroscope Cedex, France
Faculty of Engineering, Kingston University, Roehampton Vale, Friars Avenue, SW15 3, DW London, UK
Department of Aeronautics and Astronautics, University of Washington, Box 352250, Seattle, WA, 98195 2250, USA
Computational fluid dynamics solutions of the Reynolds Averaged Navier-Stokes equations have been used to numerically predict the thrust of a thermally choked ram accelerator in subdetonative velocity regime. Studies were focused on a projectile operating in a 38-mm-diameter ram accelerator tube loaded with premixed propellant gas; methane/oxygen/nitrogen at 5.15 MPa fill pressure. Simulations were carried out for a series of incoming velocities. The shear stress transport turbulence model (SST) and the eddy dissipation combustion model (EDM) with five-step reaction mechanism were used to simulate the fully turbulent reactive flow field around the projectile. The predicted projectile thrust-velocity agreed well with the experimental measurements, in addition, the CFD predicted pressure variation and magnitude along projectile axial direction also agreed well with the test data. The present investigation reveals some key features of the shock-wave system around the projectile, which are important in determining the characteristics of the thermally choked propulsive mode. These findings are useful in understanding the characteristics of high speed turbulent combustion process in the ram accelerator.
(Received February 24 2010)
(Revised December 6 2010)
(Accepted February 16 2011)
(Online publication July 21 2011)