27th Joint Propulsion Conference

Conference · Tue Jan 01 00:00:00 EST 1991

OSTI ID:5516645

Yungster, S

A computational study of the ram accelerator, a ramjet-in-tube device for accelerating projectiles to ultrahigh velocities, is presented. The analysis is performed using a fully implicit TVD scheme that efficiently solves the Reynolds-averaged Navier-Stokes equations and the species continuity equations associated with a finite rate combustion model. Previous analyses of this concept were based on inviscid assumptions. The present results indicate that viscous effects are of primary importance; in all the cases studied, shock-induced combustion always started in the boundary layer. The effects of Mach number, mixture composition, pressure, and turbulence are investigated for various configurations. Two types of combustion processes, one stable and the other unstable, were observed depending on the inflow conditions. In the unstable case, a detonation wave is formed, which propagates upstream and unstarts the ram accelerator. In the stable case, a solution that converges to steady-state is obtained, in which the combustion wave remains stationary with respect to the ram accelerator projectile. The possibility of stabilizing the detonation wave by means of a backward facing step is also investigated. In addition to these studies, two numerical techniques were tested. These two techniques are vector extrapolation to accelerate convergence, and a diagonal formulation that eliminates the expense of inverting large block matrices that arise in chemically reacting flows.

• Research Organization: National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center
• OSTI ID: 5516645
• Report Number(s): N-91-24541; NASA-TM-104439; ICOMP-91-10; E-6278; NAS-1.15:104439; AIAA-91-1916; CONF-910605-; CNN: NASA ORDER C-99066-G
• Resource Relation: Conference: 27. propulsion conference and exhibition, Sacramento, CA (United States), 24-26 Jun 1991; Other Information: Original contains color illustrations; sponsored by AIAA, SAE, ASME, and the American Society for Electrical Engineers
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COMBUSTION KINETICS
COMPUTERIZED SIMULATION
BOUNDARY LAYERS
DETONATION WAVES
NAVIER-STOKES EQUATIONS
STABILIZATION
SUPERSONIC FLOW
TURBULENCE
VISCOUS FLOW
CHEMICAL REACTION KINETICS
DIFFERENTIAL EQUATIONS
EQUATIONS
FLUID FLOW
KINETICS
LAYERS
PARTIAL DIFFERENTIAL EQUATIONS
REACTION KINETICS
SHOCK WAVES
SIMULATION
400800* - Combustion
Pyrolysis
& High-Temperature Chemistry