Journal ArticleDOI
Ram accelerator - A new chemical method for accelerating projectilesto ultrahigh velocities
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The Ram Accelerator as discussed by the authors is based on gas-dynamic principles similar to those of an air-breathing ramjet but operates in a different manner, where the center body of a ramjet travels through a tube filled with a premixed gaseous fuel and oxidizer mixture, and the tube becomes the outer cowling of the ramjet.Abstract:
A new method for accelerating projectiles from velocities of ~0.7 km/s up to -12 km/s using chemical energy is presented in this paper. The concept, called the "ram accelerator," is based on gasdynamic principles similar to those of an airbreathing ramjet but operates in a different manner. The projectile, which resembles the center body of a ramjet, travels through a tube filled with a premixed gaseous fuel and oxidizer mixture. The tube becomes the outer cowling of the ramjet, and the energy release process travels with the projectile. By tailoring the propellant mixture along the tube, a nearly constant acceleration can be achieved. In principle, the ram accelerator can be scaled for projectile masses ranging from grams to hundreds of kilograms and is capable of ballistic efficiencies as high as 30%. A straightforwar d, quasisteady, one-dimensional approach is used to model the acceleration process. The experimental facility developed to investigate the concept is described, and the results of recent experiments are presented. The velocity range of 690-1500 m/s has been explored in a 4.88-m long, 38-mm bore accelerator tube. Using methane, oxygen, and various diluents, accelerations of up to 16,000 g have been achieved with 75 gm projectiles and gas fill pressures of 20 atm. Proof of concept has been demonstrated, and agreement between theory and experiment has been found to be very good.read more
Citations
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Review of Propulsion Applications of Detonation Waves
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Claude R. Phipps,Mitat A. Birkan,Willy Bohn,Hans-Albert Eckel,Hideyuki Horisawa,Thomas Lippert,M. M. Michaelis,Yuri Rezunkov,Akihiro Sasoh,Wolfgang O. Schall,Stefan Scharring,John E. Sinko +11 more
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Kinetics modeling of shock-induced ignition in low-dilution CH4/O2 mixtures at high pressures and intermediate temperatures
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Morphology of standing oblique detonation waves
TL;DR: In this article, a theoretical analysis is made of supersonic flow of a combustible gas mixture past a wedge or an inclined wall, which shows that, for approach velocities roughly 25% or more greater than the Chapman-Jouguet velocity of the reactant mixture, there exists a usefully wide range of turning angles within which ODWs may be attached or stabilized.
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Operational characteristics of the thermally choked ram accelerator
TL;DR: In this article, a thermally choked ram accelerator, a ramjet-in-tube device for accelerating projectiles to ultrahigh velocities, is investigated theoretically and experimentally.
References
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Computational investigation of oblique detonation ramjet-in-tube concepts
D. W. Bogdanoff,D. C. Brackett +1 more
TL;DR: In this article, three oblique detonation ramjet-in-tube drive modes are presented; the operational velocities for the present results range from 3.5 to 10.0 km/s.