Heterogeneous detonation supported by fuel fogs or films
Decane and hexadecane fog detonation propagation in gaseous oxygen
Bowen, J. R.↗
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Theoretical analysis of a rotating two-phase detonation in liquid rocket motors.
A nonlinear analysis to study tangential mode shock instabilities in a thin annular chamber is carried out by employing a one dimensional two phase detonation wave as a reaction model. It is assumed that phase change and reaction take place only within the wave, which is treated as a discontinuity. The annulus is unrolled and the flow is considered as two dimensional with the coordinate system fixed on the wave front. Between waves, the flow is assumed to be isentropic with no interaction between droplets and burned gases. Jump conditions across the wave are solved for two phase flow. The average pressure along the injection plate is related to the design chamber pressure by the use of overall conservation equations. The wave strength is written in terms of the design parameters of the chamber. The results compare favorably with existing experiments. Finally, the effects of drop size on the wave strength are discussed and a simple criterion which sets the lower limit of validity for this strong wave analysis, is presented.
Shen, P. I.-W.↗
Lateral expansion of a laser-supported detonation wave in a gas.
A model satisfying the conditions in the burnt (ionized) and ambient undisturbed gases is presented for the two-dimensional case of the absorption wave resulting from the interaction of a laser beam with the plasma it generates in the gas through which the beam propagates. The flowfield of the rarefaction wave resulting from the laser-supported detonation is discussed, along with the computed shock and flow deflection angles.
Howe, J. T.↗
On detonation waves supported by diffusion flames.
An eigenvalue condition to determine propagation velocity of detonation waves in a tube is derived for the case where the oxidizer and fuel are in the gaseous and condensed phase, respectively, so that the combustion occurs only within the peripheral boundary layer. It is shown that the self-sustained shock propagation is possible if core streamtube constriction, due to combustion in the boundary layer, is strong enough to form a converging nozzle, and for a sonic throat to exist.
Fujitsuna, Y.↗
Time variation in the reaction-zone structure of two-phase spray detonations.
A detailed theoretical analysis of the time-varying detonation structure in a monodisperse spray is presented. The theory identifies experimentally observed reaction-zone overpressures as deriving from blast waves formed therein by the explosive ignition of the spray droplets, and follows in time the motion, change in strength, and interactions of these blast waves with one another, and with the leading shock. The results are compared with experimental data by modeling the motion of a finite-size circular pressure transducer through the theoretical data field in an x-t space.
Pierce, T. H.↗
Two phase detonation studies
An experimental study of the passage of a shock wave over a burning fuel drop is described. This includes high speed framing photographs of the interaction taken at 500,000 frames per second. A theoretical prediction of the ignition of a fuel drop by a shock wave is presented and the results compared with earlier experimental work. Experimental attempts to generate a detonation in a liquid fuel drop (kerosene)-liquid oxidizer drop (hydrogen peroxide)-inert gas-environment are described. An appendix is included which gives the analytical prediction of power requirements for the drop generator to produce certain size drops at a certain mass rate. A bibliography is also included which lists all of the publications resulting from this research grant.
Nicholls, J. A.↗
Detonation propulsion for high pressure environments
One limitation encountered by chemical rocket propulsion in high pressure planetary atmospheres is illustrated by the conflict between the dependence of specific impulse on the ratio of chamber pressure to ambient pressure and the dependence of the motor structural design on the difference between the pressures. This work proposes to resolve the difficulty by employing detonating propellant in which the high pressures necessary for efficient propulsion are developed over a short time and need not be contained statically. Experimental results are presented to substantiate this claim of relatively high performance, together with an analytical development that approximately describes the flow dynamics.
Varsi, G.↗
Carbon detonation supernovae
Arguments aimed at linking main sequence stars in the mass range 4-8 solar masses with type II supernovae and pulsars are presented. In this regard, the problematic evolution of the growing carbon cores before ignition is found to be best rationalized in terms of convective Urca losses. Some calculations on the parameters of carbon detonation models are listed, and the use of a standard numerical hydrodynamic code to deal with these models is discussed.
Buchler, J.-R.↗
Measurements and calculations of detonation propulsion performance in helium
Previously obtained results are extended to helium ambient gas to help in the assessment of performance in the atmospheres of the major planets. Measurements confirm benefits derived form detonating propellant over conventional chemical rocket propulsion. Benefits however, are reduced at high pressures in low molecular weight gas. Numerical calculations by means of a monodimensional hydrodynamic code follow the different trends obtained experimentally for high and low molecular weight gas and also offer new insights on the time behavior of the process.
Kim, K.↗
Computer Program for Calculation of Complex Chemical Equilibrium Compositions, Rocket Performance, Incident and Reflected Shocks, and Chapman-Jouguet Detonations. Interim Revision, March 1976
A detailed description of the equations and computer program for computations involving chemical equilibria in complex systems is given. A free-energy minimization technique is used. The program permits calculations such as (1) chemical equilibrium for assigned thermodynamic states (T,P), (H,P), (S,P), (T,V), (U,V), or (S,V), (2) theoretical rocket performance for both equilibrium and frozen compositions during expansion, (3) incident and reflected shock properties, and (4) Chapman-Jouguet detonation properties. The program considers condensed species as well as gaseous species.
Sanford Gordon↗
Oblique detonation wave ramjet
Two conceptual designs of the oblique detonation wave ramjet are presented. The performance is evaluated for stoichiometric hydrogen-air equivalence ratios of phi = 1/3, 2/3 and 1 for a range of flight Mach numbers from 6 to 10.
Morrison, R. B.↗
The role of gas phase reactions in the deflagration-to-detonation transition of high energy propellants
The inadequacies of the two commonly used assumptions are shown, along with the need for considering gas phase reactions. Kinetic parameters that describe the gas phase reactions for several ingredients are provided, and the first steps in convective combustion leading to deflagration to detonation transition are described.
Boggs, T. L.↗
Observations of long delays to detonation in propellant for tests with marginal card gaps
Using the large-scale card gap tests with pin and high-speed framing camera techniques, VRP propellant, and presumably others, were found to transit to detonation at marginal gaps after a long delay. In addition, manganin-constantan gauge measurements were made in the card gap stack.
Olinger, B.↗
Screen Secures Detonator to Explosive Charge
Brass screen sleeve attaches blasting cap to fuse, shaped charge, detonating cord, or other formed explosive. Screen makes it easy to control distance between cap and charge, because user can see both parts, and to cool cap by convection, making use of low-cost blasting caps possible for some hot environments.
Moshenrose, H. D.↗
Detonation propulsion experiments and theory
Test data are presented for the use of a single detonation of explosives in long-cone, short-cone, straight, and firing-plug nozzles to provide propulsion in a simulated Jupiter atmosphere, as well as the ambient gases N, CO2 and He. The long-cone nozzle yielded a progressive increase with ambient pressure for the higher molecular weight gases CO2 and N, while the lower molecular weight He and simulated Jupiter atmosphere showed a specific pulse decrease with increasing ambient pressure. The short-plug nozzle yielded a small specific impulse reduction with increasing ambient pressure, and its results were found to be nearly independent of ambient gas molecular weight. All data gathered are analyzed by using first principles, approximate blast wave theory predictions, and two-dimensional numerical calculations. Rarefaction and oscillatory wave phenomena are found to significantly influence specific impulse.
Back, L. H.↗
The structure and evolution of galacto-detonation waves - Some analytic results in sequential star formation models of spiral galaxies
Waves of star formation in a uniform, differentially rotating disk galaxy are treated analytically as a propagating detonation wave front. It is shown, that if single solitary waves could be excited, they would evolve asymptotically to one of two stable spiral forms, each of which rotates with a fixed pattern speed. Simple numerical solutions confirm these results. However, the pattern of waves that develop naturally from an initially localized disturbance is more complex and dies out within a few rotation periods. These results suggest a conclusive observational test for deciding whether sequential star formation is an important determinant of spiral structure in some class of galaxies.
Cowie, L. L.↗
Analytical and experimental validation of the Oblique Detonation Wave Engine concept
The Oblique Detonation Wave Engine (ODWE) for hypersonic flight has been analytically studied by NASA using the CFD codes which fully couple finite rate chemistry with fluid dynamics. Fuel injector designs investigated included wall and strut injectors, and the in-stream strut injectors were chosen to provide good mixing with minimal stagnation pressure losses. Plans for experimentally validating the ODWE concept in an arc-jet hypersonic wind tunnel are discussed. Measurements of the flow field properties behind the oblique wave will be compared to analytical predictions.
Adelman, Henry G.↗
Laser supported detonation wave source of atomic oxygen for aerospace material testing
A pulsed high-flux source of nearly monoenergetic atomic oxygen was developed to perform accelerated erosion testing of spacecraft materials in a simulated low-earth orbit (LEO) environment. Molecular oxygen is introduced into an evacuated conical expansion nozzle at several atmospheres pressure through a pulsed molecular beam valve. A laser-induced breakdown is generated in the nozzle throat by a pulsed CO2 TEA laser. The resulting plasma is heated by the ensuing laser-supported detonation wave, and then it rapidly expands and cools. An atomic oxygen beam is generated with fluxes above 10 to the 18th atoms per pulse at 8 + or - 1.6 km/s with an ion content below 1 percent for LEO testing. Materials testing yielded the same surface oxygen enrichment in polyethylene samples as observed on the STS mission, and scanning electron micrographs of the irradiated polymer surfaces showed an erosion morphology similar to that obtained on low earth orbit.
Krech, Robert H.↗