Author: J. Kasahara
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Jiun-Ming Li
Publisher: Springer
ISBN: 3319689061
Category : Technology & Engineering
Languages : en
Pages : 246

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This book focuses on the latest developments in detonation engines for aerospace propulsion, with a focus on the rotating detonation engine (RDE). State-of-the-art research contributions are collected from international leading researchers devoted to the pursuit of controllable detonations for practical detonation propulsion. A system-level design of novel detonation engines, performance analysis, and advanced experimental and numerical methods are covered. In addition, the world’s first successful sled demonstration of a rocket rotating detonation engine system and innovations in the development of a kilohertz pulse detonation engine (PDE) system are reported. Readers will obtain, in a straightforward manner, an understanding of the RDE & PDE design, operation and testing approaches, and further specific integration schemes for diverse applications such as rockets for space propulsion and turbojet/ramjet engines for air-breathing propulsion. Detonation Control for Propulsion: Pulse Detonation and Rotating Detonation Engines provides, with its comprehensive coverage from fundamental detonation science to practical research engineering techniques, a wealth of information for scientists in the field of combustion and propulsion. The volume can also serve as a reference text for faculty and graduate students and interested in shock waves, combustion and propulsion.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Research studies investigating the performance optimization and fundamental physics of pulse detonation engines (PDE) were performed. Experimental and computational methods were developed and used in these studies. Four primary research tasks were established. The first research task was to obtain detailed measurements of a PDE exhaust plume for a variety of operating conditions and engine geometries. Shadowgraph visualizations in conjunction with OH* and CH* chemiluminescence imaging were performed. The PDE plume visualizations provided a means of studying the flowfield behavior associated with PDE ejectors and exhaust nozzles as well as providing explanations for the observed acoustic behavior of the PDE. The second research task was to quantify the thrust augmentation of PDE-ejectors. Significant losses in the ejector entrainment were observed when the ejector inlet was not of an aerodynamic shape. Performance measurements of axisymmetric PDE-ejector systems showed the thrust augmentation to be a strong function of the ejector length-to-diameter ratio, ejector axial placement and PDE fill-fraction. Peak thrust augmentation levels were recorded to be approximately 20% for a straight-ejector and 65% for a diverging-ejector. An increase in thrust augmentation was obtained with a reduction in fill-fraction. Performance measurements of PDE converging and diverging exhaust nozzles were also obtained at various operating conditions of the engine. At low fill-fractions, both converging and diverging exhaust nozzles were observed to adversely affect the PDE performance. At fill-fractions close to and greater than 1, the converging nozzles showed the best performance due to increased PDE blow-down time (maintaining PDE chamber pressure) and acceleration of the primarily subsonic exhaust flow. The fourth research task was to perform a detailed far-field study of PDE acoustics. The acoustic energy of the PDE blast-wave was observed to be highly directional. Very good agreement was obtained between the experimental data and model predictions for the radial decay in peak pressure as well as the characteristic times of the blast-wave pulses. Converging exhaust nozzles were observed to produce a global reduction in PDE noise, while diverging nozzles affected only the downstream noise.

Author: Andrew George Naples
Publisher:
ISBN:
Category : Engines
Languages : en
Pages : 155

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Abstract: An experimental study was done to examine the effects of elevated initial tube pressure in the PDE. Measured parameters were the ignition time, DDT run-up distance, DDT times, and C-J velocity. Mixed with air, three fuels, i.e., aviation gasoline, ethylene, and hydrogen, were tested at various initial pressures and equivalence ratios. A stock automotive ignition system was employed, along with a transient and thermal plasma ignition system, to quantify the benefits of each. Measured results show a reduction in the ignition time of roughly 50% and in the DDT distance of roughly 30%, for all three fuels at an initial tube pressure of 3 atmospheres. At roughly 2 atmospheres of initial pressure the thermal plasma ignition system showed no benefit over the stock automotive ignition system. In addition to the experimental results, a brief Chemkin analysis was done to model the stock automotive ignition system.

Author: Aaron J. Glaser
Publisher:
ISBN:
Category :
Languages : en
Pages : 241

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The acoustic signature of a pulse detonation engine was characterized in both the near-field and far-field regimes. Experimental measurements were performed in an anechoic test facility designed for jet noise testing. Both shock strength and speed were mapped as a function of radial distance and direction from the PDE exhaust plane. It was found that the PDE generated pressure field can be reasonably modeled by a theoretical point-source explosion. The effect of several exit nozzle configurations on the PDE acoustic signature was studies. These included various chevron nozzles, a perforated nozzle, and a set of proprietary noise attenuation mufflers.

Author: Jeffrey Thomas Gross
Publisher:
ISBN:
Category : Combustion
Languages : en
Pages : 148

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"The purpose of this thesis is to present experimental measurements and analytical calculations of thrust, pressure, and wave speed from a single-pulse detonation. In addition, it will present an analytical discussion of the effects of friction on detonation tube performance"--Abstract, leaf iii.

Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 584

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Author: R. J. Litchford
Publisher:
ISBN:
Category : Detonation waves
Languages : en
Pages : 52

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Author: American Institute of Aeronautics and Astronautics
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 960

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Author: Robert B. Driscoll
Publisher:
ISBN:
Category :
Languages : en
Pages : 105

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An experimental investigation was carried out to study the travel of a shockwave through a crossover tube and analyze the ability to cause shock initiated detonation. This concept involved using a pulse detonation engine (PDE) as a driver to produce a shockwave. This shockwave travelled to a second, adjacent detonation tube. In this driven PDE, the shockwave would reflect off of the inner, concaved wall causing shock initiated detonation. A preliminary study using a dual PDE crossover tube system yielded experimental results that have shown successful cases where reflected shockwaves are used to cause direct detonation initiation. For that study, two reactant-filled PDEs were connected through an air-filled crossover tube, with the driver PDE ignited. High speed pressure sensors were used to verify combustion wave speeds. Preliminary results showed shock initiated detonation to be possible when using a dual PDE crossover system. Additionally, a parametric study was carried out to investigate shock initiated detonation within a dual PDE crossover system. Shockwaves produced by a driver PDE were carried through crossover tubes of varying lengths and bends to the driven PDE. The driving PDE was ignited using a traditional spark plug. From burning wave speeds measured by high speed pressure sensors, results have shown a transferred shockwave reflecting off the wall of the driven PDE will achieve shock initiated detonation. However, the results have also yielded cases where the initial shockwave reflection does not directly initiate a detonation in the driven PDE, but rather causes ignition leading to accelerated deflagration to detonation transition (DDT). Overall results have shown that for specific tube geometries, there is a maximum effective crossover tube length in which shock initiated detonation is possible. Furthermore, shadowgraph techniques were used to capture and study the propagation of a transferred shockwave produced by a driving detonation tube. To accomplish this, a single PDE was used to drive a shockwave through a clear, composite, transfer tube. Shock attenuation data was gathered during this study. This information created a relation between shock strength and crossover tube length. Also, regardless of the filling conditions of the transfer tube, all shock waves reach similar attenuation rates at relatively the same transfer tube length. Moreover, a vortex plume study was carried out to capture and study shock Mach number decay as a planar shockwave transitions to a spherical shockwave at the exit of a transfer tube. Transfer tubes of varying lengths and bends were used in the study. General Attenuation Law was used to further understand the relation between spherical shock strength and propagation distance. Results showed that a bend placed at the end of the transfer tube enhances the strength of a planar shockwave. Finally, with the aid of the two shadowgraph experiments, a correlation between maximum effective crossover tube length and shock strength was created. Performance in the driven PDE begins to decrease when the incident shock strength decreases below M = 2.0.