Experimental Investigations of Mixing Characteristics in Model Rotating Detonation Engine Geometries PDF Download
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Author: Richard Blümner
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Richard Blümner
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Andrew Ryan Mizener
Publisher:
ISBN:
Category : Acoustic phenomena in nature
Languages : en
Pages : 226
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The rotating detonation engine (RDE) is a promising propulsion concept that has the potential to offer increased thermodynamic performance in a compact package with no moving parts. A series of analytical and experimental investigations was carried out on RDEs with the joint goal of investigating swirl, torque, and a range of other design parameters of interest. The model and experimental facility were then applied to related problems with the goal of advancing the understanding of RDE applications. A flexible, low-order, semi-empirical model for a rotating detonation engine was presented. The model was formulated to be able to run broad parametric analyses more efficiently than numerical modeling. The presence of swirl at the exit plane of RDEs is still debated, so the model was formulated to leave open this possibility. Parametric analysis was conducted to determine the effect of a range of engine design parameters on performance. Exit swirl and torque were shown to be small but not uniquely zero. The model was combined with a waverider forebody model. Together, these were used to conduct parametric analysis of the sensitivity of integrated performance to freestream, waverider forebody, and RDE design parameters. Practical limitations on the Mach number of detonation engines operating in supersonic flows were presented and discussed. Peak performance was seen at the point of maximum forebody pressure recovery. Thrust and torque were shown to be sensitive to body shape and freestream parameters, while specific impulse and thrust-specific fuel consumption were not. The design of a rotating detonation engine and experimental test facility were presented and discussed. The facility was designed and instrumented to allow the measurement of resultant torque on the engine as well as take thrust and pressure readings. A series of tests was conducted using the engine, with no steadily-propagating detonation waves detected. Pressure, torque, thrust, and frequency data were presented and discussed. A high-speed camera was used to visualize the exhaust plume and the flame structure inside the annulus, which similarly failed to detect a detonation wave. The camera was then used to conduct high-speed visualizations of the ignition process inside the engine for both spark plug and predetonator igniters. Both methods showed the creation of two counter-rotating detonation waves which intersected and canceled each other out on the far side of the annulus. Pressure waves were observed to continue to rotate for several periods before dying out. The qualitative observations from the visualizations were supported by the pressure data. Detailed visualizations were performed to quantitatively investigate the propagation of the initial combustion front around the annulus for varying degrees of injector swirl. Predetonator ignition was observed to directly initiate a detonation, whereas deflagration-to-detonation transition was observed for spark plug ignition. Injector swirl promoted transition in combustion waves propagating into the swirl and depressed it in waves propagating with the swirl. Overdriven detonations were observed for both ignition methods. A discussion of the possible causes for the failure to sustain a detonation wave was presented and discussed.
Author: Eric A. Wheeler
Publisher:
ISBN:
Category :
Languages : en
Pages : 40
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Generating supersonic exhaust without using converging-diverging geometry is an attractive feature desired in all propulsion devices that have supersonic flows. The inherent increased thermodynamic efficiency of combustion by detonation and supersonic azimuthal velocity of the detonation wave front both lend to a sense of curiosity about the possibility of supersonic axial exhaust velocity. Numerical simulations and some experiments have shown that there are oblique shock waves in the exhaust, which are inexorably linked to the detonation wave front. Do these phenomena create the necessary conditions for this to be possible? Experimental investigation into the exhaust characteristics of a rotating detonation engine have yielded very positive results and are discussed in this paper. Also, this engine features a unique injection method for fuel and oxidizer. While there has been some latent desire to explore the flow characteristics of the mixing zone ahead of detonation, aberrant pressure transducer readings on the front end wall of the combustor has been the catalyst into undertaking this task. The results of CFD analysis show possible explanations for this unusual behavior, along with possible explanations for additional effects of engine operation.
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 : 22
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Author: Robert Francis Burke
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Conventional engines are limited by the efficiency of their combustion mode. Compared to present constant pressure deflagration-based engines, detonation-based systems can realize a higher thermodynamic cycle efficiency, making them an attractive candidate for next generation propulsion systems that will take humanity to hypersonic speeds and even to Mars. For all its performance gains, detonation engines are still far off from implementation. One system, the rotating detonation engine (RDE) is promising as a detonation-based engine concept for its stability, simplicity, and versatility. For these reasons, RDEs have been the subject of studies internationally in efforts to understand their operation and integration into conventional technology. RDEs are on the cusp of field use, considered at technology readiness level 5 with prototype demonstrations occurring today; however, there are still significant barriers holding back this technology from widespread adoption. The work of this dissertation confronts each of these barriers with experimental methods. Using multiple different RDE test facilities, investigations into injection, fueling, exhaust, detonability, and integration were conducted, targeting research gaps in each barrier. As a result, many novel advancements have been made from these studies such as the first demonstration of hydrogen and oxygen rotating detonations, the detonability of sustainable solid particle fuels, and the effect of fuel stratification on rotating detonation propagation. Altogether, the work presented depicts the RDE from a complete perspective by advancing current RDE research through multiple channels with the intention of advancing the technology readiness level of RDEs.
Author:
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ISBN:
Category : Aeronautics
Languages : en
Pages : 1042
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Author: John H. S. Lee
Publisher: Cambridge University Press
ISBN: 9780521897235
Category : Technology & Engineering
Languages : en
Pages : 400
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This book introduces the detonation phenomenon in explosives. It is ideal for engineers and graduate students with a background in thermodynamics and fluid mechanics. The material is mostly qualitative, aiming to illustrate the physical aspects of the phenomenon. Classical idealized theories of detonation waves are presented first. These permit detonation speed, gas properties ahead and behind the detonation wave, and the distribution of fluid properties within the detonation wave itself to be determined. Subsequent chapters describe in detail the real unstable structure of a detonation wave. One-, two-, and three-dimensional computer simulations are presented along with experimental results using various experimental techniques. The important effects of confinement and boundary conditions and their influence on the propagation of a detonation are also discussed. The final chapters cover the various ways detonation waves can be formed and provide a review of the outstanding problems and future directions in detonation research.
Author: Craig A. Nordeen
Publisher:
ISBN:
Category :
Languages : en
Pages : 201
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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.
