Characterization of Ethylene/JP-10 Fuel Injection Profiles for a Valveless Pulse Detonation Engine PDF Download
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Author:
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ISBN:
Category : Mechanical engineering
Languages : en
Pages : 65
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Book Description
Practical use of the pulse detonation engine as a form of propulsion for future aircraft and missile platforms depends upon the ability to reliably detonate a fuel air mixture at high frequencies in order to produce an acceptable level of thrust, and to take advantage of the higher thermodynamic efficiency available from the pulse detonation engine combustion cycle. This research thesis focused on improving and mapping fuel fraction delivery profiles for a valveless pulse detonation engine. The gas dynamic conditions downstream of inlet manifold isolation chokes were evaluated for a number of geometries with Computational Fluid Dynamics software in an effort to reduce areas of recirculation in the inlet manifold of the engine and improve fuel delivery profiles. Based on the results from this modeling a new inlet manifold configuration was designed, installed and evaluated in laboratory experimentation. Laboratory testing was performed at multiple air and fuel mass flow rates using ethylene as the fuel. Absorption spectroscopy, using a He-Ne laser tuned to the 3.39m︡ wavelength with known spectroscopic fuel absorption cross sections, was used to measure fuel mass fraction profiles for each engine inlet geometry at various flow rates. Additionally, JP10 fuel concentration profiles were determined for several fuel injector actuation pressures and at various alignments using the same diagnostic approach.
Author:
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 65
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Book Description
Practical use of the pulse detonation engine as a form of propulsion for future aircraft and missile platforms depends upon the ability to reliably detonate a fuel air mixture at high frequencies in order to produce an acceptable level of thrust, and to take advantage of the higher thermodynamic efficiency available from the pulse detonation engine combustion cycle. This research thesis focused on improving and mapping fuel fraction delivery profiles for a valveless pulse detonation engine. The gas dynamic conditions downstream of inlet manifold isolation chokes were evaluated for a number of geometries with Computational Fluid Dynamics software in an effort to reduce areas of recirculation in the inlet manifold of the engine and improve fuel delivery profiles. Based on the results from this modeling a new inlet manifold configuration was designed, installed and evaluated in laboratory experimentation. Laboratory testing was performed at multiple air and fuel mass flow rates using ethylene as the fuel. Absorption spectroscopy, using a He-Ne laser tuned to the 3.39m︡ wavelength with known spectroscopic fuel absorption cross sections, was used to measure fuel mass fraction profiles for each engine inlet geometry at various flow rates. Additionally, JP10 fuel concentration profiles were determined for several fuel injector actuation pressures and at various alignments using the same diagnostic approach.
Author:
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ISBN:
Category : Mechanical engineering
Languages : en
Pages : 63
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Book Description
The Pulse Detonation Engine offers the Department of Defense a new low cost, light weight, and efficient solution to supersonic flight on many of its small airborne platforms. In the past, both liquid fuel and gaseous fuel designs have been partially developed and tested. Several aspects of these configurations have led to the need for the development of a new design, in particular the reduction of total pressure losses, and the removal of auxiliary oxygen system previously required to initiate a detonation wave in fuel-air mixtures within practical distances. Furthermore, higher repetition rates are required for practical thrust levels, as well as the use of liquid fuels, as these are more attractive due to their higher energy densities. A new PDE configuration was designed to operate on the liquid fuel, JP-10. The fuel injection system was characterized using laser diagnostics so that the fuel injection strategy could be optimized for the specified operating conditions. The timing parameters for the fuel-air injection profile were characterized as well in order to deliver the desired amount and duration. This was a concurrent effort with computational simulations of the internal flow paths, design/integration of a novel transient plasma ignition system, and ongoing developments of a performance measurement test rig.
Author: Nicole K. Wittmers
Publisher:
ISBN: 9781423521754
Category :
Languages : en
Pages : 79
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Book Description
Operational characteristics of a valveless pulse detonation engine system were characterized by experimental measurements of thrust, fuel flow, and internal gas dynamics. The multi-cycle detonation experiments were performed on an axis-symmetric engine geometry operating on an ethylene/air mixture. The detonation diffraction process from a small initiator combustor to a larger diameter main combustor in a continuous airflow configuration was evaluated during multi-cycle operation of a pulse detonation engine and was found to be very successful at initiating combustion of the secondary fuel/air mixture at high frequencies. The configuration was used to demonstrate the benefit of generating an overdriven detonation condition near the diffraction plane for enhanced transmission of the larger combustor. Results have shown that the addition of optical sensors, such as tunable diode lasers, to provide fuel profile data are invaluable for providing high fidelity performance results. The performance results demonstrated the ability of the valveless pulse detonation engine to run at efficiencies similar to valved pulse detonation engine geometries and may be a low-cost alternative to conventional air-breathing propulsion systems.
Author: C. M. Brophy
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author:
Publisher:
ISBN:
Category : Engineering
Languages : en
Pages : 55
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Book Description
Rapid and efficient initiation of hydrocarbon/air mixtures has been identified as one of the critical and enabling technologies for Pulse Detonation Engines (PDEs). Although the NPS Rocket Propulsion Laboratory has successfully demonstrated fuel/air detonations in a valveless pulse detonation engine using ethylene, propane, and JP-10 fuels, past engine designs have relied upon a sensitive fuel/oxygen initiator unit. To realize the increased thermodynamic efficiencies of PDEs and thus compete with ramjets and other supersonic platforms, it is imperative to eliminate any need for supplementary oxygen in an air-breathing PDE design. This thesis examined ignition technologies and initiator designs which did not require auxiliary oxygen, including capacitive discharge systems and the developing technology of Transient Plasma Ignition (TPI). The current NPS pulse detonation engine architecture was modified to evaluate the various ignition strategies in a PDE operating on an ethylene/air mixture at simulated supersonic cruising conditions. Comparisons were based upon ignition success rate, ignition delay time, detonation wave speed, and Deflagration-to-Detonation (DDT) distance. Reliability and performance of the TPI system proved to be superior to conventional ignition systems. Furthermore, successful initiation of a PDE operating at a frequency of up to 40 hertz was demonstrated without the use of supplementary oxygen.
Author: Timothy M. Helfrich
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 336
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Author: R. Akbar
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Patrick D. Hutcheson
Publisher:
ISBN:
Category : Computational fluid dynamics
Languages : en
Pages : 117
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Book Description
The initiation of a detonation in Pulse Detonation Engines (PDE) has been identified as one of the critical and enabling technologies for PDEs. In particular, the iniation of practical fuel-air mixtures containing liquid droplets without supplementary oxygen or other high loss mechanisms is a capability that could enable the PDE to exceed the performance of ramjets and expendable turbo-machinery based systems. Although past engine designs have relied upon a sensitive fuel/oxygen initiator unit or unrealistic gaseous fuels such as ehtylene and propane, a PDE was designed and partially tested that has eliminated the requirement for supplementary oxygen as well as enabling the use of a JP-10, high-density liquid fuel. Air flow through segments of this PDE was simulated using Computational Fluid Dynamics and experimentally evaluated in the laboratory at simulated flight conditions, including supersonic cruising conditions. The spiral lines initiator demonstrated a lower total pressure loss with compared to the geometry with rings, and thus was the preferred initiator configuraiton. Experimental values for the turbulence were found to be significantly lower than the computed values at similar conditions when using the k-e model. Finally, successful ignitions of the JP-10/Air initiator at frequencies of up to 20 Hz were experimentally demonstrated.
Author: Eric A. Nagley
Publisher:
ISBN:
Category : Jet planes
Languages : en
Pages : 218
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Author: T. Hikmet Karakoc
Publisher: Springer
ISBN: 3030141950
Category : Technology & Engineering
Languages : en
Pages : 159
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Book Description
This book provides readers with a basic understanding of the concepts and methodologies of sustainable aviation.The book is divided into three sections : basic principles the airport side, and the aircraft side. In-depth chapters discuss the key elements of sustainable aviation and provide complete coverage of essential topics including airport, energy, and noise management along with novel technologies, standards and a review of the current literature on green airports, sustainable aircraft design, biodiversity management, and alternative fuels. Engineers, researchers and students will find the fundamental approach useful and will benefit from the many engineering examples and solutions provided.
