Optimal Area Profiles for Ideal Single Nozzle Air-Breathing Pulse Detonation Engines PDF Download
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Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721584437
Category :
Languages : en
Pages : 32
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Book Description
The effects of cross-sectional area variation on idealized Pulse Detonation Engine performance are examined numerically. A quasi-one-dimensional, reacting, numerical code is used as the kernel of an algorithm that iteratively determines the correct sequencing of inlet air, inlet fuel, detonation initiation, and cycle time to achieve a limit cycle with specified fuel fraction, and volumetric purge fraction. The algorithm is exercised on a tube with a cross sectional area profile containing two degrees of freedom: overall exit-to-inlet area ratio, and the distance along the tube at which continuous transition from inlet to exit area begins. These two parameters are varied over three flight conditions (defined by inlet total temperature, inlet total pressure and ambient static pressure) and the performance is compared to a straight tube. It is shown that compared to straight tubes, increases of 20 to 35 percent in specific impulse and specific thrust are obtained with tubes of relatively modest area change. The iterative algorithm is described, and its limitations are noted and discussed. Optimized results are presented showing performance measurements, wave diagrams, and area profiles. Suggestions for future investigation are also discussed. Paxson, Daniel E. Glenn Research Center NASA/TM-2003-212496, AIAA Paper 2003-4512, NAS 1.15:212496, E-14057
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721584437
Category :
Languages : en
Pages : 32
Get Book Here
Book Description
The effects of cross-sectional area variation on idealized Pulse Detonation Engine performance are examined numerically. A quasi-one-dimensional, reacting, numerical code is used as the kernel of an algorithm that iteratively determines the correct sequencing of inlet air, inlet fuel, detonation initiation, and cycle time to achieve a limit cycle with specified fuel fraction, and volumetric purge fraction. The algorithm is exercised on a tube with a cross sectional area profile containing two degrees of freedom: overall exit-to-inlet area ratio, and the distance along the tube at which continuous transition from inlet to exit area begins. These two parameters are varied over three flight conditions (defined by inlet total temperature, inlet total pressure and ambient static pressure) and the performance is compared to a straight tube. It is shown that compared to straight tubes, increases of 20 to 35 percent in specific impulse and specific thrust are obtained with tubes of relatively modest area change. The iterative algorithm is described, and its limitations are noted and discussed. Optimized results are presented showing performance measurements, wave diagrams, and area profiles. Suggestions for future investigation are also discussed. Paxson, Daniel E. Glenn Research Center NASA/TM-2003-212496, AIAA Paper 2003-4512, NAS 1.15:212496, E-14057
Author: Daniel E. Paxson
Publisher:
ISBN:
Category :
Languages : en
Pages : 22
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Book Description
Author:
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 510
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Book Description
Author:
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 508
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Book Description
Author:
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 570
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Book Description
Author:
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 548
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Book Description
Author:
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ISBN:
Category : Gas-turbines
Languages : en
Pages : 682
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Book Description
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: John P. Robinson
Publisher:
ISBN: 9781423536000
Category :
Languages : en
Pages : 94
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Book Description
The feasibility of utilizing detonations for air-breathing propulsion is the subject of a significant research effort headed by the Office of Naval Research. Pulse Detonation Engines (PDE) have a theoretically greater efficiency than current combustion cycles. However, pulse detonation technology must mature beginning with research in the fundamental process of developing a detonation wave. This thesis explores various ignition conditions which minimize the deflagration-to- detonation transition distance (Xddt) of a single detonation wave in a gaseous mixture.
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.
