Download or read book A Simplified Model for Detonation Based Pressure Gain Combustors written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2019-01-19 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: A time-dependent model is presented which simulates the essential physics of a detonative or otherwise constant volume, pressure-gain combustor for gas turbine applications. The model utilizes simple, global thermodynamic relations to determine an assumed instantaneous and uniform post-combustion state in one of many envisioned tubes comprising the device. A simple, second order, non-upwinding computational fluid dynamic algorithm is then used to compute the (continuous) flowfield properties during the blowdown and refill stages of the periodic cycle which each tube undergoes. The exhausted flow is averaged to provide mixed total pressure and enthalpy which may be used as a cycle performance metric for benefits analysis. The simplicity of the model allows for nearly instantaneous results when implemented on a personal computer. The results compare favorably with higher resolution numerical codes which are more difficult to configure, and more time consuming to operate. Paxson, Daniel E. Glenn Research Center NASA/TM-2010-216821, AIAA Paper 2010-6717, E-17450

Download or read book A Simplified Model for Detonation Based Pressure Gain Combustors written by Daniel E. Paxson and published by BiblioGov. This book was released on 2013-07 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: A time-dependent model is presented which simulates the essential physics of a detonative or otherwise constant volume, pressure-gain combustor for gas turbine applications. The model utilizes simple, global thermodynamic relations to determine an assumed instantaneous and uniform post-combustion state in one of many envisioned tubes comprising the device. A simple, second order, non-upwinding computational fluid dynamic algorithm is then used to compute the (continuous) flowfield properties during the blowdown and refill stages of the periodic cycle which each tube undergoes. The exhausted flow is averaged to provide mixed total pressure and enthalpy which may be used as a cycle performance metric for benefits analysis. The simplicity of the model allows for nearly instantaneous results when implemented on a personal computer. The results compare favorably with higher resolution numerical codes which are more difficult to configure, and more time consuming to operate.

Download or read book A Simplified Model for Detonation Based Pressure gain Combustors written by Daniel E. Paxson and published by . This book was released on 2010 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Summary of Pressure Gain Combustion Research at NASA written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2019-01-13 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: NASA has undertaken a systematic exploration of many different facets of pressure gain combustion over the last 25 years in an effort to exploit the inherent thermodynamic advantage of pressure gain combustion over the constant pressure combustion process used in most aerospace propulsion systems. Applications as varied as small-scale UAV's, rotorcraft, subsonic transports, hypersonics and launch vehicles have been considered. In addition to studying pressure gain combustor concepts such as wave rotors, pulse detonation engines, pulsejets, and rotating detonation engines, NASA has studied inlets, nozzles, ejectors and turbines which must also process unsteady flow in an integrated propulsion system. Other design considerations such as acoustic signature, combustor material life and heat transfer that are unique to pressure gain combustors have also been addressed in NASA research projects. In addition to a wide range of experimental studies, a number of computer codes, from 0-D up through 3-D, have been developed or modified to specifically address the analysis of unsteady flow fields. Loss models have also been developed and incorporated into these codes that improve the accuracy of performance predictions and decrease computational time. These codes have been validated numerous times across a broad range of operating conditions, and it has been found that once validated for one particular pressure gain combustion configuration, these codes are readily adaptable to the others. All in all, the documentation of this work has encompassed approximately 170 NASA technical reports, conference papers and journal articles to date. These publications are very briefly summarized herein, providing a single point of reference for all of NASA's pressure gain combustion research efforts. This documentation does not include the significant contributions made by NASA research staff to the programs of other agencies, universities, industrial partners and professional society commit

Download or read book Investigation of Pulse Detonation Engine Flow Conditions for Turbomachinery Integration written by Luis Estefano Ferrer-Vidal España-Heredia and published by . This book was released on 2014 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis discusses the effects of unsteady pressure gain combustion devices on gas turbine efficiency as well as current models for pulse detonation engine operation. A new simplified linear model for pulse detonation combustors is presented and compared to experimental data. The model is implemented as an element in a cycle analysis code using Numerical Propulsion System Simulation (NPSS).

Download or read book Detonation Physics Based Modelling Design of a Rotating Detonation Engine written by Sean Francis Connolly-Boutin and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A rotating detonation engine (RDE) is a new, more thermodynamically efficient, propulsion concept that replaces the traditional constant pressure combustion mechanism found in all currently used rockets and power generation devices. The constant pressure combustion is replaced by a detonation wave: a coupled shock-flame complex propagating at speeds of up to 2-3 km/s and generating combustion products at pressures 5-10 times the initial reactant pressure. This pressure gain through the combustion process leads to more compact, simpler devices that no longer require (or depend less upon) initial reactant precompression. Detonation-based cycles also have the added advantage of being theoretically more thermodynamically efficient than their constant pressure combustion counterparts. As such, RDEs have become increasingly popular in the propulsion research community, although there is still a lack of understanding in the underlying physics which govern their operability, though the existence of a minimum mass flow rate limit for stable operation has been observed. To help engineers and researchers design an RDE, a model was developed which combines geometric properties, 1D isentropic flow, and detonation physics to predict the stable operating bounds of an RDE. An engine testing facility was also constructed in collaboration with McGill University to test RDEs and confirm the performance of the prediction model developed.

Download or read book New Detonation Concepts for Propulsion and Power Generation written by Eric M. Braun and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of related analytical and experimental studies are focused on utilizing detonations for emerging propulsion and power generation devices. An understanding of the physical and thermodynamic processes for this unsteady thermodynamic cycle has taken over 100 years to develop. An overview of the thermodynamic processes and development history is provided. Thermodynamic cycle analysis of detonation-based systems has often been studied using surrogate models. A real gas model is used for a thermal e ciency prediction of a detonation wave based on the work and heat speci ed by process path diagrams and a control volume analysis. A combined rst and second law analysis aids in understanding performance trends for di erent initial conditions. A cycle analysis model for an airbreathing, rotating detonation wave engine (RDE) is presented. The engine consists of a steady inlet system with an isolator which delivers air into an annular combustor. A detonation wave continuously rotates around the combustor with side relief as the ow expands towards the nozzle. Air and fuel enter the combustor when the rarefaction wave pressure behind the detonation front drops to the inlet supply pressure. To create a stable RDE, the inlet pressure is matched in a convergence process with the average combustor pressure by increasing the annulus channel width with respect to the isolator channel. Performance of this engine is considered using several parametric studies. RDEs require a fuel injection system that can cycle beyond the limits of mechanical valves. Fuel injectors composed of an ori ce connected to a small plenum cavity were mounted on a detonation tube. These fuel injectors, termed uidic valves, utilize their geometry and a supply pressure to deliver fuel and contain no moving parts. Their behavior is characterized in order to determine their feasibility for integration with high-frequency RDEs. Parametric studies have been conducted with the type of fuel injected, the ori ce diameter, and the plenum cavity pressure. Results indicate that the detonation wave pressure temporarily interrupts the uidic valve supply, but the wave products can be quickly expelled by the fresh fuel supply to allow for refueling. The interruption time of the valve scales with injection and detonation wave pressure ratios as well as a characteristic time. The feasibility of using a detonation wave as a source for producing power in conjunction with a linear generator is considered. Such a facility can be constructed by placing a piston{spring system at the end of a pulsed detonation engine (PDE). Once the detonation wave re ects o the piston, oscillations of the system drive the linear generator. An experimental facility was developed to explore the interaction of a gaseous detonation wave with the piston. Experimental results were then used to develop a model for the interaction. Governing equations for two engine designs are developed and trends are established to indicate a feasible design space for future development.

Download or read book Ejector Enhanced Pulsejet Based Pressure Gain Combustors written by Daniel E. Paxson and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ejector enhanced pulsejet based pressure gain combustors written by Daniel E. Paxson and published by . This book was released on 2005 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Detonation Phenomenon written by John H. S. Lee and published by Cambridge University Press. This book was released on 2008-06-30 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Active Flow and Combustion Control 2018 written by Rudibert King and published by Springer. This book was released on 2018-09-03 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book reports on the latest theoretical and experimental findings in the field of active flow and combustion control. It covers new developments in actuator technology and sensing, in robust and optimal open- and closed-loop control, as well as in model reduction for control, constant volume combustion and dynamic impingement cooling. The chapters reports oncutting-edge contributions presented during the fourth edition of the Active Flow and Combustion Control conference, held in September 19 to 21, 2018 at the Technische Universität Berlin, in Germany. This conference, as well as the research presented in the book, have been supported by the collaborative research center SFB 1029 on “Substantial efficiency increase in gas turbines through direct use of coupled unsteady combustion and flow dynamics”, funded by the DFG (German Research Foundation). It offers a timely guide for researchers and practitioners in the field of aeronautics, turbomachinery, control and combustion.

Download or read book Propulsion and Power written by Joachim Kurzke and published by Springer. This book was released on 2018-05-28 with total page 766 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is written for engineers and students who wish to address the preliminary design of gas turbine engines, as well as the associated performance calculations, in a practical manner. A basic knowledge of thermodynamics and turbomachinery is a prerequisite for understanding the concepts and ideas described. The book is also intended for teachers as a source of information for lecture materials and exercises for their students. It is extensively illustrated with examples and data from real engine cycles, all of which can be reproduced with GasTurb (TM). It discusses the practical application of thermodynamic, aerodynamic and mechanical principles. The authors describe the theoretical background of the simulation elements and the relevant correlations through which they are applied, however they refrain from detailed scientific derivations.

Download or read book Investigation of Methane fueled Rotating Detonation Combustor Exhaust Flow Field Via Time resolved Particle Image Velocimetry written by Daniel Depperschmidt and published by . This book was released on 2019 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rotating detonation combustors (RDCs) as a form of pressure gain combustion (PGC) have received increased research attention in the power generation and aerospace/defense propulsion fields due to the potentially substantial thermal efficiency advantages associated with its operation cycles as compared to traditional constant pressure combustion systems. However, significant scientific exploration must still be conducted to maximize the potential benefits of RDCs, including the implementation of proper flow conditioning devices downstream of the combustor to reduce losses associated with the inherently unsteady, shock-laden flow field. This is particularly true in power generation applications, wherein existing gas turbines prefer homogenous inlet flow conditions. Presently, there is a lack of experimental data to provide quantified measurements of the flow field emanating from RDCs. Application and analysis of diagnostics capable of accurately resolving the high-speed, high-enthalpy, and unsteady flow field has innate challenges. However, the insights provided by such measurements are necessary for further development of the technology, and when validating/refining numerical models. In this dissertation, time-resolved particle image velocimetry (TR PIV) is applied to further the understanding of the exhaust flow field of RDCs operated with gaseous methane fuel and in multiple geometric configurations and inlet condition. To the best knowledge of the author, this represents the first successful application of the TR-PIV diagnostic technique to evaluate RDC exhaust flow fields. Through the parametric variation of RDC operation conducted in this dissertation, the influence of combustor-exit area constriction and flow conditioning geometries on the resulting exhaust flow field were assessed. Three geometric configurations of the RDC were evaluated using two different PIV interrogation plane locations allowing for the discretization of the complex exhaust flow into axial, circumferential and radial components. It was found that the exhaust flow field was unsteady in every configuration tested. However, the unsteadiness was significantly reduced by constricting the exit flow area, and implementation of a diffuser geometry further attenuated the flow modulations and resulted in a much more uniform, axially oriented flow. This dissertation is therefore a summary of the diagnostic methodology implemented and results acquired from the application of TR-PIV to RDC exhaust flow fields.

Download or read book Transient Analysis of a Pulsed Detonation Combustor Using the Numerical Propulsion System Simulation written by Anthony Scott Hasler and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance of a hybrid mixed flow turbofan (with detonation tubes installed in the bypass duct) is investigated in this study and compared with a baseline model of a mixed flow turbofan with a standard combustion chamber as a duct burner. Previous studies have shown that pulsed detonation combustors have the potential to be more efficient than standard combustors, but they also present new challenges that must be overcome before they can be utilized. The Numerical Propulsion System Simulation (NPSS) will be used to perform the analysis with a pulsed detonation combustor model based on a numerical simulation done by Endo, Fujiwara, et. al. Three different cases will be run using both models representing a take-off situation, a subsonic cruise and a supersonic cruise situation. Since this study investigates a transient analysis, the pulse detonation combustor is run in a rig setup first and then its pressure and temperature are averaged for the cycle to obtain quasi-steady results.

Download or read book Consultation sur le livre vert sur le loisir cegep de valleyfield 12 mars 1978 written by and published by . This book was released on 1978 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Active Flow and Combustion Control 2021 written by Rudibert King and published by Springer Nature. This book was released on 2021-11-12 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book reports on the latest theoretical and experimental findings in the field of active flow and combustion control, in the context of energy conversion for power and propulsion systems. It covers new developments in actuator technology and sensing, robust and optimal open- and closed-loop control, model reduction for control purposes, and unsteady turbine cooling and performance, among other relevant topics. Gathering contributions to the Active Flow and Combustion Control (AFCC 2021), held virtually on September 28-29, 2021, from the Technische Universität Berlin, Germany, this book describes research that has been carried out within, and supported by, the collaborative research center SFB 1029 on “Substantial efficiency increase in gas turbines through direct use of coupled unsteady combustion and flow dynamics”, and funded by the German Research Foundation (DFG). It highlights theoretical and practical aspects, and corresponding solutions, that are important for the development of future energy conversion systems, thus offering a timely guide for researchers and practitioners in the field of aeronautics, turbomachinery, control and combustion.

Download or read book Gas Turbines for Electric Power Generation written by S. Can Gülen and published by Cambridge University Press. This book was released on 2019-02-14 with total page 735 pages. Available in PDF, EPUB and Kindle. Book excerpt: Everything you wanted to know about industrial gas turbines for electric power generation in one source with hard-to-find, hands-on technical information.