Author: Stuart Hersh
Publisher:
ISBN:
Category : Boron as fuel
Languages : en
Pages : 46
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Book Description
The program is directed towards answering the following question. Given a boron combustible particle of known initial size and composition moving at a high relative velocity in a gaseous medium, how are the combustion behavior and particle dynamics influenced by the particle (gas relative velocity, gas composition, temperature, and pressure anticipated in operational combustors. The role of the shock tube in answering this question is discussed. An 'ideal' experiment is postulated and several possible practical experimental techniques are assessed relative to this standard. To aid in the assessment of the practicality of an experimental technique, a computer program was developed to compute particle trajectories for shock tube flows. Some preliminary experiments aimed at establishing the applicability of a reflected shock technique to the measurement of burning particle drag coefficients were carried out. The results of these experiments yielded very high values of the drag coefficient. At the present time, it is not known if this result was due to the roughness of the particles, static charge effects, the effect of combustion or the preliminary nature of the experiments. In all probability a combination of the above factors is involved. (Author).
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 464
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Book Description
Author: Marta Marimon Mateu
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
A computationally efficient, quasi-one-dimensional, supersonic combustion model has been developed to simulate high-speed engine flowfields such as in a scramjet. The model can be used in design and optimization studies, where a wide range of engine inlet conditions may be encountered. The model solves a series of ordinary differential equations that come from the equations of fluid motion coupled with combustion. The effects of area change, wall skin friction, mass injection, fuel mixing, and heat transfer are included. The equations are derived assuming an open thermodynamic system with equilibrium or with finite-rate chemistry. Results will show the differences on combustor performance between considering equilibrium or not. The inclusion of chemical kinetics allows for a prediction of fuel ignition, a finite rate process that inherently cannot be predicted using equilibrium methods. Therefore, incorporating the timescales of fuel mixing and ignition is crucial for an accurate prediction of combustor performance in most scramjet operating conditions. Furthermore, the effects of dissociation, fuel mixing and friction are discussed. Eventually, a simple analysis of the air inlet and the nozzle is developed in order to have an overall vision of the scramjet and its feasibility.
Author: Gautam Choubey
Publisher: Butterworth-Heinemann
ISBN: 0323995667
Category : Technology & Engineering
Languages : en
Pages : 198
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Book Description
Scramjet Combustion explores the development of a high-speed scramjet engine operating in the supersonic/hypersonic range for various air and space transport applications. The book explains the basic structure, components, working cycle, and the relevant governing equations in a clear manner that speaks to both advanced and more novice audiences. Particular attention is paid to efficient air–fuel combustion, looking at both the underlying fundamentals of combustion as well strategies for obtaining optimum combustion efficiency. Methods for reaching the chemically correct air–fuel ratio, subsequent flame, and combustion stabilization as air enters at supersonic speed are also outlined. Further, it includes the continuous on-going efforts, innovations, and advances with respect to the design modification of scramjet combustors, as well as different strategies of fuel injections for obtaining augmented performance while highlighting the current and future challenges. Outlines the fundamentals of scramjet engines including their basic structure and components, working cycle, governing equations, and combustion fundamentals affecting the combustion and mixing processes Presents new design modifications of scramjet combustors and different fuel injection strategies including combined fuel injection approaches Discusses core topics such as chemical kinetics in supersonic flow, fuel–air mixing methods, strategies for combating combustion difficulties, and subsequent flame and combustion stabilization that can be applied to scramjets Describes the pedagogy for computational approaches in simulating supersonic flows
Author: William H. Heiser
Publisher: AIAA
ISBN: 9781563470356
Category : Science
Languages : en
Pages : 632
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Book Description
An almost entirely self-contained engineering textbook primarily for use in undergraduate and graduate courses in airbreathing propulsion. It provides a broad and basic introduction to the elements needed to work in the field as it develops and grows. Homework problems are provided for almost every individual subject. An extensive array of PC-based user-friendly computer programs is provided in order to facilitate repetitious and/or complex calculations. Annotation copyright by Book News, Inc., Portland, OR
Author: Mingbo Sun
Publisher: Springer Nature
ISBN: 9811535957
Category : Technology & Engineering
Languages : en
Pages : 380
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Book Description
This book describes the unsteady phenomena needed to understand supersonic combustion. Following an initial chapter that introduces readers to the basic concepts in and classical studies on unsteady supersonic combustion, the book highlights recent studies on unsteady phenomena, which offer insights on e.g. interactions between acoustic waves and flames, flow dominating instability, ignition instability, flame flashback, and near-blowout-limit combustion. In turn, the book discusses in detail the fundamental mechanisms of these phenomena, and puts forward practical suggestions for future scramjet design.
Author: Mohammed Kamel
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659387043
Category :
Languages : en
Pages : 208
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Book Description
The design and off-design studies of the hypersonic air-breathing engines face many challenges, due to the complexity of their internal flows. The mixing and combustion processes in Supersonic-Combustion Ramjet (scramjet) engines involve complicated aerothermochemical features, such as: the interactions between shock-waves and boundary-layer, the shock induced-combustion and the recirculation zones. In this study, a numerical solver is developed and validated to be an efficient design tool capable of simulating these complicated flow features of the supersonic combustors. For the code validation, several test cases are considered to monitor the code ability to solve for the diffusive and turbulent fluxes, and the chemical source term. In addition, the code is validated by resolving the transverse sonic injection into supersonic air flow in the case of Helium injection from a flat plate, and in the case of Hydrogen injection in a single-strut scramjet engine. The effectiveness of this injection technique in mixing and flame-holding is demonstrated. The results show good agreement with the previous numerical and experimental investigations, and prove the simulator's accuracy.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 648
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Book Description
A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).
Author: M. Champion
Publisher: Springer Science & Business Media
ISBN: 9401154325
Category : Science
Languages : en
Pages : 413
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Book Description
Proceedings of the IUTAM Symposium held in Poitiers, France, 2-6 October 1995
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
"Performance, heating and weight considerations indicate that hypersonic air breathing power plants require fuel injection and combustion in a supersonic air stream. Considering first the combustion problem: Dissociation effects limit the maximum static temperature attainable by chemical fuels, therefore careful control of the static temperature must be obtained by expansion occurring simultaneously with the heat release. Secondly, since reaction rates vary with static temperature this form of combustion must be clearly understood if successful operation is to be obtained. Furthermore, simultaneous expansion is required for large values of heat release if shock waves (with accompanying losses) are to be avoided in the combustion zone. In order that the chemical reaction should proceed at the required rate, high initial static temperatures are necessary. (These are obtained in the free flight case by partial conversion of the total temperature to static temperature). The reaction rate also depends on pressure hence a range of pressures should be investigated. It can thus be seen that investigation of the combustion phenomenon requires a facility having moderate Mach Numbers and pressures and high total temperatures. Considering next the fuel injection problem: It is anticipated that fuel injection will present a further problem since it is again important that strong shock waves are avoided, and in addition the practical means of using the fuel to cool the surfaces must be determined. These two problems are complementary, and following their successful solution, high efficiency intake designs and integrated engine configurations may be considered." --
