Download or read book Combustion Instability Analytical Survey written by LIBRARY OF CONGRESS WASHINGTON D C AEROSPACE TECHNOLOGY DIV. and published by . This book was released on 1965 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid rocket engines are subject to a wide variety of types of combustion instability. The two basic instability modes are 'chugging, ' a low-frequency instability mode which is caused by interaction between the chamber pressure and the injection flow rate fluctuations, and 'screaming, ' a more harmful high-frequency, acoustic instability mode which may lead to burnout of the motor due to increased heat flux. Only two articles on low-frequency instability were found in Soviet open literature. Experimental studies or analyses of high-frequency instability which take into account actual engine operation, i.e., mixing, evaporation, dissociation fuel atomization, etc., were not found in the literature surveyed. However, several theoretical studies were found which deal with highfrequency instability under idealized conditions. The majority of the Soviet studies included in this report deal with the interaction of shock and pressure waves with the flame front. These studies are of high phenomenological interest and are indirectly applicable to combustion stability analysis. (Author).
Download or read book Combustion Instability Modeling and Analysis written by and published by . This book was released on 1995 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO(subscript x) emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors. The present study represents a coordinated effort between industry, government and academia to investigate gas turbine combustion dynamics. Specific study areas include development of advanced diagnostics, definition of controlling phenomena, advancement of analytical and numerical modeling capabilities, and assessment of the current status of our ability to apply these tools to practical gas turbine combustors. The present work involves four tasks which address, respectively, (1) the development of a fiber-optic probe for fuel-air ratio measurements, (2) the study of combustion instability using laser-based diagnostics in a high pressure, high temperature flow reactor, (3) the development of analytical and numerical modeling capabilities for describing combustion instability which will be validated against experimental data, and (4) the preparation of a literature survey and establishment of a data base on practical experience with combustion instability.
Download or read book Flameholder Combustion Instability Study Volume I Analytical Considerations written by W. Jansen and published by . This book was released on 1978 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rumble is characterized as a combination of stable and unstable longitudinal acoustic modes that interact with each other while exchanging energy. The final result is a system oscillation of finite amplitude with a frequency that bears no relation to the acoustic frequency, but occurs at a level somewhere among those of the modes under consideration. The present work involves a non-linear theory which allows for the inclusion of rumble-related phenomena that a linear theory cannot handle while using a combustion model previously derived in linear stability work. The final equations have been programmed for use in a digital computer. The use of the computer program is explained in this document, and illustrations with sample input and output are given. (Author).
Download or read book Thermoacoustic Combustion Instability Control written by Dan Zhao and published by Academic Press. This book was released on 2023-02-13 with total page 1145 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoacoustic Combustion Instability Control: Engineering Applications and Computer Codes provides a unique opportunity for researchers, students and engineers to access recent developments from technical, theoretical and engineering perspectives. The book is a compendium of the most recent advances in theoretical and computational modeling and the thermoacoustic instability phenomena associated with multi-dimensional computing methods and recent developments in signal-processing techniques. These include, but are not restricted to a real-time observer, proper orthogonal decomposition (POD), dynamic mode decomposition, Galerkin expansion, empirical mode decomposition, the Lattice Boltzmann method, and associated numerical and analytical approaches. The fundamental physics of thermoacoustic instability occurs in both macro- and micro-scale combustors. Practical methods for alleviating common problems are presented in the book with an analytical approach to arm readers with the tools they need to apply in their own industrial or research setting. Readers will benefit from practicing the worked examples and the training provided on computer coding for combustion technology to achieve useful results and simulations that advance their knowledge and research. Focuses on applications of theoretical and numerical modes with computer codes relevant to combustion technology Includes the most recent modeling and analytical developments motivated by empirical experimental observations in a highly visual way Provides self-contained chapters that include a comprehensive, introductory section that ensures any readers new to this topic are equipped with required technical terms
Download or read book Solid Propellant Combustion Analytical Survey written by LIBRARY OF CONGRESS WASHINGTON D C AEROSPACE TECHNOLOGY DIV. and published by . This book was released on 1966 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: The survey consists of two parts. Part I contains a general discussion of selected articles on solid propellant combustion and Part II comprises the abstracts of these articles. The information in Part I is divided into 8 sections: (1) The effect of pressure; (2) Particle size, porosity, and density; (3) The effect of temperature; (4) Condensed phase reactions; (5) Ignition characteristics; (6) Additives and catalytic effects; (7) Theoretical stability criteria; (8) Miscellaneous. The material reviewed indicates that Soviet investigators are placing particular emphasis on the following three areas: the relationships between the pressure and the burning velocity; the effect of porosity, particle size, and density on burning velocity and instability; and condensed-phase reactions. These three subjects are discussed somewhat further by the analyst in the Introduction which includes the analyst's evaluation of Soviet combustion research. Part II includes 73 abstracts. (Author).
Download or read book Analysis of Combustion Instability in Liquid Fuel Rocket Motors written by K. Wong and published by . This book was released on 1979 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of this study is the development of a new analytical technique to be used in the solution of nonlinear velocity-sensitive combustion instability problems. Such a method should be relatively easy to apply and should require relatively little computation time. In an attempt to achieve this aim, the orthogonal collocation method is investigated first. However, it is found that the results are heavily dependent on the location of the collocation points and characteristics of the equations. Therefore, the method is rejected as unreliable. Next, the Galerkin method, which has proved to be very successful in analysis of the pressure sensitive combustion instability, is considered. This method is found to work very well. It is found that the pressure wave forms exhibit a strong second harmonic distortion and a variety of behaviors are possible depending on the nature of the combustion process and the parametric values involved. Finally, a one-dimensional model provides further insight into the problem by allowing a comparison of Galerkin solutions with more exact finite-difference computations. (Author).
Download or read book A Study of Nonlinear Combustion Instability written by Eric James Jacob and published by . This book was released on 2009 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion instability (CI) has been persistent in all forms of propulsion since their inception. CI is characterized by pressure oscillations within the propulsion system. If even a small fraction of the dense energy within the system is converted to acoustic oscillations the system vibrations can be devastating. The coupling of combustion and uid dynamic phenomena in a nonlinear system poses CI as a signicant engineering challenge. Drawing from previous analysis, second order acoustic energy models are taken to third order. Second order analysis predicts exponential growth. The addition of the third order terms capture the nonlinear acoustic phenomena (such as wave steepening) observed in experiments. The analytical framework is derived such that the energy sources and sinks are properly accounted for. The resulting third order solution is compared against a newly performed simplied acoustic closed tube experiment. This experiment provides the interesting result that in a forced system, as the 2nd harmonic is driven, no energy is transferred back into the 1st mode. The subsequent steepened waveform is a summation of 2nd mode harmonics (2, 4, 6, 8 ...) where all odd modes are nonexistent. The current third order acoustic model recreates the physics as seen in the experiment. Numerical experiments show the sensitivity of the pressure wave limit cycle amplitude to the second order growth rate, highlighting the importance of correctly calculating the growth rates. The sensitivity of the solution to the third order parameter is shown as well. Exponential growth is found if the third order parameter is removed, and increased nonlinear behavior is found if it retained and as it is increased. The solutions sensitivity to this term highlights its importance and shows the need for continued analysis via increasing the models generality by including neglected eects. In addition, the aect of a time varying second order growth rate is shown. This eect shows the importance of modeling the system in time because of the time lag between changes in the growth rate to a change in the limit cycle amplitude.
Download or read book Analysis of a Combustion Instability Problem Using the Technique of Multiple Scales written by C. E. Mitchell and published by . This book was released on 1970* with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stability Analysis of a Liquid Fuel Annular Combustion Chamber written by and published by . This book was released on 1979 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: High frequency combustion instability continues to be a major problem in the development and operation of rocket engines. Most mathematical models simulating this phenomena involve the derivation and solution of complex non- linear differential equations. In an effort to overcome the mathematical difficulties associated with the solution of the nonlinear combustion instability problems, two methods of analysis were developed. In investigating the problems of combustion instability in an annular combustion chamber, a modified Galerkin method was used to produce a set of modal amplitude equations from the general non-linear partial differential acoustic wave equation. From these modal amplitude equations, the two-variable perturbation method was used to develop a set of approximate equations of a given order of magnitude. These equations were modeled to show the effects of velocity sensitve combustion instabilities by evaluating the effects of certain parameters in the given set of equations. From evaluating these effects, one can ascertain which parameters cause instabilities to occur in the combustion chamber. In this analysis, it is assumed that in the annular combustion chamber, the liquid propellants are injected uniformly across the injector face, the combustion processes are distributed throughout the combustion chamber and that no time delay occurs in the combustion processes.
Download or read book Analytical Investigation of Combustion Instability in Solid Propellant Rockets written by IIT RESEARCH INST CHICAGO ILL. and published by . This book was released on 1963 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress is reported on studies concerning the use of a fluid dynamic model for the combustion zone of a solid propellant rocket undergoing erosive burning. Work involved the debugging of a computer program, trial calculations using the program, and a study of the gas-phase reaction kinetics involved in nitrocellulosenitroglycerin combustion.
Download or read book Liquid Propellant Rocket Combustion Instability written by David T. Harrje and published by . This book was released on 1972 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt: The solution of problems of combustion instability for more effective communication between the various workers in this field is considered. The extent of combustion instability problems in liquid propellant rocket engines and recommendations for their solution are discussed. The most significant developments, both theoretical and experimental, are presented, with emphasis on fundamental principles and relationships between alternative approaches.
Download or read book Liquid Propellant Rocket Combustion Instability written by and published by . This book was released on 1972 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Nonlinear Analytical Model of High frequency Combustion Instability in a Rocket Engine written by Zhenguo Wang and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parametric Study of Rocket Motor Combustion Instability written by John R. Osborn and published by . This book was released on 1970 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research program has been concerned with an experimental and analytical investigation conducted for evaluating the influence of combustion chamber pressure and propellant temperature effects on liquid rocket combustion dynamics. The experimental program was conducted with a small-scale rocket engine thrust chamber assembly using bi-phase propellants. Air was used as the oxidizer and normal heptane was used as the fuel. Chamber pressures investigaged ranged from 250 to 1000 psia; values below the critical pressure of the fuel to ones considerably above it. The values for the initial temperature of the injected fuel ranged from 520 to 910R. It was found that increasing the chamber pressure has a strong stabilizing effect, increasing the initial fuel temperature has a slight destabilizing effect, and decreasing the drop size has a strong destabilizing effect. Two combustion models were used for obtaining analytical predictions of the stability behavior for correlating the experimental results and for determining the validity of the models. General agreement was found between the experimental results and the analytical predictions. (Author).
Download or read book Ramjet Engines written by Mikhail Makarovich Bondari͡u︡k and published by . This book was released on 1969 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High frequency Combustion Instability written by R. G. Peoples and published by . This book was released on 1961 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analytical and experimental studies of stable and unstable combustion phenomena were conducted to determine the parameters affecting inherent stability. It was demonstrated that inherent stability is determined by the amount of pressure-sensitive energy available to a given pressure perturbation, and by the relationship between replenishment of this energy and the time period of the perturbation. Analytical concepts describing the support mechanism and experimental data indicating the complexity of a nonlinear perturbation were established. (Author).
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
