Download or read book The Coupling of Vibrational Relaxation and Dissociation written by M. Greenblatt and published by . This book was released on 1964 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coupled Vibration and Dissociation Relaxation Behind Strong Shock Waves in Carbon Dioxide written by Franz Hindelang and published by . This book was released on 1967 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: The harmonic oscillator rigid-rotator model has been used to calculate the relaxation region behind a shock wave in carbon dioxide. Finite relaxation rates for the three different vibrational modes and two dissociation reactions are included. Models for the coupling between the vibrational relaxation and the dissociation process are based on the assumption that dissociation can proceed from any vibrational level with equal probability. Two different models for the vibrational excitation have been examined. Solutions have been obtained for the interdependent fluid-flow, chemical rate, and vibrational relaxation-rate equations incorporating estimated rate coefficients. Results are presented in the form of flow-field profiles for density, pressure, translational and vibrational temperatures, and species concentrations. The effects of vibrational excitation, vibration-dissociation coupling, and energy exchange between the vibrational modes are investigated. The effect of vibrational relaxation and vibration-dissociation coupling is much stronger in CO2 with three different vibrational modes than in diatomic gases with only a single mode. The results of this study show that the effect of coupled vibrational relaxation and dissociation can sometimes alter the flow-field profiles by a factor of 2 compared to similar calculations without such coupling. For vibrational relaxation the results indicate that the shock-wave profiles depend primarily on the rate at which the translational energy is fed into internal modes and not so strongly on the energy distribution among the modes.
Download or read book A Simplified Molecular Model for Studying Vibration dissociation Coupling in Fluid Flows written by Walter Albert Reinhardt and published by . This book was released on 1969 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: A simplified mathematical model is derived that is useful for studying the effects of vibration-dissociation coupling in fluid flows. The derivation is based on energy-moment procedure for simplifying the master equations. To obtain the model equations it is assumed that the vibrational energy can be approximated by the introduction of two vibrational temperatures. The effects of molecular anharmonicity are also accounted for in an approximate manner. The parameters contained within the equations are evaluated by making comparisons with experimental data. It is shown that the model contains the minimum required structure allowing favorable agreement with existing experimental data. Numerical solutions are given for the quasi-steady zone behind a normal shock wave, for the complete structure of a shock wave, and for nozzle flow. The results provide the appropriate pre-exponential temperature dependence of the effective dissociation rate, yield and induction time before dissociation is observed, and, in the case of expanding flow, yield one-fourth less effective relaxation time than the Landau-Teller theory. The thermodynamic quantities for the vibrational mode (partition function, internal energy, and specific heat) agree accurately with like quantities evaluated from spectroscopic data. By the introduction of appropriate assumptions it is shown that the equations reduce to a form identical to the Marrone-Treanor model except for a "truncation factor". When the vibrational temperatures are not large, the model is identical to that of Landau and Teller. The numerical procedure used to integrate the system of rate and flow equations is also described.
Download or read book Vibration and Dissociation Coupling Behind Strong Shock Waves written by Charles E. Treanor and published by . This book was released on 1962 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: The coupling between vibrational relaxation and dissociation is discussed. A model for computations of dissociation behind strong shock waves is presented. It is shown that the loss of vibrational energy during dissociation introduces an inverse temperature dependence into the observed dissociation rate of O2 between 4000 and 8000K. Changing the model so that dissociation from higher vibrational levels is enhanced results in a dissociation-incubation time immediately behind the shock. The vibrational-energy distribution behind the shock is calculated, and shown to depart considerably from a Boltzmann distribution. The molecular model, which uses a Boltzmann distribution, is shown to give the same result as the non-Boltzmann model for both the nonequilibrium dissociation rate and the dissociation incubation time. (Author).
Download or read book Vibrational Relaxation Effects in Dissociation Rate constant Measurements written by Charles E. Treanor and published by . This book was released on 1962 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Dissociation on the Rate of Vibrational Relaxation written by Charles E. Treanor and published by . This book was released on 1962 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Two Different Interpretations of Measured Dissociation rate Constants and Their Effects on Coupled Vibrational dissociational Flows of Oxygen Over a Wedge written by Fred R. DeJarnette and published by . This book was released on 1967 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vibration Dissociation Coupling in Nonequilibrium Flows written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2019-01-04 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The final report on research between North Carolina State University and the NASA Ames Research Center is presented. The research was aimed at using the Schwartz, Slawsky, Herzfeld (SSH) theory to simulate the vibrational relaxation of nitrogen molecules undergoing dissociation or recombination over a wide range of conditions. The results of these simulations were then treated as exact, and they were used to develop a model for the coupled vibration-dissociation process. This new model is simple enough to be used in computational fluid dynamics codes, but still captures the physics of the complex process. The model is used to simulate the flow over typical geometries to test it and to determine how much impact it has on the flow field. The key elements of this research are summarized. Candler, Graham V. NASA-CR-191775, NAS 1.26:191775 NCA2-519...
Download or read book A SHOCK TUBE STUDY OF THE COUPLING OF THE 02 Ar RATES OF DISSOCIATION AND VIBRATIONAL RELAXATION written by and published by . This book was released on 1962 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this investigation was to determine how the dissociation rate will be affected by a lack of vibrational equilibrium. Studies of the dissociation rate of dilute O2 - Ar mixtures were made in a 24 in. diameter shock tube from 5000 - 18,000 deg K. The O2 concentration was monitored by its absorption of 1470A radiation. An Arrhenius plot of the data yielded a straight line from 5000 - 11,000 deg K, the rate constant being given by kd = 2.9 (! 12%) x 10 to the 14th power exp ( -D/RT) cc/mole-sec. Above 11,000 degrees the data deviate from the line given by this equation - at 18000 degrees kd being .45 times the calculated value. An incubation time, t, was observed during which dissociation does not proceed to a significant extent. The ratio of this incubation time to the vibrational relaxation time (obtained by extrapolating Camac's low temperature results) when plotted against translational temperature, displays a slight negative temperature dependence. At 18,000 degrees t/ v=0.4, at 8000 degrees t/ v=1, and at 5500 degrees we estimate that t/ v 2.
Download or read book Chemical Relaxation with Preferential Dissociation from Excited Vibrational Levels written by Paul V. Marrone and published by . This book was released on 1963 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Note written by and published by . This book was released on 1971 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Two Vibration dissociation Coupling Models on Nonequilibrium Hypersonic Flow of Nitrogen Over a Wedge written by Fred R. DeJarnette and published by . This book was released on 1966 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Report written by and published by . This book was released on 1969 with total page 1158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1976 with total page 978 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Progress in Aeronautical Sciences written by D. Küchemann and published by Elsevier. This book was released on 2016-07-04 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress in Aeronautical Sciences, Volume 6 reviews advances in aeronautical sciences and considers a wide range of problems related to aerodynamics, including some classical problems of fluid motion and those affecting hypersonic aircraft. Topics covered range from equations of gas flow at low density; nonequilibrium expansion flows of dissociated oxygen and ionized argon around a corner; and the role of spatially growing waves in the theory of hydrodynamic stability. This volume is comprised of five chapters and begins with a discussion on flows of gases where the density of the gas is too low for equations of continuum gas dynamics to be applicable. The kinetic theory of gases is used to derive the equations governing such flows. The second chapter deals with the nature of shock waves in flows of electrically conducting gases subjected to magnetic fields. The third chapter is concerned with the theory of two-dimensional flows of dissociated oxygen or ionized argon expanding around a corner. The fourth chapter goes back to the classical problem of hydrodynamic stability and the possible mechanics underlying the transition from the laminar to a turbulent state of the flow. The last chapter describes a future type of aircraft that can fly at hypersonic speeds. This book will be a useful resource for students and practitioners in the field of aeronautics.
Download or read book Theory of the Effects of Electronic Excitation on the Vibrational and Dissociative Relaxation of Diatomic Molecules written by David K. Taylor and published by . This book was released on 1965 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: A theory of the relaxation of dissociation and vibration of diatomic molecules, including the effects of electronic excitation of the molecules, of the finiteness of the number of vibrational levels and of the coupling between dissociation and vibration, is developed. The derived dissociation and recombination rate constants as well as the incubation times are in good agrement with experimental data that cover the range from 5000 K to 18,000 K. (Author).
Download or read book Physical and Chemical Processes in Gas Dynamicsphysical and Chemical Kinet Ics and Thermodynamics written by G. G. Chernyi and published by AIAA. This book was released on 2004 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
