[PDF] Combined Experimental Analytical Investigation Of Afterburning Solid Rocket Exhaust Plume Properties To Improve Signature Level Prediction Capability eBook

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Page : 190 pages
File Size : 15,46 MB
Release : 1990
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Describes experimental work performed on a high-speed pre-mixed hydrogen-air jet flame in a co-flowing annular air flow in the presence and absence of base flow at the exit. Includes details on the high-speed flame in a coaxial air facility which was designed, built, and tested to simulate (in a first approximation) rocket exhaust flow conditions. In addition, a new high spatial resolution computer-controlled three-dimensional gear was built to traverse the investigated flow field. The main experimental tool was a two-dimensional laser Doppler velocimeter with data acquisition and processing system. The tool was used to measure the two main velocity components. Other measurements included turbulence intensities and mean temperatures at various downstream sections. The measured initial and flow field data will serve to evaluate the validity of various turbulence models and to predict the structure of rocket exhaust plumes. Moreover, the experiments established the effect of the base flow on the turbulence structure of the exhaust plume.

Author : Frederick S. Simmons
Publisher : AIAA (American Institute of Aeronautics & Astronautics)
Page : 312 pages
File Size : 45,27 MB
Release : 2000
Category : Science
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This new book deals with the phenomenology of rocket exhaust plumes as the targets of space-based surveillance systems. Topics include the physical and chemical processes in rocket engines and their exhaust plumes, particularly in regard to flow properties, gas dynamics, and radiative mechanisms that are responsible for the generation of emission in rocket exhaust plumes at infrared and other wavelengths. System designers in a number of defense-related areas will be able to put the information in this book to immediate use.

Author : Joshua M. Kutrieb
Publisher :
Page : 93 pages
File Size : 27,45 MB
Release : 2001-12
Category : Plumes (Fluid dynamics)
ISBN : 9781423524724

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Interest in accurate detection and targeting of aggressor missiles has received considerable interest with the national priority of developing a missile defense system. Understanding the thermal signatures of the exhaust plumes of such missiles is key to accomplishing that mission. Before signature models can be precisely developed for specific rockets, the radiation of the molecular or combustion species within those plumes must be accurately predicted. A combination translation/rotation scanning diagnostic technique has been developed to map the combustion species of a rocket plume and characterize its radiation properties. Using new infrared spectrometer and fiber optic cable technology to transmit the signal spectrum of interest, the custom designed mechanism can sweep through two dimensions of a steady-state rocket exhaust. A glow bar, or blackbody simulator, is shuttered on the opposite side of the plume, allowing the spectrometer to measure both the emission and absorption spectra. This thesis demonstrated the first time use of fiber optic cable to transmit infrared emission/absorption (E/A) spectra from a rocket plume to an infrared detector. This new fiber optic configuration allows for rapid translation and rotation around the rocket plume, establishing the capability for rapid spatial characterization of the combustion species present. Experimental results may then be compared to DoD rocket plume model predictions to highlight areas for improvement.

Author : H. S. Pergament
Publisher :
Page : 28 pages
File Size : 14,97 MB
Release : 1970
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The influence of chemical kinetic and turbulent transport coefficients on afterburning rocket exhaust plume properties was analyzed in terms of predicted radar attenuations transverse to solid propellant plumes. A model of parallel turbulent mixing and nonequilibrium combustion and ionization was used to determine whether varying these coefficients, which are input data to the model, over their ranges of uncertainty has a significant effect on the predicted attenuation. The results of the study demonstrate that significant differences in predicted attenuation levels can result when the important reaction rate and turbulent transport coefficients are varied within their respective error bounds. This establishes the framework within which to interpret radar attenuation data taken at sea level and under simulated altitude conditions. It is also shown that a better laboratory determination of the rate coefficient for the dominant charge-producing reaction, K + Cl yielding K(+) + Cl( - ), is of particular importance if more accurate attenuation predictions are to be made. It was concluded that realistic calculations of solid propellant exhaust plume electrical properties must take chemical kinetics into account. (Author).

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Page : 24 pages
File Size : 23,38 MB
Release : 1984
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The exhaust plume of a minimum-smoke solid rocket contains significant concentrations of hydrogen and carbon monoxide which when mixed with ambient air react to water and carbon dioxide producing visible flash and increased infrared radiation. Both reactions produce undesirable signatures and interference with optical guidance systems. Potassium salts have been added to propellant charges to inhibit afterburning in both guns and rockets. They have not always been effective, the inhibiting effect of the salt being related to gas composition and temperature in a complex manner which is not completely understood. Further, there is disagreement as to whether it is KOH, KO2, or K that is most important in the afterburning suppression. The results are presented here of the first year of the investigation on the efficacy of each of these on the combustion of diluted H2/CO-O2-N2 mixtures. Potassium added to the fuel-side of a H2-CO-N2-O2 flat diffusion flame at near stoichiometry is more effective in inhibiting the flame reactions than KOH added to a H2-N2-O2 flame at a stoichiometric ratio of 0.61. A description is given of burner, optical and flow metering system used in experiments. Originator supplied keywords include: Rocket plume afterburning, Combustion, and Flame spectroscopy.

Author : Larry R. Ring
Publisher :
Page : 107 pages
File Size : 40,74 MB
Release : 1973
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Results are presented of a study for evaluating the applicability and accuracy of rocket motor and exhaust plume gasdynamic analytical models. Evaluation of these analytical models was based upon correlation of analytical predictions with experimental data obtained in the High Altitude Plume Radiation Program. The effects of oxidizer-to-fuel ratio gradients, combustion efficiency, combustion chamber mixing, nozzle throat expansion and chemistry model were ascertained. Non-continuum effects and closed form analytical techniques were also considered. (Modified author abstract).

Author : Richard Shao-Lin Lee
Publisher :
Page : 59 pages
File Size : 40,43 MB
Release : 1968
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An improved aerodynamic model is proposed for the exhaust plume issuing from a low-altitude rocket nozzle exit into quiescent ambient air in which chemical reactions and compressibility predominate. The model is based on the presently available knowledge and established aerodynamic principles for the various flow regimes involved. The major assumptions made are individually substantiated by related experimental evidence in existing literature. A theoretical analysis is carried over the whole flow region based on the Karman's integral approach to find solutions for the gross aerodynamic and thermodynamic behavior of the plume. Theory incorporating on empirically derived constants provides the required radial distribution function for the integration. Solutions are obtained for the velocity, density, temperature and chemical composition fields for extended regions of the plume. These results will provide the much needed framework for the understanding of the elements which contribute to the phenomenon of radar attenuation of rocket exhaust plumes. (Author).

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Publisher :
Page : 253 pages
File Size : 50,15 MB
Release : 1976*
Category : Graphite
ISBN :

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A combined experimental and analytic program was conducted to develop improved procedures for predicting the ablation performance of graphite materials in rocket nozzles. Particular emphasis was placed on conditions representative of the throat region of an MX nozle design which would use graphite materials that are representative of the current state of materials development. New kinetic response correlation functions were developed for G-90 and ATJ bulk graphites, 15% silicon carbide modified pyrolytic graphite, c plane pyrolytic graphite, and Pyrocarb 901 carbon-carbon. These functions were included into the Aerotherm GASKET code along with several modifications to improve on thermochemical modeling accuracy. This modified code, GASKET2, includes a number of new chemical species, improved generalized input requirements, and kinetically controlled carbon sublimation models. The GASKET2 code was used in a number of performance studies to predict the performance of a number of rocket nozzles to be tested in other Air Force programs. The rocket nozzle ablation performance prediction procedures for several rocket motor fabricators were mutually compared to determine the probable ranges of predicted variables. These ranges were used in an ablation rate sensitivity study to define the most critical parameters. The mass transfer coefficient and the kinetic rate constants were shown to be the most critical parameters to be accurately known. (Author).

Author : Kaare J. Nygaard
Publisher :
Page : 32 pages
File Size : 14,58 MB
Release : 1977
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Pergament and Jensen recently have developed a model for estimating the densities of neutral and charged species for an afterburning plume of a solid fuel rocket as a function of distance along the plume. They have compared the predicted electron densities with experimental radar cross section measurements of electron density and find agreement at least within an order of magnitude. The predictions of the model are dependent on the accuracy with which the rate constants used are known. This report describes the work done under AFOSR 74-2672 toward rate constant measurements for those reactions that Pergament and Jenson pointed out as critical to the model and poorly known; dissociative attachment of electrons in HC1, collisional ionization of potassium and chlorine, and three body recombination of potassium. The reactions are closely related in the rocket plume, but diverse experimental procedures are required to measure the rates of the reactions. Potassium is a contaminant of the perchlorate oxidizer in some solid fuels, but because of its low ionization potential, it can make an inordinately large contribution to ionization in the plume.