Download or read book Modeling Solid Propellant Ignition Events written by Daniel Austin Smyth and published by . This book was released on 2011 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation documents the building of computational propellant/ingredient models toward predicting AP/HTPB/Al cookoff events. Two computer codes were used to complete this work; a steady-state code and a transient ignition code.

Download or read book U S Army Workshop on Solid Propellant Ignition and Combustion Modeling written by Martin S. Miller and published by . This book was released on 1997-07 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: A workshop with the objective to view the current state of the art of energetic-material combustion models within the context of future requirements of gun interior-ballistics (IB) models was held at the U.S. Army Research Laboratory (ARL), Aberdeen Proving Ground, MD, on 9 and 10 April 96. The workshop was motivated by the recognition that modeling and simulation will be an essential cost-saving and time-saving tool in the design, development, testing, and evaluation of future gun-propulsion systems, and that, under current funding constraints, research on the underlying fundamentals must be carefully directed toward the most critical technology barriers. To facilitate this process, a perspective was presented on the fundamental physics and chemistry currently utilized in IB codes (XKTC, etc.) and the extensions planned for advanced codes (the NGEN family). The state of the art in fundamental descriptions of energetic-material combustion was then summarized and discussed with the intent of giving focus to those issues that could impact the future development needs of the IB research community.

Download or read book U S Army Workshop on Solid Propellant Ignition and Combustion Modeling written by and published by . This book was released on 1997 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: A workshop with the objective to view the current state of the art of energetic-material combustion models within the context of future requirements of gun interior-ballistics (IB) models was held at the U.S. Army Research Laboratory (ARL), Aberdeen Proving Ground, MD, on 9 and 10 April 96. The workshop was motivated by the recognition that modeling and simulation will be an essential cost-saving and time-saving tool in the design, development, testing, and evaluation of future gun-propulsion systems, and that, under current funding constraints, research on the underlying fundamentals must be carefully directed toward the most critical technology barriers. To facilitate this process, a perspective was presented on the fundamental physics and chemistry currently utilized in IB codes (XKTC, etc.) and the extensions planned for advanced codes (the NGEN family). The state of the art in fundamental descriptions of energetic-material combustion was then summarized and discussed with the intent of giving focus to those issues that could impact the future development needs of the IB research community.

Download or read book Nonsteady Burning and Combustion Stability of Solid Propellants written by Martin Summerfield and published by AIAA. This book was released on 1992 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book CFD Modelling of Solid Propellant Ignition written by and published by . This book was released on 1907 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid propellant is the highly energetic fuel burnt in the combustion chamber of ballistic weapons. It is manufactured, for this purpose, in either granular or stick form. Internal ballistics describes the behavior within the combustion chamber throughout the ballistic cycle upto projectile exit from the muzzle of the gun barrel. Over the last twenty years this has been achieved by modelling the process using two-phase flow equations. The solid granules or sticks constitute the first phase, which can be assumed to be incompressible over typical pressure ranges within the chamber. The gas-phase is composed of both the original ambient gas contained around the propellant and additional gas produced by the propellant gasifying on heating. Equations can be derived that describe the conservation of mass, momentum and energy in terms of average flow variables. The equations are a highly non-linear system of partial-differential- equations. High-speed flow features are observed in internal ballistics and ordinary fini te- difference methods are unsuitable numerical methods due to inaccurate prediction of discontinuous flow features. Modern shock-capturing methods are employed, which solve the system of equations in conservation form, with the ability to capture shocks and contact discontinuities. However, although the numerical solutions compare well with experiment over the bulk of the combustion chamber, the ignition models used in internal ballistics are unreliable. These are based on either gas or solid-surface temperature achieving some empirically measured 'ignition temperature' after which the propellant burns according to an empirical pressure dependent burning law. Observations indicate that this is not an adequate representation of ignition. Time differences between first solid gasification and ignition imply two distinct processes occurring.]Further, ignition occurring in gas-only regions indicates that ignition is controlled by a gas-phase reaction. This thesi.

Download or read book A Unified Theory of Solid Propellant Ignition Part 1 Development of Mathematical Model written by H. H Bradley (Jr) and published by . This book was released on 1974 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: The governing equations of solid propellant ignition in one space dimension are derived from conservation and transport considerations. The resulting mathematical model contains as subcases the existing gas phase, solid phase, and surface ignition theories. More important, it allows the effect of the site of chemical reaction on the ignition transient to be examined with consistent and compatible boundary conditions. Surface regression and the first order effect of nonunity Lewis number are retained to allow examination of the effect of these phenomena which are often neglected. Several second order terms are dropped from the more general equations in the interest of mathematical tractability; these include variable specific heat and transport coefficients. Finally, the physical equations are transformed for computer coding. (Modified author abstract).

Download or read book Solid Propellant Underwater Ignition Modeling written by A. B. Vorozhtsov and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Report on JANNAF Workshop Influence of Gas Phase Chemical Kinetics on Low Pressure Ignition and Flamespreading in Solid Propellant written by George K. Keller and published by . This book was released on 1988 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: A workshop on the subject influence of Gas-Phase Chemical Kinetics on the Low-Pressure Ignition and Flamespreading in Solid Propellants was held at Hampton, VA, on 23 and 24 October 1986 in conjunction with the 23rd JANNAF Combustion Meeting. The objectives of the workshop were to a) force a synergisitc interaction between those whose measurements have provided evidence for the participation of chemical kinetics in low-pressure solid propellant burning and those who are striving to simulate these events with interior ballistic models and b) address problems of anomalous ignition behavior in gun propelling charges. The workshop participants a) reviewed the evidence for the participation of chemical kinetics in the low-pressure burning of solid propellants, b) reviewed model simulations which include finite-rate kinetics, and c) determined which model simulations and further experimental characterizations would be most fruitful. This report documents the workshop. (AW).

Download or read book Ignition of Composite Propellants Under Rapid Pressure Loading written by and published by . This book was released on 1981 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive theeoretical model for ignition of composite solid propellants was proposed as a framework for formulating ignition models for different propellants under a wide range of operating conditions. Detailed chemical kinetics information for the AP/PBAA propellants was incorporated into the proposed theoretical model for ignition of composite solid propellants, enabling a more complete description of source terms in the gas-phase energy and species equations. Solid-phase energy equations were coded and implemented on a computer. Numerical solutions of the solid-phase subprogram were successfully checked against analytic solutions for some limiting cases. Using actual measured heat flux near the propellant surface as an input to the solid-phase equations, predictions for the ignition delay time were made. Effects of pressurization rate, crack-gap width, and igniter-flame temperature on the ignition of AP-based composite solid propellants located at the tip of an inert crack were studied. The ignition process was observed by using a high-speed camera ( -40,000 pictures/s) and a fast-response photodiode system. Heat flux to the propellant surface was measured with a thin film heat-flux gage. A bright luminous zone behind the reflected compression wave was observed at high pressurization rates. The decrease in ignition delay with increasing pressurization is caused by enhanced heat feedback to the propellant surface at higher pressurization rates.

Download or read book A Model of the Ignition of a Heterogeneous Solid Rocket Propellant written by Larry Sidney Bouck and published by . This book was released on 1966 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ignition transient Modeling for Solid Propellant Rocket Motors written by P. V. S. Alavilli 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 A Unified Theory of Solid Propellant Ignition Part 3 Computer Solutions written by H. H Bradley (Jr) and published by . This book was released on 1975 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computer solutions are obtained for several ignition models involving either surface or gaseous exothermic chemistry. Surface regression and convection of products from the surface are found to be limiting for the surface reaction of gaseous oxidizer and solid fuel. Fast gas phase reactions cannot in general be distinguished from surface and solid phase reactions by the experimental determination of the dependence of ignition time on igniting flux; a more usable technique may be the effect of concentration on ignition regimes. Slow gas phase reactions would be best studied by photographic observation of the developing gaseous reaction zone. Further analyses, coupled with judiciously chosen numerical solutions, offer a reasonable path to the solution of the remaining unresolved questions. (Author).

Download or read book Transient Ignition Mechanisms of Confined Solid Propellants Under Rapid Pressurization written by Kenneth K. Kuo and published by . This book was released on 1980 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive theoretical model was formulated to study the transient ignition mechanisms of solid propellants under rapidly varying pressure conditions. The model considers a two-dimensional geometry to describe the ignition of a heterogeneous propellant. The rate of pressurization has been included in the energy equation to simulate rocket motor ignition conditions. The model does not make any a priori assumption of solid-phase, heterogeneous, or gas-phase ignition mechanism. Chemical reactions are considered in the gas phase, at the interface as well as in the subsurface. The most up-to-date chemical kinetics information is included in the model. A generalized ignition criterion has been proposed which allows ignition to occur at any site.

Download or read book Research on Solid Propellant Ignition Part I Theoretical Search for Analytical Solutions to the Gas Phase Ignition Problem Part Ii Effects of Fuel Volatility and Other Physical and Chemical Factors on Ignitability written by C. H. WALDMAN and published by . This book was released on 1966 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanism of ignition being analyzed is based on the hypothesis that the runaway reaction occurs in the gas phase, in a thin boundary layer adjacent to the solid propellant surface being heated, between the reactive fuel and oxident vapors liberated from the surface. Differential equations can be written for the diffusion of vapors from the surface, reaction in the gas phase, heat feedback to the surface, and heating up of the surface. As a first treatment the propellant is taken as a simple fuel and the oxidant is available only in the gas phase. An experimental study was conducted to determine the ignition delay time for various hydrocarbons and for solid propellants when exposed suddenly to a hot, high pressure oxidizing atmosphere. The main purpose was to measure effects that would help in a diagnostic way to decide whether the gas phase theory of ignition is based on the correct physical model. Attempts were made to relate the ignition delay to physical and chemical properties of the fuel to test the hypothesis that the ignition reaction of these compounds starts in the gas phase. A 19 foot long, 1.6 inch I.D. shock tube was used as an investigating tool. The test gas was heated to 1400K behind the reflected shock wave at the end wall of the shock tube. (Author).

Download or read book Ignition Response of Solid Propellants to Radiation and Conduction written by S. Henry Inami and published by . This book was released on 1968 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental measurements were carried out on the ignition response of solid propellants to radiative and to conductive heat transfer. The propellants were composed of ammonium perchlorate and different organic binders. The experimental results were interpreted in terms of a model involving exothermic chemical reaction in the condensed phase of the propellant. The heat release rates in the surface-coupled reactions were measured independently. Such a model adequately fitted the ignition process associated with a thermal runaway in the condensed phase. A comparison of the ignition data demonstrated different response of the propellants to the mode of ignition. The importance of these results to rocket motor tests is discussed. (Author).

Download or read book Fundamentals of Solid propellant Combustion written by Kenneth K. Kuo and published by . This book was released on 1984 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Propellant Crack Tip Ignition and Propagation Under Rapid Pressurization written by and published by . This book was released on 1982 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two major tasks performed during the report period were investigation of: (1) crack tip ignition phenomena under rapid pressurization and (2) crack propagation. Ignition of AP-based composite solid propellants located at the tip of an inert crack was investigated both experimentally and theoretically. Results indicate that the ignition-delay time decreases and the heat flux to the propellant surface increases as the pressurization rate is increased. In the theoretical investigation of the tip ignition event a comprehensive model for ignition of AP-based composite solid propellants was developed and numerical solutions were obtained. Crack propagation in a burning composite solid propellant subjected to rapid pressurization in the order of 10 GPa/s was investigated experimentally. The effect of pressurization rate on both crack propagation velocity and time variation of crack shape was studied. Experimental results indicated that the crack velocity increases as the pressurization rate is raised.