Characterisation of the Thermal and Chemical Behaviour of an Energetic Material and the Heat Release Rate Issue PDF Download

Author: Hubert Biteau
Publisher:
ISBN:
Category :
Languages : en
Pages : 392

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Book Description

Author: Hubert Biteau
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Energetic materials encompass a wide range of chemical compounds all associated with a significant risk of fire and explosion. They include explosives, fireworks, pyrotechnics, powders, propellants and other unsteady chemicals. These materials store a high level of chemical energy and are able to release it rapidly without external contribution of oxygen or any other oxidizer. The behaviour of these materials in case of explosive detonations is relatively wellknown from empirical and practical points of view. However, fundamental scientific questions remain unanswered related to the mechanisms of heat release. The current understanding of these mechanisms lacks appropriate thermochemical characterisation. The aim of the study is the analysis of thermal and chemical characteristics of energetic materials under conditions that exclude detonations. Detonation is excluded in order to better isolate the thermal and chemical mechanisms involved in the burning process. The experimental work has been conducted using the FM Global Fire Propagation Apparatus (FPA) [ASTM E2058-03]. One of the benefits of using this experimental apparatus rather than the Cone Calorimeter is that it allows controlling the feed of heat and oxidizer to the reaction zone. The material chosen to conduct experiments on is a ternary smoke powder based on a mixture of starch and lactose as fuel components and potassium nitrate as oxidizer. This product is currently used by fire brigades to assess smoke venting systems efficiency of buildings. The kinetics associated with the combustion of the material was assessed slow enough to allow measuring instruments to capture the thermal and chemical evolution during combustion reaction. Thermal analysis has first been carried out by means of DSC, TGA, DTA, MS and FTIR data in order to understand the decomposition of the material and its energetic evolution when undergoing heating. However, if the latter methods help defining the decomposing path of the material, they do not provide an integral view of its combustion behaviour, in particular, the emissions of toxics which are kinetic path dependent. Subsequently, combustion tests have been carried out using the FPA. Its ability to capture the evolution of gases emissions formed during the reaction has been proved. The influence of two configuration parameters on the combustion behaviour and on the gaseous emissions of the material has been investigated. The proportion fuel/oxidizer has been varied as well as the composition of the reacting atmosphere. Results shows that the quantity of oxidizer in the material affects the kinetics of the reactions taking place in the condense phase. Increasing the concentration of potassium nitrate in the mixture enhanced the reaction rate of the smouldering combustion. Higher quantity of volatiles is released which favoured the initiation of a diffusion flame regime in the gaseous phase, above the sample. While the kinetics of the condense phase is governed by the oxidizer concentration, experiments show that the flaming regime is influenced by the concentration of oxygen (O2) in the reacting atmosphere. A transition from diffusion to premixed flame is found when the concentration of O2 surrounding the sample is reduced below 18%. An analytical model has been used to explain the existence of a transition for a critical O2 concentration. Finally, thermal and combustion analyses have allowed to characterise the behaviour of the material under critical conditions, in terms of decomposition taking place in the condense phase but also potential toxic emissions that can be released. Toxicity, kinetics, temperature evolution do not provide a complete view of the combustion phenomenon. Beside these elements that characterise the behaviour of a material for given conditions as well as also the degree of fire hazard encountered, the energetic issue holds as an essential feature that cannot be neglected. The heat release rate (HRR) is a critical parameter that defines a fire. It does not constitute an intrinsic material property but it describes the energetic response of the couple formed by the material and its environment. Oxygen Consumption calorimetry (OC) and Carbon Dioxide Generation calorimetry (CDG) are widespread methods to calculate the HRR resulting from a combustion reaction. Apparatuses such as the FPA or the cone calorimeter have already proved their potential to qualify the burning behaviour of common fuels in addition to polymers when their data are combined with an adapted calorimetric procedure. The same approach has been applied to energetic materials. However, prior to using these techniques, it is fundamental to have identified their restrictions. These techniques provide approximate estimations of the HRR. Results are affected by the propagation of uncertainties. Several sources of uncertainties can be found. One can cite: 1. Uncertainties associated with the sample material; 2. Uncertainties associated with the test conditions; 3. Uncertainties associated with the measurements; 4. Uncertainties associated with calculation assumptions. If uncertainties cannot always be estimated, the three first sources cited have received attention in the past from the scientific community, alike the last one. The restrictions associated with the assumptions developed for using the OC and CDG principles have to be clarified. The limits of validity of the hypotheses have to be clearly defined. In particular, the present dissertation questions the relevance of the energy constants that have been specified for OC and CDG as well as their related uncertainties. One of the purposes of the research deals with the ability to estimate accurate error bars for the calculation of the HRR. Once uncertainties related to the calorimetric methods are assessed, a method adapted from the basic OC and CDG principles is introduced that allows estimating the HRR of energetic materials. The approach is based on considering the chemical decomposition of the burning compound and defining a fictitious molecule for which energy coefficients can be calculated. Nevertheless, it requires the material to be known. Finally, the question of the advantage brought by these techniques over others, in terms of accuracy, is discussed within the framework of unconventional products, such as energetic materials or compounds whose composition is ignored. The results from this work will contribute to the development of fireanalysis methodologies and validate their use with energetic materials.

Author:
Publisher: Elsevier
ISBN: 0080530915
Category : Science
Languages : en
Pages : 475

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Book Description
This volume provides an overview of current research and recent advances in the area of energetic materials, focusing on explosives and propellants. The contents and format reflect the fact that theory, experiment and computation are closely linked in this field. The challenge of developing energetic materials that are less sensitive to accidental stimuli continues to be of critical importance. This volume opens with discussions of some determinants of sensitivity and its correlations with various molecular and crystal properties. The next several chapters deal in considerable detail with different aspects and mechanisms of the initiation of detonation, and its quantitative description. The second half of this volume focuses upon combustion. Extensive studies model ignition and combustion, with applications to different propellants. The final chapter is an exhaustive computational treatment of the mechanism and kinetics of combustion initiation reactions of ammonium perchlorate. Overall, this volume illustrates the progress that has been made in the field of energetic materials and some of the areas of current activity. It also indicates the challenges involved in characterizing and understanding the properties and behaviour of these compounds. The work is a unique state-of-the-art treatment of the subject, written by pre-eminent researchers in the field. - Overall emphasis is on theory and computation, presented in the context of relevant experimental work - Presents a unique state-of-the-art treatment of the subject - Contributors are preeminent researchers in the field

Author: Ulrich Teipel
Publisher: John Wiley & Sons
ISBN: 3527604936
Category : Science
Languages : en
Pages : 643

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Book Description
Incorporation of particular components with specialized properties allows one to tailor the end product's properties. For instance, the sensitivity, burning behavior, thermal or mechanical properties or stability of energetic materials can be affected and even controllably varied through incorporation of such ingredients. This book examines particle technologies as applied to energetic materials such as propellants and explosives, thus filling a void in the literature on this subject. Following an introduction covering general features of energetic materials, the first section of this book describes methods of manufacturing particulate energetic materials, including size reduction, crystallization, atomization, particle formation using supercritical fluids and microencapsulation, agglomeration phenomena, special considerations in mixing explosive particles and the production of nanoparticles. The second section discusses the characterization of particulate materials. Techniques and methods such as particle size analysis, morphology elucidation and the determination of chemical and thermal properties are presented. The wettability of powders and rheological behavior of suspensions and solids are also considered. Furthermore, methods of determining the performance of particular energetic materials are described. Each chapter deals with fundamentals and application possibilities of the various methods presented, with particular emphasis on issues applicable to particulate energetic materials. The book is thus equally relevant for chemists, physicists, material scientists, chemical and mechanical engineers and anyone interested or engaged in particle processing and characterization technologies.

Author: Donald L Thompson
Publisher: World Scientific
ISBN: 9814480908
Category : Science
Languages : en
Pages : 531

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Book Description
Few books cover experimental and theoretical methods to characterize decomposition, combustion and detonation of energetic materials. This volume, by internationally known and major contributors to the field, is unique because it summarizes the most important recent work, what we know with confidence, and what main areas remain to be investigated. Most chapters comprise summaries of work spanning decades and contain expert commentary available nowhere else. Although energetic materials are its focus, this book provides a guide to modern methods for investigations of condensed and gas-phase reactions. Although these energetic reactions are complex and difficult to study, the work discussed here provides readers with a substantial understanding of the behavior of materials now in use, and a predictive capability for the development of new materials based on target properties.

Author: Kenneth K. Kuo
Publisher: Begell House Publishers
ISBN:
Category : Combustion
Languages : en
Pages : 1114

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Book Description
This edited book contains state-of-the-art information associated with energetic material combustion. There are twelve topical areas, including: Reaction Kinetics of Energetic Materials (Solid, Liquid, and Gel Propellants); Recycling of Energetic Materials; Combustion Performance of Hybrid and Solid Rocket Motors; Ignition and Combustion of Energetic Materials; Energetic Material Defects and Rocket Engine Flowfields; Metal Combustion; Pyrolysis and Combustion Processes of New Ingredients and Applications; Theoretical Modeling and Numerical Simulation of Combustion Processes of Energetic Materials; Combustion Diagnostic Techniques; Propellant and Rocket Motor Stability; Commercial Applications of Energetic Materials (Airbags, Gas Generators, etc.); and Thermal Insulation and Ablation Processes.

Author: Alexander S. Shteinberg
Publisher: Springer Science & Business Media
ISBN: 3540788611
Category : Science
Languages : en
Pages : 203

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Book Description
Modern energetic materials include explosives, blasting powders, pyrotechnic m- tures and rocket propellants [1, 2]. The study of high-temperature decomposition of condensed phases of propellants and their components (liquid, solid and hybrid) is currently of special importance for the development of space-system engineering [3, 4]. To better understand the burning mechanisms (stationary, nonstationary, - steady) of composite solid propellants and their components, information about the macrokinetics of their high-temperature decomposition is required [5]. To be able to evaluate the ignition parameters and conditions of safe handling of heat-affected explosives, one needs to know the kinetic constants of their high-temperature - composition. The development of new composite solid propellants characterized by high performance characteristics (high burning rates, high thermal stability, stability to intrachamber perturbations, and other aspects) is not possible without quanti- tive data on the high-temperature decomposition of composite solid propellants and their components [6]. The same reasons have resulted in signi?cant theoretical and practical interest in the high-temperature decomposition of components of hybrid propellants. It is known that hybrid propellants have not been used very widely due to the low bu- ing (pyrolysis) rates of the polymer blocks in the combustion chambers of hybrid rocket engines. To increase the burning rates it is necessary to obtain information about their relationships to the corresponding kinetic and thermophysical prop- ties of the fuels.

Author: WeiQiang Pang
Publisher: Springer Nature
ISBN: 9811548315
Category : Technology & Engineering
Languages : en
Pages : 556

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Book Description
This book focuses on the combustion performance and application of innovative energetic materials for solid and hybrid space rocket propulsion. It provides a comprehensive overview of advanced technologies in the field of innovative energetic materials and combustion performance, introduces methods of modeling and diagnosing the aggregation/agglomeration of active energetic metal materials in solid propellants, and investigates the potential applications of innovative energetic materials in solid and hybrid propulsion. In addition, it also provides step-by-step solutions for sample problems to help readers gain a good understanding of combustion performance and potential applications of innovative energetic materials in space propulsion. This book serves as an excellent resource for researchers and engineers in the field of propellants, explosives, and pyrotechnics.

Author: Manoj K. Shukla
Publisher: Springer
ISBN: 3319592084
Category : Science
Languages : en
Pages : 484

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Book Description
This book offers a comprehensive account of energetic materials, including their synthesis, computational modeling, applications, associated degradation mechanisms, environmental consequences and fate and transport. This multi-author contributed volume describes how armed forces around the world are moving their attention from legacy explosive compounds, which are heat and shock sensitive (thus posing greater challenges in terms of handling and storage), to the insensitive munitions compounds/formulations such as insensitive munitions explosive (IMX) and the Picatinny Arsenal Explosive (PAX) series of compounds. The description of energetic materials focuses on explosives, pyrotechnic compositions, and propellants. The contributors go on to explain how modern generation energetic compounds must be insensitive to shock and heat but at the same time yield more energy upon explosion. Nanoinspired and/or co-crystallized energetic materials offer another route to generate next-generation energetic materials, and this authoritative book bridges a large gap in the literature by providing a comprehensive analysis of these compounds. Additionally, it includes a valuable overview of energetic materials, a detailed discussion of recent advances on future energetic compounds, nanotechnology in energetic materials, environmental contamination and toxicity, assessment of munitions lethality, the application quantitative structure–activity relationship (QSAR) in design of energetics and the fate and transport of munition compounds in the environment.

Author: Samuel L. Manzello
Publisher: Springer
ISBN: 9783319520896
Category : Technology & Engineering
Languages : en
Pages : 0

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Book Description
This reference work encompasses the current, accepted state of the art in the science of wildfires and wildfires that spread to communities, known as wildland-urban interface (WUI) fires. 171 author contributions include accepted knowledge on these topics from throughout the world, all written by the leading researchers, experts, practitioners, and academics. This encyclopedia is an invaluable reference for newcomers to the field, as well as researchers, students, developers, and professionals who are interested in exploring this dynamic area. General Sections include: Combustion Coordination System Locations Fire Whirls Firebrands and Embers Incident Management Team (IMT) Support Locations Incident Response Support Locations On-the-Incident Locations Soot and Effects on Wildland/WUI Fire Behavior Weathering Effects on Fire Retardant Wood Treatments Wildland Firefighting Locations Wildland Fuel Treatments