Characteristics of aluminum agglomeration at burning surface in AP/AN composite propellants

2012 ◽  
Author(s):  
Sho Oide ◽  
Kenichi Takahashi ◽  
Takuo Kuwahara
Keyword(s):  
Burning Surface

Thermal Decomposition of Li(NTO)·2H2O and Na(NTO)·H2O (NTO = Anion of 3-Nitro-1,2,4-triazol-5-one): Kinetics Derived from T-jump/FTIR Spectroscopy

2006 ◽  
Vol 71 (1) ◽  
pp. 129-137 ◽  
Author(s):  
Yuanhua Sun ◽  
Tonglai Zhang ◽  
Jianguo Zhang ◽  
Xiaojing Qiao ◽  
Li Yang ◽  
...  
Keyword(s):  
Ftir Spectroscopy ◽  
Energetic Material ◽  
Burning Surface ◽  
High Sensitivity ◽  
Control Voltage ◽  
Differential Scanning Colorimetry ◽  
Voltage Trace ◽  
Dsc Method ◽  
Phase Chemistry ◽  
Kinetics Of

A "snapshot" simulation of the surface reaction zone is captured by a thin film of material heated rapidly to temperatures characteristic of the burning surface by using the T-jump/FTIR spectroscopy. The time-to-exotherm (tx) kinetics method derived from the control voltage trace of the Pt filament can be introduced to resolve the kinetics of an energetic material owing to its high sensitivity to the thermochemical reactions. The kinetic parameters of the two title compounds are determined under different pressures. The results show that Li(NTO)·2H2O and Na(NTO)·H2O (NTO = anion of 3-nitro-1,2,4-triazol-5-one) exhibit weak pressure dependence, their decomposition is dominated by the condensed phase chemistry irrespective of the pressure in the 0.1-1.1 MPa range. The values of Ea determined here are smaller than those given by a traditional non-isothermal differential scanning colorimetry (DSC) method, which might be resembled as the surface of explosion more closely and enabled the pyrolysis surface to be incorporated into models of steady and possibly unsteady combustion. The kinetics can also be successfully used to understand the behavior of the energetic material in practical combustion problems.

scholarly journals Measurements in Solid Propellant Plumes at Ambient Conditions

2011 ◽  
Author(s):  
Jonathan L. Height ◽  
Burl A. Donaldson ◽  
Walter Gill ◽  
Christian G. Parigger
Keyword(s):  
Temperature Distribution ◽  
Solid Propellant ◽  
Aluminum Particle ◽  
Burning Surface ◽  
Ambient Conditions ◽  
Aluminum Particles ◽  
Open Atmosphere ◽  
Particle Ignition ◽  
Accident Scenarios ◽  
Color Pyrometer

The study of aluminum particle ignition in an open atmosphere propellant burn is of particular interest when considering accident scenarios for rockets carrying high-value payloads. This study investigates the temperature of an open atmosphere Atlas V solid propellant burn as a function of height from the burning surface. Two instruments were used to infer this temperature: a two-color pyrometer and a spectrometer. The spectra were fitted to a model of energy states for aluminum monoxide. The temperature which provided the best match between the model and data was taken as the reaction temperature. Emissions above 30 inches from the surface of the propellant were not sufficiently strong for data reduction, perhaps obscured by the alumina smoke cloud. The temperature distribution in the plume increased slightly with distance from the burning surface, presumably indicating the delay in ignition and heat release from the larger aluminum particles in the propellant. The pyrometer and spectrometer results were found to be in excellent agreement indicating plume temperatures in the range of 2300K to 3000K.

scholarly journals Improvement of CFD models of tunnel fire development based on experimental data

2017 ◽  
Vol 21 (suppl. 3) ◽  
pp. 705-716 ◽  
Author(s):  
Barbara Vidakovic ◽  
Milos Banjac
Keyword(s):  
Experimental Data ◽  
Combustion Process ◽  
Burning Surface ◽  
Physical Structure ◽  
Cfd Model ◽  
Change Rate ◽  
Flamelet Model ◽  
Tunnel Fire ◽  
Cfd Models ◽  
Combustion Processes

This paper, dealing with the problems of mathematical description of the tunnel fire development process with the use of experimental data, outlines the procedure of correction of the existing and obtaining of an improved CFD model package. The improved CFD model was developed on the basis of detailed analysis and comparison of experimental and numerical results, through consideration of the physical structure of all processes affecting combustion. During the analysis it was noticed that the existing CFD model in the part covering combustion based on the so-called steady laminar flamelet model, treats the combustion process almost as a direct correlation between the processes of mixing gasses and heat release rate. This potential deficiency has been overcome by correction of the model in the section defining boundary condition for the burning surface and by establishing a direct correlation between the measured value of the fuel mass change rate and the amount of heat released from burning surface. In this way a modification of complex stoichiometric combustion processes was avoided, while providing the model that better describes and predicts the course of events in this type of complex, anisotropic and turbulent flow of gases in the tunnel.

Solid Rocket Motor Internal Ballistics Simulation Considering Complex 3D Propellant Grain Geometries

2018 ◽  
pp. 146-169
Author(s):  
Guilherme Lourenço Mejia
Keyword(s):  
Solid Propellant ◽  
Structural Integrity ◽  
Combustion Process ◽  
Burning Surface ◽  
Chamber Pressure ◽  
Computational Tool ◽  
Solid Rocket Motor ◽  
Rocket Motors ◽  
Internal Ballistics ◽  
Solid Rocket

Solid rocket motors (SRM) are extensively employed in satellite launchers, missiles and gas generators. Design considers propulsive parameters with dimensional, manufacture, thermal and structural constraints. Solid propellant geometry and computation of its burning rate are essential for the calculation of pressure and thrust vs time curves. The propellant grain geometry changes during SRM burning are also important for structural integrity and analysis. A computational tool for tracking the propagation of tridimensional interfaces and shapes is then necessary. In this sense, the objective of this work is to present the developed computational tool (named RSIM) to simulate the burning surface regression during the combustion process of a solid propellant. The SRM internal ballistics simulation is based on 3D propagation, using the level set method approach. Geometrical and thermodynamic data are used as input for the computation, while simulation results of geometry and chamber pressure versus time are presented in test cases.

Introducing fire

2018 ◽  
Author(s):  
Andrew C. Scott
Keyword(s):  
Volcanic Activity ◽  
Burning Surface ◽  
Lightning Strikes ◽  
World Today ◽  
The World ◽  
Surface Vegetation

Fire has a bad reputation. Wildfires raging across parts of California and Australia make headlines. In the news bulletins, it is a destructive force that has to be quenched. But that is far from the whole story. Fire has a long history. In our deep past, wildfire helped shape aspects of our planet, and plants and animals have adapted to it in a variety of ways. In this book, we will follow the story of fire through time. But we begin with the present, with the fires that occur around the world today, and how satellites are changing our view of wildfire. Most of us have little or no experience of a wildfire, apart from those dramatic scenes shown on our television sets from time to time. Almost invariably, two questions are asked: who started the fire, and how quickly can it be put out? Reasonable though they seem, these two questions betray a potential misunderstanding of how fire works on our planet. We assume that the fire was started by humans, either accidentally or deliberately. This may indeed be true, but more than half of the fires started across the globe have a natural cause—mostly lightning strikes, but also other causes such as volcanic activity. Every moment of every day, a fire is burning somewhere in the world. The second assumption is that a fire should always be suppressed. But should we always be rushing to put out a vegetation fire? Wildfire is one of nature’s most frightening manifestations. Winds and storms may die down, and we can seek shelter from them, but fire can be difficult to outrun and escape. Many who are killed by wildfire have underestimated this force of nature, and even those with experience in putting out fires can find themselves cut off, and succumbing to the flames. As we shall discover, not all vegetation burns in the same way, and there are many different kinds of fire, from those burning surface vegetation to those moving through the crowns of trees. Their consequences may also be very different.

scholarly journals Finocyl Grain Design Using the Genetic Algorithm in Combination with Adaptive Basis Function Construction

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Saeed Mesgari ◽  
Mehrdad Bazazzadeh ◽  
Alireza Mostofizadeh
Keyword(s):  
Genetic Algorithm ◽  
Level Set Method ◽  
Level Set ◽  
Computer Aided Design ◽  
Optimization Design ◽  
Design Method ◽  
Burning Surface ◽  
Aided Design ◽  
Function Construction

This study deals with the application of optimization in Finocyl grain design with ballistic objective functions using a genetic algorithm. The classical sampling method is used for space filling; a level-set method is used for simulating the evaluation of a burning surface of the propellant grain. An algorithm is developed beside the level-set code that prepares the initial grain configuration using a computer-aided design (CAD) to export generated models to the level-set code. The lumped method is used to perform internal ballistic analysis. A meta-model is used to surrogate the level-set method in an optimization design loop. Finally, a case study is done to verify the proposed algorithm. Observed results show that the grain design method reduced the design time significantly, and this algorithm can be used in designing any grain type.

scholarly journals Burning rate of solid homogeneous energetic materials with a curved burning surface

2019 ◽  
Vol 1250 ◽  
pp. 012041
Author(s):  
S.A. Rashkovskiy ◽  
V.G. Krupkin ◽  
V.N. Marshakov
Keyword(s):  
Burning Rate ◽  
Energetic Materials ◽  
Burning Surface
Sign in / Sign up

Export Citation Format

Share Document