One and two dimensional numerical simulation of deflagration to detonation transition phenomenon in solid energetic materials

Narin, Bekir
In munitions technologies, hazard investigations for explosive (or more generally energetic material) including systems is a very important issue to achieve insensitivity. Determining the response of energetic materials to different types of mechanical or thermal threats has vital importance to achieve an effective and safe munitions design and since 1970’s, lots of studies have been performed in this research field to simulate the dynamic response of energetic materials under some circumstances. The testing for hazard investigations is a very expensive and dangerous topic in munitions design studies. Therefore, especially in conceptual design phase, the numerical simulation tools for hazard investigations has been used by ballistic researchers since 1970s. The main modeling approach in such simulation tools is the numerical simulation of deflagration-todetonation transition (DDT) phenomenon. By this motivation, in this thesis study, the numerical simulation of DDT phenomenon in solid energetic materials which occurs under some mechanical effects is performed. One dimensional and two dimensional solvers are developed by using some well-known models defined in open literature for HMX (C4 H8 N8 O8) with 73 % particle load which is a typical granular, energetic, solid, explosive ingredient. These models include the two-phase conservation equations coupled with the combustion, interphase drag interaction, interphase heat transfer interaction and compaction source terms. In the developed solvers, the governing partial differential equation (PDE) system is solved by employing high-order central differences for time and spatial integration. The two-dimensional solver is developed by extending the complete two-phase model of the one-dimensional solver without any reductions in momentum and energy conservation equations. In one dimensional calculations, compaction, ignition, deflagration and transition to detonation characteristics are investigated and, a good agreement is achieved with the open literature. In two dimensional calculations, effect of blunt and sharp-nosed projectile impact situations on compaction and ignition characteristics of a typical explosive bed is investigated. A minimum impact velocity under which ignition in the domain fails is sought. Then the developed solver is tested with a special wave-shaper problem and the results are in a good agreement with those of a commercial software.


Conceptual internal design and computational fluid dynamics analysis of a supersonic inlet
Alemdaroğlu, Mine; Özyörük, Yusuf; Department of Aerospace Engineering (2005)
In this thesis, the conceptual internal design of the air inlet of a supersonic, high altitude, solid propellant ramjet cruise missile is performed. Inviscid, compressible CFD analysis of the designed inlet is made in order to obtain qualitative and quantitative performance characteristics of the inlet at different operating conditions. The conceptual design of the inlet is realized by using analytical relations and equations, correlations derived from numerous available past experimental data and state-of-...
Small-size unmanned model helicopter guidance and control
Karasu, Çağlar; Leblebicioğlu, Mehmet Kemal; Department of Electrical and Electronics Engineering (2004)
The deployment of unmanned aerial vehicles (UAV) in military applications increased the research about them and the importance of them. The unmanned helicopters are the most agile and maneuverable vehicles among the unmanned aerial vehicles (UAV). The ability of hovering and low speed cruise makes them even more attractive. Such abilities supply more areas to deploy the usage of the unmanned helicopters like search & rescue, mapping, surveillance. Autonomy is the key property for these vehicles. In order to...
Development of a sabot design tool for aeroballistic range testing
Kafdağlı, Karaca Efe; Kayran, Altan; Department of Aerospace Engineering (2006)
The aim of this thesis is to investigate the general design and analysis principles of sabots and to develop a sabot design tool. Structures which support and align the models in gun bore, and separate without disturbing the flight path of models are called sabots. In the scope of this study, structurally critical regions and loads acting on sabots due to acceleration in the gun are determined. To calculate the loads acting and to size the sabots, approximate relations are derived by the help of strength of...
A tool for designing robust autopilots for ramjet missiles
Kahvecioğlu, Alper; Alemdaroğlu, Hüseyin Nafiz; Department of Aerospace Engineering (2006)
The study presented in this thesis comprises the development of the longitudinal autopilot algorithm for a ramjet powered air-to-surface missile. Ramjet Missiles have short time-of-flight, however they suffer from limited angle of attack margins due to poor operational-region characteristics of the ramjet engine. Because of such limitations and presence of uncertainties involved, Robust Control Techniques are used for the controller design. Robust Control Techniques not only provide an easy limitation/uncer...
Numerical and experimantal analysis of flapping motion in hover, application to micro air vehicles
Kurtuluş, Dilek Funda; Alemdaroğlu, Hüseyin Nafiz; Department of Aerospace Engineering (2005)
The aerodynamics phenomena of flapping motion in hover are considered in view of the future Micro Air Vehicle applications. The aim of this work is to characterize the vortex dynamics generated by the wing in motion using direct numerical simulation and experimental analysis then to propose a simplified analytical model for prediction of the forces in order to optimize the parameters of the motion leading to maximum force. A great number of cases are investigated corresponding to different angles of attack,...
Citation Formats
B. Narin, “One and two dimensional numerical simulation of deflagration to detonation transition phenomenon in solid energetic materials,” Ph.D. - Doctoral Program, Middle East Technical University, 2010.