Begell House Inc.
International Journal of Energetic Materials and Chemical Propulsion
IJEMCP
2150-766X
10
1
2011
PRE- AND POST-COMBUSTION CHARACTERISTICS OF BORON NANOPARTICLES IN AN ETHANOL SPRAY FLAME
1-17
10.1615/IntJEnergeticMaterialsChemProp.2012002669
Srinibas
Karmakar
Department of Aerospace Engineering, Indian Institute of Technology
Kharagpur, Kharagpur, West Bengal 721302, India
Jacob
Hanberry
Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803, USA
Kerry M.
Dooley
Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803, USA
Sumanta
Acharya
Mechanical, Materials and Aerospace Engineering Department, Illinois Institute of Technology,
Chicago, IL 60616
boron
nanoparticles
amorphous
crystalline
combustion
boron oxide
boric acid
Nanoscale metallic and metalloid boron particles have high volumetric heating values and are therefore attractive fuel additives for air-breathing propulsion systems. This paper deals with an experimental investigation of the physical and chemical characteristics of boron nanoparticles before and after combustion in a hydrocarbon (ethanol) spray flame. Several characterization techniques, such as (SEM, TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), porosimetry, elemental analysis, and thermogravimetric analysis (TGA), have been employed with pre- and post-combustion particles. The results suggest that almost all the injected boron, in an initially mostly amorphous form, is converted into a crystalline oxide upon combustion. As the boron oxides cool, they absorb water to eventually form crystalline H3BO3. The product particles are found to be clusters or aggregates similar in structure to the boron nanoparticles. No evidence of unburnt boron was found in the post-combustion particles.
HIGH-REACTIVITY ALUMINUM POWDERS
19-32
10.1615/IntJEnergeticMaterialsChemProp.2012001355
Valery
Rosenband
Faculty of Aerospace Engineering, Technion- Israel Institute of Technology, Haifa 32000, Israel
Alon
Gany
Faculty of Aerospace Engineering, Technion - Israel Institute of Technology,
Haifa, 3200003, Israel
materials
aluminum powder
ignition
combustion
Aluminum powders are used in propellant, pyrotechnic, and explosive formulations, as well as in combustion systems, to increase energy and energy density. However, aluminum particles are usually covered by an oxide protective layer, causing long ignition delays. Shortening ignition time and enhancing combustion can be accomplished by activating the metal particle surfaces or by using powders with a high reaction surface. Methods of promoting ignition and increasing activation of aluminum particles are developed and discussed, including nickel and iron coating as well as a formation of porous aluminum particles. Study of the effectiveness of the methods developed reveals remarkable ignition enhancement of the aluminum powders..
DISCOVERY OF ENERGETIC MATERIALS BY A THEORETICAL METHOD (DEMTM)
33-44
10.1615/IntJEnergeticMaterialsChemProp.2011003997
Lulu
Huang
Center for Computational Materials Science, Naval Research Laboratory, Washington, DC 20375-5341, USA
Lou
Massa
Hunter College and the Graduate School, City University of New York, New York, NY 10065, USA
Jerome
Karle
Laboratory for the Structure of Matter, Research Laboratory, Washington, DC 20375-5341, USA
explosive energy
shock velocity
crystal density
heat of formation
CL20
HMX
RDX
TNT
PETN
It is suggested that quantum chemical calculations can he effective for discovery of new energetic materials (DEMTM). The key quantity for such discovery, which is unknown hut can he calculated, is the heat of formation for a tentative explosive material under investigation. There are two components to the heat of formation of the solid material, viz., the heat of formation of the gas phase of the tentative explosive, and its heat of sublimation. We show the former quantity can he obtained by ah initio quantum chemical B3LYP/6-31G(d,p) calculations, and the later quantity by use of an empirical packing energy formula due to Gavezzotti. The computer program CHEETAH converts the heat of formation into the calculated explosive properties of a material. In this paper we test the calculation methodology for obtaining explosive properties against five of the best known and most used explosive materials, viz., CL20, HMX, RDX, TNT, and PETN, and reproduce their known energetic characteristics with highly satisfactory accuracy. Thus the computational methodology we outline here should prove to be useful to search across a database of tentative explosive materials to assess their prospective usefulness as explosives
HIGH-NITROGEN AND HIGH-OXYGEN EXPLOSIVES AS POSSIBLE REPLACEMENTS FOR RDX
45-54
10.1615/IntJEnergeticMaterialsChemProp.2012001361
Thomas M.
Klapötke
Department of Chemistry, Energetic Materials Research, Ludwig Maximilian University of Munich,
Butenandtstr. 5-13 (D), 81377 Munich, Germany
Michael
Gobel
Energetic Materials Research, Lud-wig-Maximilian University of Munich, Butenandtstr. 5-13, D 81377 Munich, Germany
Jorg
Stierstorfer
Energetic Materials Research, Lud-wig-Maximilian University of Munich, Butenandtstr. 5-13, D 81377 Munich, Germany
energetic materials
explosives
RDX replacements
synthesis
New high explosives are desired for munitions (e.g., warheads) for replacement of toxic hexogen. One approach is the synthesis of high-nitrogen, high-oxygen explosives, which show promising detonation parameters. In this paper, we present a selection of the most promising candidates investigated in the last several years: the neutral compounds, N3,N6-bis-(2,2,2-trinitroethyl)-1,2,3,4-tetrazine-3,6-diamine (BiTNEAT) and bistetrazolylamine (H2BTA), and the two promising ionic compounds, triaminoguanidinium dinitramide (TAG-DN) and triaminoguanidinium 1-methyl-5-nitriminotet-razolate (TAG-1-MeAtNO2. Also, two very high explosives, 5-nitriminotetrazole (H2AtNO2) and 5-aminotetrazolium dinitramide, are mentioned.
ATOMIZATION OF GEL FUELS USING IMPINGING-JET ATOMIZERS
55-65
10.1615/IntJEnergeticMaterialsChemProp.2012002786
Anat
Desyatkov
Faculty of Aerospace Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
Gabriela
Adler
Faculty of Aerospace Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
Oleg
Prokopov
Faculty of Aerospace Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
Benveniste
Natan
Faculty of Aerospace Engineering, Technion − Israel Institute of Technology,
Haifa 320003, Israel
gel
atomizer
impinging jets
The performance of impinging-jet atomizers for gelled fluids was examined. An injection system based on prefixing the mass flow rate of the atomized fluid was designed and built. Plain and gelled water were used as working fluids. Three types of impinging jet atomizers (doublet, triplet, and quadruplet) at two impinging angles were utilized. The results indicate a tendency of the droplet size to decrease with the mass flow rate growth. Gels were more difficult to atomize than Newtonian fluids. The triplet atomizer was found to be superior to the doublet and quadruplet atomizers. The lowest Sauter mean diameter values obtained were 8 μm for water and 10 μm for gel with the triplet injector.
APPLICATION OF NANOMETER MATERIALS FOR SOLID PROPELLANTS
67-83
10.1615/IntJEnergeticMaterialsChemProp.2012001373
Fengsheng
Li
National Special Superfine Powder Engineering Research Center, Nanjing University of Science & Technology, Nanjing, 210094, China
Wei
Jiang
National Special Superfine Powder Engineering Research Center, Nanjing University of Science & Technology, Nanjing, 210094, China
Xiaode
Guo
National Special Superfine Powder Engineering Research Center, Nanjing University of Science & Technology
Leili
Liu
National Special Superfine Powder Engineering Research Center of China, Nanjing University of Science & Technology, Nanjing 210094, People’s Republic of China
Miaomiao
Li
National Special Superfine Powder Engineering Research Center of China, Nanjing University of Science & Technology, Nanjing 210094, People’s Republic of China
Weifan
Chen
National Special Superfine Powder Engineering Research Center of China, Nanjing University of Science & Technology, Nanjing 210094, People’s Republic of China
Shixi
Wua
National Special Superfine Powder Engineering Research Center of China, Nanjing University of Science & Technology, Nanjing 210094, People’s Republic of China
nanometer materials
propellants
applications
Nanometer materials have been of great interest due to their potential applications in many important fields of science and technology. Great effort has been made to study the application of nanometer materials for propellants. In this paper, the effects of nanometer materials on the energy and combustion performance of solid propellants, which include nanometer metal materials, metallic nanocomposites, nanometer metal oxides, nanometer rare earth materials, nanometer oxidizers, carbon nanotubes, and nanometer explosives, are reported. The research results show that nanometer metal particles, nanometer metal oxides, and nanometer rare earth materials can promote the high-temperature decomposition of ammonium perchlorate, increase the burning rates of ammonium perchlorate/hydroxyl-terminated polybutadiene propellants, and decrease their pressure exponents. Nanometer oxidizers can increase the burning rates of solid propellants.