Begell House Inc.
International Journal of Energetic Materials and Chemical Propulsion
IJEMCP
2150-766X
7
2
2008
FORMATION OF PYROPHORIC IRON PARTICLES BY H2 REDUCTION OF OXALATE AND OXIDES
87-97
10.1615/IntJEnergeticMaterialsChemProp.v7.i2.10
Rajesh V.
Shende
Chemical and Biological Engineering Department, South Dakota School of Mines and Technology, Rapid City, South Dakota 57701
Alok
Vats
South Dakota School of Mines & Technology, Rapid City, SD 57701 USA
Zachary D.
Doorenbos
South Dakota School of Mines & Technology, Rapid City, SD 57701 USA
Deepak
Kapoor
Armament Research, Development, and Engineering Center, Picatinny Arsenal, NJ 07806 USA
Darold
Martin
Armament Research, Development, and Engineering Center, Picatinny Arsenal, NJ 07806 USA
Jan
Puszynski
SDSM&T
The thermal decomposition and reduction of Fe-oxalate to form pyrophoric iron particles were investigated. Decomposition and reduction experiments were performed in a tubular quartz reactor at 450−520°C under reducing environment of 5−50 vol% H2 and 95−50 vol% N2. Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) revealed that the decomposition of Fe-oxalate in an inert atmosphere is a two-step process involving the removal of water and decomposition of oxalate to iron oxides. In the presence of H2, the products of decomposition are reduced into α-Fe particles. The results have shown that Fe-particles generated from oxalate are pyrophoric in air and burn within 15−30 seconds with maximum temperatures generated in the range of 620−820°C. The effect of reduction temperature, H2 concentration, and sample geometry on pyrophoric behavior was also investigated. In other efforts, Fe-oxalate was synthesized from FeCl2.2H2O and its pyrophoric performance was compared with the commercial material.
NEW HTPB/AP/Al PROPELLANT COMBUSTION PROCESS IN THE PRESENCE OF ALUMINUM NANO-PARTICLES
99-122
10.1615/IntJEnergeticMaterialsChemProp.v7.i2.20
Jean-Francois
Trubert
ONERA, 29 avenue de la Division Leclerc, 91322 Châtillon cedex, France
Jean
Hommel
ONERA, 29 avenue de la Division Leclerc, 91322 Châtillon cedex, France
Dominique
Lambert
ONERA, 29 avenue de la Division Leclerc, 91322 Châtillon cedex, France
Yves
Fabignon
ONERA−The French Aerospace Lab, Palaiseau, France
Olivier
Orlandi
SNPE Matériaux Energétiques, Centre de Recherches du Bouchet, 91710 Vert-le-Petit, France
Using the same techniques, but improved, we now have found a sensible explanation for the paradoxical results presented during the 6-ISICP, from three propellants of decreasing Al sizes. In the micrometric domain (from 5 μ;m to 100 μ;m), visualizations show the Al droplet combustion zone coming progressively closer to the combustion surface, with combustion of a higher number of smaller particles. In the nanometric domain (from 10 nm to 1 μ;m), a new Al oxidation mechanism seems to appear, directly at the surface without visible flame. Detailed visualization shows the flake detachment swirling in the gas-flow, without reacting. There is no luminous effect, which would indicate the slightest igniting or burning. Particle collection, at less than 3 mm from the surface, shows that these flakes are constituted of very small particles, close to an alumina composition. A setup improvement allows us to collect almost 100% of the emitted particles. This allows us to develop a mass balance compared to the initial Al in the sample, in order to guarantee diagnostic accuracy. Now, it is possible to assure that the size decrease in the nanometric domain leads to a new Al particle oxidation process at the propellant's combustion surface without agglomeration. The unburnt fraction determination in the collected particles shows a more advanced Al combustion. Beyond the nano-Al higher reactivity, the consequences are complete changes of the thermal and chemical particle environment and of the oxidation process. The early oxidation of the metal nanometric fraction releases more condensed energy at the combustion surface level, modifying the performance of the propellant. That will lead to an evolution of the combustion model for nano-Al propellants.
COMBUSTION CHARACTERISTICS OF HAN-BASED LIQUID MONOPROPELLANT
123-137
10.1615/IntJEnergeticMaterialsChemProp.v7.i2.30
Toshiyuki
Katsumi
Department of Mechanical Engineering, Nagaoka University of Technology, Japan
Hiroyuki
Kodama
Tokyo University, Department of Chemical System Engineering, Japan
Hidehumi
Shibamoto
Hosoya Kako Co. Ltd., Japan
Junichi
Nakatsuka
Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Japan
Katsuya
Hasegawa
Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration
Agency (JAXA), Sagamihara, Kanagawa, 252-5210, Japan
Kiyokazu
Kobayashi
Institute of Space & Astronautical Science/Japan Aeropace Exploration Agency (JAXA), Japan
Hiroyuki
Ogawa
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara-shi, Kanagawa, Kanagawa, 252-5210, Japan
Nobuyuki
Tsuboi
Kyushu Institute of Technology
Shujiro
Sawai
Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Japan
Keiichi
Hori
Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration
Agency (JAXA), Sagamihara, Kanagawa, 252-5210, Japan
A new composition of the hydroxyl ammonium nitrate (HAN)-based solution containing ammonium nitrate, methanol, and water had been developed for monopropellant in a reaction control system (RCS) as an alternative to conventional hydrazine. Comparing this solution with hydrazine, Isp is 20% higher, density is 1.4 times, the freezing point is much lower, and the toxicity is low, which makes this solution promising as a RCS propellant. The linear burning rate of the solution is moderate at the operating pressures of an RCS thruster. However, it was found that the linear burning rate had some characteristics whose mechanisms had not been understood. The combustion mechanism of this solution was investigated, the burning behavior was observed using a medium speed camera, and a temperature profile for the combustion wave was measured with a fine 2.5 μ;m-diameter thermocouple. From these results, the instability of the liquid interface may trigger a sudden increase in the burning rate to a violently high region, and methanol was found to be effective in reducing the bubble growth rate in the solution. For RCS thruster use, reactivity with several catalysts was evaluated in an open-cup test. Consequently, the S405 catalyst for hydrazine showed the best performance among Pt-based, Pd-based, Ru-based, Ir-based, and S405 catalysts. Thruster tests were conducted successfully using S405 in both the pulsing and continuous modes. As a result, it was found that S405 has little effect in activation of the reaction of methanol contained in the propellant. High-concentration Pd catalyst was found to improve the decomposition characteristic of the solution.
DEVELOPMENT OF HAN-BASED LIQUID PROPELLANT THRUSTER
139-152
10.1615/IntJEnergeticMaterialsChemProp.v7.i2.40
Tetsuya
Matsuo
Mitsubishi Heavy Industries LTD.(MHI), Japan
Hiroyuki
Mishima
Mitsubishi Heavy Industries LTD.(MHI), Japan
Kenji
Hisatsune
Mitsubishi Heavy Industries LTD.(MHI), Japan
Toshiyuki
Katsumi
Department of Mechanical Engineering, Nagaoka University of Technology, Japan
Shujiro
Sawai
Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Japan
Keiichi
Hori
Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration
Agency (JAXA), Sagamihara, Kanagawa, 252-5210, Japan
Hydrazine is used for most conventional monopropellant thrusters for spacecraft propulsion systems. Due to its toxicity, considering environmental pollution and safe handling, it has been suggested to apply "green propellants" to spacecraft propulsion systems. Among green propellants, HAN (Hydroxyl Ammonium Nitrate)-based liquid propellant has promising characteristics of lower toxicity, higher performance (higher density and specific impulse) and longer storability. Therefore, this attractive propellant is considered as a promising candidate of monopropellant for replacing hydrazine propellant. Though it has some advantages shown above, it is very difficult to control its combustion because of sometimes unpredictable reactivity under high pressure conditions. In recent research, it was found that the reactivity of HAN-based propellants can be somewhat reduced by the addition of methanol as a fuel.
In our previous study, reactivity of HAN-based propellant with methanol and some catalysts was investigated. In the measurement, oxidizer-rich propellant shows higher reactivity with S-405, which is used commonly for hydrazine monopropellant thrusters. Then, firing tests with a thruster were conducted to understand the effects of methanol additive amount. Although stable combustion was observed, thruster performance was much lower than predicted.
In this study, more firing tests were conducted with changes of methanol additive ratio and thruster configuration (combustion chamber length and catalyst bed layer length) to obtain fundamental combustion characteristics of HAN-based thruster for higher thruster performance. As a result, some valuable data as well as development problems for higher-performance thruster design were successfully obtained.
STUDY OF THE COMBUSTION MECHANISM OF AN-BASED PROPELLANTS
153-170
10.1615/IntJEnergeticMaterialsChemProp.v7.i2.50
Valery
Sinditskii
Mendeleev University of Chemical Technology
Viacheslav Yu.
Egorshev
Department of Chemical Engineering, Mendeleev University of Chemical Technology, 9 Miusskaya Sq., 125047, Moscow, Russia
Derek
Tomazi
Politecnico di Milano, Dipartimento di Energetica, 32 Piazza Leonardo da Vinci, 20133 Milano
This paper discusses results obtained in studying the combustion mechanism of ammonium nitrate (AN)-based propellants. For this purpose, a row of progressively complicated AN-based systems: AN/catalyst; AN/catalyst/binder; AN/catalyst/binder/ammonium perchlorate (AP); and AN/catalyst/binder/AP/Al has been studied. It was shown that successive addition of AP and Al to the binary mixture of a catalyzed AN/binder yields a regular increase in the burning rate, accompanied by a small change in the pressure exponent. On the basis of flame structure investigation, it has been determined that the surface temperature of catalyzed AN as well as AN-based propellants is controlled by the dissociative evaporation of the salt. Analysis of obtained results allows for the suggestion of a combustion mechanism for AN-based propellants, which is based on the leading role of heat release in the condensed phase.