Arkhipov, Vladimir A.

Glotov, Oleg

Kiskin, Alexander

Korotkikh, Alexander G.

Slyusarskiy, Konstantin

Zarko, Vladimir E.

English

Tomsk State University Repository

EFFECT OF IRON AND BORON POWDERS ON IGNITION AND COMBUSTION OF ALUMINIZED COMPOSITE SOLID PROPELLANTSAlexander Korotkikh1, 2, Vladimir Arkhipov2, Oleg Glotov3, Vladimir Zarko2, 3, Alexander Kiskin3, Konstantin Slyusarskiy11 Institute of Power Engineering, Tomsk Polytechnic University, 30, Lenin Ave., Tomsk, 634050, Russia2 Research Institute of Applied Mathematics and Mechanics, Tomsk State University, 36, Lenin Avenue, Tomsk, 634050, Russia3 Institute of Chemical Kinetics and Combustion of SB RAS, 3, Institutskaya Str., Novosibirsk, 630090, RussiaE-mail: korotkikh@tpu.ruAbstractThe effect of ultrafine powders (UFPs) of iron and amorphous boron in the composite solid propellants (CSPs) on the basis of ammonium perchlorate (AP), butadiene rubber and aluminum UFP Alex on the characteristics of ignition and combustion, also on the composition of condensed combustion products (CCPs) was studied. It was found that partial replacement Alex by iron UFP in CSP decreases theignition time 1.3–1.9 times under initiation by CO2-laser in the air at the range of heat flux density 55–220 W/cm2 and the increase of the recoil force of gasification products outflow from burning surface by 27 % in the period of stationary combustion of samples and the increase of the burning rate 1.3–1.4 times at the range of nitrogen pressure 2.0–7.5 MPa and reduction of the average diameter of particles d43of CCPs from 37.4 m to 33.5 m at nitrogen pressure 4 MPa. Upon partial replacement of Alex by amorphous boron UFP in CSP the ignition times are decreased 1.2–1.4 times, the recoil force of gasification products outflow from burning surface is increased by 9 % and the burning rate of CSP does not change in the above pressure range, while the average diameter of particles d43 of CCPs is reduced to 32.6 m.Keywords: composite solid propellant, aluminum powder, iron, boron, ignition, recoil force, combustion, condensed combustion products1. IntroductionThe modern composite solid propellants (CSPs) contain as the oxidizer crystals of ammonium perchlorate (AP), ammonium nitrate (AN) and nitramines (RDX, HMX, CL-20) [1–2], combustible-binder – inert or energetic polymer rubber, and metal fuel – aluminum powder with typical content up to 22 wt. % [3–5]. These systems are used as the energy source of solid rocket motors and gas generators for various purposes. Adjustment of the CSP burning rate is mainly achieved by introduction in propellant formulation the catalysts, through partial or complete replacement of AP and AN by nitramines, by changes of the excess oxidizer factor, as well as the changing of the particle size of oxidizer and metal powders.As the burning catalysts of CSPs metal oxides: MnO2, Ni2O3, Cr2O3, MgO, Fe2O3, Co2O3, CuO, SiO2, copper, iron, zinc, cadmium and magnesium salts of chromic and metachromic acids, complex cyanides of copper, iron and nickel are used [6–9]. The most common and versatile in this group of catalysts are the systems containing copper, chromium, boron and iron [10–12].This paper presents the experimental results on ignition and combustion processes of CSPs based on aluminum ultrafine powder (UFP) Alex, containing additives of iron and amorphous boron UFPs and the methods for determining the set of ignition and combustion parameters: the gasification and ignition times, the recoil force of gasification products outflow, the burning rate of samples, and the quantitative and phase compositions, the size distribution of particles of condensed combustion products (CCPs).2. Experimental2.1. The CSP samplesWe studied the samples of CSP on the basis of bidisperse AP (fraction less than 50 m and 160–315 m in the ratio 40/60), inert combustible-binder (19.7 wt. %) – butadiene rubber plasticized by transformer oil, and aluminum UFP Alex (15.7 wt. %) obtained in argon using electric explosion of conductors with a shelf life of more than two years. In the second and third compositions of CSPs 2 wt. % of the Alex UFP was partially replaced by 2 wt. % catalyst additives – UFPs of iron and amorphous boron. According to the measurements on the BET analyzer Nova 2200e in nitrogen the specific surface area of Alex amounts to 7.04 m2/g, iron – 1.08 m2/g, amorphous boron – 8.63 m2/g. The studied cylindrical samples of CSPs in diameter 10 mm and height 30 mm produced in the laboratory by extrusion pressing with the subsequent curing. The density of solid samples depending on the component composition was in an interval of 1.53–1.59 g/cm3.2.2. Ignition of CSPsThe ignition study of CSPs was carried with the use of set up for the radiant heating on the basis of CO2-laser with the wavelength of 10.6 m and maximal power of 100 W (Fig. 1). Prior to testing the CSP samples were cut into tablets of 5 mm in height. The CSP samples were placed in the hollow cylinder of 10 mm depth made of ebonite for inhibiting the lateral surface and making one-dimensional flow of gasification products.Fig. 1. The scheme of experimental setup based on CO2-laser:1 – CO2-laser; 2 – beam-splitting mirror; 3 – thermoelectric sensor of radiation power;4 – shutter; 5 – lens; 6 – CSP sample; 7 – photodiodes; 8 – transducerof recoil force; 9 – ADCs; 10 – PC; 11 – video cameraThe test CSP sample (6) was attached to the substrate of recoil force transducer (8) to register the gasification products outflow from the burning surface. When opening the shutter (4) the radiation was focused by the sodium chloride lens (5) to the CSP sample (6). Signals from the recoil force transducer (8) and photodiodes (7) were transmitted to the L-card-E 14-440 ADC (9) and recorded in the personal computer (10), and then processed with the software application LGraph2.The time delay of start gasification tgas of CSP sample was determined as time interval between the moments of signals change of photodiode near the shutter (7) (or a thermocouple installed in the laser beam behind the shutter), and the recoilforce transducer (8). Photodiode (7) registered the moment of opening the shutter, transducer (8) recorded the appearance of recoil force signal of gasification products flowing from the front (irradiated) sample surface. The ignition times of CSPs was determined by difference between the moments of signals from two photodiodes (7), one of which registered the appearance of flame near the end surface of CSP sample. The relative error of delay times measuring of gasification tgas and ignition tignwas equal 5–12 % at the value of confidence probability 0.9.The value of recoil force of gasification products outflow from the end surface of CSP sample during the heating of reaction layer, ignition and combustion of CSPs was determined using recoil force transducer [13].The power of laser radiation was measured by the thermoelectric sensor ofradiation power (3). The maximum radiation power was defined in the center of the laser beam.2.3. Combustion of CSPsThe study of effect of iron and amorphous boron UFPs additives on the combustion process of CSPs was carried in blow-through sampling bomb in nitrogen at different pressures [14]. We used the CSP samples in diameter 10 mm and height 25–30 mm in experiments with sampling of condensed combustion products (CCP). The lateral surface of samples was inhibited by heat resistant rubber «solpren» (a styrene/butadiene copolymer). During combustion of solpren the carbonaceous particles were formed, the contents of which in CCPs was not exceed 1 wt. %.The burning rate of CSPs was evaluated by known length and the burning time of samples, defined by a signal from a pressure sensor in bomb during the combustion. During combustion of CSP sample the gaseous and condensed combustion products passed through the metal sieve mesh packet and analytical aerosol filter which are captured solid particles of different sizes. Sampled CCP particles were divided onto four fractions – less than 80 m, 80–160 m, 160–315 m and greater than 315 m, and then subjected to a visual inspection, particle size and phase analyses.3. Results and discussion3.1. Ignition characteristics of CSPsThe values of the time of gasification and ignition, recoil force of gasification products outflow for the solid propellants samples under study in atmospheric conditions were determined with use of laser set-up, Fig. 1. Processing of signal recording from the recoil force transducer we get the time delays of gasification tgasand ignition tign,, the value of the recoil force F outflow of gasification products from the burning surface of CSP samples. Examples of records are shown in Fig. 2. The ignition time of CSPs versus the maximum value the heat flux density (in the center of the laser beam) dependences were determined, see in Fig. 3.a) b)c)Fig. 2. The signals of thermocouple (T), photodiode (Ph) and the recoil force transducer (F) that have been recorded at qmax = 65 W/cm2 over time interval embracing the heating, ignition and combustion processes for CSPs samples with Alex (а), Alex+Fe (b) и Alex+B (c)Fig. 3. The ignition time of aluminized CSPs from the heat flux densityPartial replacement of Alex by iron UFP in CSP leads to the decrease of the ignition time 1.3–1.9 times in the range of heat flux density 55–220 W/cm2. Partialreplacement of Alex by boron UFP in CSP leads to the decrease of the ignition time1.2–1.4 times in the specified range of q. For CSP sample with Alex the gasification start immediately after the shutter opens and the gasification time delay 40 times less than the ignition time at the heat radiant flux density of qmax = 65 W/cm2. For samples with Alex+Fe and Alex+B the time moments of ignition start and gasification start coincides. Partial replacement of Alex by iron UFP in CSP at the initiation a CO2-laser leads to the increase the gasification time 25 times and the increase of the recoil force of gasification products outflow from burning surface 1.3 times in the period of stationary combustion of CSPs. For the partial replacement of Alex by boron UFP in the CSP composition the gasification time increases 36 times and the recoil force of gasification products outflow increases 1.1 times. Thus, the additives of iron and boron UFPs in the aluminized CSPs allows to considerably increase the gasification time and reduce the ignition time and also increase the recoil force of gasification products outflow from the burning surface of CSP samples.3.2. Combustion characteristics of CSPsThe values of the burning rate at different nitrogen pressures were determined in the sampling bomb (Fig. 4). The values of the CSPs burning rate and the relative mass of CCPs mccp equal to the ratio of the CCPs mass Mccp to the mass of CSPsample Msamp at pressure  4 MPa are presented in Table 1.Fig. 4. The burning rate of aluminized CSPs from pressureTable 1The burning rate of CSPs and relative mass of CCPs at p  4 MPaCSP sample u, mm/s mcсp = Mcсp/Msamp1, Alex 12.4  0.2 0.30  0.042, Alex+Fe 14.7  0.2 0.29  0.033, Alex + B 12.3  0.3 0.29  0.04Partial replacement of Alex by iron UFP in CSP composition slightly decreasesthe exponent of burning rate law from 0.45 to 0.43 and the increase of the burning rate from 7.5 to 11.7 mm/s at pressure 2.2 MPa and from 14.3 to 19.7 mm/s at pressure 7.5 MPa. The mass of sampled CCPs of tested CSPs practically does not change at nitrogen pressure  4 MPa.For partial replacement of Alex by boron UFP in CSP the burning rate and relative mass of CCPs at pressure  4 MPa are virtually unchanged. The burning rates of CSPs with Alex+B are equal 8.4 mm/s at pressure 2.3 MPa and 14.6 mm/s at pressure 7.7 MPa.Obtained data of the CSPs burning rate correlates well with the data of recoilforce of gasification products outflow from burning surface of samples (see Fig. 2).3.3. Particle size and phase compositions of CCPsSampled CCPs at nitrogen pressure 4 MPa were subjected to particle size and X-ray diffraction (XRD) analyses. The mass-size distribution function of CCPs particles measured with use of Analysette 22 particle size analyzer in distilled water under the ultrasound action are presented in Fig. 5.a) b)c)Fig. 5. Differential and cumulative mass size distribution function for CCP particles of aluminized CSPs with Alex (a), Alex+Fe (b) and Alex+В (c)Particle size measurements showed that the mass fraction of CCPs particle fraction less than 10 m amounted 0.16, 0.18 and 0.27, for CSPs with Alex, Alex+Feand Alex+B, respectively, the particle fraction of CCPs less than 45 m – 0.67, 0.71, 0.74, the particle fraction of CCPs less than 100 m – 0.97, 0.99 and 0.98.Partial replacement of Alex by iron UFP in the CSP composition decreases themean particle diameter d43 from 37.4 to 33.5 m. Partial replacement of Alex by boron UFP in CSP leads to the decrease of the CCPs d43 to 32.6 m.XRD analysis of CCPs performed using the Shimadzu XRD 6000 diffractometer showed that the content of amorphous phase in the sampled CCPs in the case ofpropellant with Alex is equal 18 wt. %, in the case of propellant with Alex+Fe –d, md, md, m22 wt. % and in the case of propellant with Alex+B – 26 wt. %. The phase composition of CCPs, sampled at nitrogen pressure  4 MPa, is presented in Table 2.Table 2The phase composition (without the amorphous phase) of CCPs of aluminized CSPsContent of phases in CCPs, wt. %CSP sample -Al2O3 -Al2O3 -Al2O3 AlN C3N41, Alex 7.1 66.7 2.0 7.1 17.12, Alex+Fe 9.4 54.7 1.6 8.3 26.03, Alex+B 43.3 – – – 56.7It was found that partial replacement Alex by Fe UFP in CSP increases the content of alumina -Al2O3 (corundum) by 2.3 wt. %, aluminum nitride AlN – by 1.2 wt. %, carbon nitride C3N4 – by 8.9 wt. % and reduces the content of alumina -Al2O3 (monoclinic) by 12 wt. % in composition of sampled CCPs due to possible the catalytic effect, which reduces the temperature of the beginning of AP high temperature decomposition in the reaction layer of CSP, and the increase of the temperature in gas phase zone of chemical reactions, and also the exothermic reaction of iron and aluminum particles on the reaction layer near the surface of CSPsample.Partial replacement of Alex by boron UFP in CSP increases the content of alumina -Al2O3 by 6.1 times and carbon nitride C3N4 by 3.3 times in composition of sampled CCPs due to the possible increase of the heat release during combustion of boron UFP and, respectively, the temperature in the gas phase zone of chemical reactions.4. Conclusions1. The effects of additives of iron and amorphous boron UFPs in composite solid propellants on the basis of AP, butadiene rubber and 15.7 wt. % of aluminum Alex UFP on the ignition and combustion characteristics were studied. The ignition was performed with CO2-laser in air at atmospheric pressure. Burning rate law and condensed combustion products were studied with use of a special designed blow-through sampling bomb at nitrogen pressure from 2.0 to 7.5 MPa.2. It was found that partial replacement of Alex by 2 wt. % iron UFP in CSPdecreases the ignition time by 1.3–1.9 times at the range of heat flux density 55–220 W/cm2, the increase of the recoil force of gasification products outflow from burning surface 1.3 times in the period of stationary combustion of samples, the increase of the burning rate 1.3–1.4 times at the range of nitrogen pressure 2.0–7.5 MPa and reduction of the mean diameter of CCP particles d43 from 37.4 m to33.5 m at nitrogen pressure 4 MPa. In the sampled combustion products at 4 MPa the content of aluminum oxide -Al2O3 increases by 2.3 wt. %, aluminum nitride AlN – by 1.2 wt. % and carbon nitride C3N4 – by 8.9 wt. % due to possible the catalytic effect, which reduces the temperature of the beginning of AP high temperature decomposition in the reaction layer of CSP, and interaction of thermite mixture of aluminum and iron particles on the surface of the reaction layer of sample, and also the increase of the temperature in the gas phase zone of chemical reactions.3. Partial replacement of Alex by boron UFP in CSP decreases the ignition time1.2–1.4 times at q = 55–220 W/cm2 and the increase of the recoil force of gasification products outflow from the burning surface 1.1 times. In this the burning rate of CSP does not change at the range of pressure 2.0–7.5 MPa, the mean diameter of CCPs particles d43 is reduced to 32.6 m at pressure 4 MPa, and the content of alumina -Al2O3 and carbon nitride C3N4 are increased 6.1 times and 3.3 times in CCPs due to the possible increase of the heat release during combustion of boron UFP and the temperature in the condensed and gas phase zone of chemical reactions.AcknowledgementThis work was partially supported by the Russian Foundation for Basic Research (project No. 15-33-50066 «Research of ignition and combustion processes of high-energy nanocomposites based on ammonium nitrate» and project No. 15-03-04321 «Ignition and combustion of metal fuel particles based on aluminum and boron»).References1. Beckstead M.W., Puduppakkama K., Thakreb P., Yang V. Modeling of combustion and ignition of solid-propellant ingredients // Progress in Energy and Combustion Science 33 (2007) 497–551.2. Takahashi K., Oide Sh., Kuwahara T. Agglomeration characteristics of aluminum particles in AP/AN composite propellants // Propellants, Explosives, Pyrotechnics 38 (2013) 555–562.3. Sossi A., Duranti E., Manzoni M., Paravan C., DeLuca L.T., Vorozhtsov A.B., Lerner M.I., Rodkevich N.G., Gromov A.A., Savin E.N. Combustion of HTPB-based solid fuels loaded with coated nanoaluminum // Combustion Science and Technology 185 (2013) 17–36.4. Arkhipov V.A., Korotkikh A.G. The influence of aluminum powder dispersity on composite solid propellants ignitability by laser radiation // Combustion and Flame 159 (2012) 409–415.5. Arkhipov V.A., Bondarchuk S.S., Korotkikh A.G., Kuznetsov V.T., Gromov A.A., Volkov S.A., Revyagin L.N. Influence of aluminum particle size on ignition and nonstationary combustion of heterogeneous condensed systems //Combustion, Explosion, and Shock Waves 48 (2012) 625–635.6. Arkhipov V.A., Bondarchuk S.S., Korotkikh A.G. Comparative analysis of methods for measuring the transient burning rate. II. Research results // Combustion, Explosion, and Shock Waves 46 (2010) 570–577.7. Shioya S., Kohga M., Naya T. Burning characteristics of ammonium perchlorate-based composite propellant supplemented with diatomaceous earth // Combustion and Flame 161 (2014) 620–630.8. Ishitha K., Ramakrishna P.A. Studies on the role of iron oxide and copper chromite in solid propellant combustion // Combustion and Flame 161 (2014) 2717–2728.9. Farley C.W., Pantoya M.L., Levitas V.I. A mechanistic perspective of atmospheric oxygen sensitivity on composite energetic material reactions // Combustion and Flame 161 (2014) 1131–1134.10. Berner M.K., Talawar M.B., Zarko V.E. Nanoparticles of energetic materials: synthesis and properties (Review) // Combustion, Explosion, and Shock Waves 49 (2013) 625–647.11. McDonald B.A., Rice J.R., Kirkham M.W. Humidity induced burning rate degradation of an iron oxide catalyzed ammonium perchlorate/HTPB composite propellant // Combustion and Flame 161 (2014) 363–369.12. Zarko V.E., Glotov O.G. Formation of Al oxide particles in combustion of aluminized condensed systems (Review) // Science and Technology of Energetic Materials 74 (2013) 139–143.13. Arkhipov V.A., Kiskin A.B., Zarko V.E., Korotkikh A.G. Laboratory method for measurement of the specific impulse of solid propellants // Combustion, Explosion, and Shock Waves 50 (2014) 622–624.14. Glotov O.G., Zyryanov V.Ya. Condensed combustion products of aluminized propellants. I. A technique for investigating the evolution of disperse-phase particles // Combustion, Explosion and Shock Waves 31 (1995) 72–78.

Effect of iron and boron powders on ignition and combustion of aluminized composite solid propellants

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Effect of iron and boron powders on ignition and combustion of aluminized composite solid propellants

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