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1
Jain, Prakhar, Vineet Kumar Rathi e Shelly Biswas. "Study of Aging Characteristics for Metalized HTPB Based Composite Solid Propellants Stored in Ambient Conditions". Defence Science Journal 74, n. 5 (29 agosto 2024): 615–26. http://dx.doi.org/10.14429/dsj.74.19786.
Testo completoAbstract (sommario):
The aging of any propellant is defined as the change in the physical, chemical, and performance parameters of solid rocket propellants. The propellant’s service life and aging properties are important parameters of the study, especially for missiles and other defense applications. Hydroxyl-terminated polybutadiene (HTPB) based composite solid propellants with ammonium perchlorate (AP) are the most prominently used propellants in the operations of solid rocket motors in the defense and space sectors. Thus, studying this composite solid propellant is of essential when determining ambient service life. Performance parameters studied in this research are burn rate under high-pressure conditions in Crawford bomb setup, Thermogravimetric Analysis, and Fourier Transform Infrared Spectroscopy (FTIR). SEM and X-ray diffraction (XRD) analysis of the aged sample were also conducted to ascertain the chemical composition and morphological changes in the samples. Naturally aged propellant strands manufactured in different years have been compared with freshly prepared ones to establish a trend for deriving conclusions. The results from different analysis techniques, FTIR, XRD, and FESEM, depicted that oxidation of metals happens while aging of propellant due to atmospheric moisture, and the metal oxides prominently affect the propellant chemical composition and decomposition process of the propellant samples. The ballistic properties of the aluminium added samples showed an increment in burn rate. In contrast, the bimetal addition of aluminium and magnesium combined as an additive decreased the ballistic burn rate.
2
Aziz, Amir, Rizalman Mamat, Wan Khairuddin Wan Ali e Mohd Rozi Mohd Perang. "Review on Typical Ingredients for Ammonium Perchlorate Based Solid Propellant". Applied Mechanics and Materials 773-774 (luglio 2015): 470–75. http://dx.doi.org/10.4028/www.scientific.net/amm.773-774.470.
Testo completoAbstract (sommario):
Ammonium perchlorate (AP) based solid propellant is a modern solid rocket propellant used in various applications. The combustion characteristics of AP based composite propellants were extensively studied by many research scholars to gain higher thrust. The amount of thrust and the thrust profile, which may be obtained from a specific grain design, is mainly determined by the propellant composition and the manufacturing process that produces the solid propellant. This article is intended to review and discuss several aspects of the composition and preparation of the solid rocket propellant. The analysis covers the main ingredients of AP based propellants such as the binder, oxidizer, metal fuel, and plasticizers. The main conclusions are derived from each of its components with specific methods of good manufacturing practices. In conclusion, the AP based solid propellant, like other composite propellants is highly influenced by its composition. However, the quality of the finished grain is mainly due to the manufacturing process.
3
Poryazov, V. A., K. M. Moiseeva e A. Yu Krainov. "NUMERICAL SIMULATION OF COMBUSTION OF THE COMPOSITE SOLID PROPELLANT CONTAINING BIDISPERSED BORON POWDER". Vestnik Tomskogo gosudarstvennogo universiteta. Matematika i mekhanika, n. 72 (2021): 131–39. http://dx.doi.org/10.17223/19988621/72/11.
Testo completoAbstract (sommario):
A problem of combustion of the composite solid propellants containing various powders of metals and non-metals is relevant in terms of studying the effect of various compositions of powders on the linear rate of propellant combustion. One of the lines of research is to determine the effect of the addition of a boron powder on the burning rate of a composite solid propellant. This work presents the results of numerical simulation of combustion of the composite solid propellant containing bidispersed boron powder. Physical and mathematical formulation of the problem is based on the approaches of the mechanics of two-phase reactive media. To determine the linear burning rate, the Hermance model of combustion of composite solid propellants is used, based on the assumption that the burning rate is determined by mass fluxes of the components outgoing from the propellant surface. The solution is performed numerically using the breakdown of an arbitrary discontinuity algorithm. The dependences of the linear burning rate of the composite solid propellant on the dispersion of the boron particles and gas pressure above the propellant surface are obtained. It is shown that the burning rate of the composite solid propellant with bidispersed boron powder changes in contrast to that of the composite solid propellant with monodispersed powder. This fact proves that the powder dispersion should be taken into account when solving the problems of combustion of the composite solid propellants containing reactive particles.
4
S A, Reshmitha Shree, Saif Ahmed Ansari, Steven Raj e Sukh Arora. "EVALUATION OF SOLID ROCKET PROPELLANTS FOR LOW EARTH ORBIT". INTERANTIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT 08, n. 008 (31 agosto 2024): 1–3. http://dx.doi.org/10.55041/ijsrem37252.
Testo completoAbstract (sommario):
In contemporary aerospace technology, solid rocket propellants are commonly employed in the thriller and boost of space cargoes to LEO. These are reliable, uncomplicated, and high in thrust; and thus, can be used in both military as well as civil space ventures. This paper provides a comprehensive evaluation of five prominent solid rocket propellants: Five categories namely Ammonium Perchlorate Composite Propellant (APCP), Double-Base Propellant, Composite Modified Double Base (CMDB) Propellant, Hydroxyl-terminated polybutadiene (HTPB)-Based Propellant, and Ammonium Nitrate Composite Propellant (ANCP) have been identified. This also falls under the evaluation and includes aspects such as historical bases to see how the formulation of the propellant has changed over time regarding the development of propellant technology. In the case of each propellant, the chemical properties of the mix and reactions that its fundamental are analyzed. It also shares details regarding the changes and advancements made in the little while to enhance capability, safety, and environmental compatibility of these fuels, such as synthesizing fuels for liquid bipropellants. Some of the modern applications of technologies within the active spectrum of aerospace operations are explained in more detail to provide clients with the most versatile and essential information. Among the essentials of this work, the complex calculation of thrusts developed by the specific propellant with corresponding graphics has significant importance. These estimations afford chances of comparing the efficiency of the propellant in terms of producing thrusts as well as achieving the indicated optimal performance. Thus, the main objective of this study is to identify which of the solid rocket propellants to use in LEO missions and if any, what modifications could be made to improve them. Thus, the purpose of this paper is to contribute to the development of the constantly evolving branch of rocket propulsion by discussing the benefits and shortcomings of each propellant. These findings and recommendations could be useful in perfecting the recipes for the propellants and improving the efficiency of the subsequent missions to planets. Keywords: Aerospace, Solid rocket propellants, Thrust, Low earth orbit.
5
Zhang, Jing, Zhen Wang, Shixiong Sun e Yunjun Luo. "Preparation and Properties of a Novel High-Toughness Solid Propellant Adhesive System Based on Glycidyl Azide Polymer–Energetic Thermoplastic Elastomer/Nitrocellulose/Butyl Nitrate Ethyl Nitramine". Polymers 15, n. 18 (5 settembre 2023): 3656. http://dx.doi.org/10.3390/polym15183656.
Testo completoAbstract (sommario):
Glycidyl azide polymer (GAP)–energetic thermoplastic elastomer (GAP-ETPE) propellants have high development prospects as green solid propellants, but the preparation of GAP-ETPEs with excellent performance is still a challenge. Improving the performance of the adhesive system in a propellant by introducing a plasticizer is an effective approach to increasing the energy and toughness of the propellant. Herein, a novel high-strength solid propellant adhesive system was proposed with GAP-ETPEs as the adhesive skeleton, butyl nitrate ethyl nitramine (Bu-NENA) as the energetic plasticizer, and nitrocellulose (NC) as the reinforcing agent. The effects of the structural factors on its properties were studied. The results showed that the binder system would give the propellant better mechanical and safety properties. The results can provide a reference for the structure design, forming process, and parameter selection of high-performance GAP-based green solid propellants.
6
Zhang, Jing, Zhen Wang, Shixiong Sun e Yunjun Luo. "Influence of Solid Filler on the Rheological Properties of Propellants Based on Energetic Thermoplastic Elastomer". Materials 16, n. 2 (13 gennaio 2023): 808. http://dx.doi.org/10.3390/ma16020808.
Testo completoAbstract (sommario):
Glycidyl azide polymer-energetic thermoplastic elastomer propellant (GAP-ETPE) has high development prospects as a green solid propellant, although the preparation of GAP-ETPE with excellent performance is still a challenge. Focusing on the demand of high-strength solid propellants for free-loading rocket motors, a GAP-ETPE model propellant with excellent overall performance was prepared in this work, and the influence of adhesive structure characteristics on its fluidity was studied. Furthermore, the influence of filler on the rheological properties of the model propellant was investigated by introducing hexogen (RDX) and Al, and a corresponding two-phase model was established. The results may provide a reference for the structural design, molding process, and parameter selection of high-performance GAP-based green solid propellants.
7
Abdullah, Mohamed, F. Gholamian e A. R. Zarei. "Noncrystalline Binder Based Composite Propellant". ISRN Aerospace Engineering 2013 (24 settembre 2013): 1–6. http://dx.doi.org/10.1155/2013/679710.
Testo completoAbstract (sommario):
This study reports on propellants based on cross-linked HTPE binder plasticized with butyl nitroxyethylnitramine (BuNENA) as energetic material and HP 4000D as noncrystalline prepolymer. This binder was conducted with solid loading in the 85%. The results showed an improvement in processability, mechanical properties and burning rate. In addition, its propellant delivers (about 6 seconds) higher performance (specific impulse) than the best existing composite solid rocket propellant. Thermal analyses have performed by (DSC, TGA). The thermal curves have showed a low glass transition temperature () of propellant samples, and there was no sign of binder polymer crystallization at low temperatures (−50°C). Due to its high molecular weight and unsymmetrical or random molecule distributions, the polyether (HP 4000D) has been enhanced the mechanical properties of propellants binder polymer over a large range of temperatures [−50, 50°C]. The propellants described in this paper have presented high volumetric specific impulse (>500 s·gr·cc−1). These factors combined make BuNENA based composite propellant a potentially attractive alternative for a number of missions demanding composite solid propellants.
8
Glascock, Matthew S., Joshua L. Rovey e Kurt A. Polzin. "Impulse and Performance Measurements of Electric Solid Propellant in a Laboratory Electrothermal Ablation-Fed Pulsed Plasma Thruster". Aerospace 7, n. 6 (30 maggio 2020): 70. http://dx.doi.org/10.3390/aerospace7060070.
Testo completoAbstract (sommario):
Electric solid propellants are advanced solid chemical rocket propellants that can be controlled (ignited, throttled and extinguished) through the application and removal of an electric current. This behavior may enable the propellant to be used in multimode propulsion systems utilizing the ablative pulsed plasma thruster. The performance of an electric solid propellant operating in an electrothermal ablation-fed pulsed plasma thruster was investigated using an inverted pendulum micro-newton thrust stand. The impulse bit and specific impulse of the device using the electric solid propellant were measured for short-duration test runs of 100 pulses and longer-duration runs to end-of-life, at energy levels of 5, 10, 15 and 20 J. Also, the device was operated using the current state-of-the-art ablation-fed pulsed plasma thruster propellant, polytetrafluoroethylene (PTFE). Impulse bit measurements for PTFE indicate 100 ± 20 µN-s at an initial energy level of 5 J, which increases linearly with energy by approximately 30 µN-s/J. Within the error of the experiment, measurements of the impulse bit for the electric solid propellant are identical to PTFE. Specific impulse when operating on PTFE is calculated to be about 450 s. It is demonstrated that a surface layer in the hygroscopic electric solid propellant is rapidly ablated over the first few discharges of the device, which decreases the average specific impulse relative to the traditional polytetrafluoroethylene propellant. Correcting these data by subtracting the early discharge ablation mass loss measurements yields a corrected electric solid propellant specific impulse of approximately 300 s.
9
Kohga, Makoto, Tomoki Naya e Kayoko Okamoto. "Burning Characteristics of Ammonium-Nitrate-Based Composite Propellants with a Hydroxyl-Terminated Polybutadiene/Polytetrahydrofuran Blend Binder". International Journal of Aerospace Engineering 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/378483.
Testo completoAbstract (sommario):
Ammonium-nitrate-(AN-) based composite propellants prepared with a hydroxyl-terminated polybutadiene (HTPB)/polytetrahydrofuran (PTHF) blend binder have unique thermal decomposition characteristics. In this study, the burning characteristics of AN/HTPB/PTHF propellants are investigated. The specific impulse and adiabatic flame temperature of an AN-based propellant theoretically increases with an increase in the proportion of PTHF in the HTPB/PTHF blend. With an AN/HTPB propellant, a solid residue is left on the burning surface of the propellant, and the shape of this residue is similar to that of the propellant. On the other hand, an AN/HTPB/PTHF propellant does not leave a solid residue. The burning rates of the AN/HTPB/PTHF propellant are not markedly different from those of the AN/HTPB propellant because some of the liquefied HTPB/PTHF binder cover the burning surface and impede decomposition and combustion. The burning rates of an AN/HTPB/PTHF propellant with a burning catalyst are higher than those of an AN/HTPB propellant supplemented with a catalyst. The beneficial effect of the blend binder on the burning characteristics is clarified upon the addition of a catalyst. The catalyst suppresses the negative influence of the liquefied binder that covers the burning surface. Thus, HTPB/PTHF blend binders are useful in improving the performance of AN-based propellants.
10
He, Zhong Qi, Ke Zhou e Shu Pan Yin. "Security Analysis on Single-Screw Extrusion Process of Solid Propellant by Numerical Simulation". Advanced Materials Research 997 (agosto 2014): 605–9. http://dx.doi.org/10.4028/www.scientific.net/amr.997.605.
Testo completoAbstract (sommario):
Solid propellants are flammable, explosive, which maybe initiated unexpectedly under specific excitation conditions through high-speed screwing. Though single-screw extrusion process for solid propellant occurred a large proportion accidents, the rheological parameters of the propellant material were difficult to get yet, which affects the process safety greatly. In this paper, the CFD software, POLYFLOW, and a numerical simulation method were adopted to investigate the rheological parameters in single-screw extrusion process of solid propellant. By analyzing the rheological state of a solid propellant in the screw extrusion process, the applicable numerical model was established with a substitute material for the propellant. As a result, distributions of key parameters, such as material temperature, pressure, viscosity, were obtained. The simulation shows that the material has relatively higher pressure, temperature and smaller viscosity at the screw edge, where solid propellant components were mixing and plasticizing severely, also where needs pay much attention to for safety reasons.
11
Jayaraman, Kandasamy, Ponnurengam Malliappan Sivakumar, Ali Zarrabi, R. Sivakumar e S. Jeyakumar. "Combustion Characteristics of Nanoaluminium-Based Composite Solid Propellants: An Overview". Journal of Chemistry 2021 (19 maggio 2021): 1–12. http://dx.doi.org/10.1155/2021/5520430.
Testo completoAbstract (sommario):
The nanosized powders have gained attention to produce materials exhibiting novel properties and for developing advanced technologies as well. Nanosized materials exhibit substantially favourable qualities such as improved catalytic activity, augmentation in reactivity, and reduction in melting temperature. Several researchers have pointed out the influence of ultrafine aluminium (∼100 nm) and nanoaluminium (<100 nm) on burning rates of the composite solid propellants comprising AP as the oxidizer. The inclusion of ultrafine aluminium augments the burning rate of the composite propellants by means of aluminium particle’s ignition through the leading edge flames (LEFs) anchoring above the interfaces of coarse AP/binder and the binder/fine AP matrix flames as well. The sandwiches containing 15% of nanoaluminium solid loading in the binder lamina exhibit the burning rate increment of about 20–30%. It was noticed that the burning rate increment with nanoaluminium is around 1.6–2 times with respect to the propellant compositions without aluminium for various pressure ranges and also for different micron-sized aluminium particles in the composition. The addition of nano-Al in the composite propellants washes out the plateaus in burning rate trends that are perceived from non-Al and microaluminized propellants; however, the burning rates of nanoaluminized propellants demonstrate low-pressure exponents at the higher pressure level. The contribution of catalysts towards the burning rate in the nanoaluminized propellants is reduced and is apparent only with nanosized catalysts. The near-surface nanoaluminium ignition and diffusion-limited nano-Al particle combustion contribute heat to the propellant-regressing surface that dominates the burning rate. Quench-collected nanoaluminized propellant residues display notable agglomeration, although a minor percentage of the agglomerates are in the 1–3 µm range; however, these are within 5 µm in size. Percentage of elongation and initial modulus of the propellant are decreased when the coarse AP particles are replaced by aluminium in the propellant composition.
12
Wang, Qizhou, Guang Wang, Zhejun Wang, Hongfu Qiang, Xueren Wang e Shudi Pei. "Strain-rate correlation of biaxial tension and compression mechanical properties of HTPB and NEPE propellants". AIP Advances 12, n. 5 (1 maggio 2022): 055005. http://dx.doi.org/10.1063/5.0083205.
Testo completoAbstract (sommario):
An effective biaxial tension and compression test method is proposed based on the shortcomings of current research for the mechanical properties of solid propellants under complex stress states. The equal proportion biaxial tension and compression test of HTPB (Hydroxyl-terminated polybutadiene) and NEPE (NitrateEster Plasticized Polyether) solid propellants is performed at different rates while at room temperature, and the damage morphology of the tension–compression zone is analyzed using micro-CT. The results show that the failure mode of the solid propellant under biaxial tension and compression loading is similar to that under uniaxial tension. Meanwhile, the compressive strength is much greater than the tensile strength, which will eventually cause tensile failure. With an increased loading rate, the growth trend of the initial modulus, ultimate strength, and maximum elongation of the propellant is gradually flattened, and the damage degree is gradually reduced. Additionally, damage that forms in the HTPB propellant is from dewetting and particle fracture while that for the NEPE propellant is from matrix tearing. The porosity can be used as the meso-damage parameter of the propellant.
13
Pang, W. Q., F. Q. Zhao, L. T. DeLuca, C. Kappenstein, H. X. Xu e X. Z. Fan. "Effects of Nano-Sized Al on the Combustion Performance of Fuel Rich Solid Rocket Propellants". Eurasian Chemico-Technological Journal 18, n. 3 (5 novembre 2016): 197. http://dx.doi.org/10.18321/ectj425.
Testo completoAbstract (sommario):
Several industrial- and research – type fuel rich solid rocket propellants containing nano-metric aluminum metal particles, featuring the same nominal composition, were prepared and experimentally analyzed. The effects of nano-sized aluminum (nAl) on the rheological properties of metal/HTPB slurries and fuel rich solid propellant slurries were investigated. The energetic properties (heat of combustion and density) and the hazardous properties (impact sensitivity and friction sensitivity) of propellants prepared were analyzed and the properties mentioned above compared to those of a conventional aluminized (micro-Al, mAl) propellant. The strand burning rate and the associated combustion fl ame structure of propellants were also determined. The results show that nAl powder is nearly “round” or “ellipse” shaped, which is different from the tested micrometric Al used as a reference metal fuel. Two kinds of Al (nAl and mAl) powder can be dispersed in HTPB binder suffi ciently. The density of propellant decreases with increasing mass fraction of nAl powder; the measured heat of combustion, friction sensitivity, and impact sensitivity of propellants increase with increasing mass fraction of nAl powder in the formulation. The burning rates of fuel rich propellant increase with increasing pressure, and the burning rate of the propellant loaded with 20% mass fraction of nAl powder increases 77.2% at 1 MPa, the pressure exponent of propellant increase a little with increasing mass fraction of nAl powder in the explored pressure ranges.
14
Yao, Er Gang, Feng Qi Zhao, Si Yu Xu, Rong Zu Hu, Hui Xiang Xu e Hai Xia Hao. "Combustion Characteristics of Composite Solid Propellants Containing Different Coated Aluminum Nanopowders". Advanced Materials Research 924 (aprile 2014): 200–211. http://dx.doi.org/10.4028/www.scientific.net/amr.924.200.
Testo completoAbstract (sommario):
Aluminum nanopowders coated with oleic acid (nmAl+OA), perfluorotetradecanoic acid (nmAl+PA) and nickel acetylacetonate (nmAl+NA) were prepared. The combustion characteristics of hydroxyl terminated polybutadiene (HTPB) composite solid propellants containing different coated aluminum nanpowders were investigated. The result shows that the burning rate of the propellant sample containing nmAl+NA is the highest at different pressure, the maximum burning rate is up to 26.13 mm·s-1at 15 MPa. The burning rates of propellant samples containing nmAl+OA and nmAl+PA are almost the same at different pressures, and higher than the propellant samples containing untreated aluminum nanopowders only at the pressure range of 10 ~ 15 MPa. The flame brightness of different propellants under different pressure is not the same. The flame brightness is increased with the pressure increasing. The flame center zone brightness of the propellant containing nmAl+PA and nmAl+NA is brighter under 4 MPa, and the brightness of nmAl+NA is the brightest. The surface coating of aluminum nanopowder has little effect on the combustion flame temperature of solid propellant. The burning surface temperature increases with the pressure increasing.
15
Ma, Xuhang, Chuntao Li, Pengchen Jiang, Fangyi Xu, Xiangyu Song e Wei Li. "Modeling method of random collision of ellipsoidal particles in mechanical simulation for high energy solid propellant". Journal of Physics: Conference Series 2882, n. 1 (1 novembre 2024): 012093. http://dx.doi.org/10.1088/1742-6596/2882/1/012093.
Testo completoAbstract (sommario):
Abstract It is based on the molecular dynamics algorithm of elliptical optimization to establish a mesostructure model of oval particles of high-energy solid propellant considering gradation and controllable filling rate according to the mesostructure characteristics of high-energy solid propellant. The bilinear cohesion model was applied to describe the interface damage behavior and carry out the high-energy propellant tensile test at three rates. The rationality of the elliptical particle model has been verified between the comparison of the calculated results with the experimental results established to describe the micromechanical behavior of high-energy propellants, which is to reveal the mesoscopic damage law of high-energy solid propellant under different tensile rates in this paper.
16
Yang, Sa, Guo Qiang He, Yang Liu e Jiang Li. "Turbocharged Solid Propellant Ramjet for Tactical Missile". Applied Mechanics and Materials 152-154 (gennaio 2012): 204–9. http://dx.doi.org/10.4028/www.scientific.net/amm.152-154.204.
Testo completoAbstract (sommario):
Turbocharged solid propellant ramjet (TSPR) is the combination of solid propellant gas generator air turbo ramjet (ATR)with solid ramjet, is cycle of augmented ATR, the parametric performance calculation were carried out for TSPR, The effects of independent design parameters including parameters of compressor and turbine and propellants were studied and the preferred compressor, turbine and propellants were obtained for TSPR; The operation envelop of TSPR and ATR were obtain under the preferred component limitation, the results shows that TSPR offers wide speed-altitude operation envelope, high specific thrust, high specific impulse, it is combining the advantages of the ATR and solid ramjet, and suitable for tactical missiles application meets potential requirements for boosting and cruising.
17
Tao, Ruyi, Shenshen Cheng, Xinggan Lu, Shao Xue e Xiaoting Cui. "The Application of the Particle Element Method in Tubular Propellant Charge Structure: Lumped Element Method and Multiple-Element Method". Energies 17, n. 17 (2 settembre 2024): 4384. http://dx.doi.org/10.3390/en17174384.
Testo completoAbstract (sommario):
Due to the orderly arrangement of tubular propellant, the permeability of combustion gases is improved, which is beneficial for enhancing the safety of the combustion system. However, current internal ballistic gas-solid flow calculation methods adopt a quasi-fluid assumption, which cannot accurately account for the characteristics of long tube shapes. Additionally, tubular propellants exhibit both overall movement and parameter distribution characteristics, necessitating the decoupling of gas and solid phases. These two deficiencies in previous studies have limited the effectiveness of gas-solid flow simulations for tubular propellant. This paper proposes a numerical calculation model suitable for tubular propellant charging based on the particle element method for internal ballistic two-phase flow. Firstly, considering the overall movement characteristics of tubular propellants, the concept of blank particle elements is introduced to represent pure gas phase regions. Then, based on computational requirements, the tubular propellants are divided to form the lumped element method and the multiple-element method. The moving boundary method is used to calculate the movement process of the propellant bed particle group and is compared with experimental results to verify the applicability of the two methods in tubular propellant beds. Analysis results show that the particle element method can effectively capture changes in the flow field inside the chamber and the position of tubular propellants. The lumped element method can quickly obtain the flow field distribution characteristics inside the chamber, while the multiple-element method can capture parameter distribution characteristics at different positions of the tubular propellants while ensuring overall movement.
18
Song, Shixiong, Quanbin Ren, Min Tang, Jiawei Shi e Jiawei Wang. "A Study on Ultra-Low-Pressure Ratio Technology on the Basis of 3D-Printed Propellant for a Solid Rocket Motor". Aerospace 10, n. 10 (29 settembre 2023): 862. http://dx.doi.org/10.3390/aerospace10100862.
Testo completoAbstract (sommario):
Fused deposition technology (FDM), as an additive manufacturing (AM) technology, holds immense potential in the field of solid grain manufacturing. It can accomplish complex grain shaping with ultra-low-pressure ratios, which are challenging to achieve using conventional grain manufacturing processes. In this work, solid propellants with complex structures were made by using 3D printing. The obtained sample grains of the solid propellants had a complete structure, which conformed to the design model and had no obvious defects. Then, the combustion and mechanical properties of the printed solid propellant were obtained and analyzed. The results show that the composition of the printed solid propellant is more uniform and the performance is better than that of the conventional solid propellant. In addition, by conducting a motor experiment, it was verified that the 3D-printed grains with complex structures have the characteristic of an “ultra-low pressure ratio”. The comparative analysis revealed that the maximum working pressure was reduced by about 19.5%, the bearing load of the shell was reduced, and the mass of the shell and other bearing parts was reduced by 11.5%. The research in this paper shows that 3D-printed solid propellant technology can realize the formation of grains with complex structure, which can directly promote the solid rocket motor to obtain the “ultra-low pressure ratio” characteristic, and greatly improve the performance of solid rocket motors.
19
Hwang, Gyeong-Seop, Si-Hyeon Jo e Dong-Hee Kim. "Risk Assessment Using Overpressure and Impulse for Abnormal Explosion of Composite Solid Propellants". Fire Science and Engineering 38, n. 1 (28 febbraio 2024): 92–100. http://dx.doi.org/10.7731/kifse.676b9b7c.
Testo completoAbstract (sommario):
In this study, the risks were investigated by probabilistic analysis of the effects on the person and structure located around the composite solid propellant when it explodes abnormally. Two types of solid propellants of different sizes and three TNT equivalents of composite propellants were applied to empirical correlation to derive incident pressure and impulse. These were used in probit analysis, and the effects on the person and structure were quantitatively analyzed to determine the risk of solid propellant explosion. The larger the propellant and the more the TNT equivalent, the higher the incident pressure and impulse. Moreover, the amount of propellant had a more significant effect on the impulse than the incident pressure. The effects of the incident pressure and impulse on human were observed to be greater in the order of probability of ruptured eardrums, death from head impact, death from whole-body displacement impact, and death from lung damage. Furthermore, the effects on the structure were observed to be greater in the order of probability of breakage of window, minor damage, major damage, and collapse of the building.
20
Pourpoint, Timothee L., Tyler D. Wood, Mark A. Pfeil, John Tsohas e Steven F. Son. "Feasibility Study and Demonstration of an Aluminum and Ice Solid Propellant". International Journal of Aerospace Engineering 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/874076.
Testo completoAbstract (sommario):
Aluminum-water reactions have been proposed and studied for several decades for underwater propulsion systems and applications requiring hydrogen generation. Aluminum and water have also been proposed as a frozen propellant, and there have been proposals for other refrigerated propellants that could be mixed, frozen in situ, and used as solid propellants. However, little work has been done to determine the feasibility of these concepts. With the recent availability of nanoscale aluminum, a simple binary formulation with water is now feasible. Nanosized aluminum has a lower ignition temperature than micron-sized aluminum particles, partly due to its high surface area, and burning times are much faster than micron aluminum. Frozen nanoscale aluminum and water mixtures are stable, as well as insensitive to electrostatic discharge, impact, and shock. Here we report a study of the feasibility of an nAl-ice propellant in small-scale rocket experiments. The focus here is not to develop an optimized propellant; however improved formulations are possible. Several static motor experiments have been conducted, including using a flight-weight casing. The flight weight casing was used in the first sounding rocket test of an aluminum-ice propellant, establishing a proof of concept for simple propellant mixtures making use of nanoscale particles.
21
Cui, Huiru, Xuan Lv, Yurong Xu, Zhiwen Zhong, Zixiang Zhou e Weili Ma. "A Step-by-Step Equivalent Microprediction Method for the Mechanical Properties of Composite Solid Propellants considering Dewetting Damage". International Journal of Aerospace Engineering 2022 (14 febbraio 2022): 1–12. http://dx.doi.org/10.1155/2022/2427463.
Testo completoAbstract (sommario):
Reliable prediction of the macromechanical properties of composite solid propellants in the microscale can accelerate the development of propellants with high mechanical properties. According to the characteristics of the composition ratio of a four-component hydroxyl-terminated polybutadiene (HTPB) propellant with the component ammonium perchlorate (AP), hydroxyl-terminated polybutadiene, aluminum powder (AL), and cyclotrimethylenetrinitramine (or RDX for short), an improved random delivery algorithm was developed to separately model filler particles with the different sizes. A step-by-step equivalent representative volume element (RVE) model was generated to reflect the microstructures of the propellant. The isotropy and uniformity of the RVE model were also tested using a two-point probability function. The Park-Paulino-Roesler (PPR) cohesive model was introduced to simulate the particle debonding (or dewetting) in solid propellant. The stress-strain curves of the propellant were obtained by the macroscopic test with the extension rate 200 mm/min at different temperatures. Based on these experimental data, the 8 characteristic parameters suitable for the microinterface of the propellant were obtained by using an inversion optimization method. A microscale finite element prediction model of the propellant considering dewetting damage was constructed to study the evolution process of the microdamage of the propellant. The predicted stress-strain curves of the propellant under different loading conditions were in good agreement with the test results.
22
Darabkhanid, H. G., e N. S. Mehdizadeh. "Solid propellants burning enhancement using foil embedding method". Aeronautical Journal 112, n. 1138 (dicembre 2008): 725–32. http://dx.doi.org/10.1017/s0001924000002694.
Testo completoAbstract (sommario):
Abstract The method of metal embedding is widely employed in solid propellant motors with end-burning configuration, thereby significantly improving the burning rate of the propellants. In this study, the cylindrical foil embedding method is applied to double-base solid propellant, as a new method, and the effects of the type and thickness of the foil on the burning surface, as well as the burning rate, are experimentally investigated. It is shown that by using the foil embedding method, the burning characteristics of solid propellants can be improved. Results have been compared to some available data. To the best of the author’s knowledge there are no published data available on this method.
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Ye, Guanlin, Weiyong Zhou e Zhibin Shen. "Investigation into mechanical properties of PBT propellant under accelerated aging at alternating temperature and constant strain". Journal of Physics: Conference Series 2285, n. 1 (1 giugno 2022): 012037. http://dx.doi.org/10.1088/1742-6596/2285/1/012037.
Testo completoAbstract (sommario):
Abstract Solid propellants are typical viscoelastic materials that are subject to chemical ageing and mechanical damage under whole life cycle conditions. Through high and low temperature cycling tests on PBT propellant specimens under constant strain conditions, the effects of mechanical damage and temperature ageing on the mechanical properties of PBT propellant are simulated and analysed during the motor delivery, storage and operational duty cycles of PBT propellants subjected to environmental loads. The tests show that: during the ageing process of PBT propellant in the simulated natural environment, the tensile strength will gradually increase due to the influence of temperature load and manoeuvring load, and the initial modulus will increase due to the influence of internal stresses generated by curing and cooling, which will reduce the tensile strength, both of which will jointly affect the mechanical properties of the propellant. The force-thermal coupling accelerated ageing experiment can simulate the ageing process of solid motor pillars under natural conditions and predict their mechanical properties at various time stages.
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Kozin, V. S. "Effect of the thermal and gas-dynamic properties of solid rocket propellant particles on the propellant combustion rate". Technical mechanics 2021, n. 1 (30 aprile 2021): 63–67. http://dx.doi.org/10.15407/itm2021.01.063.
Testo completoAbstract (sommario):
The aim of this work is to eliminate the explosion possibility of a rocket engine that operates on a fast-burning solid propellant. The problem is considered by analogy with experiments conducted earlier. Various ways to increase the propellant combustion rate are presented. Examples of how the solid propellant combustion rate depends on the metal fuel and the oxidizer particle size are given. It is shown that unstable combustion of a solid propellant at high combustion chamber pressures is due to unstable combustion of the gas phase in the vicinity of the bifurcation point. Zeldovich’s theory of nonstationary powder combustion is applied to analyzing the explosion dynamics of the Hrim-2 missile’s solid-propellant sustainer engine. This method of analysis has not been used before. The suggested version that this phenomenon is related to the aluminum particle size allows one to increase the combustion rate in the combustion chamber of a liquid-propellant engine, thus avoiding the vicinity of the bifurcation point. The combustion of solid propellants differing in aluminum particle size is considered. The metal fuel and the oxidizer particle sizes most optimal in terms of explosion elimination are determined and substantiated. The use of submicron aluminum enhances the evaporation of ammonium perchlorate due to the infrared radiation of aluminum particles heated to an appropriate radiation temperature. This increases the gas inflow into the charge channel, thus impeding the suppression of ammonium perchlorate sublimation by a high pressure, which is important in the case where the engine body materials cannot withstand a high pressure in the charge channel. This increases the stability and rate of solid propellant combustion. It is shown that the Hrim-2 missile’s solid propellant cannot be used in the Hran missile. The combustion rate is suggested to be increased by using fine-dispersed aluminum in the solid propellant.
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Sheikholeslam, Mohammad Reza Zadeh, Daryoosh Kazemi e Hooman Amiri. "Experimental Analysis of the Influence of Length to Diameter Ratio on Erosive Burning in a Solid Tubular Propellant Grain". Applied Mechanics and Materials 110-116 (ottobre 2011): 3394–99. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.3394.
Testo completoAbstract (sommario):
Erosive burning usually refers to the increase in the propellant burning rate caused by high velocity combustion gasses flowing over the propellant surface. It may seriously affect the performance of solid-propellant rocket motors [1]. A series of experiments had been made to study the effects of length to the diameter ratio in a single tubular propellant grain on the erosive burning phenomenon. In the same combustion pressure and different grain geometries, the burning pattern ofAP1based propellantwere recorded. Furthermore, pressure-time curve for each condition was obtained. The mean velocity gradient is obtained by some thermo-gas-dynamical analysis on experimental data. The results can be used for preliminary design ofAPbased tubular propellant rocket motors. This method may be used for other types of tubular solid propellants which defer in chemical formulation.
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O¨zu¨pek, S¸, e E. B. Becker. "Constitutive Modeling of High-Elongation Solid Propellants". Journal of Engineering Materials and Technology 114, n. 1 (1 gennaio 1992): 111–15. http://dx.doi.org/10.1115/1.2904130.
Testo completoAbstract (sommario):
A phenomenological approach is used to represent the nonlinear viscoelastic behavior of solid propellants. A three-dimensional finite strain viscoelastic model, modified by a strain softening function that accounts for damage effects, is considered in the research. Some of the significant aspects of high-elongation propellants are incorporated into the constitutive model. The resulting stress-strain relation is applied to a particular high-elongation propellant by means of the related material characterization. The response predicted by the model is compared with the experimental data for different loading conditions. The model predicts the propellant behavior quite well at uniaxial strain magnitudes up to 50 percent. Numerical analysis of very general geometries and loadings are possible, since a fully general model is calibrated.
27
Runtu, Khevinadya Ramadhani, Wahyu Sri Setiani e Mala Utami. "Application Energetic Materials for Solid Composite Propellant to Support Defense Rocket Development". International Journal of Social Science Research and Review 6, n. 1 (6 gennaio 2023): 153–59. http://dx.doi.org/10.47814/ijssrr.v6i1.756.
Testo completoAbstract (sommario):
In its application in space technology, solid composite propellants are often used as fuel in rockets for military purposes. Increasing the energy of the propellant is carried out by observing two stages, the use of energetic materials and improvements to the process technology. The current development of propellant technology makes it possible to use new energetic materials, simple formulations, high energy, and smokeless. The purpose of this research is to find out developments related to the use of highly energetic materials as raw materials for composite propellants for defense rockets at the Rocket Technology Research Center, ORPA-BRIN. This study uses qualitative analysis methods with research designs in the literature studies and simulation results. In the context of mastering rocket propellant technology in Indonesia, the application of highly energetic materials is expected to be able to solve the problem of rocket propulsion performance. Currently, the Rocket Technology Research Center, ORPA-BRIN is developing a smokeless propellant composite with a composition based on the energetic materials AP/HTPB/Al and an oxidizing agent RDX. From the results of the combustion simulation software ProPEP and RPA, it shows that the composition of the resulting combustion gaseous (Al2O3 and HCl) shows a decrease when using RDX energetic material-based propellant. It's known that RDX can significantly reduce smoke in propellant combustion products. The application of the new highly energetic materials compound is expected to significantly solve the problem of solid rocket propulsion performance.
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Xiong, Weiqiang, Yunjie Liu, Tianfu Zhang, Shixi Wu, Dawen Zeng, Xiang Guo e Aimin Pang. "Effect of Al–Li Alloy on the Combustion Performance of AP/RDX/Al/HTPB Propellant". Aerospace 10, n. 3 (25 febbraio 2023): 222. http://dx.doi.org/10.3390/aerospace10030222.
Testo completoAbstract (sommario):
Aluminium–lithium alloy (Al–Li alloy) powder has excellent ignition and combustion performance. The combustion product of Al–Li alloy powder combined with ammonium perchlorate is gaseous at the working temperature of solid rocket motors, which greatly reduces the loss of two-phase flow. Experimental investigations were thoroughly conducted to determine the effect of the Al–2.5Li (2.5 wt% lithium) content on propellant combustion and agglomeration based on thermogravimetry-differential scanning calorimetry, heat combustion, laser ignition, combustion diagnosis, a simulated 75 mm solid rocket motor and a condensed combustion products (CCPs) collection device. The results show that the exothermic heat and weight gain upon the thermal oxidation of Al–Li alloy is obviously higher than those of Al powder. Compared with the reference propellant’s formulation, Al–2.5Li leads to an increase in the burning rate and a decrease in the size of the condensed combustion products of the propellants. As the Al–2.5Li alloy content gradually increases from 0 wt% to 19 wt%, the burning rate increases from 5.391 ± 0.021 mm/s to 7.244 ± 0.052 mm/s at 7 MPa of pressure; meanwhile, the pressure exponent of the burning rate law is changed from 0.326 ± 0.047 to 0.483 ± 0.045, and the d43 of the combustion residue is reduced from 165.31 ± 36.18 μm to 12.95 ± 4.00 μm. Compared to the reference propellant’s formulation, the combustion efficiency of the HTPB propellant is increased by about 4.4% when the Al–2.5Li alloy content is increased from 0 to 19%. Therefore, Al–2.5Li alloy powder is a promising fuel for solid propellants.
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Srivastava, Sachin, G. Hamshitha, V. Jagannath, Gaurav Kothenty, Subham Haldar, Ajith Raj Rajendran e Subham Thapliyal. "Numerical Studies of Solid Rocket Propellant PMMA-PBAN-ALF3-Nitrocellulose-Difluoramine". Journal of Physics: Conference Series 2856, n. 1 (1 ottobre 2024): 012010. http://dx.doi.org/10.1088/1742-6596/2856/1/012010.
Testo completoAbstract (sommario):
Abstract The aim of the new investigation is the evaluation of solid rocket Propellant. In which performing numerical analysis of solid rocket propellant and calculating the constraints involved as derived from thrust i.e. velocity involved in the solid rocket propulsion motor usage. This paper aims to show the viability of solid rocket propellant for modern and future applications. Solid rocket motors are simple in design and fabricating. The need for a propellant that produces the same specific impulse as another chemical rocket engine. So it is needed to have a solid rocket motor with an enhanced combustion characteristic at a reasonable O/F ratio. For a healthy ecology, an economically reliable, highly effective, and environmentally concerned propellant is constantly suitable. As a superior alternative among the already used propellants in the sector, the paper suggested fuel PolyMethyl MethAcrylate (PMMA), PolyButadiene AcryloNitrile (PBAN) CoPolymer, and Aluminum hydride (AlH3), and oxidizers such as Nitrocellulose and Difluoramine. The desired O/F ratio for the technical criteria was found to result in a high combustion characteristic. With the features discovered through numerical and analytical research, we have suggested a design for the SRM that includes post-combustion, which enhances the reaction and creates the innovative elements of the existing SRM.
30
Yue, Songchen, Lu Liu, Huan Liu, Yanfeng Jiang, Peijin Liu, Aimin Pang, Guangxue Zhang e Wen Ao. "Agglomerate Size Evolution in Solid Propellant Combustion under High Pressure". Aerospace 10, n. 6 (30 maggio 2023): 515. http://dx.doi.org/10.3390/aerospace10060515.
Testo completoAbstract (sommario):
Solid propellant combustion and flow are significantly affected by condensed combustion products (CCPs) in solid rocket motors. A new aluminum agglomeration model is established using the discrete element method, considering the burning rate and formulation of the propellant. Combining the aluminum combustion and alumina deposition model, an analytical model of the evolution of CCPs is proposed, capable of predicting the particle-size distribution of completely burned CCPs. The CCPs near and away from the propellant burning surface are collected by a special quench vessel under 6~10 MPa, to verify the applicability of the CCP evolution model. Experimental results show that the predicted error of the proposed CCP evolution model is less than 8.5%. Results are expected to help develop better analytical tools for the combustion of solid propellants and solid rocket motors.
31
Lin, Guomin, Yixue Chang, Yu Chen, Wei Zhang, Yanchun Ye, Yanwen Guo e Shaohua Jin. "Synthesis of a Series of Dual-Functional Chelated Titanate Bonding Agents and Their Application Performances in Composite Solid Propellants". Molecules 25, n. 22 (16 novembre 2020): 5353. http://dx.doi.org/10.3390/molecules25225353.
Testo completoAbstract (sommario):
Titanate-based bonding agents are a class of efficient bonding agents for improving the mechanical properties of composite solid propellants, a kind of special composite material. However, high solid contents often deteriorate the rheological properties of propellant slurry, which limits the application of bonding agents. To solve this problem, a series of long-chain alkyl chelated titanate binders, N-n-octyl-N, N-dihydroxyethyl-lactic acid-titanate (DLT-8), N-n-dodecyl-N, N-dihydroxyethyl-lactic acid-titanate (DLT-12), N-n-hexadecyl-N, N-Dihydroxyethyl-lactic acid-titanate (DLT-16), were designed and synthesized in the present work. The infrared absorption spectral changes of solid propellants caused by binder coating and adhesion degrees of the bonding agents on the oxidant surface were determined by micro-infrared microscopy (MIR) and X-ray photoelectron spectroscopy (XPS), respectively, to characterize the interaction properties of the bonding agents with oxidants, ammonium perchlorate (AP) and hexogen (RDX), in solid propellants. The further application tests suggest that the bonding agents can effectively interact with the oxidants and effectively improve the mechanical and rheological properties of the four-component hydroxyl-terminated polybutadiene (HTPB) composite solid propellants containing AP and RDX. The agent with longer bond chain length can improve the rheological properties of the propellant slurry more significantly, and the propellant of the best mechanical properties was obtained with DLT-12, consistent with the conclusion obtained in the interfacial interaction study. Our work has provided a new method for simultaneously improving the processing performance and rheological properties of propellants and offered an important guidance for the bonding agent design.
32
Lv, Xiang, Rong Ma, Yuxin An, Zhimin Fan, Dongliang Gou, Peijin Liu e Wen Ao. "Effects of Ammonium Perchlorate and CL-20 on Agglomeration Characteristics of Solid High-Energy Propellants". Energies 15, n. 20 (13 ottobre 2022): 7545. http://dx.doi.org/10.3390/en15207545.
Testo completoAbstract (sommario):
Energy density, which is an important indicator of the performance of solid propellants, is known to increase with the addition of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20). However, it remains unclear how CL-20 affects the decomposition of ammonium perchlorate (AP) and energy release. Here, the effects of CL-20 on the combustion performance and agglomeration of propellants were investigated. The addition of CL-20 decreased AP decomposition temperature and the energy required for the transformation of AP crystals from orthorhombic to cubic. The burning rate and pressure exponent of the propellant with 42% CL-20 were significantly higher than those of the propellant containing 20% CL-20. Thus, adding CL-20 to the propellant improves the energy characteristics and burning rate and the pressure exponent increases. At low combustion chamber pressure, the agglomeration of the propellant containing a high content of CL-20 will be blown away from the combustion surface only after staying on that surface for a short time. In this process, the probability of volume growth of the agglomeration after merging with other agglomerations greatly decreases, thus reducing the overall agglomerate particle sizes; further, the addition of a small amount of CL-20 to the propellant may lead to a reduction in agglomerate particle sizes. AP with a smaller particle size weakens the agglomeration in the combustion process and decreases the number of agglomerates with large particle sizes. These findings lay the foundation for the development of novel high-energy propellants.
33
Aswin, C., S. Srichand Vishnu, D. Aravind Kumar, S. Deepthi, S. K. Kumaresh, M. Arun e V. R. Sanal Kumar. "Studies on Ignition Delay and Flame Spread in High-Performance Solid Rocket Motors". Applied Mechanics and Materials 232 (novembre 2012): 316–21. http://dx.doi.org/10.4028/www.scientific.net/amm.232.316.
Testo completoAbstract (sommario):
Accurate prediction of ignition delay and flame spread rate in solid propellant rocket motors is of great topical interest. In this paper using a standard k-ω turbulence model numerical studies have been carried out to examine the influence of solid rockets port geometry on ignition delay and the flame spread pattern. We observed that with the same inflow conditions and propellant properties heat flux histories and ignition time sequence are different for different port geometries. We conjectured from the numerical results that in solid rocket motors with highly loaded propellants, mass flux of the hot gases moving past the burning surface is large. Under these conditions, the convective flux to the surface of the propellant will be enhanced, which in turn enhance the local Reynolds number. This amounts a reduction in heat transfer film thickness and enhanced heat transfer to the propellant with consequent enhancement in the dynamic burn rate resulting the undesirable starting pressure transient. We concluded that, the more accurate description of gas phase to surface heat transfer process will give a better prediction and control of ignition delay and flame spread rate in solid propellant rockets.
34
Junqueira Pimont, Lia, Paula Cristina Gomes Fernandes, Luiz Fernando de Araujo Ferrão, Marcio Yuji Nagamachi e Kamila Pereira Cardoso. "Study on the Mechanical Properties of Solid Composite Propellant Used as a Gas Generator". Journal of Aerospace Technology and Management, n. 1 (21 gennaio 2020): 7–10. http://dx.doi.org/10.5028/jatm.etmq.65.
Testo completoAbstract (sommario):
A gas generating propellants are used as initiators of liquid rocket propellants turbopumps and have as desired characteristic a high-volume production of low-temperature gas. In this context, some formulations of composite propellant containing polyurethane (based on liquid hydroxyl-terminated polybutadiene), guanidine nitrate, ammonium perchlorate, and additives were evaluated and characterized in order to verify their potential as gas generator propellant, as well as to evaluate the influence of additives on mechanical properties. The formulations were prepared, analyzed, and tested for mechanical properties.
35
Kuo, K. K., W. H. Hsieh, K. C. Hsieh e M. S. Miller. "Modeling of Hot Fragment Conductive Ignition of Solid Propellants With Applications to Melting and Evaporation of Solids". Journal of Heat Transfer 110, n. 3 (1 agosto 1988): 670–79. http://dx.doi.org/10.1115/1.3250544.
Testo completoAbstract (sommario):
A comprehensive theoretical model has been formulated for studying the degree of vulnerability of various solid propellants being heated by hot spall fragments. The model simulates the hot fragment conductive ignition (HFCI) processes caused by direct contact of hot inert particles with solid propellant samples. The model describes the heat transfer and displacement of the hot particle, the generation of the melt (or foam) layer caused by the liquefaction, pyrolysis, and decomposition of the propellant, and the regression of the propellant as well as the time variation of its temperature distributions. To validate partially the theoretical model in the absence of the necessary chemical kinetic data, an ice melting and evaporation experiment was designed and conducted. These experiments provide features of the conductive heating, melting, and evaporating processes. Calculated results compare well with experimental data in temperature–time traces, spall particle sinking velocity, and displacement.
36
Megaraj, Meikandan, e Nancy Grace N. "A Review on Residual Solid Propellant Disposal Methods Using HRIM, RISK Score Matrix, Safety Consequence Analysis and Environmental Impact Analysis". International Journal of Occupational Safety and Health 12, n. 3 (27 giugno 2022): 246–55. http://dx.doi.org/10.3126/ijosh.v12i3.41375.
Testo completoAbstract (sommario):
Introduction: Solid propellants are high energetic materials used for Launch vehicles and military applications. During solid propellant processing residual propellant generates due to less pot life, machining for insulation lining, scaled and sub scaled trials for mechanical and ballistic properties prediction. A conventional method for disposal of residual propellant is open-air burning; other alternate methods in the literature are incineration, wet air oxidation and molten salt destruction. Methods: Hazard assessment is carried out for the disposal methods both conventional and alternate. Preliminary hazard analysis (PHA), Hazard Risk Index Matrix (HRIM), Risk Score Matrix and as low as reasonably practicable (ALARP) are used to assess the Hazard. Results: Based on the study and calculations Open air burning is having less risk score and medium level safety risk acceptance and tolerable risk which can mitigate. Open-air burning is the safest, efficient and cost-effective way to dispose of the high energetic material but the disadvantage of this method is environmental pollution, high temperature and toxic gases exposure to fire personnel. Based on safety consequences analysis, the 1 gram of solid propellant is found to be 1.308 grams of Trinitrotoluene (TNT) equivalency, and one-time open burning creates 3.822 KPa overpressure on the atmosphere where minimum overpressure to create damage effect is 5 KPa. Conclusion: The environmental impact analysis for disposing of solid propellant gives information about different pollutants, their concentrations in the atmosphere at different altitudes and their impact. Solid propellants are hazard reactive materials they were the one exception under the Resource Conservation and Recovery Act (RCRA) that controls the destruction of hazardous waste.
37
Zhao, Jiuling. "Effect of particle/matrix interface parameters on mechanical properties of high-energy propellant based on three-dimensional RVE model". Journal of Physics: Conference Series 2783, n. 1 (1 giugno 2024): 012067. http://dx.doi.org/10.1088/1742-6596/2783/1/012067.
Testo completoAbstract (sommario):
Abstract For composite solid propellant, the interface is the medium to transfer the load between particles and matrix. Because there are a large number of particle/matrix interface layers in the propellant, the mechanical properties of the interface become an important factor affecting the macro-mechanical properties of the propellant. It is necessary to study the influence of different interface mechanical parameters on the mechanical properties of high-energy propellants. In this paper, the three-dimensional representative volume element (RVE) model of solid propellant is established, and the three-dimensional bilinear cohesion interface parameters are established for this model. The influence law of interface parameters on its mechanical properties is obtained through simulation research. The results show that both the interfacial strength and the maximum failure displacement of the interface affect the tensile strength of high-energy propellant, and the interfacial strength plays a leading role and is very significant.
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Korotkikh, Alexander, Ivan Sorokin e Ekaterina Selikhova. "Ignition and combustion of high-energy materials containing aluminum, boron and aluminum diboride". MATEC Web of Conferences 194 (2018): 01055. http://dx.doi.org/10.1051/matecconf/201819401055.
Testo completoAbstract (sommario):
Boron and its compounds are among the most promising metal fuel components to be used in solid propellants for solid fuel rocket engine and ramjet engine. Papers studying boron oxidation mostly focus on two areas: oxidation of single particles and powders of boron, as well as boron-containing composite solid propellants. This paper presents the results of an experimental study of the ignition and combustion of the high-energy material samples based on ammonium perchlorate, ammonium nitrate, and an energetic combustible binder. Powders of aluminum, amorphous boron and aluminum diboride, obtained by the SHS method, were used as the metallic fuels. It was found that the use of aluminum diboride in the solid propellant composition makes it possible to reduce the ignition delay time by 1.7–2.2 times and significantly increase the burning rate of the sample (by 4.8 times) as compared to the solid propellant containing aluminum powder. The use of amorphous boron in the solid propellant composition leads to a decrease in the ignition delay time of the sample by a factor of 2.2–2.8 due to high chemical activity and a difference in the oxidation mechanism of boron particles. The burning rate of this sample does not increase significantly.
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Yogeshkumar, Velari, Nikunj Rathi e P. A. Ramakrishna. "Solid Fuel rich Propellant Development for use in a Ramjet to Propel an Artillery Shell". Defence Science Journal 70, n. 3 (24 aprile 2020): 329–35. http://dx.doi.org/10.14429/dsj.70.15061.
Testo completoAbstract (sommario):
This study describes the development of a fuel-rich propellant to be used in a solid fuel ramjet to provide active propulsion to a 155 mm artillery shell. Fuel-rich propellants consisting of aluminum, ammonium perchlorate and hydroxyl terminated polybutadiene were developed and their ballistic properties were measured to choose the appropriate fuel for the ramjet application. The attempts made were to enhance the burn rates of the propellant to provide required burn rates at lowest possible pressures in primary combustor of the ramjet. The propellant selection was done with reference of working time period of the base bleed unit, to calculate the required burn rate and corresponding pressure in primary combustor. It was observed that the fuel rich propellant of composition 35% ammonium perchlorate with 1 % Iron oxide embedded on it, 30 % mechanically activated aluminum with 10% polytetrafluoroethylene, and 25 % HTPB was found suitable for the above application. This provided the higher burn rates among all developed propellants with high pressure index of 0.58. This makes it suitable for the ramjet requiring higher burn rates at lower possible primary chamber pressures. The Young’s modulus and tensile strength of this propellant was measured to be 1.73 MPa and 0.24 MPa, respectively.
40
Xie, Zhi Min, Si Chi Chen e You Shan Wang. "Relaxation Properties of the Solid Propellant Based on Hydroxyl-Terminated Polybutadiene". Advanced Materials Research 989-994 (luglio 2014): 172–76. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.172.
Testo completoAbstract (sommario):
The polymer-based propellant is a typical viscoelastic material. Better understanding of the relaxation properties of the propellant in the storage conditions is of great importance for predicting the lifetime. Due to the component complexity of the composite propellants, the transformation relation between the relaxation modulus and the complex modulus may not be suitable for all kinds of propellants. In the present work, we focused on the transformation of the relaxation modulus and complex modulus for the HTPB propellant. The master curves for the relaxation modulus and the storage modulus of the aged/unaged HTPB propellants were obtained by performing the stress relaxation tests and DMA tests, respectively. It was found that there existed a great difference in the double logarithmic plot between relaxation modulus and storage modulus master curves. Moreover, the testing results for the relaxation modulus and the storage modulus were well fitted by an empirical transformation relation with three segment-related coefficients. These three coefficients were determined by using the unaged samples, and then were applied to estimate the relaxation modulus of the aged samples. A good agreement between the calculation and the experimental results was also found, revealing that the three coefficients were insensitive to the aging time.
41
Dong, Ge, Hengzhi Liu, Lei Deng, Haiyang Yu, Xing Zhou, Xianqiong Tang e Wei Li. "Study on the interfacial interaction between ammonium perchlorate and hydroxyl-terminated polybutadiene in solid propellants by molecular dynamics simulation". e-Polymers 22, n. 1 (1 gennaio 2022): 264–75. http://dx.doi.org/10.1515/epoly-2022-0016.
Testo completoAbstract (sommario):
Abstract The interfacial interaction between the main oxidant filler ammonium perchlorate (AP) and hydroxyl-terminated polybutadiene (HTPB) matrix in AP/HTPB propellants were studied via an all-atom molecular dynamics simulation. The results of the simulation showed the effects of the microscopic cross-linked structure of the matrix, stretching rate during uniaxial stretching, and contact area between the filler and matrix on the mechanical properties, such as the stress and strain of the composite solid propellant. Among the aforementioned factors, the stretching rate considerably affects the mechanical properties of the solid propellant, and the maximum stress of the solid propellant proportionally increases with the stretching rate. When defects were introduced on the surface of the AP filler, the contact area between the filler and matrix affected the strain type of the matrix molecules. Owing to the interaction between the molecules and atoms, the strain behaviour of the matrix molecule changed with the change in its microscopic cross-linked structure during uniaxial stretching. Molecular dynamics simulations were used to explore the characteristics at the AP–HTPB interface in AP/HTPB propellants. The aforementioned simulation results further revealed the interfacial interaction mechanism of the AP–HTPB matrix and provided a theoretical basis for the design of high-performance propellants.
42
Bergman, Yoel. "THE NEW 1942 METHOD FOR PROPELLANT DESIGN AND LATER UPDATES". Journal of the International Committee for the History of Technology 28, n. 2 (15 dicembre 2023): 128–35. http://dx.doi.org/10.11590/icon.2023.2.07.
Testo completoAbstract (sommario):
The brief research reviews the history of an innovative method in propellant technology. In 1942, the renowned US scientist Joseph Hirschfelder led a team that devised a simple calculative method for helping to design wartime solid propellants, whose gas, when burnt, served to drive projectiles in gun barrels. The method estimated the temperature of the gas for each propellant and other factors. Until then, these were estimated through a rigorous theoretical process. The simplified theoretical approach of the new method gave nearly the same temperatures and other important values, all with basic arithmetic. It was later refined by others, for better accuracy, and applied for designing solid rocket propellants, through a short theoretical adaptation.
43
Chengyin, Tu, Chen Xiong, Zhuang Yuqian e Chen Fan. "Research on aluminum agglomeration characteristics of Al/NEPE propellant". Journal of Physics: Conference Series 2478, n. 3 (1 giugno 2023): 032052. http://dx.doi.org/10.1088/1742-6596/2478/3/032052.
Testo completoAbstract (sommario):
Abstract Adding aluminum particles to solid propellants is used to improve the energy density of the propellant and the specific impulse of the engine. However, the aluminum particles will agglomerate to form large-sized condensed combustion products, which can cause nozzle erosion and two-phase flow loss. Therefore, it is necessary to study the aluminum agglomeration characteristics of solid propellants. In this paper, the combustion process of the Al/NEPE propellant was recorded by a high speed camera and a fiber optic spectrometer, and the condensed combustion products of the propellant were collected. The microstructure of the condensed combustion products was analyzed by a scanning electron microscope coupled with energy dispersive (SEM-EDS). These results show that the agglomeration process of aluminum particles may go through three stages: accumulation, aggregation and agglomeration. The condensed combustion products are mainly divided into aluminum agglomerates and smoke oxide particles. Generally, the size of agglomerates exceeds 50 μm, while the size of smoke oxide particles is less than 1 μm.
44
Qin, Zhao, Jiang Wu, Rui Qi Shen, Ying Hua Ye e Li Zhi Wu. "Laser-Controlled Combustion of Solid Propellant". Advanced Materials Research 884-885 (gennaio 2014): 87–90. http://dx.doi.org/10.4028/www.scientific.net/amr.884-885.87.
Testo completoAbstract (sommario):
This paper describes experimental work on laser-controlled combustion of solid propellants. Combustion of AP/HTPB, including ignition, combustion, extinction and re-ignition could be controlled by CO2 laser irradiation at the back pressure of 0.1, 0.3 and 0.5 MPa in nitrogen. Burning rate of propellant increased linearly with the increasing of laser power density. Vieilles law was used here to check pressure effect to burning rate, pressure exponent under different power density (except 0.5 MW/m2) are very close to 0.17.
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Mukhtar, Amir, Habib Nasir e Hizba Waheed. "Pressure-Time Study of Slow Burning Rate Ap/HTPB Based Composite Propellant by Using Closed Vessel Test (CVT)". Key Engineering Materials 778 (settembre 2018): 268–74. http://dx.doi.org/10.4028/www.scientific.net/kem.778.268.
Testo completoAbstract (sommario):
The Closed vessel (CV) is an equipment used to study the ballistic parameters by recording burning time history, pressure buildup during the process and vivacity of the propellants. It is an apparatus which consists of strong pressure vessel, piezo-electric pressure transducers, sensors and dedicated software. To save time and resources this method is employed instead of dynamic firing while doing research and development of propellants. A measured amount of propellant charge is loaded in the vessel and fired remotely. Ignition is provided by the filament which ignites the black powder charge. In this study, we have used Closed Vessel Tests (CVT) for the first time for recording the ballistic parameters of slow burning composite rocket propellant. We developed a set of composite solid propellant samples containing a mixture of bimodal Ammonium Perchlorate (AP) as an oxidizer, Hydroxy-terminated Polybutadiene (HTPB) as a binder as well as fuel, Dioctyl Sebacate (DOS) as plasticizer, 1-(2-methyl) Aziridinyl Phosphine Oxide (MAPO) as bonding agent and Toluene Diisocyanate (TDI) as curator. Samples were developed by changing the solid loading percentage of bimodal AP particles. By increasing the percentage of AP, the oxidizer-fuel ratio (O/F) increases which effects the ballistic parameters. It is observed that maximum pressure and vivacity increases with increase in solid filler in the propellants. As quantity of AP increases, rate of rise of pressure also increases. CVT firing of each sample was done three times to obtain average burning time and pressure buildup history to evaluate the effect of oxidizer loadings on ballistic parameters of the composite propellant.
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Traissac, Y., J. Ninous, R. Neviere e J. Pouyet. "Mechanical Behavior of a Solid Composite Propellant during Motor Ignition". Rubber Chemistry and Technology 68, n. 1 (1 marzo 1995): 146–57. http://dx.doi.org/10.5254/1.3538726.
Testo completoAbstract (sommario):
Abstract In order to understand the behavior of composite propellants during motor ignition, a particular study about mechanical and ultimate properties of a Hydroxy-Terminated Polybutadiene (HTPB) filled propellant under superimposed hydrostatic pressure was carried out. The mechanical response of the propellant was obtained for uniaxial tensile and simple shear tests at various temperatures, strain rates and superimposed pressures from atmospheric pressure to 15 MPa. The experimentally observed ultimate properties were found to be strongly pressure sensitive and the data were formalized in a specific stress failure criterion.
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Ma, Jiaju. "Analysis of the characteristics of rocket propellant". Theoretical and Natural Science 5, n. 1 (25 maggio 2023): 490–95. http://dx.doi.org/10.54254/2753-8818/5/20230296.
Testo completoAbstract (sommario):
Rocket propellant is an important part of the rocket. Solid or liquid propellant will burn in the engine combustion chamber, and then a large amount of high-pressure gas will be generated. High-pressure gas will be ejected from the engine nozzle at a high speed, generating a reaction force on the rocket, so that the rocket will advance in the opposite direction of the gas injection. This paper mainly analyzes the advantages and disadvantages of current propellants and conceives a theoretically feasible propellant selection method. The main method of research is to calculate the theory of each propellant and make diagrams. Some of the research data were based on existing research reports. Each fuel has its own characteristics, they have one aspect of excellent ability, such as heat conduction, high thrust, high reliability. This paper summarizes the characteristics of current propellants and provides a more convenient query for future researches.
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CEGŁA, Marcin, Janusz ZMYWACZYK e Piotr KONIORCZYK. "Analysis of Thermal Decomposition of Solid Rocket Propellants". Problems of Mechatronics Armament Aviation Safety Engineering 10, n. 2 (30 giugno 2019): 43–54. http://dx.doi.org/10.5604/01.3001.0013.2115.
Testo completoAbstract (sommario):
The paper presents results of thermal decomposition analysis of selected solid rocket propellants. Homogeneous propellant PAC and heterogeneous propellant H2 were subjected to simultaneous thermal analysis with the use of NETZSCH STA 2500 Regulus device with five heating rates of 2.5, 5, 7.5, 10 and 15 K/min. The method combines TG, DTG and DTA analytical techniques in a single measurement. The aim of the conducted experiments was to study thermal decomposition of these energetic materials as well as to determine activation energy of the decomposition process and the preconditioning factor from the TG curves. The tested materials properties and chemical composition along with a brief description of the experimental procedure are described. The inverse procedure of calculating the activation energy, based on the Ozawa-Flynn-Wall model is described. Finally, the results of thermal decomposition of two tested solid rocket propellants are presented along with maximum decomposition rates and percentage of mass loss.
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Hu, Zhenyuan, Kaining Zhang, Qiqi Liu e Chunguang Wang. "NEPE Propellant Mesoscopic Modeling and Damage Mechanism Study Based on Inversion Algorithm". Materials 17, n. 6 (11 marzo 2024): 1289. http://dx.doi.org/10.3390/ma17061289.
Testo completoAbstract (sommario):
To accurately characterize the mesoscopic properties of NEPE (Nitrate Ester Plasticized Polyether) propellant, the mechanical contraction method was used to construct a representative volume element (RVE) model. Based on this model, the macroscopic mechanical response of NEPE propellant at a strain rate of 0.0047575 s−1 was simulated and calculated, and the parameters of the cohesive zone model (CZM) were inversely optimized using the Hooke–Jeeves algorithm by comparing the simulation results with the results of the uniaxial tensile test of NEPE propellants. Additionally, the macroscopic mechanical behavior of NEPE composite solid propellants at strain rates of 0.00023776 s−1 and 0.023776 s−1 was also predicted. The mesoscopic damage evolution process of NEPE propellants was investigated by the established model. The study results indicate that the predicted curves are relatively consistent with the basic features and change trends of the test curves. Therefore, the established model can effectively simulate the mesoscopic damage process of NEPE composite solid propellants and their macroscopic mechanical properties.
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Wu, Qiu, Jiangong Zhao e Quanbin Ren. "Effects of Wire-Wrapping Patterns and Low Temperature on Combustion of Propellant Embedded with Metal Wire". Aerospace 11, n. 8 (6 agosto 2024): 639. http://dx.doi.org/10.3390/aerospace11080639.
Testo completoAbstract (sommario):
Incorporating silver wires into propellant has emerged as a highly effective strategy for enhancing propellant burning rates, a technique extensively deployed in the construction of numerous fielded sounding rockets and tactical missiles. Our research, employing a multi-faceted approach encompassing thermogravimetric-differential scanning calorimetry measurements (TG-DSC), combustion diagnoses, burning rate tests, and meticulous collection of condensed combustion products, sought to elucidate how variations in silver wire quantity and winding configuration impact the combustion properties of propellants. Our findings underscore the remarkable efficacy of double tightly twisted silver wire in significantly boosting propellant burning rates under ambient conditions. Moreover, at lower temperatures, the reduced gap between the propellant and silver wire further magnifies the influence of silver wire on burning rates. However, it is noteworthy that the relationship between burning speed and combustion efficiency is not deterministic. While a smaller cone angle of the burning surface contributes to heightened burning rates, it concurrently exacerbates the polymerization effect of vapor phase aluminum particles, consequently diminishing propellant combustion efficiency. Conversely, propellants configured with sparsely twinned silver wires exhibit notable enhancements in combustion efficiency, despite a less pronounced impact on the burning rate attributed to the larger cone angle of the burning surface. Remarkably, these trends persist at lower temperatures. Based on the principle of heat transfer balance, a theoretical model for the combustion of propellants with wire inserts is developed. The reliability of this theoretical model is validated through a comparison of calculated values with experimental data. Our research outcomes carry significant implications for guiding the application and advancement of the silver wire method in solid propellants for solid rocket motors, offering valuable insights to inform future research and development endeavors in this domain.