Papers by Keyword: Solid Propellant

Abstract: Aiming at the shortcomings of large volume, high cost and long detection cycle of traditional solid propellant aging detection methods, a solid propellant aging detection method based on impedance spectroscopy is proposed. Firstly, the internal impedance of the solid propellant changes after aging, and a portable solid propellant impedance spectrum acquisition system based on impedance spectroscopy is designed based on the principle of electrochemical impedance spectroscopy, and the real and imaginary parts of the impedance spectrum are obtained. Secondly, in order to reduce the data dimension of the classification algorithm, the KPCA (Nuclear Principal Component Analysis) feature extraction algorithm is used to extract the impedance spectrum features of the solid propellant. Then, according to the impedance spectrum characteristics, the BP neural network is used for classification training, and the correspondence between the impedance spectrum and the aging time is obtained. Finally, the feasibility and effectiveness of the proposed method are verified on the physical platform, and the results show that the proposed method has the advantages of high precision and accurate classification, and can effectively predict the aging degree of solid propellant.

Abstract: From the microscopic point of view, combining experiment with simulation, the thermal decomposition mechanism of solid propellant was discussed. At first, the thermo gravimetric curves of HTPB film and propellant were studied based on DSC-TG thermal analysis experiment technology. The thermal decomposition process of propellant was simulated by establishing the physical model of meso-structure cell. The results show that the simulation is consistent with the experimental trend. The above research is helpful to further understand the thermal decomposition mechanism of propellant.

Abstract: This document In the process of propellant heat transfer, the specific heat capacity is an important thermodynamic parameter, and temperature is an important factor affecting the specific heat capacity. In this paper, the initial specific heat capacity of HTPB propellant and its components was measured by DSC, and the specific heat capacity value was modified based on the synchronous weight loss curve, and the variation law of specific heat capacity of propellant and its components with temperature increase was obtained. The modified variable specific heat capacity is used to simulate the burning experiment of solid propellant, and the macroscopic curve is compared with the experimental curve. The results show that the absolute error between the simulated ignition delay time and ignition temperature and the experimental results is less than 10%, which indicates that this method provides the key technical parameters for evaluating the weight loss material of propellant, and provides an important parameter basis for designing the heat dissipation mechanism of new propellant.

Abstract: One of the key factors that play an important role in the performance of a solid propellant rocket is dependent on its burning rate. A strand burner is a type of apparatus used to measure the propellant burning rate at elevated pressure. This study investigates the relation between burning rates of aluminized ammonium perchlorate at low pressure. Chamber pressure was varied from 1 atm, 3 atm, 5 atm and 7 atm. This study shows that propellant burning rate is about 50%-62% higher when the burn rate test is conducted at atmospheric condition compared to when it is done in inert gas. The investigation’s results also revealed an increasing propellant burning rate when the chamber pressure is increased. In conclusion, the burning condition and chamber pressure influences the propellant burning rate.

Abstract: 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.

Abstract: The strain-stress state of the solid propellant rocket engines (SPRE) is simulated under impact. Orthotropic organoplastic is the material of the shell. The effect of orientation of elastic and strength properties of the shell material on the strain-stress state of the solid propellant is investigated. Normal interaction of single steel cylinder strikers and oblique impact, both simultaneous and at different times of multiple, converging steel spheric particles with SPRE are considered in the work. The investigation is conducted numerically. The numerical modeling was carried out in three-dimensional statement by a method of finite elements in frameworks of the continual approach of the mechanics of deformable solid. The destruction of the anisotropic material is described by tensor polynomial criterion of the fourth degree, which takes into account the influence of hydrostatic pressure.

Abstract: Hydroxyl terminated epoxidized natural rubber (HTENR) was prepared by oxidative degradation of epoxidized natural rubber (ENR) with cobalt (II) acetylacetonate (co (II) aa) as a chemical agent in toluene as a solvent. Different of cobalt amount and reaction time used to study the effect on molecular weight. It was found that the number average molecular weight (Mn) and weight average molecular weight (Mw) depended on the reaction time and cobalt amount. Burning rate of solid propellant based on HTENR binder is 2.93mm/s which is approximately same with HTPB binder with 3.0mm/s. As a conclusion, HTENR binder is suitable to be used as a binder for solid rocket propellant.

Abstract: An experimental study was conducted to get the ignitibility of NEPE propellant under different CO₂ laser heat fluxes. The combustion flame temperature distribution of NEPE propellant was measured using an infrared thermometer. Results show that the ignition delay time tends to decrease with the increase of laser heat flux, and there exists a significant value. The ignition delay time decreases fast when the heat flux is less than this value, but varies little when the heat flux is greater than this value. Laser irradiation had a significant effect on the combustion of NEPE propellant and after the laser unloading, the flame temperature of the propellant dose not decline immediately, but fall rapidly after a short delay.

Abstract: 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.

Abstract: This paper reviews domestic and foreign study result of the calculation method and variation of solid propellant and other viscoelastic material ratio of solid propellant, the viscoelastic material's Poisson's ratio as well as Poisson's ratio's influence on the structure performance of solid propellant.