scholarly journals Evaluation of elastomeric heat shielding materials as insulators for solid propellant rocket motors: A short review

2020 ◽  
Vol 18 (1) ◽  
pp. 1452-1467
Author(s):  
Javier Carlos Quagliano Amado ◽  
Pablo Germán Ross ◽  
Natália Beck Sanches ◽  
Juliano Ribeiro Aguiar Pinto ◽  
Jorge Carlos Narciso Dutra
Keyword(s):  
High Performance ◽  
Short Review ◽  
Rocket Engines ◽  
Solid Rocket Motor ◽  
Composite Propellant ◽  
Rocket Motors ◽  
Polyhedral Oligosilsesquioxane ◽  
Combustion Gases ◽  
Solid Rocket ◽  
Heat Shielding

AbstractThis review addresses a comparison, based on the literature, among nitrile rubber (NBR), ethylene-propylene-diene-monomer rubber (EPDM), and polyurethane (PU) elastomeric heat shielding materials (EHSM). Currently, these are utilized for the insulation of rocket engines to prevent catastrophic breakdown if combustion gases from propellant reaches the motor case. The objective of this review is to evaluate the performance of PU–EHSM, NBR–EHSM, and EPDM–EHSM as insulators, the latter being the current state of the art in solid rocket motor (SRM) internal insulation. From our review, PU–EHSM emerged as an alternative to EPDM–EHSM because of their easier processability and compatibility with composite propellant. With the appropriate reinforcement and concentration in the rubber, they could replace EPDM in certain applications such as rocket motors filled with composite propellant. A critical assessment and future trends are included. Rubber composites novelties as EHSM employs specialty fillers, such as carbon nanotubes, graphene, polyhedral oligosilsesquioxane (POSS), nanofibers, nanoparticles, and high-performance engineering polymers such as polyetherimide and polyphosphazenes.

scholarly journals Precise Design of Solid Rocket Motor Heat Insulation Layer Thickness under Nonuniform Dynamic Burning Rate

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Ran Wei ◽  
Futing Bao ◽  
Yang Liu ◽  
Weihua Hui
Keyword(s):  
Open Source ◽  
Burning Rate ◽  
High Performance ◽  
Traditional Approach ◽  
Computation Time ◽  
Solid Rocket Motor ◽  
Validation Data ◽  
Solid Rocket Motors ◽  
Rocket Motors ◽  
Solid Rocket

With the purpose of obtaining optimal designs of the heat insulating layers in solid rocket motors, we have proposed a numerical approach to compute the ideal thickness of the heat insulating layer. The proposed method is compatible with solid rocket motors that have any shape and any manner of erosion. The nonuniform dynamic burning rate is taken into consideration to achieve higher accuracy. A high-performance code is developed that uses triangular geometry as an input to allow exchanging data from any CAD platform. An improved geometric intersection algorithm is developed to generate the required sampling points, saving 35% computation time compared to its open source equivalent. Parallel computing technology is utilized to further improve the performance. All operations of the proposed approach can be executed automatically by programs, eliminating the manual work of gathering data from CAD software in the traditional approach. Validation data shows that the proposed approach saves 3.85% of the mass compared to the ordinary design approach. Performance profiling shows that the implemented code operates within 5 seconds, which is much faster than the unoptimized open source version.

Solid Rocket Motor Internal Ballistics Simulation Considering Complex 3D Propellant Grain Geometries

2018 ◽  
pp. 146-169
Author(s):  
Guilherme Lourenço Mejia
Keyword(s):  
Solid Propellant ◽  
Structural Integrity ◽  
Combustion Process ◽  
Burning Surface ◽  
Chamber Pressure ◽  
Computational Tool ◽  
Solid Rocket Motor ◽  
Rocket Motors ◽  
Internal Ballistics ◽  
Solid Rocket

Solid rocket motors (SRM) are extensively employed in satellite launchers, missiles and gas generators. Design considers propulsive parameters with dimensional, manufacture, thermal and structural constraints. Solid propellant geometry and computation of its burning rate are essential for the calculation of pressure and thrust vs time curves. The propellant grain geometry changes during SRM burning are also important for structural integrity and analysis. A computational tool for tracking the propagation of tridimensional interfaces and shapes is then necessary. In this sense, the objective of this work is to present the developed computational tool (named RSIM) to simulate the burning surface regression during the combustion process of a solid propellant. The SRM internal ballistics simulation is based on 3D propagation, using the level set method approach. Geometrical and thermodynamic data are used as input for the computation, while simulation results of geometry and chamber pressure versus time are presented in test cases.

scholarly journals Comparison Of Solid Rocket Motor Thrust Modulation Technique

2021 ◽  
Author(s):  
Clayton Edward Wozney
Keyword(s):  
Longitudinal Axis ◽  
Rocket Motor ◽  
Chamber Pressure ◽  
The Novel ◽  
Solid Rocket Motor ◽  
Nozzle Throat ◽  
Solid Rocket Motors ◽  
Rocket Motors ◽  
Lower Chamber ◽  
Solid Rocket

The thrust profiles of solid rocket motors are usually determined ahead of time by propellant composition and grain design. Traditional techniques for active thrust modulation use a moveable pintle to dynamically change the nozzle throat diameter, increasing the chamber pressure and therefore thrust. With this approach, high chamber pressures must be endured with only modest increases in thrust. Alternatively, it has been shown that spinning a solid rocket motor on its longitudinal axis can increase the burning rate of the propellant and therefore the thrust without the resulting high chamber pressures. Building on prior experience modelling pressure-dependent, low-dependent and acceleration-dependent burning in solid rocket motors, an internal ballistic simulation computer program is modified for the present study where the use of the pintle nozzle and spin-augmented solid rocket motor combustion approaches, for a reference cylindrical-grain motor, are compared. This study confirms that comparable thrust augmentation can be gained at lower chamber pressures using the novel spin-acceleration approach, relative to the established pintle-nozzle approach, thus potentially providing a significant design advantage.

Numerical simulation of ignition transient in solid rocket motor: a revisit

2017 ◽  
Vol 89 (6) ◽  
pp. 936-945 ◽  
Author(s):  
Junaid Godil ◽  
Ali Kamran
Keyword(s):  
Flow Field ◽  
Motor Development ◽  
Solid Propellant ◽  
Research Effort ◽  
Solid Rocket Motor ◽  
Content Type ◽  
Rocket Motors ◽  
One Dimensional ◽  
Erosive Burning ◽  
Solid Rocket

Purpose The capability to predict and evaluate the motor pressure during each phase by means of a numerical analysis can significantly increase the efficiency of the preliminary design process with a reduction of both the motor development and operational costs. This paper aims to perform numerical simulation to analyze the ignition transient in solid rocket motor by solving Euler equation coupled with some semi-empirical correlations. These relations take into account the main phenomena affecting the ignition transient. Coupling relationships include the heat transfer of the gas to the propellant and erosive burning rate relationship. Design/methodology/approach The current research effort divides motor into series of control volumes along the port axis, and the variation of port area, burning surface and burning rate along the port are taken into account. A set of governing equations are then solved using explicit, time-dependent, predictor-corrector finite difference method. The numerical model helps to capture and embed shock wave associated with igniter flow within the solution. Second-order artificial viscosity dampens out the numerical oscillations due to sharp gradient within the flow field. The developed computer code predicts the start-up characteristics of motor. The study also provides comparison of simulation results with in-house experimental motor. Findings Simulations are performed with and without erosive burning to demonstrate that the flow model is a good physical approximation of motor. Numerical results calculated by this model without erosive burning are not in good agreement with experimental results. This minor discrepancy has motivated the inclusion of erosive burning in numerical model. The simulated results are then compared with the experimental data for head-end and rear-end pressure. The agreement between simulation and experiment is remarkable. In summary, major finding of this study is that unsteady quasi-one-dimensional gas dynamic model can capture the flow field in the motor during ignition transient effectively. Research limitations/implications Unsteady quasi-one-dimensional gas dynamic model can capture the flow field in the motor during ignition transient effectively. However, in systems where two- and three-dimensional effects are pre-dominant, one would require to develop a more elaborate, multi-dimensional model which will allow for further understanding of the flow behavior and eventually lead to modeling of rocket motors with more complex geometries. Practical implications The close agreement between experimental and simulation results can be considered as forced to some degree, because the general mathematical model of erosive burning contains a free variable erosive burning exponent. However, in future, this variable can be established a priori by erosive burning tests. Originality/value The solid propellant ignition process consists of series of rapid events and must be completed in a fraction of a second. An understanding of the dynamics of ignition has become increasingly vital with the development of larger and more sophisticated solid propellant rocket motors. This research effort provides the simulation framework to predict and evaluate the motor pressure during each phase by means of a numerical analysis, thus significantly increasing the efficiency of the preliminary design process with a reduction of both the motor development and operational costs.

Energy partitioning in high speed impact of analogue solid rocket motors

1999 ◽  
Vol 103 (1029) ◽  
pp. 519-528
Author(s):  
W. P. Schonberg
Keyword(s):  
High Speed ◽  
Failure Modes ◽  
Rocket Motor ◽  
Solid Rocket Motor ◽  
Solid Rocket Motors ◽  
Rocket Motors ◽  
Response Characteristics ◽  
Fast Running ◽  
Solid Rocket ◽  
Full Scale Tests

Abstract Modelling the response of solid rocket motors to bullet and fragment impacts is a high priority among the military services from standpoints of both safety and mission effectiveness. Considerable effort is being devoted to characterising the bullet and fragment vulnerability of solid rocket motors, and to developing solid rocket motor case technologies for preventing or lessening the violent responses of rocket motors to these impact loadings. Because full-scale tests are costly, fast-running analytical methods are required to characterise the response of solid rocket motors to ballistic impact hazards. In this study, a theoretical first-principles-based model is developed to determine the partitioning of the kinetic energy of an impacting projectile among various solid rocket motor failure modes. Failure modes considered in the analyses include case perforation, case delamination, and fragmentation of the propellant simulant material. Energies involved in material fragmentation are calculated using a fragmentation scheme based on a procedure developed in a previous impact study utilising propellant simulant material. The model is found to be capable of predicting a variety of response characteristics for analogue solid rocket motors under high speed projectile impact that are consistent with observed response characteristics. Suggestions are made for improving the model and extending its applicability to a wider class of impact scenarios.

Classification and Inspection of Debonding Defects in Solid Rocket Motor Shells Using Machine Learning Algorithms

2021 ◽  
Vol 16 (7) ◽  
pp. 1082-1089
Author(s):  
Xufei Guo ◽  
Yanwei Yang ◽  
Xingcheng Han
Keyword(s):  
Machine Learning ◽  
Layer Structure ◽  
Rocket Motor ◽  
Machine Learning Algorithms ◽  
Support Vector ◽  
Interface Debonding ◽  
Solid Rocket Motor ◽  
Solid Rocket Motors ◽  
Rocket Motors ◽  
Solid Rocket

Debonding problems along the propellant/liner/insulation interface are a critical factor affecting the integrity of solid rocket motors and one of the major causes of their structural failure. Due to the complexity of interface debonding detection and its low accuracy, a method of wavelet packet transform (WPT) combined with machine learning is proposed. In this research, multi-layer structure specimens were prepared to simulate the structure of a solid rocket motor. First, ultrasonic non-destructive testing technology was used to obtain defect data. Then, WPT algorithm was employed to extract characteristic signals of the defect data. Moreover, k-nearest neighbor model, Random Forest model and support vector machine model were applied to the classification. The results showed that the accuracies of the three models were 84.67%, 90.66% and 95.33%, respectively. Positive results indicate that WPT with machine learning model exhibited excellent classification performance. Therefore, WPT combined with machine learning can achieve a precise classification of debonding defects and has the potential to assist or even automate the debonding inspection process of solid rocket motors.

Solid-fuel Rocket Engines: Layered Composite Materials Manufacturing and Thermal Diffusivity Measurements

2014 ◽  
Vol 33 (2) ◽  
pp. 171-177 ◽  
Author(s):  
Adam Dominiak ◽  
Michał Rąpała ◽  
Roman Domański ◽  
Bartosz Bartkowiak ◽  
Piotr Darnowski
Keyword(s):  
Composite Materials ◽  
Thermal Diffusivity ◽  
Solid Fuel ◽  
High Performance ◽  
Phenol Formaldehyde ◽  
Basalt Fiber ◽  
Layered Composite ◽  
Rocket Engines ◽  
Rocket Motors ◽  
Diffusivity Measurements

AbstractThis communication presents thermal diffusivity measurements of fourteen layered insulating composite materials. Composite materials that were taken under investigation contained matrixes based on epoxy and phenol-formaldehyde resins and reinforcements, such as glass, basalt fiber and wrapping or ceramic paper. They were all prepared by the Rocket Section of the Students Space Association (RS-SSA). Manufacturing process of samples is described. Additional objective of this research was to obtain the quality of such prepared materials and if they are reliable enough to be used in solid-fuel rocket motors. Use of composite materials to build combustion chamber walls of solid fuel rocket engines, rather than metal, leads to weight reduction and increases amount of fuel that rocket can carry. That improves performances and gives new possibilities for rocket applications. To apply new high performance solid fuels, development of new composite materials was required. Analysis of thermal properties gives the answer, which material should be used for new solid-fuel rockets designed by RS-SSA.

EPDM-based heat-shielding materials modified by hybrid elastomers of silicone or polyphosphazene

2019 ◽  
Vol 31 (9-10) ◽  
pp. 1112-1121 ◽  
Author(s):  
Shaojun Wu ◽  
Shuangkun Zhang ◽  
Raheel Akram ◽  
Abbas Yasir ◽  
Bowen Wang ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
State Of The Art ◽  
Ablation Rate ◽  
Solid Rocket Motor ◽  
Ablation Resistance ◽  
Linear Ablation ◽  
Insulation Systems ◽  
Solid Rocket ◽  
Heat Shielding ◽  
Methyl Phenyl

The erosion resistances of ethylene propylene diene monomer (EPDM) insulations are often inadequate for advanced solid rocket motor (SRM) applications. EPDM modification by blending secondary matrixes is a feasible approach to improve the ablative properties of EPDM insulations. The addition of flexible inorganic hybrid rubbers as a secondary matrix, such as silicones and polyphosphazenes, may impart EPDM insulations with better ablative performance. The blends of EPDM/hybrid rubbers represent the state-of-the-art heat-shielding materials for SRM. In the present work, methyl-phenyl silicone/EPDM and poly(diaryloxyphosphazene)/EPDM insulation systems with various blending ratios of secondary matrixes have been prepared. The ablative properties of the insulations were examined by oxy-acetylene ablation tests, and the results showed that these properties could be enhanced accordingly by blending with hybrid rubbers under appropriate proportions. The unique charred layers resulting from the hybrid rubbers contributed to their excellent ablation properties. For example, the silicone/EPDM insulations exhibited a more significant improvement of ablation resistance properties. With a 1:1 blending ratio of silicone/EPDM, the linear ablation rate was 0.06 mm s−1 after 20 s of oxy-acetylene ablation. The enhancement in the ablative resistance was attributed to the charred layers with bunches of embedded compact microtubes with a length of 2–3 mm, which consisted of silicon carbide, silicon dioxide, and Si–O–C ceramics.

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