Solid Propellant Rocket Motors Research Articles

Guided Filter-Based Edge Detection Algorithm for ICT Images of Solid Rocket Motor Propellant

As the nondestructive testing method based on industrial computerized tomography (ICT) is widely used in solid rocket motor (SRM) propellant defect detection, the demand for a corresponding image processing algorithm is increasing. In order to extract better defect information on SRM propellants, we studied the edge detection algorithm for their ICT images. This paper proposes a guided filter-based edge detection algorithm for ICT images of SRM propellants with much noise. The algorithm innovatively uses guided filters to converge the detection results of type I edges with good edge continuity to type II edges with clear positioning. The obtained type III edges have good edge continuity and clear positioning. The experimental results show that the proposed algorithm can achieve edge detection effectively.

Thrust termination of solid rocket motor

Rocket motors are engines that create the necessary thrust for the rocket motion. There are different types of rocket motors based on the propellant state, such as solid propellant rocket motors, liquid propellant rocket motors, and hybrid propellant rocket motors. One of the biggest disadvantages of solid propellant rocket motors, in comparison to liquid and hybrid propellant rocket motors, is that they are extremely difficult to extinguish, necessitating the use of specific devices. This paper reviews various ways for thrust termination such as fluid injection, rapid increase in throat area, and sudden opening of an additional port at the forward section of the motor, which increases the depressurization rate (dp/dt) required for extinguishing. The rate of depressurization varies depending on propellant components, combustion pressure, and exhaust pressure, and may be investigated using experimental approaches. The change in the critical area for a motor can be predicted by using MATLAB code to ensure the complete extinguishing by decreasing the pressure under the deflagrationlimit with high depressurization rate.

Performance Comparison of Control Strategies for a Variable-Thrust Solid-Propellant Rocket Motor

This paper deals with a performance comparison of the control algorithm for a variable-thrust solid-propellant rocket motor (VTSRM). To do this, we develop a simulation model of a VTSRM considering characteristic changes in the combustor and design control systems for pressure and thrust. We use three types of control algorithms for the pressure control: classical PID control, feedback linearization control, and fuzzy PID control, and two control algorithms for thrust control: classical PID control and fuzzy PID control. Finally, we compare the performance of each control system through a numerical simulation using step responses. Through this work, we check that feedback linearization is better in pressure control, and fuzzy PID control is more appropriate in thrust control. Especially using fuzzy PID control, we can get fast settling with a small undershoot even if the system is a nonminimum phase system.

Grain Configuration of Solid Rocket Motor

The solid rocket motor upper stage for a space launch vehicle is a more efficient propulsion technology than the liquid rocket motor upper stage. Its grain design has the potential to be crucial in terms of lowering inert mass by adopting improved volume efficiency with the lowest practicable sliver size while keeping maximum strength. Specifically, the strategy for (3D) grain arrangement of the slot for the upper stage solid rocket engine has been described in this paper. The complex configuration is established by the design process, which takes place under a parametric model of geometry in (CAD) software and is typified by varied dynamics. When constructing solid propellant rocket motors, grain arrangement is a vital and critical step. Accurate estimates of grain geometric properties play a key role in performance prediction and can be a vital and critical stage in the design of solid propellant rocket motors. This research study proposes an effective performance-matching design framework for solid rocket motors that are tuned to suit a range of thrust performance criteria. The framework is constructed utilising an innovative and specialised general design technique that was designed to evaluate the general design parameters, which is given in this study. Because of the findings obtained, it can be stated that the recommended framework is a practical and efficient approach for solid rocket engine design and development.

Bimetallic ruthenium compound derived from 6,12-dihydroindeno[1,2-b]fluorene ligand as burning rate catalyst for solid rocket motor propellant

We reported the synthesis of a novel bimetallic compound with the formula [(Cp*Ru)2-IF] derived from 6,12-dihydroindeno[1,2-b]fluorene ligand (IFH2). This compound was characterized by 1H and 13C NMR, elemental analysis, FT-IR, and UV-vis.The bimetallic compound was tested as a burning rate catalyst on the thermal decomposition of ammonium perchlorate. It was assessed by differential scanning calorimetry technique (DSC) analysis to understand its catalytic behavior further. [(Cp*Ru)2-IF] shows a decrease in the decomposition temperature of AP to 381°C, increasing the energy release to 1271 J•g−1. In addition, this compound leads to the lowest activation energy (20.7 kJ•mol−1), suggesting a suitable and competitive alternative to be used as a modifier for composite solid propellants.

Assessment of Mechanical Properties of Aged Composite Propellant Using Non‐Destructive Indentation Technique in Solid Propellant Rocket Motor

AbstractAgeing study of composite propellant is one of the important aspects for the long term usage of a solid propellant rocket motor (SPRM). The assessment of mechanical properties is essential to predict the structural performance of rocket motors before its flight test. Mostly, the study of ageing behavior of composite propellant is limited to sample level which is subjected to either for normal ageing or accelerated ageing. In the present study, an attempt was made to assess the aging behavior of HTPB based composite propellant at full scale rocket motor level using a non‐destructive indentation technique. The mechanical properties of naturally aged HTPB based composite propellant samples were comprehensively studied by both Universal Testing Machine (UTM) and indentation technique. The mathematical correlation was developed using least square method between UTM and indentation data. An attempt was made to establish the method to assess the aging behavior of composite propellant by indentation technique directly. The developed correlation was validated on aged composite propellant samples. Further, indentation technique was used to assess the mechanical properties of the propellant of in‐flight fielded SPRM which was 11 years old.

Combustion-mode transition of a solid propellant rocket motor by nitrogen gas injection and combustion gas release

Combustion-mode transition of a solid propellant rocket motor by nitrogen gas injection and combustion gas release

Static Firing Tests of Solid Propellant Rocket Motors: Uncertainty Levels of Thrust Measurements

Static firing tests of solid propelled rocket motors (SRMs) are important tests in aerospace industry during the development of new motors as well as to assure the quality of a motor batch. This type of test allows the operator to obtain the measured “thrust versus time of burning” graphic yielded by the motor during burning to verify whether the motor performance matches the project requirements. Laboratory Quality Certificates and good measurement practices make necessary the evaluation of the typical uncertainty of these test results, which demand a wide number of instruments, called measurement chain. This work aims to present the uncertainty levels expressed to the thrust values gathered during a SRM static firing test for two differently configured measurement chains. In order to estimate the uncertainty of a complete measurement chain, the theories of expanded and combined uncertainties are employed. It was possible to verify that in the analyzed case the use of signal amplifiers increased the measurement uncertainty of the chain.

Bimetallic Ruthenium Compound Derived from 6,12-Dihydroindeno[1,2-B]Fluorene Ligand as Burning Rate Catalyst for Solid Rocket Motor Propellant

Bimetallic Ruthenium Compound Derived from 6,12-Dihydroindeno[1,2-B]Fluorene Ligand as Burning Rate Catalyst for Solid Rocket Motor Propellant

Investigation of Heat Transfer in the Combustion Chamber of a Solid-Propellant Rocket Motor Within the Framework of the Homogeneous Gas Model

Investigation of Heat Transfer in the Combustion Chamber of a Solid-Propellant Rocket Motor Within the Framework of the Homogeneous Gas Model

Study of Intra-Chamber Processes in Solid Rocket Motors by Fiber Optic Sensors.

In this study, an experimental study of the burning rate of solid fuel in a model solid propellant rocket motor (SRM) E-5-0 was conducted using a non-invasive control method with fiber-optic sensors (FOSs). Three sensors based on the Mach–Zehnder interferometer (MZI), fixed on the SRM E-5-0, recorded the vibration signal during the entire cycle of solid fuel burning. The results showed that, when using MZI sensors, the non-invasive control of solid fuel burnout is made possible both by recording the time of arrival of the combustion front to the sensor and by analyzing the peaks on the spectrogram of the recorded FOS signal. The main mode of acoustic vibrations of the chamber of the model SRM is longitudinal, and it changes with time, depending on the chamber length. Longitudinal modes of the combustion chamber were detected by MZI only after the combustion front passed its fixing point, and the microphone was unable to register them at all. The results showed that the combustion rate was practically constant after the first second, which was confirmed by the graph of the pressure versus time at the nozzle exit.

Certain analysis of a solid rocket motor (SRM) with modified pentagonal grain configuration

Solid propellant rocket motors (SRMs) have wide range of usage in satellite launchers. SRM uses solid propellant grains with different types of perforations. Usage of perforations with cornered shapes (i.e., square, rectangle, pentagon etc.) results in higher burning rate which results in sudden decrease of chamber pressure (or thrust). Since change of state of burning is not desirable, these kinds of perforations cannot be used for SRMs. Better reduction in burning rate can be achieved by changing the geometrical configuration of these shapes which enables the usage of cornered shapes as grain perforations in SRMs. Design and analysis of grain configurations with number of web steps can be used as tool for predicting the performance of rocket motors. Burn back steps of the grain can be predicted for required intervals of time by 2D design using CATIA. In this study, burn back steps of 3D grains with different types of pentagonal configuration perforations was investigated. For each web step, a 3D model was prepared and a required performance characteristic was obtained using analytical calculations. CFD simulation of the 3D grain was done in ANSYS (FLUENT) to assure the validity of the grain geometry of SRM. Various types of CFD models were used for CFD simulation in the field of SRM in this study, standard k-ɛ model is used for simulation purpose.

Life Interval Prediction for Aging Solid-Propellant Rocket Motors with Uncertain Chemical Parameters

Predictions of the remaining lifetime of aging solid-propellant rocket motors are affected by the uncertainties of various chemical parameters in the reaction. This paper proposes a nonprobabilistic interval method for evaluating the life bounds of aging solid-propellant rocket motors. In this method, chemical uncertainties in the aging process are represented by uncertain-but-bounded initial parameters, and the uncertainties arising in aging solid-propellant rocket motors are described by an interval model. A sparse regression Legendre inclusion function is then employed to establish an interval model for aging solid-propellant rocket motors, which can be directly solved in deterministic form using the finite element method. Finally, in conjunction with the deterministic solutions, the sparse regression Legendre interval algorithm is employed to obtain the bounds of the storage life related to the uncertain interval parameters. The effectiveness of the proposed method is verified by considering an uncertain storage life prediction problem under the accelerated thermoaging process with constant temperature conditions. The proposed method provides a reliable tool for predicting the storage life of aging solid-propellant rocket motors.

Analysis of Load Optimization in Solid Rocket Motor Propellant Grain with Pressure Cure

At present, the casting of large-size motors often adopts pressure cure. This technology can effectively reduce the risk of damage to the structural integrity of the grain in the case-bonded casting solid rocket motor. In this paper, ABAQUS is used to establish a finite element model of star-shaped grains. The whole process of pressure cure was simulated and modeled, and the Python script was redeveloped. The Evol evolutionary algorithm was used in ISIGHT to optimize the load parameters such as pressure value, attenuation coefficient of the relief curve, and the attenuation coefficient of the cooling curve. The effects of different pressure values and different cooling and depressurizing rates on the residual stress and strain were analyzed. The optimization results show that the closer the pressure value is to the theoretical pressure, the more significant the effect of pressure cure. However, the effect of stress and strain reduction in different directions is slightly different. The different cooling and pressure relief rates have a great influence on the process quantity. Pressure cure works best when the pressure attenuation coefficient is equal to 6850, and the temperature attenuation coefficient is equal to 8650. The optimization analysis of pressure curing provides a reference for engineering practice.

Particle-free zone of the two-phase flow in a convergent-divergent nozzle

The gas-particle two-phase flow in a convergent-divergent nozzle is encountered in many applications like solid-propellant rocket motors (SRMs). The “Particle-free Zone” adjacent to the nozzle wall is crucial for the nozzle performance which is closely related to the specific impulse of the motor. Though it has been usually observed by many investigators, the existence of the particle-free zone in different nozzles and its effect on nozzle performance are still ambiguous. In this research, we investigated the two-phase flow with monodispersed micron particles in a nozzle using a two-way coupled Eulerian-Lagrangian model and found that the particle-free zone does not exist for smallest particles (dp = 1.0 μm). Moreover, we built a theoretical model for predicting the extent of the particle-free zone by calculating the trajectory of the particle closest to the nozzle wall. The effects of the particle size, total pressure, total temperature and nozzle geometry on the particle-free zone were studied. Finally, we analyzed the nozzle performance and found that the gas velocity at the outlet and the thrust do not change with particle size monotonously, and the medium-sized particles cause the largest thrust loss.

Low-Thrust Solid Rocket Motors for Small, Fast Aircraft Propulsion: Design and Development

Small, low-thrust, long-burn-time solid propellant rocket motors could provide propulsion for a new class of kilogram-scale, transonic, uncrewed aerial vehicles (UAVs). This paper investigates technological challenges of small, low-thrust solid rocket motors: slow-burn solid propellants, motors that have low thrust relative to their size (and thus have low chamber pressure), thermal protection for the motor case, and small nozzles that can withstand long burn times. Slow-burn propellants were developed using ammonium perchlorate and 0–20% oxamide (burn-rate suppressant), with burn rates of at 1 MPa. Using these propellants, a low-thrust motor successfully operated at a thrust/burn area ratio 10 times less than that of typical solid rocket motors. This kilogram-scale motor can provide 5–10 N of thrust for 1–3 min. An ablative thermal protection liner was tested in these firings, and a new ceramic-insulated nozzle was demonstrated. This paper shows that small, low-thrust solid motors are feasible and presents a baseline design for the integration of such a motor into a small UAV.

Investigation of Acoustic Instability in Solid-Propellant Rocket Motors with the Use of a Pulsed T-Burner

Investigation of Acoustic Instability in Solid-Propellant Rocket Motors with the Use of a Pulsed T-Burner

솔리드 모델링과 레벨셋 기법을 이용한 고체 로켓 추진기관 성능해석

The performance prediction and grain burn-back analysis of rocket motor are important steps in the designing of a solid propellant rocket motor. The grain burn-back analysis of the solid grain identifies the burning surface area at each burning step in order to predict pressure-time history of the rocket motor. In this study, the shape of propellant grains was conveniently designed based on a solid modeling program of conventional purpose and the internal ballistics analysis was performed using a Matlab code which was developed to analyze the grain burn-back for this shape model. Upon carrying several analyses for rocket motors, it was confirmed that the developed code is suitable and useful.

Multimodal optical excitation pulsed thermography: Enhanced recognize debonding defects of the solid propellant rocket motor cladding layer

We demonstrated the multimodal optical excitation pulsed thermography, and this technique can enhance the defect detectability and the depth-resolution dynamic range for the propellant /cladding layer interface debonding defects of the solid propellant rocket motor. Firstly, three-dimensional (3D) thermal-wave model which stimulated by a pulse excitation thermal source was built. The temperature field distribution and the thermal-wave diffusion behavior were analyzed. Subsequently, multiple feature extraction algorithms were proposed and applied to extract characteristic images. The experimental set-up was developed and utilized to detect cladding layers with artificial defects. The results demonstrate that pulse thermography optimized by PLSR and ICA can achieve better detection of interface debonding defects. The characteristic profiles were analyzed to evaluate the ability of feature images to characterize the defect diameter and depth. The results depict that the 1st independent component has a better detection effect for defect depth and diameter.

Experimental techniques for characterization of particles in plumes of sub-scale solid rocket motors

An innovative collection methodology based on a recently developed supersonic probe enabled the collection of alumina particulate from the exhaust plume of a sub-scale solid propellant rocket motor and the comparison with quench collection bomb analysis of propellant incipient agglomeration. Laser diffraction, scanning electron microscopy, and X-ray spectroscopic methods were used to determine particle size, morphology, crystalline nature, and elemental composition. A significant reduction of the particle size occurred across the rocket nozzle. The size distribution resulting from the expansion was monomodal and centered around 2μm to 3μm. Propellants containing lower aluminum mass fraction led to number-based distribution in the sub-micrometric region while, for higher metal loading, particle distributions were sensibly shifted towards larger size in the same rocket operative conditions. Similarly, the size was identified to be weakly dependent on chamber pressure, with an increase of the former as the latter decreased. The Hermsen correlation supported and verified the experimental analysis. The majority of the particles was composed by γ-alumina phase, had a typical size lower than 3μm, and was characterized by smooth surfaces. Occurrences of spitting and collision-to-coalescence phenomena were identified and analyzed.