Showing papers on "Solid-fuel rocket published in 2019"
TL;DR: In this paper, the authors review the critical physical processes of ammonium perchlorate (AP) propellant combustion and explore the different experimental and computational avenues used to shed light on such a complex phenomenon.
78 citations
TL;DR: In this article, aluminum particle burn in a gap created between a downward facing combusting propellant surface and an upward facing inert surface was modeled with sensitivity testing on the surface velocity, surface temperature, surface radiation, particle diameter, turbulent Prandtl number and turbulent Schmidt number.
41 citations
TL;DR: In this paper, a simplified axisymmetric 2D numerical simulation model is developed to simulate the flow field of the SRM, in which the two-phase flow consists of seeded inert Al2O3 particles and burned gas.
30 citations
TL;DR: In this article, a new solid rocket scramjet equipped with two combined cavity and strut device was studied by experimental and numerical approaches, and the experimental results showed that the combined cavity can play a role as ignition and flame holding in the solid rocket scrambling combustor.
23 citations
TL;DR: In this article, a sensitivity analysis was conducted on an aluminum particle combustion simulation in an upward burning solid rocket propellant, via a computational fluid dynamics code, with comparison to experimental data.
20 citations
TL;DR: In this paper, the influence of vortex generator on the performance of a solid rocket scramjet was investigated by means of direct-connected fire tests, and the experimental results showed that compared with the benchmark configuration, the configurations with vortex generator can promote significantly the ignition and stable combustion of the primary fuel-rich mixture produced in the gas generator.
18 citations
TL;DR: In this paper, a high-order numerical solver is used to simulate the internal ballistic simulation of solid rocket motors via the source terms in gas-phase governing equations, and the analysis of high-amplitude pressure oscillations, which are the primary symptom of nonlinear thermoacoustic instabilities, provides the insight into the nature of the longitudinal instability growth process after the pulse triggering.
18 citations
TL;DR: In this article, a new scramjet combustor configuration using solid fuel, namely, the solid fuel rocket scramjet (SFRSCRJ) combustor is proposed, and a numerical study was conducted to simulate a flight environment of Mach 6 at a 25 km altitude.
Abstract: Scramjet based on solid propellant is a good supplement for the power device of future hypersonic vehicles. A new scramjet combustor configuration using solid fuel, namely, the solid fuel rocket scramjet (SFRSCRJ) combustor is proposed. The numerical study was conducted to simulate a flight environment of Mach 6 at a 25 km altitude. Three-dimensional Reynolds-averaged Navier–Stokes equations coupled with shear stress transport (SST) k − ω turbulence model are used to analyze the effects of the cavity and its position on the combustor. The feasibility of the SFRSCRJ combustor with cavity is demonstrated based on the validation of the numerical method. Results show that the scramjet combustor configuration with a backward-facing step can resist high pressure generated by the combustion in the supersonic combustor. The total combustion efficiency of the SFRSCRJ combustor mainly depends on the combustion of particles in the fuel-rich gas. A proper combustion organization can promote particle combustion and improve the total combustion efficiency. Among the four configurations considered, the combustion efficiency of the mid-cavity configuration is the highest, up to about 70%. Therefore, the cavity can effectively increase the combustion efficiency of the SFRSCRJ combustor.
14 citations
TL;DR: In this paper, the influence of changes in lobe sweep angle and height on the mixing and heat release characteristics of a solid fuel scramjet combustor on the basis of a staggered support plate structure was investigated.
13 citations
TL;DR: In this paper, the flame dynamics of ammonium perchlorate/hydroxyl-terminated polybutadiene (AP/HTPB) composite propellant subject to the acoustic oscillation in a solid rocket motor (SRM) is investigated numerically.
13 citations
TL;DR: In this article, a graphite-based nozzle coupled with a combustion flow field is studied in a hybrid rocket motor with a star grain, and the results indicate that the nozzle erosion is greatly influenced by the inner flow field.
TL;DR: In this article, the role of aluminum combustion on the stability of solid rocket motors is investigated, and an experimental setup known as the velocity-coupled T-burner is described.
Abstract: This paper reports experimental and numerical works devoted to the role of aluminum combustion on the stability of solid rocket motors. An experimental setup, known as the velocity-coupled T-burner...
TL;DR: In this paper, the authors reported a novel and facile route to prepare nano-structured Fe2O3 with enhanced catalytic activity in the ballistic modification of ammonium perchlorate (AP)-based composite solid rocket propellant.
Abstract: Space launch vehicles and strategic military vehicles commonly employ composite solid rocket propellants containing Fe2O3 as ballistic modifier. Nanoscale catalysts, including nanoscale Fe2O3, have been reported to exhibit superior activity in the thermal decomposition and combustion of composite rocket propellants. However, scalable methods to prepare such nano-structured catalysts with high performance as ballistic modifiers and systematic studies relating the synthesis parameters to the catalyst characteristics and consequently to the thermal and combustion properties of the composite propellant are scarce. In this paper, we report a novel and facile route to prepare nano-structured Fe2O3 with enhanced catalytic activity in the ballistic modification of ammonium perchlorate (AP)-based composite solid rocket propellant. A submerged spray precipitation method using air-assisted liquid-centered coaxial atomization has been developed to prepare these nano-structured Fe2O3 catalysts. The prepared Fe2O3 catalysts possess higher surface area and exhibit superior activity in the thermal sensitization of AP, leading to an 88% increase in the burning rate of AP-based composite solid rocket propellants, than the Fe2O3 catalyst prepared via traditional precipitation method. Merits of the developed preparatory route, influence of the atomization process on the nano-structure morphology and subsequent benefits of these nano-structured catalysts on the ballistic properties of AP-based propellants are demonstrated and discussed in this paper.
TL;DR: In this paper, the impact of ultrafine aluminum particles on combustion characteristics of double-base propellant was evaluated using a small-scale ballistic evaluation test motor, and the results confirmed that aluminum is an outstanding energetic ingredient for solid rocket propulsion.
TL;DR: In this article, a three-dimensional stress analysis of a rocket motor under cyclic temperature loading was performed and the novelty of the analysis lies in the use of a propellant constitutive model that accounts fo...
Abstract: A three-dimensional stress analysis of a rocket motor under cyclic temperature loading was performed. The novelty of the analysis lies in the use of a propellant constitutive model that accounts fo...
09 Apr 2019
TL;DR: Boron-Based Fuel-Rich Solid Rocket Propellant Technology as discussed by the authors is a professional book that systematically introduces the latest research progress for boronbased fuel-rich solid propellants.
Abstract: Boron-Based Fuel-Rich Solid Rocket Propellant Technology is a professional book that systematically introduces the latest research progress for boron-based fuel-rich solid propellants. It covers surface modifications, coating and agglomerating techniques, granulation, and characterization of amorphous boron powders, and its application to fuel-rich solid rocket propellants. Technologies for controlling the processing methods and combustion performance of fuel-rich propellants are examined, and the book concludes with a summary of the research progress in boron-based fuel-rich solid propellants and a look forward to the foreseeable development trends of military applications.
TL;DR: The internal ballistic analysis of a solid rocket motor mainly relies on an accurate computation of the transient burning surface geometry of the propellant during combustion phase as discussed by the authors, which is a reliable and reliable method.
Abstract: The internal ballistic analysis of a solid rocket motor mainly relies on an accurate computation of the transient burning surface geometry of the propellant during combustion phase. A reliable and ...
01 Sep 2019
TL;DR: In the present research, an efficient performance matching optimization approach is proposed and applied to the solid rocket motor design and results indicate that the proposed approach is practical and efficient.
Abstract: Solid rocket motor design matching the thrust requirement of the overall vehicle has become an exigent task. In the present research, an efficient performance matching optimization approach is prop...
TL;DR: In this article, the authors improved understanding of the combustion properties of agglomerate-reduced propellants under solid rocket motor conditions and compared their combustion properties between combustor conditions.
Abstract: To improve understanding of the combustion properties of agglomerate-reduced propellants under solid rocket motor conditions and to compare their combustion properties between combustor conditions ...
TL;DR: In this article, a theoretical analysis is conducted to determine the heat release rate fluctuations produced by the burning droplet cloud for small acoustic disturbances, and two contributions to heat release fluctuations are identified: the first originates from fluctuations of the evaporation rate due to the oscillating flow around the droplets.
Abstract: Combustion of aluminum droplets released by the solid propellant is widely used to increase the thrust in solid rocket motors. The combustion dynamics of the released droplet cloud in the unsteady flow is however susceptible to trigger thermoacoustic instabilities. A theoretical analysis is conducted to determine the heat release rate fluctuations produced by the burning droplet cloud for small acoustic disturbances. Two contributions to heat release fluctuations are identified. The first originates from fluctuations of the evaporation rate due to the oscillating flow around the droplets. This leads to local fluctuations of the volumetric rate of heat release within the droplet cloud. The second one originates from the motion of the boundary of the burning droplet cloud at the end of the combustion process. This motion is due to droplet lifetime oscillations leading to an additional source of heat release disturbances. Both contributions to heat release disturbances take place within the acoustic boundary layer along the solid propellant surface. Quasi-steady models for the response of the droplet diameter fluctuations and droplet velocity fluctuations are derived. Combined with a model for the gas velocity fluctuations within the acoustic boundary layer they lead to expressions for the resulting heat release rate disturbances within the droplet cloud and at its boundary. Results are compared to a previous low order model and to numerical flow simulations. It is shown that the new model leads to close agreement with simulations over the entire flow. The derived expressions yield a better understanding on heat release disturbances and can be used to predict the linear stability of a solid rocket motor at reduced computational costs.
TL;DR: In this paper, the development of phase stabilized ammonium nitrate (PSAN) and ammonium dinitramide (ADN) based green oxidizers has been discussed.
TL;DR: In this paper, the effects of additive's properties on the solid rocket propellants combustion arc were investigated using ANN methods. But, the results predicted are within desirable limits accepted in combustion conditions, while some of the regularly measured kinetic parameters extracted from noncombustion conditions could be related to properties at combustion conditions.
Abstract: The efforts of Russian-Indian research team for application of the data science methods, in particular, artificial neural networks for development of the multi-factor computational models for studying effects of additive's properties on the solid rocket propellants combustion arc presented. The possibilities of the artificial neural networks (ANN) application in the generalisation of the connections between the variables of combustion experiments as well as in forecasting of ``new experimental results'' are demonstrated. The effect of particle size of catalyst, oxidizer surface area and kinetic parameters like activation energy and heat release on the final ballistic property of AP-HTPB based propellant composition has been modelled using ANN methods. The validated ANN models can predict many unexplored regimes, like pressures, particle sizes of oxidiser, for which experimental data are not available. Some of the regularly measured kinetic parameters extracted from non-combustion conditions could be related to properties at combustion conditions. Results predicted are within desirable limits accepted in combustion conditions.
TL;DR: In this paper, the combustion characteristics of hydroxylterminated polybutadiene and nitrate ester plasticized polyether propellants were investigated using real-time X-ray radiography technology and an overload simulation erosion motor.
TL;DR: In this paper, an intrusive technique for particles capturing in supersonic high temperature flows to be used in solid rocket motors plume characterization is proposed to handle a progressive deceleration and cooling down of the exhaust gas, aiming at preserving liquid particles from breakup.
24 May 2019
TL;DR: The pressure trend of the SRM obtained was also compared to those in well-established literature, thus, the pseudo-numerical approach put forward proves to be effective.
Abstract: To characterize SRM, the motor needs to be tested on a static test rig and certain performers indicators evaluated. In this study, the thrust with time from the SRM was acquired via a Digital Acquisition (DAQ) System and saved in Microsoft Excel® format(.csv). These thrust and time of the tested motor were then imported into MATLAB® for the purpose of computing burn time, maximum thrust, average thrust, total impulse, specific impulse and chamber pressure of the motor. The specific impulse and combustion chamber pressure for the SRM were computed in a novel approach which we call Pseudo-numerical approach (combination of experimental result with numerical computation). In this approach, first, we modelled the depleting propellant mass in the combustion chamber with a novel mathematical expression. This novel expression was then used in computing specific impulse of the SRM. Second, the total surface area of the propellant grain was modelled as a hollow cylinder with depleting dynamics during motor operation, in a similar manner with the propellant mass. Third, multiplying the reciprocal of the propellant grain surface area with the experimental force gave use the pseudo-numerically computed chamber pressure. The pressure trend of the SRM obtained was also compared to those in well-established literature, thus, the pseudo-numerical approach put forward proves to be effective.
Dissertation•
16 Jan 2019
TL;DR: In this article, an analytical two-dimensional planar incompressible frictionless model using the so-called Vortex Sound Theory was used to predict the limit-cycle amplitude. But the model was not applied to the case of a choked nozzle.
Abstract: Solid Rocket Motors (SRMs) can display self-sustained acoustic oscillations driven by coupling between hydrodynamic instabilities of the internal flow and longitudinal acoustic standing waves. The hydrodynamic instabilities are triggered by the acoustic standing wave and results in the formation of coherent vortical structures. For nominal ranges of flow conditions the sound waves generated by the interaction between these vortices and the choked nozzle at the end of the combustion chamber reinforces the acoustic oscillation. Most available literature on this subject focuses on the threshold of instability using a linear model. The focus of this work is on the prediction of the limit-cycle amplitude. The limit-cycle is reached due to nonlinear saturation of the source, as a consequence of the formation of large coherent vortical structures. In this case the vortex-nozzle interaction becomes insensitive to the amplitude of the acoustic standing wave. Hence, one can focus on the sound generation of a vortex with the nozzle. Sound production can be predicted from an analytical two-dimensional planar incompressible frictionless model using the so-called Vortex Sound Theory. In this model the vorticity is assumed to be concentrated in a line vortex. Experiments indicate that the volume of cavities around so-called “integrated nozzles” have a large influence on the pulsation amplitude for large SRMs. This is due to the acoustical field normal to the vortex trajectory, induced by the compressibility of the gas in this cavity. As an alternative to the incompressible analytical model a compressible frictionless model with an internal Euler Aeroacoustic (EIA) flow solver is used for simulations of vortex-nozzle interaction. A dedicated numerical simulation study focusing on elementary processes such as vortex-nozzle and entropy spot-nozzle interaction allows a systematic variation of relevant parameters and yields insight which would be difficult by means of limit cycle studies of the full engine. A systematic study of the vortex-nozzle interaction in the case of a choked nozzle has been undertaken. The results are summarized by using a lumped element model for plane wave propagation, which is based on theoretical scaling laws. From EIA simulations it appears that sound due to vortex-nozzle interaction is mainly generated during the approach phase and that for the relevant parameter range there is no impingement of the vortex on the nozzle wall as has been suggested in the literature. Using an energy balance approach, a single fit-parameter model is formulated which qualitatively predicts limit-cycle observations in cold gas-scale experiments reported in the literature. Finally the Euler model is used to compare the sound production by vortex-nozzle interaction with that due to the ingestion of an entropy non-uniformity also called entropy spot. In addition to insight, this study provides a systematic procedure to develop a lumped element model for the sound source due to non-homogeneous flow-nozzle interactions in SRMs. Such lumped models based on experimental data or a limited number of flow simulations can be used to ease the design of SRMs.
TL;DR: In this paper, a double-layer time-varying axially moving free-free beam model of a large aspect-ratio solid rocket motor (SRM) is presented.
17 Jun 2019
TL;DR: In this article, the authors used a laser to illuminate fine particles generated in the wind tunnel to visualize flow structures, including BSM plume shapes and shock wave and other flow features.
Abstract: Planar flow visualizations were obtained in a wind tunnel test in the NASA Langley Research Center’s Unitary Plan Wind Tunnel using the laser-light-sheet method. This method uses a laser to illuminate fine particles generated in the wind tunnel to visualize flow structures. The test article was designed to simulate the separation of the two solid rocket boosters (SRBs) from the core stage of the NASA Space Launch System (SLS) at Mach 4 using a scale model. The test was run on of the SLS Block 1B Cargo (27005) configuration and the SLS Block 1B Crew (28005) configuration. Planar flow visualization was obtained only on the crew configuration. Air at pressures up to 1500 psi was used to simulate plumes from the booster separation motors (BSMs) located at the nose, and aft skirt of the two boosters. The facility free stream was seeded with water vapor, which condensed and froze into small ice crystals in the tunnel nozzle expansion. A continuous wave green (532 nm) laser sheet was used to illuminate the ice crystals, and the resulting Mie-scattered light was collected with a camera. The resulting images clearly identify shock waves and other flow features including BSM plume shapes. Measurements were acquired for different BSM pressures and booster separation locations.
TL;DR: In this paper, first-principles calculations, analytic modeling, and experiments were used to combine first-and second-order principles for solid oxidants in chemical looping combustion and solid rocket engines.
Abstract: Solid oxidants are critical for solid fuel oxidation, such as in chemical looping combustion and solid rocket engines. By combining first-principles calculations, analytic modeling, and experiments...