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An improved constant volume cycle model for performance analysis and shape design of PDRE nozzle

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Applied Mathematics and Mechanics(English Edition) 2018年第2期39卷 193-206页

作者： Guangyu LI Xiaowei LI Jue DING Peifen WENG Zhanbin LU Shanghai Institute of Applied Mathematics and Mechanics Shanghai University

An improved constant volume cycle （CVC） model is developed to analyze the nozzle effects on the thrust and specific impulse of pulse detonation rocket engine （PDRE）. Theoretically, this model shows that the thrust coefficient/specific impulse of PDRE is a function of the nozzle contraction/expansion ratio and the operating frequency. The relationship between the nozzle contraction ratio and the operation frequency is obtained by introducing the duty ratio, by which the key problem in the theoretical design can be solved. Therefore, the performance of PDRE can be accessed to guide the preliminary shape design of nozzle conveniently and quickly. The higher the operating frequency of PDRE is, the smaller the nozzle contraction ratio should be. Besides, the lower the ambient pressure is, the larger the expansion ratio of the nozzle should be. When the ambient pressure is 1.013 × 105 Pa, the optimal expansion ratio will be less than 2.26. When the ambient pressure is reduced to vacuum, the extremum of the optimal thrust coefficient is 2.236 9, and the extremum of the specific impulse is 321.01 s. The results of the improved model are verified by numerical simulation.

关键词： pulse detonation rocket engine （PDRE） nozzle specific impulse thrust,constant volume cycle （CVC） model

Impacts of laser pulse width and target thickness on laser micro-propulsion performance

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Plasma Science and Technology 2022年第10期24卷 113-126页

作者：王思博杜邦登杜宝盛郑永赞洪延姬叶继飞邢宝玉李承霖张永昊 State Key Laboratory of Laser Propulsion and Application Space Engineering UniversityBeijing 101416People's Republic of China Technical Institute of Physics and Chemistry Chinese Academy of SciencesBeijing 100190People's Republic of China

In order to optimize the laser ablation performance of a micro-thruster with 1U dimensions,which employs a micro semiconductor laser,the impacts of pulse width and glycidyl azide polymer(GAP)thickness on thrust performance were researched.The results showed that with a GAP thickness of 200μm,the single-pulse impulse(I)increased gradually with the increase in the laser pulse width from 50 to 800μs,while the specific impulse(I_(sp)),impulse coupling coefficient(Cm)and ablation efficiency(η)all reached optimal values with a 200μs pulse width.It is worth noting that the optimal pulse width is identical to the ignition delay time.Both Cmandηpeaked with a pulse width of 200μs,reaching 242.22μN W^(-1)and 35.4%,respectively.With the increase in GAP thickness,I and Cmincreased gradually.GAP of different thicknesses corresponded to different optimal laser pulse widths.Under a certain laser pulse width,the optimal GAP thickness should be the most vertical thickness of the ablation pit,and the various propulsion performance parameters at this time were also optimal.With the current laser parameters,the optimal GAP thickness was approximately 150μm,I_(sp)was approximately 322.22 s,andηwas approximately 34.94%.

关键词： laser micro-propulsion pulse width target thickness specific impulse ablation efficiency

Numerical modelling of the hybrid rocket engine performance

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Propulsion and Power Research 2021年第1期10卷 15-22页

作者： Marian Gieras Aleksander Gorgeri a Institute of Heat Engineering Warsaw University of TechnologyWarsaw00-665Poland Łukasiewicz Research Network e Institute of Aviation Warsaw02-256Poland

The purpose of this paper is to present method of the numerical modeling of the hybrid rocket engine's work as a tool for designing engines of this type.The model is intended as an accurate and simple to use development tool for use in preliminary design stages of hybrid rocket engines,improving the effectiveness and quality of this process.General assumptions underlying the use of a model are presented,together with an analysis of past work in this field.Results of an extensive experimental campaign are presented and compared with the results of numerical modelling in order to calibrate the proposed model and evaluate its accuracy.Parameter variation and optimization were conducted,proving functionality of the methodology.Presented numerical calculations show that the adopted approach to reduce the analysis time and complexity was correct.This method of numerical calculation of hybrid engine working parameters combines aspects of accuracy and simplicity at the early design stage to avoid timeconsuming and costly changes in subsequent detailed stages of design.

关键词： Hybrid rocket engine Combustion Multi-phase flow Regression specific impulse

Computational Study of Azide-oxirane as High-energy-density Materials

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Chinese Journal of Structural Chemistry 2020年第7期39卷 1261-1265页

作者： LI Bu-Tong LI Lu-Lin YANG Chuan School of Chemistry and Materials Science Guizhou Education UniversityGuiyang 550018China

The azide oxiranes were studied at the CCSD(T)/cc-PVDZ//MP2/cc-PVDZ level in this paper.The sublimation enthalpies and heats of formation both in gas phase and solid state were calculated.The thermodynamics stability was predicted by using the bond dissociation energy and characteristic height,through which all title compounds are confirmed to be more stable than hexanitrohexaazaisowurtzitane(CL-20)and A,B1 and D are less sensitive than hexahydro-1,3,5,-trinitro-1,3,5-triazine(RDX).Furthermore,the detonation property was measured by the specific impulse.The detonation performance of the title compounds is comparable to that of RDX.Our results can provide basic information for the molecular design of novel high-energy-density compounds.

关键词： high-energy-density materials specific impulse isodesmic reactions

Solid-like ablation propulsion generation in nanosecond pulsed laser interaction with carbon-doped glycerol

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Chinese Physics B 2017年第3期26卷 369-372页

作者：郑志远张思齐梁田齐婧汤唯冲肖珂高禄高华张自力 School of Science China University of Geosciences Beijing 100083 China

A solid-like propellant of carbon-doped glycerol ablated by a nanosecond pulsed laser is investigated. The results show that the specific impulse increases with increasing carbon content, and a maximum value of 228 s is obtained. The high specific impulse is attributed to the low ablated mass loss that occurs at high carbon content. More importantly, with increasing carbon content, the properties of the doped glycerol approach to those of a solid. These results indicate that propulsion at the required coupling coefficient and specific impulse can be realized by doping a liquid propellant with an absorber.

关键词： laser plasma propulsion liquid specific impulse

Experimental and numerical investigation on alternatives to sandy gravel

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Defence Technology（防务技术） 2024年第1期31卷 130-141页

作者： V.Denefeld H.Aurich Fraunhofer Institute for High-Speed Dynamics Ernst-Mach-Institut(EMI)Ernst-Zermelo-Str.479104FreiburgGermany Fraunhofer Institute for High-Speed Dynamics Ernst-Mach-Institut(EMI)Am Christianswuhr 279400KandernGermany

The NATO agreement STANAG 4569 defines the protection levels for the occupants of logistic and light armored vehicle.The Allied Engineering Publication,AEP-55,Volume 2 document outlines the test conditions for underbelly improvised explosive device(IEDs),which must be buried in water-saturated sandy gravel.The use of sandy gravel has some drawbacks,for instance reproducibility,time consumption,and cost.This paper focuses on the investigation of four alternatives to sandy gravel,which could produce similar specific and cumulative impulses:a concrete pot filled with water,a concrete pot filled with quartz sand,a steel pot without filling and a concrete pot filled with glass spheres(diameter 200μm—300μm)and different water contents.The impulses are measured with a ring technology developed at the Fraunhofer EMI.A numerical soil model based on the work of Marrs,2014 and Fi serov a,2006 and considering the soil moisture was used to simulate the experiments with glass spheres at different water contents,showing much better agreement with the experiments than the classical Laine&Sandvik model,even for high saturation levels.These results can be used to create new test conditions at original scale that are more cost-effective,more reproducible and simpler to manage in comparison to the current tests carried out with STANAG sandy gravel.

关键词： Improvised explosive device(IED) specific impulse Momentum transfer Sandy gravel Glass spheres Numerical model Soil moisture

Theoretical investigation on water/metal fuel ramjet motor-thermodynamic cycle and thermodynamic calculation

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航空动力学报 2010年第5期25卷 1129-1138页

作者： YANG Ya-jing HE Mao-gang School of Aerospace Xi'an Jiaotong UniversityXi'an 710049China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power EngineeringXi'an Jiaotong UniversityXi'an 710049China

For achieving high-speed requirement of underwater vehicle,a conceptual engine,which utilizes the hydroreactive characteristic of several metals under supercavitation environment,has been put forward. Especially,in order to obtain specific impulse as great as possible,a dual water injection system is taken into account. Then thermodynamic cycle model,which lead the improvement of power plant and energy system,is introduced in detail,and thermal efficiency is also analyzed. Furthermore,for investigating the performance of this kind of engine system,detailed thermodynamic calculation and analysis are achieved. Especially,regarding hydroreactive metal fuel Mg/AP/HTPB as our target fuel-rich propellant,considering its obvious deficient oxygen property and the energy property of magnesium/water reaction,theoretical calculation method is established by integrating chemical non-equilibrium with chemical equilibrium. Accordingly,low limit of primary water/fuel ratio is determined. In addition,the qualitative and quantitative relationship of performance parameters,such as theoretical specific impulse,nozzle exit temperature,characteristic velocity,etc.,versus water/fuel ratio is investigated respectively.

关键词： hydroreactive metal fuel water ramjet thermodynamic cycle thermal efficiency specific impulse

Innovative Metallized Formulations for Solid Rocket Propulsion

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含能材料 2012年第4期20卷 465-474页

作者： Luigi T DeLUCA Luciano GALFETTI Filippo MAGGI Giovanni COLOMBO Alice REINA Stefano DOSSI Daniele CONSONNI Melissa BRAMBILLA SPLab Dipartimento di Ingegneria AerospazialePolitecnico di MilanoI-20156 MilanItaly

Several metallized solid rocket propellants,AP/Metal/HTPB in the ratio 68/18/14,were experimentally analyzed at the Space Propulsion Laboratory of Politecnico di Milano.Effects of the metals(micrometric and nanometric Al,B,Mg,and a variety of dual metals) on the performance of the propellant were studied and contrasted to a conventional micrometric aluminum(30 μm average grain size) taken as reference.It is shown that the propellant microstructure plays a fundamental role in controlling the critical aggregation/agglomeration phenomena occurring below and near the burning surface.Two specific effects of microstructure in terms of steady burning rate and average agglomerate size are illustrated.

关键词： solid propellants metal powders combustion specific impulse burning rate agglomeration

High-energy Metal Fuels for Rocket Propulsion： Characterization and Performance

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火炸药学报 2013年第6期36卷 1-14页

作者： Luigi T. DELUCA Filippo MAGGI Stefano DOSSI Volker WEISER Andrea FRANZIN Volker GETTWERT Thomas HEINTZ SPLab Dipartimento di Scienze e Tecnologie Aerospaziali Politeenico di Milano 1-20156 Milan Italy Fraunhofer-Institut fur Chemische Teehnologie (ICT) Joseph von-Fraunhofer-Str. 7 Pfintzal D-76327 Germany

A joint international effort to improve solid propellant performance within the framework of a FP7European Project was described.Several metallized solid rocket propellants,of the broad family AP/HTPB/Metal in the ratio 68/14/18,were experimentally analyzed seeking to optimize the delivered specific impulse by identifying the most suitable high-energy fuel.Keeping the same nominal composition,different metallic fuels(including micrometric and nanometric Al,AlH3,and a variety of dual metal compositions)were characterized,tested,and contrasted to a conventional micrometric aluminum(30μm average grain size)certified for space flights.In order to overcome the intrinsic performance limitations of the matrix AP/HTPB,a new matrix consisting of ADN/GAP satisfying also the need for environmentally benign propellant formulation was considered as well.A comparative analysis between the two solid propellant systems in terms of ideal thermochemistry and experimental combustion properties reveals advantages and disadvantages of both.Overall,it is judged worthwhile to develop ADN/GAP propellants,with or without metallic fuels,to enhance the current status of solid rocket propulsion.Controlling morphology and mechanical properties of ADN/GAP compositions and understanding their flame structure and aggregation/agglomeration properties are the main issues still challenging industrial users.

关键词： solid rocket propellants AP/HTPB ADN/GAP metals combustion specific impulse burning rate agglomeration