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design and experimental research of a sub-Newton N_(2)O monopropellant thruster with inner-heater

Chinese Journal of Aeronautics 2022年第5期35卷 309-318页

作者： Kaiyang LI Jie FANG Wei SUN Bing SUN Guobiao CAI School of Astronautics Beihang UniversityBeijing 100083China key laboratory of spacecraft design optimization and dynamic simulation technologies of Ministry of Education Beihang UniversityBeijing 100083China China Academy of Space Technology Beijing 100094China

Nitrous oxide(N_(2)O)is a green propellant with excellent application prospects.A subNewton N_(2)O monopropellant thruster with inner-heater and a N_(2)O self-pressurization stable supply system with regenerative heat compensation are designed in this paper.The experimental research of the thruster is described,including measurements of preheating power,activation temperature,vacuum thrust,specific impulse,life-span and pulsed operation performance.By inserting the heater into the catalyst-bed,preheating efficiency of the heater is significantly improved compared to the thruster with outer-heater.Thus,the preheating power demand of the thruster is successfully reduced to around 10 W.The mean vacuum thrust of 322 mN is attained and the corresponding specific impulse reaches 162s at the mass flow rate of 0.2 g/s.Successful activation temperature of 523 K is achieved,and the activation performance of the thruster is affected by the loading factor.A long term hot-firing test longer than 12000 s is attained.The pulsed operation performance of the inner-preheating thruster is also studied by measuring chamber pressure.Impulses with different magnitudes are produced by adjusting the opening duration of the control valve.A minimum impulse of 81 mN·s is attained.Finally,the performance of the thruster is evaluated by comparison with other thrusters of the same type.The results indicate that the proposed thruster with inner-heater is superior in terms of preheating power,activation temperature and specific impulse performance.

关键词： Green propellant Monopropellant thruster Nitrous oxide Regenerative heat compensation Self-pressurization

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Model-free adaptive optimal design for trajectory tracking control of rocket-powered vehicle

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Chinese Journal of Aeronautics 2020年第6期33卷 1703-1716页

作者： Wenming NIE Huifeng LI Ran ZHANG School of Astronautics Beihang UniversityBeijing 100083China key laboratory of spacecraft design optimization and dynamic simulation technologies Ministry of EducationBeijing 100083China

An adaptive optimal trajectory tracking controller is presented for the Solid-RocketPowered Vehicle(SRPV)with uncertain nonlinear non-affine dynamics in the framework of adaptive dynamic programming.First,considering that the ascent model of the SRPV is non-affine,a model-free Single Network Adaptive Critic(SNAC)method is developed based on the dynamic neural network and the traditional SNAC method.This developed model-free SNAC method overcomes the limitation of the traditional SNAC method that can only be applied to affine systems.Then,a closed-form adaptive optimal controller is designed for the non-affine dynamics of SRPVs.This controller can adjust its parameters under different flight conditions and converge to the approximate optimal controller through online self-learning.Finally,the convergence to the approximate optimal controller is proved.The theoretical analysis of the uniformly ultimate boundedness of the tracking error is also presented.simulation results demonstrate the effectiveness of the proposed controller.

关键词： Adaptive dynamic programming dynamic neural network Model-free Solid-rocket-powered vehicle Trajectory tracking

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Index allocation for a reusable LOX/CH4 rocket engine

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Chinese Journal of Aeronautics 2021年第2期34卷 432-440页

作者： Yi LI Jie FANG Bing SUN Kaiyang LI Guobiao CAI School of Astronautics Beihang UniversityBeijing 100083China key laboratory of spacecraft design optimization and dynamic simulation technologies(Beihang University) Ministry of EducationBeijing 100083China

Reusable rocket engines are the core components of reusable launch vehicles, and have thus become a major focus of aerospace engineering research in recent years. In practice, subsystem design is based on the overall index allocation of an engine;therefore, a multidisciplinary optimization approach is necessary. In this study, design of a reusable methane/liquid oxygen(LOX/CH4)rocket engine with a gas generator cycle was investigated using multidisciplinary optimization. Two parameters were chosen as design variables: pressure and fuel mix ratio of the main combustion chamber. optimization objectives were specific impulse, structural mass, and life cycle cost of the reusable rocket engine, and constraints were assigned to each discipline according to rocket design requirements. Then, an optimization model was developed, and optimal design parameters were acquired for the LOX/CH4 rocket engine. The proposed method is effective for designing the index allocation of reusable rocket engines and takes into account the multidisciplinary nature of complex systems.

关键词： Index allocation Mass model Multidisciplinary optimization Reliability Rocket engines

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Multi-disciplinary design optimization with fuzzy uncertainties and its application in hybrid rocket motor powered launch vehicle

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Chinese Journal of Aeronautics 2020年第5期33卷 1454-1467页

作者： Pengcheng WANG Hui TIAN Hao ZHU Guobiao CAI School of Astronautics Beihang UniversityBeijing 100083China key laboratory of spacecraft design optimization&dynamic simulation technologies of Ministry of Education Beihang UniversityBeijing 100083China

In this paper,an Uncertainty-based Multi-disciplinary design optimization (UMDO)method combining with fuzzy theory and Multi-Discipline Feasible (MDF) method is developed for the conceptual design of a Hybrid Rocket Motor (HRM) powered Launch Vehicle (LV).In the method proposed,membership functions are used to represent the uncertain factors,the fuzzy statistical experiment is introduced to analyze the propagation of uncertainties,and means,standard deviations and credibility measures are used to delineate uncertain responses.A geometric programming problem is solved to verify the feasibility of the Fuzzy-based Multi-Discipline Feasible(F-MDF) method.A multi-disciplinary analysis of a three-stage HRM powered LV involving the disciplines of propulsion,structure,aerodynamics and trajectory is implemented,and the mathematical models corresponding to the F-MDF method and the MDF method are established.A two-phase optimization method is proposed for multi-disciplinary design optimization of the LV,including the orbital capacity optimization phase based on the Ziolkowski formula,and the scheme trajectory verification phase based on the 3-degree-of-freedom point trajectory simulation.The correlation coefficients and the quadratic Response Surface Method (RSM) based on Latin Hypercube Sampling (LHS) are adopted for sensitive analysis of uncertain factors,and the Multi-Island Genetic Algorithm (MIGA) is adopted as the optimization algorithm.The results show that the F-MDF method is applicable in LV conceptual design,and the design with the F-MDF method is more reliable and robust than that with the MDF method.

关键词： Fuzzy theory Hybrid Rocket Motor(HRM) Launch Vehicle(LV) Sensitive Analysis(SA) Uncertainty-based Multi-disciplinary design optimization(UMDO)

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Three-dimensional numerical analysis on combustion performance and flow of hybrid rocket motor with multi-segmented grain

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Chinese Journal of Aeronautics 2020年第4期33卷 1181-1191页

作者： Hui TIAN Yu DUAN Hao ZHU School of Astronautics Beihang UniversityBeijing 100083China key laboratory of spacecraft design optimization&dynamic simulation technologies Ministry of EducationBeihang UniversityBeijing 100083China

This paper presents the combustion characteristics in hybrid rocket motors with multisegmented grain through three-dimensional numerical simulations.Multi-segmented grain is composed of several thin grains with two or more ports.The numerical model consists of Navier-Stokes equations with turbulence,solid fuel pyrolysis,chemical reactions,a fluid–solid coupling model and a regression rate model.The simulations adopt 90%Hydrogen Peroxide(HP)and PolyEthylene(PE)as the propellant combination.The effects of the rotation,port number,fuel grain segment number and mid-chamber length on the flow field and combustion performances are analyzed.The results indicate that the multi-segmented grain configuration can strengthen the flow field,and the regression rate and combustion efficiency are enhanced.Take the cases with two grain segments and three ports for example,the regression rate is increased by 32.4%-45.1%and the combustion efficiency increases by 6%-8.6%in different rotation angles.

关键词： Combustion efficiency Hybrid rocket motor Multi-segmented grain Regression rate Rotation angle

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The azimuthal currents in the ion-driven magnetic nozzle

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Propulsion and Power Research 2022年第4期11卷 457-472页

作者： Zhiyuan Chen Yibai Wang Haibin Tang Junxue Ren Min Li Peng Wu Jinbin Cao School of Astronautics Beihang UniversityBeijing102206China key laboratory of spacecraft design optimization and dynamic simulation technologies Ministry of EducationBeijing102206China laboratory of Space Environment Monitoring and Information Processing Ministry of Industry and Information TechnologyBeijing102206China Innovation Academy of Microsatellites Chinese Academy of SciencesShanghai201203China School of Space and Environment Beihang UniversityBeijing102206China

Ion-driven magnetic nozzles(Ti>Te)are designed as intrinsic parts of cutting-edge propulsive technologies such as variable specific impulse magnetoplasma rockets(VASIMRs)and applied-field magnetoplasmadynamic thrusters.Employing a two-dimensional axisymmetric particle-in-cell(PIC)code,in the ion-driven magnetic nozzle,the compositions and distributions of azimuthal currents in different axial regions are investigated under various inlet ion temperatures Ti0 and found to differ dramatically from that in the electron-driven magnetic nozzles.Previously reported to be all paramagnetic and vanishing under a high magnetic field,the azimuthal currents resulting from the E 3 B drift are shown to turn diamagnetic and sustain a considerable magnitude when Ti0 is considered.The previously reported profile of diamagnetic drift current is altered by the introduction of inlet ion temperature,and the paramagnetic part is significantly suppressed.Moreover,a wide range of paramagnetic currents appear downstream due to the inward detachment of ions,which can also be reduced by increasing inlet ion temperature.Albeit considered in this paper,the azimuthal currents resulting from grad-B and curvature drift are still negligible in all cases of interest.The magnitude of diamagnetic azimuthal currents increases with amplifying Ti0,indicating a clear physical image of energy transformation from ion thermal energy to the directed kinetic energy through electromagnetic processes in the magnetic nozzle.Additionally,the magnetic inductive strength also has noticeable impacts on the azimuthal currents,the current magnitude tends to decrease as the magnetic field increases,and over-increment of it may result in larger divergence angles and lower nozzle efficiency.

关键词： Magnetic nozzle Azimuthal current Ion temperature Electric propulsion

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Coupling plasma plume of a low-power magnetically shielded Hall thruster with a hollow cathode

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Chinese Journal of Aeronautics 2020年第12期33卷 3018-3026页

作者： Guangchuan ZHANG Junxue REN Wei LIANG Ning OUYANG Chao LU Haibin TANG School of Space and Environment Beihang UniversityBeijing 100083China School of Astronautics Beihang UniversityBeijing 100083China Shanghai Institute of Space Propulsion Shanghai 201112China key laboratory of spacecraft design optimization&dynamic simulation technologies Ministry of EducationBeijing 100083China laboratory of Space Environment Monitoring and Information Processing Ministry of Industry and Information TechnologyBeijing 100083China

The coupling region of a Hall thruster with a hollow cathode is the region between the cathode and the thruster plume.The characteristics of plasma in that region are complicated and strongly associated with the thruster working conditions and the cathode position.In this paper,a laboratory 100 W class magnetically shielded Hall thruster was coupled with a hollow cathode.Optical imaging and electrostatic probe were employed to monitor and scan the plasma plume.Plume characteristics in the coupling region in non-self-sustained mode and self-sustained mode were compared.Evolution of the coupling plume with the cathode position was studied.Experiments show that,when turning the thruster into self-sustained mode or moving the cathode further away axially,the discharge current can be reduced by 6.4–10.6%restraining the electron current and improving ionization.In particular,when the cathode is moved further,the electron conduction near the channel walls is suppressed.The electron current is reduced by 27.4%and the ion beam current is increased by 7%.Overall,this work shows that the working mode of the thruster and the position of the cathode greatly affect the coupling plasma plume.Both play an important role in improving the utilizations of propellant and current.

关键词： Coupling region Electron conduction Hall thruster Hollow cathode Utilizations of propellant and current

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Bearing Failure optimization of Composite Double-Lap Bolted Joints Based on a Three-Step Strategy Marked By Feasible Region Reduction and Model Decoupling

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Computers, Materials & Continua 2020年第2期62卷 977-999页

作者： Fengrui Liu Wanting Yao Xinhong Shi Libin Zhao Jianyu Zhang School of Astronautics Beihang UniversityBeijing100191China key laboratory of spacecraft design optimization and dynamic simulation technologies Ministry of EducationBeihang UniversityBeijing100191China State key laboratory for Strength and Vibration of Mechanical Structures Xi’an Jiaotong UniversityXi’an710049China Institute of Solid Mechanics Beihang UniversityBeijing100191China College of Aerospace Engineering Chongqing UniversityChongqing400044China

To minimize the mass and increase the bearing failure load of composite double-lap bolted joints,a three-step optimization strategy including feasible region reduction,optimization model decoupling and optimization was presented.In feasible region reduction,the dimensions of the feasible design region were reduced by selecting dominant design variables from numerous multilevel parameters by sensitivity analyses,and the feasible regions of variables were reduced by influence mechanism analyses.In model decoupling,the optimization model with a large number of variables was divided into various sub-models with fewer variables by variance analysis.In the third step,the optimization sub-models were solved one by one using a genetic algorithm,and the modified characteristic curve method was adopted as the failure prediction method.Based on the proposed optimization method,optimization of a double-lap single-bolt joint was performed using the ANSYS®code.The results show that the bearing failure load increased by 13.5%and that the mass decreased by 8.7%compared with those of the initial design of the joint,which validated the effectiveness of the three-step optimization strategy.

关键词： Composite bolted joints sensitivity analysis optimization

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Model of CEL for 3D Elements in PDMs of Unidirectional Composite Structures

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Computer Modeling in Engineering & Sciences 2019年第1期118卷 157-176页

作者： Tianliang Qin Libin Zhao Jifeng Xu Fengrui Liu Jianyu Zhang Beijing key laboratory of Civil Aircraft Structures and Composite Materials BASTRI of COMACBeijing102211China School of Astronautics Beihang UniversityBeijing100191China key laboratory of spacecraft design optimization and dynamic simulation technologies Minisitry of EducationBeihang UniversityBeijing 100191China State key laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong UniversityXi'an 710049China College of Aerospace Engineering Chongqing UniversityChongqing400044China.

Progressive damage models(PDMs)have been increasingly used to simulate the failure process of composite material structures.To accurately simulate the damage in each ply,3D PDMs of composite materials have received more attention recently.A characteristic element length(CEL),which is an important dimensional parameter of PDMs for composite materials,is quite difficult to obtain for 3D elements,especially considering the crack directions during damage propagation.In this paper,CEL models for 3D elements in PDMs of unidirectional composite structures are presented,and their approximate formulae are deduced.The damage in unidirectional composite materials can be divided into fiber cracks and inter-fiber cracks.The fiber crack and inter-fiber crack directions are considered in the CEL derivations,and thus,the CELs of 3D elements that have various damage modes and damage directions could be obtained relatively precisely.Static tensile and compressive tests of open-hole laminates were conducted,and the corresponding numerical analyses by the progressive damage method,including the proposed CEL models and those models from the literature,were performed.The numerical results are in good agreement with the experimental results,which proves the fidelity and effectiveness of the proposed CEL models.In addition,the proposed CEL models have better performance in improving the mesh independence of the numerical models.

关键词： Laminates finite element analysis(FEA) mechanical testing progressive damage analysis CEL.

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A Ply-By-Ply Discretized 2D FEA Approach with the Integrated XFEM-CE Strategy for Predicting Multiple Failures in Laminated Composite Structures

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Computer Modeling in Engineering & Sciences 2019年第7期120卷 215-234页

作者： Yana Wang Ruodi Jia Fengrui Liu School of Astronautics Beihang UniversityBeijing100191China Aeronautical Material Testing Research Center AECC Beijing Institute of Aeronautical MaterialsBeijing100095China Beijing key laboratory of Aeronautical Material Testing and Evaluation Beijing100095China key laboratory of Aeronautical Material Testing and Evaluation Aero Engine Corporation of ChinaBeijing100095China key laboratory of spacecraft design optimization and dynamic simulation technologies Minisitry of EducationBeihang UniversityBeijing100191China State key laboratory for Strength and Vibration of Mechanical Structures Xi’an Jiaotong UniversityXi’an710049China.

Delamination and matrix cracking are two common failure mechanisms in composite structures,and are usually coupled with each other,leading to multiple failures pattern.This paper proposed a fast damage prediction methodology for composite laminated structures based on the ply-by-ply 2D(two dimensional)FE model of composite laminates in the transverse plane.The layer-wise 2D FE model was firstly used in conjunction with the integrated XFEM/CE strategy,which simulated the interface delamination with cohesive elements and the intra-ply matrix crack with XFEM(extended finite element method).To realize ply-by-ply 2D FE(finite element)modeling of composite laminates,two 2D material models were developed based on the plane stress assumption and plane strain assumption,respectively.A general crack propagation scheme was developed in the framework of the integrated XFEM-CE method.Adopting the 2D material model based on the plane strain assumption,a ply-by-ply discretized 2D FEA procedure was conducted for an out-of-plane composite Pi joint under the static tensile load.The predicted load-displacement response and damage evolution process showed good agreement with the experimental results,which verified the proposed approach.

关键词： Composites laminate strength finite element analysis

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