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Numerical study on ignition start-up process of an underwater solid rocket motor across a wide depth range

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Chinese Journal of Aeronautics 2024年第10期37卷 136-157页

作者： Deyou WANG Shipeng LI Ge JIN Ruyao WANG Dian GUAN Ningfei WANG School of Aerospace engineering Beijing Institute of TechnologyBeijing 100081China Beijing system Design institute of Electro-mechanic engineering Beijing 100854China

Solid rocket motors have important applications in the propulsion of trans-media vehicles and underwater launched *** this paper,the ignition start-up process of an underwater solid rocket motor across a wide depth range has been numerically studied.A novel multi-domain integrated model has been developed by combining the solid propellant ignition and combustion model with the volume of fluid multiphase *** integrated model enables the coupled simulation of the propellant combustion and gas flow inside the motor,along with the gas jet evolution in the external water *** detailed flow field developments in the combustion chamber,nozzle,and wake field are carefully *** variation rules of the internal ballistics and thrust performance are also *** effects of environmental medium and operating depth on the ignition start-up process are systematically *** results show that the influence of the operating environment on the internal ballistic characteristics is primarily reflected in the initial period after the nozzle closure *** development of the gas jet in water lags significantly compared with that in *** the water depth increases,the ignition delay time of the motor is shortened,and the morphology evolution of the gas jet is significantly compressed and ***,the necking and bulging of the jet boundary near the nozzle outlet and the consequent shock oscillations are intensified,resulting in stronger fluctuations in the wake pressure field and motor thrust.

关键词： Underwater propulsion Solid rocket motor Ignition start-up process Underwater gas jet Thrust oscillation

Time-varying parameters estimation with adaptive neural network EKF for missile-dual control system

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Journal of systems engineering and Electronics 2024年第2期35卷 451-462页

作者： YUAN Yuqi ZHOU Di LI Junlong LOU Chaofei School of Astronautics Harbin Institute of TechnologyHarbin 150001China Beijing institute of Electronic system engineering Beijing 100854China

In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LSTM) neural network is nested into the extended Kalman filter(EKF) to modify the Kalman gain such that the filtering performance is improved in the presence of large model uncertainties. To avoid the unstable network output caused by the abrupt changes of system states,an adaptive correction factor is introduced to correct the network output online. In the process of training the network, a multi-gradient descent learning mode is proposed to better fit the internal state of the system, and a rolling training is used to implement an online prediction logic. Based on the Lyapunov second method, we discuss the stability of the system, the result shows that when the training error of neural network is sufficiently small, the system is asymptotically stable. With its application to the estimation of time-varying parameters of a missile dual control system, the LSTM-EKF shows better filtering performance than the EKF and adaptive EKF(AEKF) when there exist large uncertainties in the system model.

关键词： long-short-term memory(LSTM)neural network extended Kalman filter(EKF) rolling training time-varying parameters estimation missile dual control system

Phase equilibrium data prediction and process optimizationin butadiene extraction process

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Chinese Journal of Chemical engineering 2024年第7期71卷 1-12页

作者： Baowei Niu Yanjie Yi Yuwen Wei Fuzhen Zhang Lili Wang Li Xia Xiaoyan Sun Shuguang Xiang institute of Process system engineering College of Chemical EngineeringQingdao University of Science and TechnologyQingdao 266042China

In response to the lack of reliable physical parameters in the process simulation of the butadiene extraction,a large amount of phase equilibrium data were collected in the context of the actual process of butadiene production by *** accuracy of five prediction methods,UNIFAC(UNIQUAC Functional-group Activity Coefficients),UNIFAC-LL,UNIFAC-LBY,UNIFAC-DMD and COSMO-RS,applied to the butadiene extraction process was verified using partial phase equilibrium *** results showed that the UNIFAC-DMD method had the highest accuracy in predicting phase equilibrium data for the missing ***-RS-predicted multiple systems showed good accuracy,and a large number of missing phase equilibrium data were estimated using the UNIFAC-DMD method and COSMO-RS *** predicted phase equilibrium data were checked for *** NRTL-RK(non-Random Two Liquid-Redlich-Kwong Equation of State)and UNIQUAC thermodynamic models were used to correlate the phase equilibrium *** device simulations were used to verify the accuracy of the thermodynamic model applied to the butadiene extraction *** simulation results showed that the average deviations of the simulated results using the correlated thermodynamic model from the actual values were less than 2%compared to that using the commercial simulation software,Aspen Plus and its *** average deviation was much smaller than that of the simulations using the Aspen Plus database(>10%),indicating that the obtained phase equilibrium data are highly accurate and *** best phase equilibrium data and thermodynamic model parameters for butadiene extraction are *** improves the accuracy and reliability of the design,optimization and control of the process,and provides a basis and guarantee for developing a more environmentally friendly and economical butadiene extraction process.

关键词： Butadiene extraction Phase equilibrium data Prediction methods Thermodynamic modeling Process simulation

High-precision analytical solutions for Earth coverage of constellation equipped with reentry glide vehicles

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Chinese Journal of Aeronautics 2024年第9期37卷 385-398页

作者： Ping MA Weibo SUN Jie GAO Tao CHAO Control and Simulation Center Harbin Institute of TechnologyHarbin 150001China Beijing institute of Spacecraft system engineering Beijing 100094China

To efficiently and accurately design satellite constellations equipped with Reentry Glide Vehicles(RGVs),new analytical solutions are developed for calculating their coverage ***,a new coverage model is established by approximating the Reentry Reachable Domain(RRD).However,the computation of real-time relative distances between satellites and targets,which is essential for coverage analysis based on this model,imposes a significant compu-tational *** address this challenge,a coverage analysis method based on two-dimensional map theory is *** method represents the coverage conditions of a target as a fixed area on a two-dimensional map and transforms the satellite trajectory into a series of parallel *** determining the intersection points between these lines and the area boundaries,the coverage ana-lytical solutions for a target point are *** this basis,coverage theorems are presented for rapid calculation of the constellation coverage performance for an *** results demon-strate the effectiveness and high precision of the proposed analytical solutions.

关键词： Constellation Analytical solutions Reentry glide vehicle Reentry reachable domain Two-dimensional map

Re-entry rocket basic flow characteristics and thermal environment of different retro-propulsion modes

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Chinese Journal of Aeronautics 2024年第7期37卷 190-203页

作者： Yifei SU Peijie SUN Yangwen CUI Guigao LE School of Mechanical engineering Nanjing University of Science and TechnologyNanjing 210094China Shanghai institute of Aerospace system engineering Shanghai 200000China Southwest institute of Technology and engineering Chongqing 400039China

During the supersonic re-entry of multi-nozzle heavy rockets into the atmosphere,the basic flow state becomes increasingly complex due to the coupling effect between the retropropulsion plumes and the freestream.A numerical method using the hybrid Reynolds-Averaged Navier-Stokes and Large Eddy Simulation(RES)method and discrete coordinate method is developed to accurately estimate the thermal *** addition,finite rate chemical kinetics is used to calculate the afterburning *** numerical results agree well with wind tunnel data,which confirms the validity and accuracy of the numerical *** are conducted for the heavy carrier rocket re-entry from 53.1 km to 39.5 km altitude with 180°angle of attack by using three different Supersonic Retro-Propulsion(SRP)*** numerical results reveal that these three SRP flow fields are all Short Penetration Models(SPM).As the re-entry altitudes decrease,both the plume-plume interaction and the plume-freestream interaction become *** highest temperatures in the plume shear layers of the three SRP modes increase by 8.36%,7.33%and 6.92%respectively after considering afterburning reactions,and all occur at a reentry altitude of 39.5 *** the rocket re-enters the atmosphere,the maximum heat flux on the rocket base plate of three SRP modes stabilizes at 290,170 and 200 kW/m^(2) respectively,but the maximum heat flux on the side wall increases *** the altitude declines to 39.5 km,the extreme heat flux of the three modes increase by 84.16%,49.45%and 62.97%respectively compared to that at 53.1 km.

关键词： Re-entry rocket Multi-nozzle Supersonic retro propulsion Thermal environment Afterburning effect

Experimental and numerical flutter analysis of a folding fin with multiple asymmetric free-plays

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Chinese Journal of Aeronautics 2024年第5期37卷 332-348页

作者： Chenyu LIU Chao AN Changchuan XIE Xin ZHANG Lan YANG School of Aeronautic Science and engineering Beihang UniversityBeijing 100191China Beijing institute of Electronic system engineering Beijing 100854China Beijing institute of Astronautical systems engineering Beijing 100076China

Experimental folding fin models with an adjustable free-play are tested in a wind *** fin structure is modeled using the free-interface component mode synthesis method,and its free-play is modeled as four independent nonlinear springs with asymmetric stiffness.A nonplanar unsteady vortex-lattice method considering compressibility is employed to address nonlinear deformation and high subsonic *** spline interpolation is improved through projection and *** aeroelastic characteristics of folding fins with different free-play magnitudes,initial conditions and elastic-axis positions are analyzed using an established time-marching method because of its relatively small computation scale and high *** results show good consistency among the presented method,the wind tunnel test and the harmonic balance *** is a negative correlation between the critical speed of divergent motion and the ratio of the initial condition to the free-play *** either the free-play magnitude or the initial condition is extreme(tiny or vast),the system nonlinearity degenerates to ***,the flutter prevention design of a linear model can be applied to a nonlinear model,such as moving the elastic-axis position *** presented fin configuration exhibits an unstable limit cycle oscillation because the orders of coupled flutter modes do not change with variations in equivalent linear stiffness.

关键词： Free-play Limit cycle oscillation Flutter Component mode synthesis Vortex-lattice method

A solution using only electromagnetic coils for relative pose control in satellite docking

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Chinese Journal of Aeronautics 2024年第3期37卷 258-281页

作者： Guangzheng RUAN Lijian WU Bo WANG Yaobing WANG Runqi HAN College of Electrical engineering Zhejiang UniversityHangzhou 310012China Beijing institute of Spacecraft system engineering Beijing 100094China

This paper proposes an electromagnetic coil topology and its control strategy,which can be incorporated into the electromagnetic docking device to achieve relative pose control in satellite *** target satellite has a main coil;the chaser satellite possesses a main coil of the same size accompanied by six and four evenly arranged secondary coils inside and outside the main coil,*** coil on the target satellite is DC energized,while the currents in the coils of the chaser satellite are *** remove the coupling between the pitch/yaw torque and translational force,the internal and external secondary coils of the chaser satellite interact with the main coil of the target satellite to perform the control of relative pitch/yaw and relative translation,respectively,so relative pose control can be *** torque and force vectors exerted by the secondary coils of the chaser satellite are synthesized onto the pitch and yaw axes of the body *** to their spatial composition relationship,the formulas are proposed,which obtain the magnetic moment vectors of the coils from the set torques and *** controllers regulating pitch/yaw,translation,and distance utilize a three-loop cascaded structure that consists of an outer position loop,a middle velocity loop and an inner current *** control strategy is verified by dynamics simulation.

关键词： Electromagnetic docking 6 degree of freedom Relative pose control Coil array Far field model Motion decoupling

A dual-mode integration framework and application to agile feedback design of launch vehicles

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International Journal of Mechanical system Dynamics 2024年第2期4卷 226-239页

作者： Wenfeng Zhang Xiaoshuang Cai Zhendong Liu Shan Luo Rendong Yu Shanghai institute of Aerospace system engineering ShanghaiChina

In recent decades,the design of complex systems like launch vehicles in the aerospace industry has presented engineers with challenges that go beyond system *** such as time-to-market pressures and intricate industrial processes have underscored the increasing significance of agile design *** design is derived from the simplification of the design process and enhancing cross-domain data transmission and *** methods based on model-based system engineering have improved iteration times in system architecture design,challenges persist in cross-domain data *** to the diversity of complex system models and data,a single-mode integration method is difficult to realize the data link construction of all tools *** address this challenge,this paper proposes a dualmode data integration framework with expansibility,universality,and cost-efficiency which leverages the benefits of Remote Procedure Call and Intermediate Exchange Module,addressing the challenge of constructing cross-domain data links under single-mode *** this study,two critical requirements of the first-and second-stage separation systems,namely,weight and minimum separation gap,are selected for data feedback.A Modelica-based multiphysics simulation model is developed in MWorks;visualization and computation of the minimum gap are carried out in *** bridge the gap between domain-specific tools,Matlab and Functional Mock-up Unit modules are introduced as middleware,facilitating data feedback *** entire simulation process is orchestrated using activity diagrams in the MagicDraw *** study delves into the influence of critical design parameters,such as the initial angular velocity of separation and the thrust of the retro rocket,on the minimum separation *** provides an analysis of minimum separation gap variations under uncertain operating conditions and examines design ***,the paper highlights the signifi

关键词： data feedback dual-mode data integration FMU launch vehicle MBSE Modelica

Cooperative guidance law with maneuverability awareness:A decentralized solution

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Chinese Journal of Aeronautics 2024年第7期37卷 450-457页

作者： Shuyang XU Xun SONG Chaoyong LI College of Electrical engineering Zhejiang UniversityHangzhou 310027China Beijing institute of Electronic system engineering Beijing 100074China

In this paper,we propose a cooperative guidance law aimed to achieve coordinated impact angles with limited observation on target *** primary challenge lies in establishing an appropriate communication graph among all missiles and devising an algorithm to estimate target acceleration information during *** address this,we propose a specific communication topology and employ a numerical integration-based estimation ***,a distributed algorithm is introduced to facilitate consensus on target acceleration *** upon these foundations,we design an optimal-control-based distributed guidance law for each *** of the proposed guidance law is validated through numerical simulations.

关键词： Cooperative guidance Target maneuver estimation Distributed estimation Consensus Optimal control