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Auto-updating model-based control for thrust variation mitigation and acceleration performance enhancement of gas turbine aero-engines

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Propulsion and Power Research 2024年第3期13卷 394-415页

作者： Zhiyuan Wei Shuguang Zhang Research Institute of Aero-engine Beihang UniversityBeijing 102206China Beihang University Beijing 102206China aircraft/engine integrated system safety beijing key laboratory Beihang UniversityBeijing 102206China

Model-based control shows promising potential for engine performance improve-ment and future aero-propulsion *** this paper,an auto-updating thrust variation mitigation(AuTVM)control approach using on-board model strategies is proposed for gas tur-bine aero-engines under in-service degradation effects,which aims at active thrust regulation and acceleration protection in a simultaneous *** AuTVM control is integrated with an on-line block,based on a reliable on-board engine model,and an off-line part for the periodical update of control parameters via post-flight engine monitoring *** core feature of the AuTVM control is a set of auto-updating loops within the on-line part,including thrust regu-lation loop,surge margin loop,turbine entry temperature loop,and the steady loop,whose con-trol parameters are periodically adjusted with increasingflight ***,an industrial sensor-based baseline controller and two tailored model-based controllers,i.e.,a thrust variation mitigation(TVM)controller withfixed gains and a self-enhancing active transient protection(SeATP)controller with pro-active transient protection and passive thrust control,are also developed as comparison *** simulations for idle to full-power acceleration tests are carried on a validated aero-thermal turbofan engine model using publicly available degra-dation *** results demonstrate that both new engines and severely degraded en-gines regulated by the AuTVM controller show significant thrust response enhancement,compared to the baseline ***,thrust variation at the maximum steady state of degraded engines,which exists within the SeATP controller and the baseline controller,is suppressed by the proposed AuTVM *** analysis against degradation uncer-tainties and sensor accuracy confirms that the AuTVM controller owns a closer maximum steady-state thrust distribution to the desired value than those of the SeATP and the basel

关键词： Gas turbine aero-engines Auto-updating thrust variation mitigation Active transient protection Model-based control engine performance improvement Degradation effects

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Technologies and studies of gas exchange in two-stroke aircraft piston engine:A review

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Chinese Journal of Aeronautics 2024年第1期37卷 24-50页

作者： Yu ZHOU Xueyu LI Shuiting DING Shuai ZHAO Kun ZHU Longtao SHAO Farong DU Gerui WANG Zheng XU Research Institute of Aero-engine Beihang UniversityBeijing 100191China aircraft/engine integrated system safety beijing key laboratory Beijing 100191China School of Transportation Science and engineering Beihang UniversityBeijing 100191China Civil Aviation University of China Tianjin 300300China Aero engine Academy of China Beijing 101304China School of Energy and Power engineering Beihang UniversityBeijing 100191China Beihang Hangzhou Innovation Institute Yuhang Hangzhou 310052China

The in-cylinder gas exchange process is crucial to the power performance of two-stroke aircraft piston engines,which is easily influenced by complex factors such as high-altitude performance variation and in-cylinder flow *** paper reviews the development history and characteristics of gas exchange types,as well as the current state of theory and the validation methods of gas exchange technology,while also discusses the trends of cutting-edge technologies in the *** paper provides a theoretical foundation for the optimization and engineering design of gas exchange systems and,more importantly,points out that the innovation of gas exchange types,the modification of theoretical models,and the technology of variable airflow organization are the key future research directions in this field.

关键词： aircraft piston engine aircraft power systems Gas exchange High-altitude performance In-cylinder flow Two-stroke Unmanned Aerial Vehicles(UAVs)

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Ammonia storage and slip under steady and transient state in close-coupled SCR

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Journal of Environmental Sciences 2024年第4期138卷 470-481页

作者： Shiyu Liu Zhaohuan Zhang Zexian Guo Boyuan Wang Buyu Wang Xiao Ma Shijin Shuai State key laboratory of Automotive safety and Energy Tsinghua UniversityBeijing 100084China Institute for Aero engine Tsinghua UniversityBeijing 100084China

The close-coupled selective catalytic reduction(cc-SCR)catalyst is an effective technology to reduce tailpipe NOx emission during cold *** paper investigated the optimal ammonia storage under steady and transient state in the *** study showed that a trade-off between NOx conversion efficiency and ammonia slip is observed on the pareto solutions under steady state,and the optimal ammonia storage is calculated with ammonia slip less than 10μL/L based on the ChinaⅥemission *** rapid temperature increase will lead to severe ammonia slip in the transient test cycle.A simplified 0-D calculation method on ammonia slip under transient state is proposed based on kinetic model of ammonia adsorption and *** addition,the effect of ammonia storage,catalyst temperature and temperature increasing rate on ammonia slip are *** optimal ammonia storage is calculated with maximum ammonia slip less than 100μL/L according to the oxidation efficiency of ammonia slip catalyst(ASC)downstream *** was found that the optimal ammonia storage under transient state is much lower than that under steady state in cc-SCR at lower temperature,and a phase diagram is established to analyze the influence of temperature and temperature increasing rate on optimal ammonia storage.

关键词： Close-coupled SCR Ammonia storage and slip Steady and transient state Generic algorithm

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A comprehensive aerodynamic-thermalmechanical design method for fast response turbocharger applied in aviation piston engines

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Propulsion and Power Research 2024年第2期13卷 145-165页

作者： Yu Zhou Yue Song Shuai Zhao Xueyu Li Longtao Shao Huansong Yan Zheng Xu Shuiting Ding Research Institute of Aero-engine Beihang UniversityBeijing 100083China aircraft/engine integrated system safety beijing key laboratory Beijing 100083China School of Energy and Power engineering Beihang UniversityBeijing 100083China School of Transportation Science and engineering Beihang UniversityBeijing 100083China AVIC Nanjing engineering Institute of aircraft systems Nanjing 210000China Hangzhou International Innovation Institute Beihang UniversityHangzhou 311115China Civil Aviation University of China Tianjin 300300China

Limited by the poor transient response performance of turbochargers,the dynamic performance of aviation piston engines tends to *** a bid to enhance the turbocharger’s acceleration capabilities,this study scrutinizes various factors impacting its *** on the operational principles and transient response process of the turbocharger,three types of in-ertiadnamely,aerodynamic inertia(ADI),thermal inertia(TI),and mechanical inertia(MI)d are identiﬁed and addressed for *** begin,this paper pioneers the innovative deﬁnition of a method for evaluating the transient response performance of the *** method incor-porates the introduction of an ADI parameter,inspired by the deﬁnition of ***,a thin-walled volute design with a low Biot number and a lightweight turbine impeller is introduced to reduce the turbocharger’s TI and *** simulation results of theﬂowﬁeld distribution within the volute and diffuser demonstrate the comprehensive design method’s effectiveness in improving gas pressure and temperature distributions in these ***,the pressure distributionﬂuctuation in the constant moment-of-momentum volute(CMV)is 62.8%lower than that in the constant velocity moment volute(CVMV).The low-TI thin-walled volute not only en-hances the turbocharger’s response speed but also reduces its weight by approximately 40%.The impact of three types of inertia on the engine’s response speed is quantiﬁed as follows:ADI(94%)>MI(5%)>TI(1%).This conclusion has been veriﬁed through test results of both the turbocharger and the *** design method not only signiﬁcantly improves the turbo-charger’s response performance but also offers valuable insights for the optimal design of other blade mechanical systems.

关键词： Turbocharger Fast response design method Aerodynamic inertia Thermal inertia Mechanical inertia

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Crystallization management of CsPbI_(2)Br perovskites by PbAc_(2)-incorporated twice spin-coating process for efficient and stable CsPbI_(2)Br perovskite solar cells

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Journal of Energy Chemistry 2024年第10期97卷 419-428,I0008页

作者： Yu Liu Kun Lang Huifang Han Huijing Liu Yao Fu Pengchen Zou Yinhui Lyu Jia Xu Jianxi Yao State key laboratory of Alternate Electrical Power system with Renewable Energy Sources Beijing Key Laboratory of Energy Safety and Clean UtilizationNorth China Electric Power UniversityBeijing 102206China

CsPbI_(2)Br perovskite solar cell has been extensively studied due to its exceptional thermal stability and relatively stable perovskite phase ***,the presence of bromine leads to a rapid crystallization rate of CsPbI_(2)Br films,resulting in small grain size and high defect ***,CsPbI_(2)Br demonstrates poor light absorption due to its wide ***,it is crucial to control the crystallization rate and increase the film thickness to reduce defect density,enhance light absorption,and improve photovoltaic *** this study,we utilized a PbAc_(2)-incorporated twice spincoating(PTS) process to address these ***,PbAc_(2) was added to the CsPbI_(2)Br precursor solution to form a CsPbI_(2)Br film,which was then coated with the CsPbI_(2)Br precursor solution to produce the PTS film,Ac^(-)can delay the perovskite crystallization,leading to the formation of thicker and denser CsPbI_(2)Br ***,lone-pair electrons of the oxygen atom provided by Ac^(-)formed coordination bonds with under-coordinated Pb~(2+) ions to fill halogen ion vacancies,thereby reducing the defect ***,the PTS CsPbI_(2)Br device achieved a peak power conversion efficiency(PCE) of 16.19% and maintained 96.7% of its initial PCE over 1500 h at room temperature under 25% relative humidity without any encapsulation.

关键词： CsPbI_(2)Br Twice spin-coating process PbAc_(2) Crystallization management Perovskite solar cells

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Gas exchange optimization in aircraft engines using sustainable aviation fuel:A design of experiment and genetic algorithm approach

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Energy and AI 2024年第3期17卷 261-280页

作者： Zheng Xu Jinze Pei Shuiting Ding Longfei Chen Shuai Zhao Xiaowei Shen Kun Zhu Longtao Shao Zhiming Zhong Huansong Yan Farong Du Xueyu Li Pengfei Yang Shenghui Zhong Yu Zhou Hangzhou International Innovation Institute Beihang UniversityHangzhou311115China Research Institute of Aero-engine Beihang UniversityBeijing102206China Civil Aviation University of China Tianjin300300China aircraft/engine integrated system safety beijing key laboratory Beijing100083China Aero engine Academy of China Beijing101304China School of Energy and Power engineering Beihang UniversityBeijing100083China AVIC Chengdu aircraft Design and Research Institute Chengdu610091China AVIC Nanjing engineering Institute of aircraft systems Nanjing211106China School of Transportation Science and engineering Beihang UniversityBeijing100083China Faculty of Science and engineering University of Nottingham Ningbo ChinaNingbo315100China

The poppet valves two-stroke(PV2S)aircraft engine fueled with sustainable aviation fuel is a promising option for general aviation and unmanned aerial vehicle propulsion due to its high power-to-weight ratio,uniform torque output,and flexible valve ***,its high-altitude gas exchange performance remains unexplored,presenting new opportunities for optimization through artificial intelligence(AI)*** study uses validated 1D+3D models to evaluate the high-altitude gas exchange performance of PV2S aircraft *** valve timings of the PV2S engine exhibit considerable flexibility,thus the Latin hypercube design of experiments(DoE)methodology is employed to fit a response surface model.A genetic algorithm(GA)is applied to iteratively optimize valve timings for varying *** optimization process reveals that increasing the intake duration while decreasing the exhaust duration and valve overlap angles can significantly enhance high-altitude gas exchange *** optimal valve overlap angle emerged as 93°CA at sea level and 82°CA at 4000 m *** effects of operating parameters,including engine speed,load,and exhaust back pressure,on the gas exchange process at varying altitudes are further *** higher engine speed increases trapping efficiency but decreases the delivery ratio and charging efficiency at various *** effect is especially pronounced at elevated *** increase in exhaust back pressure will significantly reduce the delivery ratio and increase the trapping *** study demonstrates that integrating DoE with AI algorithms can enhance the high-altitude performance of aircraft engines,serving as a valuable reference for further optimization efforts.

关键词： Poppet valves two-stroke Design of experiment Genetic algorithm optimization Heavy fuel aircraft engine High altitude gas exchange performance

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Controlled flight of a self-powered micro blimp driven by insect-sized flapping-wing thrusters

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Chinese Journal of Aeronautics 2024年第6期37卷 127-136页

作者： Xian YU Zhiwei LIU Jiaming LENG Mingjing QI Xiaojun YAN School of Energy and Power engineering Beihang UniversityBeijing 100191China Collaborative Innovation Center of Advanced Aero-engine Beijing 100191China National key laboratory of Science and Technology on Aero-engine Aero-thermodynamics Beihang UniversityBeijng 100191China beijing key laboratory of Aero-engine Structure and Strength Beihang UniversityBeijing 100191China

Micro aerial platforms face significant challenges in achieving long controlled endurance as most of the energy is consumed to overcome the weight of the *** this study,we present a controllable micro blimp that addresses this issue through the use of a helium-filled *** micro blimp has a long axis of 23 cm and is propelled by four insect-sized flapping-wing thrusters,each weighing 80 mg and with a wingspan of 3.5 *** distributed thrusters enable controlled motions and provide the micro blimp with an advantage in flight endurance compared to multirotors or flapping-wing micro aerial vehicles at the same size *** enhance the performance of the controlled flight,we propose a wireless control module that enables manipulation from a distance of up to 100 ***,a smartphone application is developed to send instructions to the circuit board,allowing the blimp to turn left and right,ascend and descend,and achieve a combination of these movements *** findings demonstrate that this micro blimp is one of the smallest controlled self-powered micro blimps to date.

关键词： Microairvehicle aircraft control Self-powered micro blimp Flapping-wing thruster Wireless flight

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Insights into thermodynamic performance of a hypersonic precooled air-breathing engine with a complicated multi-branch closed cycle

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Chinese Journal of Aeronautics 2024年第8期37卷 106-123页

作者： Yifan WANG Zhengping ZOU Pengcheng DU Lichao YAO Huoxing LIU Yusen XU Research Institute of Aero-engine Beihang UniversityBeijing 102206China National key laboratory of Science and Technology on Aero-engine and Aero-Thermodynamics Beihang UniversityBeijing 102206China

An advanced precooled airbreathing engine with a closed Brayton cycle is a promising solution for high-speed propulsion,of which the Synergetic Air Breathing Rocket engine(SABRE)is a representative *** performance of the latest SABRE-4 cycle was analyzed in this ***,a relatively complete engine performance model that considers the characteristics of turbomachinery and heat exchangers was ***,Sobol’global sensitivity analysis of key performance parameters was carried out to identify the most influential design *** specific impulses under different target specific thrusts were obtained by particle swarm optimization,of which the thermodynamic parameters corresponding to a specific thrust of 1.12 kN·s·kg^(-1)and a specific impulse of 3163 s were chosen as the design *** different control laws were analyzed in contrast,and the charge control method had the strongest ability of thrust regulation as well as maintaining a favorable specific impulse ***,working characteristics under the charge control and over a typical flight envelope were calculated,in which the average value of the maximum specific impulse was as high as 5315 *** study would help to deepen the understanding of SABRE-4 thermodynamic characteristics and other precooled airbreathing engine cycles with similar layouts.

关键词： Hypersonic Precooled airbreathing engine Thermodynamic cycle Control law Working characteristics

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Effects of nano-metal oxide additives on ignition and combustion properties of MICs-boron rich fuels

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Defence Technology（防务技术） 2024年第9期39卷 157-167页

作者： Liang Hu Danyang Liu Kun Yang Jianying Lu Chao Shi Jianyu Wang Xinhang Liu Lang Chen State key laboratory of Explosion Science and safety Protection Beijing Institute of TechnologyBeijing100081China

Boron has been considered a promising powdered metal fuel for enhancing composite propellants'energy output due to its high energy ***,the high ignition temperature and low combustion efficiency limit the application of boron powder due to the high boiling point of the boron oxide *** research is ongoing to overcome these shortcomings,and one potential approach is to introduce a small quantity of metal oxide additives to promote the reaction of *** study prepared boron-rich fuels with 10 wt%of eight nano-metal oxide additives by mechanical ball *** effect of metal oxides on the thermo-oxidation,ignition,and combustion properties of boron powder was comprehensively studied by the thermogravimetric analysis(TG),the electrically heated filament setup(T-jump),and the laser-induced combustion *** experiments at 5 K/min found that Bi_(2)O_(3),MoO_(3),TiO_(2),Fe_(2)O_(3),and CuO can promote thermo-oxidation of *** to pure boron,Tonsetcan be reduced from 569℃to a minimum of 449℃(B/Bi_(2)O_(3)).Infrared temperature measurement in T-jump tests showed that when heated by an electric heating wire at rates from 1000 K/s to 25000 K/s,the ignition temperatures of B/Bi_(2)O_(3) are the lowest,even lower than the melting point of boron *** images and SEM for the products further showed that the high heating rate is beneficial to the rapid reaction of boron powder in the single-particle combustion ***(B/Bi_(2)O_(3),B/MoO_(3),and B/CuO)were mixed with the oxidant AP and ignited by laser to study the combustion *** results showed that B/CuO/AP has the largest flame area,the highest BO_(2) characteristic spectral intensity,and the largest burn rate for powder *** combine the advantages of CuO and Bi_(2)O_(3),binary metal oxide(CBO,mass ratio of 3:1)was prepared and the test results showed that CBO can very well improve both ignition and combustion properties of *** B/CBO/AP has the h

关键词： Boron-rich fuel Mechanical ball milling Electrically heated filament Laser-induced combustion

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Empirical model of concrete block fragment behavior under explosion loads

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Science China(Technological Sciences) 2024年第8期67卷 2515-2529页

作者： YANG Shuai NING JianGuo REN HuiLan XU XiangZhao State key laboratory of Explosion Science and safety Protection Beijing Institute of TechnologyBeijing 100081China

Concrete structures undergo integral fragmentation under explosion loads. The fragmentation degree and particle-size distribution of concrete blocks under explosion loads must be considered during mining to ensure safety. In this study, the impulse is calculated based on the relationship between overpressure and time, and the impact energy of the explosion wave is obtained based on blast theory. Subsequently, the Mohr-Coulomb shear strength fracture criterion is introduced to determine the ultimate shear stress of the concrete materials, and an empirical model that can effectively calculate the energy consumption of concrete blocks under explosion loads is established. Furthermore, concrete fragments with different particle sizes under explosion scenarios are quantitatively predicted with the principle of energy conservation. Finally, explosion tests with different top standoff distances are conducted, and the concrete fragments after the explosion tests are recovered, sieved, weighed, and counted to obtain experimental data. The effectiveness of the fragment empirical model is verified by comparing the model calculation results with the experimental data. The proposed model can be used as a reference for civil blasting, protective engineering design, and explosion-damage assessment.

关键词： concrete structures explosion loads fragment behavior empirical model

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