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Effect of expansion waves on cowl shock wave and boundary layer interaction in hypersonic inlet

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Propulsion and Power Research 2024年第1期13卷 80-97页

作者： Guangwei Wu Ziao Wang Teng Shi Zhibin Zhang Weiyu Jiang Fuxu Quan juntao chang Harbin Institute of Technology Harbin 150001China Xi’an Aerospace Propulsion Institute Xi’an 710100China Beijing Power Machinery Institute Beijing 100074China

The interaction of cowl shock wave and boundary layer has a crucial effect on the stability,operability and performance of hypersonic *** studies on inhibiting the sep-aration and managing the strength of the interaction of the shock wave and boundary layer with expansion corner have been ***,the expansion waves near the circular arc shoulder to effectively control the interaction and cowl shock arrangement is little ***,the interaction of the cowl shock wave and boundary layer under thefluence of the expansion waves is studied by inviscid and viscous numerical *** results reveal that the expansion waves have an important impact on the interaction between the cowl shock wave and boundary layer and the strength of shock wave,and that there are four types of inter-action processes with the change of the relative impingement positions of cowl shock *** expansion waves have a different influence on the shock wave and boundary layer inter-action at different incident *** the incident point of the cowl shock wave goes far downstream from the end of the circular arc shoulder,the influence of expansion waves is weakened,and the magnitude of separation zone ***,when the expansion waves are applied to the interaction of the cowl shock wave and boundary layer on the circular arc shoulder,the separation can be effectively *** particular,while the expansion waves interact with the shock wave and boundary layer in the back half of the circular arc shoulder,the separation is best *** with the upstream and downstream inci-dent points,the scale of separation area in the optimal control region is reduced by 65.3%at ***,the total pressure recovery coefﬁcientﬁrst increases and then decreases when the cowl moves from upstream to downstream,and the total pressure recovery coefﬁcient reaches the maximum value of 68.36%at the incident position of cowl shock wave d Z 8.09d0.

关键词： Boundary layer Expansion waves Cowl shock wave Separation Hypersonic inlet Circular arc shoulder Inviscid and viscous numerical simulations

Recent progress of machine learning in flow modeling and active flow control

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Chinese Journal of Aeronautics 2022年第4期35卷 14-44页

作者： Yunfei Li juntao chang Chen Kong Wen Bao School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China

In terms of multiple temporal and spatial scales, massive data from experiments, flow field measurements, and high-fidelity numerical simulations have greatly promoted the rapid development of fluid mechanics. Machine Learning(ML) provides a wealth of analysis methods to extract potential information from a large amount of data for in-depth understanding of the underlying flow mechanism or for further applications. Furthermore, machine learning algorithms can enhance flow information and automatically perform tasks that involve active flow control and optimization. This article provides an overview of the past history, current development, and promising prospects of machine learning in the field of fluid mechanics. In addition, to facilitate understanding, this article outlines the basic principles of machine learning methods and their applications in engineering practice, turbulence models, flow field representation problems, and active flow control. In short, machine learning provides a powerful and more intelligent data processing architecture, and may greatly enrich the existing research methods and industrial applications of fluid mechanics.

关键词： Data-driven modeling Flow control Flow field kinematics Machine learning Neural networks-applications

A deep learning approach for velocity field prediction in a scramjet isolator from Schlieren images

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Chinese Journal of Aeronautics 2023年第11期36卷 58-70页

作者： Chen KONG Ziao WANG Yunfei LI juntao chang School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Accurate measurements of physical parameters in a scramjet isolator are very important to promote the design and optimization of the isolator and even the *** a ground experiment,limited by the inherent characteristics of measurement technology and equipment,it is a big challenge to obtain the velocity field inside an *** this study,a deep learning approach was introduced to combine data obtained from ground experiments and numerical simulations,and a velocity field prediction model was developed for obtaining the velocity field inside an isolator based on experimental Schlieren *** velocity field prediction model was designed with convolutional neural networks as the main *** experiments of a scramjet isolator under continuous Mach number variation were carried out,and Schlieren images of the flow field inside the isolator were *** simulations of the isolator were also carried out,and the velocity fields inside the isolator under various Mach numbers were *** velocity field prediction model was trained using flow field datasets containing experimental Schlieren images and velocity field,and the mapping relationship between the experimental Schlieren images and the predicted velocity field was successfully established.

关键词： Data-driven model Deep learning Neural networks Scramjet isolator Velocity field prediction

仿真分析结合矩阵式论证解决电泳内腔漆膜质量问题

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材料保护 2024年第7期57卷 228-234,241页

作者：韦乐侠刘卫宋冰常俊桃柳州五菱新能源汽车有限公司广西柳州545007

在某款商用车产品的电泳拆车工艺验证过程中,发现A柱、B柱和C柱内腔电泳漆膜存在严重质量缺陷。采用EcoatMaster电泳仿真软件对电泳涂膜质量进行分析,针对漆膜缺陷问题,采用内板新增电泳工艺孔、整流电源设置运动矢量增压功能及车身驾... 详细信息

在某款商用车产品的电泳拆车工艺验证过程中,发现A柱、B柱和C柱内腔电泳漆膜存在严重质量缺陷。采用EcoatMaster电泳仿真软件对电泳涂膜质量进行分析,针对漆膜缺陷问题,采用内板新增电泳工艺孔、整流电源设置运动矢量增压功能及车身驾驶仓内新增辅助阳极的矩阵式组合验证方案,最终以高品质和低成本方法成功解决A柱、B柱和C柱内腔电泳漆膜品质问题,从而满足了企业的产品防腐质量要求。

关键词：涂装SE 防腐设计电泳仿真电泳漆膜辅助阳极整流电源

Combustion Stabilization based on a Center Flame Strut in a Liquid Kerosene Fueled Supersonic Combustor

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Journal of Thermal Science 2013年第5期22卷 497-504页

作者： Jichao Hu Jiang Qin juntao chang Wen Bao Youhai Zong Qingchun Yang Harbin Institute of Technology

A newly designed strut is proposed in this paper for fuel injection and flame holding in a liquid-kerosene-fueled supersonic combustor. The thickness of the strut is 8ram and the front blockage is about 8%. The characteristic of this strut is that extra oxygen can be injected through a set of orifices at the back of the strut, which can change the local flow field structure and ER （Equivalence Ratio）. Based on the above mentioned strut, a stable local flame is generated at the back of the strut and the main combustion can be organized around this local fire. Nu- merical simulation is conducted to compare the local flow field distribution at the back of the strut with/without extra oxygen injection. Experiments are conducted to test the combustion characteristics based on this fuel injec- tion and flame holding strategy. The temperature distribution which can reflect the local flame characteristic has been measured in the experiments conducted under cold incoming supersonic air flow condition. In addition, the overall combustion performance in a full-scale supersonic combustor has been evaluated in the experiments con- ducted under hot incoming supersonic air flow condition. Results show that this strut strategy is very promising since it can organize stable supersonic combustion at the center of the combustor without any cavity or rearward facing step. Besides that, even with the 8ram thick strut, the combustion can be stable in a wide range of ER from 0.25-1 by using liquid room-temperature kerosene.

关键词： strut center flame oxygen liquid-kerosene-fueled supersonic combustor

Recent research progress on airbreathing aero-engine control algorithm

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Propulsion and Power Research 2022年第1期11卷 1-57页

作者： Chengkun Lv juntao chang Wen Bao Daren Yu Harbin Institute of Technology Heilongjiang150001China

Airbreathing aero-engines are regarded as excellent propulsion devices from ground takeoff to hypersonic flight,and require control systems to ensure their efficient and safe ***,the present paper aims to provide a summary report of recent research progress on airbreathing aero-engine control to help researchers working on this ***,five control problems of airbreathing aero-engines are classified:uncertainty problem,multiobjective and multivariable control,fault-tolerant control,distributed control system,and airframe/propulsion integrated control ***,the research progress of aircraft gas turbine engine modelling,linear control,nonlinear control,and intelligent control is reviewed,and the advantages and disadvantages of various advanced control algorithms in aircraft gas turbine engines is ***,several typical hypersonic flight tests are investigated,and the modelling and control issues of dual-mode scramjet are ***,modelling,mode transition control and thrust pinch control for turbine-based combined cycle engines are ***,significant hypersonic airframe/propulsion integrated system control is ***,the study provides specific control research topics that require attention on airbreathing aero-engines.

关键词： Airbreathing aeroengine Control Aircraft gas turbine engine Dual-mode scramjet Combined cycle engine Hypersonic airframe/propulsion integrated system

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内凹通道中激波串流场特性的实验研究

海军航空大学学报 2024年第3期39卷 350-356页

作者：信宣安王子傲常军涛王刚哈尔滨工业大学先进动力技术研究所黑龙江哈尔滨150001 中国空气动力研究与发展中心超高速所四川绵阳621000

三维内转式进气道以其高总压恢复系数和高压缩效率等优势,已成为高超声速进气道的发展趋势。然而,内转式进气道流场中更为复杂的激波串结构以及激波串/边界层相互作用成为其性能发挥的关键制约因素。针对内转式进气道中复杂的流动特性,... 详细信息

三维内转式进气道以其高总压恢复系数和高压缩效率等优势,已成为高超声速进气道的发展趋势。然而,内转式进气道流场中更为复杂的激波串结构以及激波串/边界层相互作用成为其性能发挥的关键制约因素。针对内转式进气道中复杂的流动特性,文章开展了高超声速地面风洞实验研究,并对流场进行了可视化测量。首先,搭建了超声速直连式风洞实验台;然后,设计了方转圆段将内转式进气道中独特的内凹通道和矩形喷管平滑连接。结果表明:低来流马赫数下,内凹通道中的激波串前缘激波呈“λ”型,高来流马赫数下则呈“X”型,并且平直壁侧发生流动大分离,流场具有显著非对称性。此外,随着背压的增加,激波串继续向前移动,前缘激波扫掠时的测量点压力发生显著的振荡跳跃。

关键词：内转式进气道内凹通道激波串前缘激波

Minimization of Classification Samples for Supercritical and Subcritical Patterns of Supersonic Inlet

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Journal of Thermal Science 2014年第4期23卷 375-380页

作者： chang juntao ZHENG Risheng YU Daren BAO Wen CHEN Fu JIANG Weiyu ZHU Shoumei ZHENG Riheng Harbin Institute of Technology No.92.Xidazhi Street Science and Technology on Scramjet Laboratory

In order to investigate sample minimization for classification of supercritical and subcritical patterns in supersonic inlet, three optimization methods, namely, opposite one towards nearest method, closest one towards the byper-plane method and random selection method, are proposed for investigation on minimization of classification samples for supercritical and subcritical patterns of supersonic inlet. The study has been carried out to analyze wind tunnel test data and to compare the classification accuracy based on those three methods with or without priori knowledge. Those three methods are different from each other by different selecting methods for samples. The results show that one of the optimization methods needs the minimization samples to get the highest classification accuracy without priori knowledge. Meanwhile, the number of minimization samples needed to get highest classification accuracy can be further reduced by introducing priori knowledge. Furthermore, it demonstrates that the best optimization method has been found by comparing all cases studied with or without introducing priori knowledge. This method can be applied to reduce the number of wind tunnel tests to obtain the inlet performance and to identify the supercritical/subcritical modes for supersonic inlet.

关键词： Supersonic inlet Inlet supercritical/subcritical Sample minimization

Self-powered wireless environmental monitoring system for in-service bridges by galloping piezoelectric-triboelectric hybridized energy harvester

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Science China(Technological Sciences) 2024年第5期67卷 1498-1509页

作者： HUANG KangXu WANG XiaoFei WANG Li ZHOU YuHui LIU FuHai chang ShiYuan ZHU juntao ZHOU YuXuan ZHANG He LUO JiKui College of Civil Engineering and Architecture Zhejiang UniversityHangzhou310058China Anhui Transport Consulting&Design Institute Co. Ltd.Hefei230088China College of Electronics&Information Hangzhou Dianzi UniversityHangzhou310018China Center for Balance Architecture Zhejiang UniversityHangzhou310058China College of Information Science&Electronic Engineering Zhejiang UniversityHangzhou310027China

The energy harvesting technology for the ubiquitous natural wind enables a desirable solution to the issue of distributed sensors in the bridge environmental sensing Internet of Things(Io T)system being restricted to conventional energy *** this work,a self-powered system based on a compact galloping piezoelectric-triboelectric energy harvester(GPTEH)is developed to achieve efficient wind energy *** GPTEH is constructed on the prototype of a cantilever structure with piezoelectric macro-fiber composite(MFC)sheets and a rectangular bluff body with triboelectric nanogenerators(TENGs).Through a special swing-type structural design with iron blocks inside the bluff body,the GPTEH exhibits preferable aerodynamic behavior and excellent energy conversion efficiency,compared to conventional cantilever kind of piezoelectric wind energy harvester(PWEH).The GPTEH also demonstrates the capability of high output power density(PEH of 23.65 W m^(-2)and TENG of 1.59 W m^(-2)),superior response wind speed(about 0.5 m s^(-1)),and excellent long-term stability(over 14000 cyclic tests).Furthermore,a power management system is developed to efficiently utilize the output energy from GPTEH to power the sensors and wirelessly transmit environmental data to the *** proposed GPTEH-powered system exhibits a great potential for the bridge environmental monitoring and Io T technologies.

关键词： self-powered hybrid nanogenerator triboelectric nanogenerator macro-fiber composite wireless environmental monitoring system