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Particuology 2024年第7期90卷 404-411页

作者： Hanqiao Che Yuanhe Yue Zhaohua jiang Duan Li School of Mechanical Engineering Guangxi UniversityNanningGuangxi530004China School of Chemical Engineering University of BirminghamBirminghamB152TTUK Hebei Engineering Research Center of Advanced Energy Storage Technology and Equipment School of Energy and Environmental EngineeringHebei University of TechnologyTianjin300401China Hebei Key Laboratory of Thermal Science and Energy Clean Utilization School of Energy and Environmental EngineeringHebei University of TechnologyTianjin300401China School of Mechatronics and Vehicle Engineering Chongqing Jiaotong UniversityChongqing400074China School of Instrumentation and Opto-Electronic Engineering Beihang UniversityBeijing 100191China

The transient heat transfer behaviours in a packed bed have been studied using coupled computational fluid dynamics(CFD)and discrete element method(DEM).Intra-particle thermal diffusion,which is a crucial but rarely explored issue,is considered by introducing a one-dimensional diffusion equation in the DEM *** achieve a sufficiently long physical time of simulations,we further reduce the computational cost by applying periodic boundary condition to a small segment of the packed *** study demonstrates a shifting peak heat flow rate from the bottom to the top of the packed bed during the initial warming *** affirm that the influence of thermal diffusion within a particle is noteworthy only for particles exhibiting a high Biot number(e.g.,Bi=1.2).This insight enriches our understanding of heat transfer mechanisms in packed beds and their practical engineering applications.

关键词： Packed bed Intra-particle heat transfer CFD–DEM

Multi-physics multi-scale simulation of unique equiaxed-to-columnar-to-equiaxed transition during the whole solidification process of Al-Li alloy laser welding

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Journal of Materials Science & Technology 2024年第4期171卷 235-251页

作者： Chu Han Ping jiang Shaoning Geng Liangyuan Ren School of Mechanical Science and Engineering Huazhong University of Science&Technology(HUST)Wuhan430074China

In this study,a novel multi-physics multi-scale model with the dilute multicomponent phase-field method in three-dimensional(3D)space was developed to investigate the complex microstructure evolu-tion in the molten pool during laser welding of Al-Li *** accurately compute mass data within both two and three-dimensional computational domains,three efficient computing methods,including central processing unit parallel computing,adaptive mesh refinement,and moving-frame algorithm,were *** was placed on the distinctive equiaxed-to-columnar-to-equiaxed transition phenomenon that occurs during the entire solidification process of Al-Li alloy laser *** results indi-cated that the growth distance of columnar grains that epitaxially grew from the base metal(BM)de-creased as the nucleation rate *** the nucleation rate increased,the morphology of the newly formed grains near the fusion boundary(FB)changed from columnar to equiaxed,and newly formed equiaxed grains changed from having high-order dendrites to no obvious dendrite *** the nucleation rate was sufficiently high,non-dendritic equiaxed grains could directly form near the FB,and there was nearly no epitaxial growth from the ***,simulation results illustrated the com-petition among multiple grains with varying orientations that grow in 3D space near the ***,how equiaxed grain bands develop was *** equiaxed band not only hindered the growth of early columnar grains but also some of its grains could grow epitaxially to form new columnar *** predicted results were in good agreement with experimental measurements and observations.

关键词： Laser welding Al-Li alloy Equiaxed-to-columnar-to-equiaxed transition Multi-physics multi-scale model Multicomponent alloys 3D phase-field model

Numerical insight into heat transfer enhancement by granules inner-migration in a moving bed:A performance comparison between slanted-stick and plow-shaped agitator

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Particuology 2024年第6期89卷 109-116页

作者： Binfan jiang Hao Pei Dehong Xia Haiyang Wang School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China Shunde Graduate School of University of Science and Technology Beijing Guangdong 528399China Jianlong Group&USTB Joint Laboratory Beijing 100083China

Waste heat recovery of high-temperature granules is one of the most promising sustainable energy supply and carbon reduction ways for industry.A moving bed indirect heat exchanger(MBIHE)with inner-migration was proposed for granular heat *** migration and the enhanced heat transfer induced by two types of agitators(i.e.,agitator with slanted stick A_(s)and with plow-shaped surface A_(p))in the MBIHE are analyzed based on DEM coupled with *** to the effective agitation,the average heat transfer coefficient in the granule side is enhanced to∼3 times compared to that without *** heat recovery efficiency in the moving bed reached more than 70%with the agitations of either A_(s)or A_(p).The heat efficiency of A_(s)is∼7%higher than that of A_(p),but with at least 60%greater rotational *** ensure reliable agitation,the A_(p)is suggested to be adopted in the MBIHE to induce granule migration.

关键词： Waste heat recovery High-temperature granule Granule migration Heat transfer enhancement Industry energy saving

Numerical and experimental investigation into the evolution of the shock wave when a muzzle jet impacts a constrained moving body

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Defence Technology（防务技术） 2024年第3期33卷 317-326页

作者： Zijie Li Hao Wang Changshun Chen Kun jiang School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjing 210016China

The gun-track launch system is a new special launch device that connects the track outside the *** it is constrained by the track,the characteristics of development of the muzzle jet differ from those of the traditional muzzle ***,it changes from freely developing to doing so in a constrained manner,where this results in an asymmetric direction of flow as well as spatio-temporal coupling-induced interference between various shock waves and the formation of *** this background,the authors of this article formulate and consider the development and characteristics of evolution of the muzzle jet as it impacts a constrained moving *** designed simulations to test the gun-track launch system,and established a numerical model based on the dynamic grid method to explore the development and characteristics of propagation of disturbances when the muzzle jet impacted a constrained moving *** also considered models without a constrained track for the sake of *** results showed that the muzzle jet assumed a circumferential asymmetric shape,and tended to develop in the area above the *** the test platform was close to the ground,the muzzle jet was subjected to reflections from it that enhanced the development and evolution of various forms of shock waves and vortices in the muzzle jet to exacerbate its rate of distortion and asymmetric *** in turn led to significant differences in the changes in pressure at symmetric points that would otherwise have been *** results of a comparative analysis showed that the constrained track could hinder the influence of reflections from the ground on the muzzle jet to some extent,and could reduce the velocity of the shock waves inducing the motion of the muzzle as well as the Mach number of the moving *** work here provides a theoretical basis and the requisite technical support for applications of the gun-track launch *** also sheds light on the

关键词： Shock wave/vortex interference Muzzle jet Constrained boundary Dynamic grid

DCEL:classifier fusion model for Android malware detection

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Journal of Systems Engineering and Electronics 2024年第1期35卷 163-177页

作者： XU Xiaolong jiang Shuai ZHAO Jinbo WANG Xinheng jiangsu Key Laboratory of Big Data Security&Intelligent Processing Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Computer Science Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Computing and Engineering University of West LondonLondon W55RFUK

The rapid growth of mobile applications,the popularity of the Android system and its openness have attracted many hackers and even criminals,who are creating lots of Android ***,the current methods of Android malware detection need a lot of time in the feature engineering ***,these models have the defects of low detection rate,high complexity,and poor practicability,*** analyze the Android malware samples,and the distribution of malware and benign software in application programming interface(API)calls,permissions,and other *** classify the software’s threat levels based on the correlation of ***,we propose deep neural networks and convolutional neural networks with ensemble learning(DCEL),a new classifier fusion model for Android malware ***,DCEL preprocesses the malware data to remove redundant data,and converts the one-dimensional data into a two-dimensional gray ***,the ensemble learning approach is used to combine the deep neural network with the convolutional neural network,and the final classification results are obtained by voting on the prediction of each single *** based on the Drebin and Malgenome datasets show that compared with current state-of-art models,the proposed DCEL has a higher detection rate,higher recall rate,and lower computational cost.

关键词： Android malware detection deep learning ensemble learning model fusion

A Multiscale Model of Mass-Functionally Graded Beam-Fluid System Under Bending and Vibration Responses

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Acta Mechanica Solida Sinica 2024年第2期37卷 327-340页

作者： Lei Zhang Jianping Lin Jiaqing jiang Guannan Wang Department of Civil Engineering Zhejiang University866 Yuhangtang RoadHangzhou310058China Center for Balance Architecture Zhejiang UniversityHangzhou310007China College of Civil Engineering Huaqiao UniversityXiamen361021China Key Laboratory for Intelligent Infrastructure and Monitoring of Fujian Province Huaqiao UniversityXiamen361021China Department of Engineering Mechanics Zhejiang UniversityHangzhou310027China

In this paper,a multiscale model is developed for the mass functionally graded(FG)beam-fluid system to investigate its static and dynamic responses based on 3D printed porous beam free vibration tests,which are determined by two *** the microstructural level,the gradient variation is realized by arbitrary distribution of matrix pores,and the effective moduli under specific distribution are obtained using the micromechanics homogenization *** the meantime,at the structural level,the mechanical responses of FG porous beams subjected to mass loading are considered in a static fluid ***,the explicit expressions of local finite-element(FE)expressions corresponding to the static and dynamic responses are given in the *** present results are validated against numerical and experimental results from the literature and mechanical tests of 3D printed structures,with good agreement generally obtained,giving credence to the present *** this basis,a comprehensive parametric study is carried out,with a particular focus on the effects of boundary conditions,fluid density,and slenderness ratio on the bending and vibration of FG beams with several different gradations.

关键词： 3D printed test Mass functionally graded beam-fluid system Multiscale model Local finite-element expressions Static bending Free vibration

Multi-Objective Optimization of VBHF in Deep Drawing Based on the Improved QO-Jaya Algorithm

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 189-202页

作者： Xiangyu jiang Zhaoxi Hong Yixiong Feng Jianrong Tan State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province Zhejiang UniversityHangzhou 310027China Ningbo Innovation Center Zhejiang UniversityNingbo 315100China

Blank holder force(BHF)is a crucial parameter in deep drawing,having close relation with the forming quality of sheet ***,there are different BHFs maintaining the best forming effect in different stages of deep *** variable blank holder force(VBHF)varying with the drawing stage can overcome this problem at an *** optimization of VBHF is to determine the optimal BHF in every deep drawing *** this paper,a new heuristic optimization algorithm named Jaya is introduced to solve the optimization *** improved“Quasi-oppositional”strategy is added to Jaya algorithm for improving population ***,an innovated stop criterion is added for better ***,the quality evaluation criteria for wrinkling and tearing are ***,the Kriging models are developed to approximate and quantify the relation between VBHF and forming defects under random ***,the optimization models are established and solved by the improved QO-Jaya algorithm.A VBHF optimization example of component with complicated shape and thin wall is studied to prove the effectiveness of the improved Jaya *** optimization results are compared with that obtained by other algorithms based on the TOPSIS method.

关键词： Variable blank holder force Multi-objective optimization QO-Jaya algorithm Algorithm stop criterion

Soybean maize strip intercropping:A solution for maintaining food security in China

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Journal of Integrative Agriculture 2024年第7期23卷 2503-2506页

作者： jiang Liu Wenyu Yang Sichuan Engineering Research Center for Crop Strip Intercropping System/Key Laboratory of Crop Ecophysiology and Farming System in Southwest Ministry of Agriculture and Rural AffairsChengdu 611130China College of Life Science Sichuan Agricultural UniversityYa’an 625014China State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China Chengdu 611130China

The practice of intercropping leguminous and gramineous crops is used for promoting sustainable agriculture,optimizing resource utilization,enhancing biodiversity,and reducing reliance on petroleum ***,promoting conventional intercropping strategies in modern agriculture can prove *** innovative technology of soybean maize strip intercropping(SMSI)has been proposed as a *** system has produced remarkable results in improving domestic soybean and maize production for both food security and sustainable *** this article,we provide an overview of SMSI and explain how it differs from traditional *** also discuss the core principles that foster higher yields and the prospects for its future development.

关键词： strip intercropping food security soybean maize spatial arrangement

Perturbed low-thrust geostationary orbit transfer guidance via polynomial costate estimation

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Chinese Journal of Aeronautics 2024年第3期37卷 181-193页

作者： Zhao LI Hengnian LI Fanghua jiang Junfeng LI State Key Laboratory of Astronautic Dynamics Xi’an Satellite Control CenterXi’an 710043China School of Aerospace Engineering Tsinghua UniversityBeijing 100084China

This paper proposes an optimal,robust,and efficient guidance scheme for the perturbed minimum-time low-thrust transfer toward the geostationary *** Earth’s oblateness perturbation and shadow are taken into *** is difficult for a Lyapunov-based or trajectory-tracking guidance method to possess multiple characteristics at the same time,including high guidance optimality,robustness,and onboard computational *** this work,a concise relationship between the minimum-time transfer problem with orbital averaging and its optimal solution is identified,which reveals that the five averaged initial costates that dominate the optimal thrust direction can be approximately determined by only four initial modified equinoctial orbit elements after a coordinate *** on this relationship,the optimal averaged trajectories constituting the training dataset are randomly generated around a nominal averaged *** polynomial regression models are trained on the training dataset and are regarded as the costate *** the transfer,the spacecraft can obtain the real-time approximate optimal thrust direction by combining the costate estimations provided by the estimators with the current state at any ***,all these computations onboard are *** simulation results show that the proposed guidance scheme possesses extremely high guidance optimality,robustness,and onboard computational efficiency.

关键词： Low thrust Orbital transfer Trajectory optimization Guidance Indirect method Orbital averaging Machine learning Geostationary satellites

Fault diagnosis of a marine power-generation diesel engine based on the Gramian angular field and a convolutional neural network

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 470-482页

作者： Congyue LI Yihuai HU Jiawei jiang Dexin CUI Merchant Marine College Shanghai Maritime UniversityShanghai 201306China School of Mechanical and Energy Engineering Shanghai Technical Institute of Electronics&InformationShanghai 201411China

Marine power-generation diesel engines operate in harsh *** vibration signals are highly complex and the feature information exhibits a non-linear *** is difficult to extract effective feature information from the network model,resulting in low fault-diagnosis *** address this problem,we propose a fault-diagnosis method that combines the Gramian angular field(GAF)with a convolutional neural network(CNN).Firstly,the vibration signals are transformed into 2D images by taking advantage of the GAF,which preserves the temporal *** raw signals can be mapped to 2D image features such as texture and *** integrate the feature information,the images of the Gramian angular summation field(GASF)and Gramian angular difference field(GADF)are fused by the weighted average fusion ***,the channel attention mechanism and temporal attention mechanism are introduced in the CNN model to optimize the CNN learning *** the concept of residuals in the attention mechanism improves the feasibility of ***,the weighted average fused images are fed into the CNN for feature extraction and fault *** validity of the proposed method is verified by experiments with abnormal valve *** average diagnostic accuracy is 98.40%.When−20 dB≤signal-to-noise ratio(SNR)≤20 dB,the diagnostic accuracy of the proposed method is higher than 94.00%.The proposed method has superior diagnostic ***,it has a certain anti-noise capability and variable-load adaptive capability.

关键词： Multi-attention mechanisms(MAM) Convolutional neural network(CNN) Gramian angular field(GAF) Image fusion Marine power-generation diesel engine Fault diagnosis