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Computer Modeling in Engineering & Sciences 2024年第5期139卷 2175-2195页

作者： Jiawei Shi jiye Zhang State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China

Combining the detached eddy simulation(DES)method and Ffowcs Williams-Hawkings(FW-H)equation,the effect of bogie cavity end wall inclination on the flow field and aerodynamic noise in the bogie region is numerically ***,the simulation is conducted based on a simplified cavity-bogie model,including five cases with different inclination angles of the front and rear walls of the *** comparing and analyzing the flow field and acoustic results of the five cases,the influence of the regularity and mechanism of the bogie cavity end wall inclination on the flow field and the aerodynamic noise of the bogie region are ***,the noise reduction strategy determined by the results of the simplified cavity-bogie model is applied to a three-car marshaling train model to verify its effectiveness when applied to the real *** results reveal that the forward inclination of the cavity front wall enlarges the influence area of shear vortex structures formed at the leading edge of the cavity and intensifies the interaction between the vortex structures and the front wheelset,frontmotor,and front gearbox,resulting in the increase of the aerodynamic noise generated by the bogie *** backward inclination of the cavity rear wall is conducive to guiding the vortex structures flow out of the cavity and weakening the interaction between the shear vortex structures and the cavity rear wall,leading to the reduction of the aerodynamic noise generated by the bogie *** the rear end wall of the foremost bogie cavity of the head car is a feasible aerodynamic noise reduction measure for high-speed trains.

关键词： Bogie cavity flow aerodynamic noise end wall inclination

Effect of geometry simplification and boundary condition specification on flow field and aerodynamic noise in the train head and bogie region of high-speed trains

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第9期25卷 716-731页

作者： Jiawei SHI Yuan HE jiye ZHAnG Tian LI State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China Institute of Sound and Vibration Research Faculty of Engineering and Physical SciencesUniversity of SouthamptonSouthampton SO171BJUK

The purpose of this study is to determine a suitable modeling method to make computational fluid dynamics(CFD)simulation more efficient for aeroacoustics optimization of the bogie region of high-speed *** this end,four modeling methods are considered,which involve different geometry simplifications and boundary condition *** corresponding models are named the three-car marshalling model,computational domain shortening model,carbody shortening model,and sub-domain *** the detached eddy simulation(DES)model and Ffowcs Williams-Hawkings(FW-H)equation,the unsteady flow field and far-field noise of the four models are *** evaluate the effect of the different modeling methods,the time-averaged flow field,fluctuating flow field,and far-field noise results of the four models are compared and analyzed in detail with the results of the three-car marshalling model used as basis for *** results show that the flow field results of the bogie region predicted by the four models have relatively high ***,the usage of the non-time varying outlet boundary conditions in the computational domain shortening model and sub-domain model could affect the pressure fluctuation on the upstream carbody *** only the bogie region is used as the source surface,the differences between the far-field noise results of the three simplified models and the three-car marshalling model are all within 1 dB;when the train head is used as the source surface,the results of the carbody shortening model and the three-car marshalling model are more consistent.

关键词： Bogie region Train head Flow field Aerodynamic noise Geometry simplification Boundary conditions

Effect of streamlined nose length on aerodynamic performance of high-speed train with a speed of 400 km/h

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第7期25卷 525-540页

作者： nianxun LI Tian LI Zhiyuan DAI Deng QIn jiye ZHAnG State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China

The streamlined nose length(SnL)plays a crucial role in determining the aerodynamic performance of high-speed *** appropriate SnL can not only effectively reduce the magnitude of aerodynamic drag and lift forces,but also improve the performance of the high-speed train in tunnel passing and crosswind *** this study,a numerical simulation of the aerodynamic performance of high-speed trains at a speed of 400 km/h,with varying SnLs,is conducted using the k-ωshear stress transport(SST)turbulence *** different SnLs include 6.0,7.0,8.0,9.0,9.8,12.0,15.0,and 18.0 *** order to validate the accuracy of the numerical simulation,its results are compared with wind tunnel test data obtained from the *** simulation is carried out using compressible and incompressible gases to determine the effect of gas compressibility on *** impact of SnL on the aerodynamic performance of the trains is analyzed in terms of aerodynamic forces,velocity,and pressure *** comparison to the original train,the train with a 6.0 m SnL experienced a 10.8%increase in overall aerodynamic ***,the lift forces on the head and tail cars increased by 35.7%and 75.5%,*** the other hand,the train with an 18.0 m SnL exhibited a 16.5%decrease in aerodynamic ***,the lift forces on the head and tail cars decreased by 21.9%and 49.7%,*** aerodynamic drag force of the entire train varies linearly with the SnL,while the aerodynamic lift of the tail car follows a quadratic function in relation to the SnL.

关键词： Streamlined nose length(SnL) High-speed train Aerodynamic performance numerical simulation Flow structures

numerical Study on Reduction in Aerodynamic Drag and noise of High-Speed Pantograph

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 2155-2173页

作者： Deng Qin Xing Du Tian Li jiye Zhang State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China School of Electrical Engineering Southwest Jiaotong UniversityChengdu610031China

Reducing the aerodynamic drag and noise levels of high-speed pantographs is important for promoting environmentally friendly,energy efficient and rapid advances in train *** computational fluid dynamics theory and the K-FWH acoustic equation,a numerical simulation is conducted to investigate the aerodynamic characteristics of high-speed pantographs.A component optimization method is proposed as a possible solution to the problemof aerodynamic drag and noise in high-speed *** results of the study indicate that the panhead,base and insulator are the main contributors to aerodynamic drag and noise in high-speed ***,a gradual optimization process is implemented to improve the most significant components that cause aerodynamic drag and *** optimizing the cross-sectional shape of the strips and insulators,the drag and noise caused by airflow separation and vortex shedding can be *** aerodynamic drag of insulator with circular cross section and strips with rectangular cross section is the *** insulators and optimizing the chamfer angle and height of the windward surface of the strips can improve the aerodynamic performance of the *** addition,the streamlined fairing attached to the base can eliminate the complex flow and shield the radiated *** contrast to the original pantograph design,the improved pantograph shows a 21.1%reduction in aerodynamic drag and a 1.65 dBA reduction in aerodynamic noise.

关键词： High-speed pantograph aerodynamic drag aerodynamic noise reduction optimizing

Enhanced performance of solution-processed carbon nanotube transparent electrodes in foldable perovskite solar cells through vertical separation of binders by using eco-friendly parylene substrate

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Carbon Energy 2024年第7期6卷 83-93页

作者： Unsoo Kim Jeong-Seok nam Jungjin Yoon jiye Han Mansoo Choi Il Jeon Department of Mechanical Engineering Seoul National UniversitySeoulRepublic of Korea Global Frontier Center for Multiscale Energy Systems Seoul National UniversitySeoulRepublic of Korea Frontier Energy Solution SeoulRepublic of Korea Department of nano Engineering Department of Nano Science and TechnologySKKU Advanced Institute of Nanotechnology(SAINT)Sungkyunkwan University(SKKU)SuwonRepublic of Korea Department of Materials Science and Engineering Pennsylvania State UniversityUniversity ParkPennsylvaniaUSA

The successful utilization of an eco-friendly and biocompatible parylene-C substrate for high-performance solution-processed double-walled carbon nanotube(CnT)electrode-based perovskite solar cells(PSCs)was *** the use of a novel inversion transfer technique,vertical separation of the binders from the CnTs was induced,rendering a stronger p-doping effect and thereby a higher conductivity of the *** resulting foldable devices exhibited a power conversion efficiency of 18.11%,which is the highest reported among CnT transparent electrode-based PSCs to date,and withstood more than 10,000 folding cycles at a radius of 0.5 mm,demonstrating unprecedented mechanical ***,solar modules were fabricated using entirely laser scribing processes to assess the potential of the solution-processable nanocarbon ***,this is the only one to be processed entirely by the laser scribing process and to be biocompatible as well as eco-friendly among the previously reported nonindium tin oxide-based perovskite solar modules.

关键词： double-walled carbon nanotubes parylene substrates perovskite modules perovskite solar cells solution-processable electrodes surfactant removal

Aerodynamic Analysis and Optimization of Pantograph Streamline Fairing for High-Speed Trains

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Fluid Dynamics & Materials Processing 2024年第5期20卷 1075-1091页

作者： Xiang Kan Yan Li Tian Li jiye Zhang State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China Technical Center Southwest Jiaotong University Chengdu Design Institute Co.Ltd.Chengdu610031China

A pantograph serves as a vital device for the collection of electricity in ***,its aerodynamic resistance can limit the train’s running *** installing fairings around the pantograph is known to effectively reduce the resistance,in this study,different fairing lengths are considered and the related aerodynamic performances of pantograph are *** particular,this is accomplished through numerical simulations based on the k-ωShear Stress Transport(SST)two-equation turbulence *** results indicate that the fairing diminishes the direct impact of high-speed airflow on the pantograph,thereby reducing its aerodynamic ***,it also induces interferences in the flow field around the train,leading to variations in the aerodynamic resistance and lift of train *** is shown that a maximum reduction of 56.52%in pantograph aerodynamic resistance and a peak decrease of 3.38%in total train aerodynamic resistance can be achieved.

关键词： Pantograph fairing train aerodynamic numerical simulation

Influence of Anteroposterior Symmetrical Aero-Wings on the Aerodynamic Performance of High-Speed Train

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 937-953页

作者： Peiheng He jiye Zhang Lan Zhang Jiaqi Wang Yuzhe Ma State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China

The running stability of high-speed train is largely constrained by the wheel-rail coupling relationship,and the continuous wear between the wheel and rail surfaces will profoundly affect the dynamic performance of the *** recent years,under the background of increasing train speed,some scientific researchers have proposed a new idea of using the lift force generated by the aerodynamic wings(aero-wing)installed on the roof to reduce the sprung load of the carriage in order to alleviate the wear and tear of the wheel and *** on the bidirectional running characteristics of high-speed train,this paper proposes a scheme to apply aero-wings with anteroposterior symmetrical cross-sections on the roof of the *** the verification of the wind tunnel experimental data,the relatively better airfoil section and extension formof anteroposterior symmetrical aero-wing is selected respectively in this paper,and the aero-wings are fixedly connected to the roof of the train through the mounting column to conduct aerodynamic simulation *** research shows that:compared with the circular-arc and oval crosssections,this paper believes that the crescent cross-section can form greater aerodynamic lift force in a limited *** factors such as aerodynamic parameters,ground effect,and manufacturing process,this paper proposes to adopt aero-wings with arc type extension form and connect them to the roof of the train through mounting columns with shuttle *** the roof of the train is covered with aero-wings and runs at high speed,the sprung load of the carriages can be effectively ***,there are certain hidden dangers in the tail carriage due to the large amount of lift force,so,the intervention of the aero-wing lifting mechanism is *** the same time,it is necessary to optimize the overall aerodynamic drag force reduction in the followup work.

关键词： Anteroposterior symmetrical aero-wing wheel-rail wear aerodynamic lift force ground effect numerical simulation

numerical Simulations of Snow Accumulation in the Bogie Region of a Train Considering Snow Particle Rotation

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Fluid Dynamics & Materials Processing 2024年第10期20卷 2337-2352页

作者： Hong Lan jiye Zhang Yao Zhang Lu Cai State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China College of Railway Transportation Hunan University of TechnologyZhuzhou412000China GD Midea Air-Conditioning Equipment Co. Ltd.Foshan528311China

To investigate the influence of snow particle rotational motion on the accumulation of snow in the bogie region of high-speed trains,an Euler‒Lagrange numerical approach is *** study examines the effects of snow particle diameter and train speed on the ensuing *** is shown that considering snow particle rotational motion causes significant deviation in the particle trajectories with respect to non-rotating *** a deviation increases with larger snow particle diameters and higher train *** snow accumulation on the overall surface of the bogie increases,and the amount of snow on the vibration reduction device varies *** certain conditions,the amount of accumulated snow can increase by several orders of magnitudes.

关键词： High-speed train bogie snow particle rotation discrete phase model snow accumulation

numerical Study on the Effect of Vortex Generators on the Aerodynamic Drag of a High-Speed Train

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Fluid Dynamics & Materials Processing 2024年第2期20卷 463-473页

作者： Tian Li Hao Liang Zerui Xiang jiye Zhang State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China School of Design Southwest Jiaotong UniversityChengdu610031China

A relatively high aerodynamic drag is an important factor that hinders the further acceleration of high-speed *** the shear stress transport(SST)k-ωturbulence model,the effect of various vortex generator types on the aerodynamic characteristics of an ICE2(Inter-city Electricity)train has been *** results indi-cate that the vortex generators with wider triangle,trapezoid,and micro-ramp arranged on the surface of the tail car can signiﬁcantly change the distribution of surface pressure and affect the vorticity intensity in the *** alteration effectively reduces the resistance of the tail ***,the micro-ramp vortex generator with its convergent structure at the rear exhibits enhancedﬂow-guiding capabilities,resulting in a 15.4%reduction in the drag of the tail car.

关键词： Vortex generator aerodynamic drag reduction numerical simulation

Structure and thermoelectric properties of half-Heusler-like TiFeCu_(x)Sb alloys

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Journal of Materiomics 2024年第3期10卷 523-530页

作者： Siyuanyang Yin Qizhu Li Shaoqin Wang Jiajun Chen Zirui Dong Yubo Zhang Binghui Ge jiye Zhang Jun Luo School of Materials Science and Engineering Shanghai University99 Shangda RoadShanghai200444China Institutes of Physical Science and Information Technology Anhui University111 Jiulong RoadHefei230601China Minjiang Collaborative Center for Theoretical Physics College of Physics and Electronic Information EngineeringMinjiang University200 Xiyuangong RoadFuzhou350108China Interdisciplinary Materials Research Center School of Materials Science and EngineeringTongji University4800 Caoan RoadShanghai201804China

Previous research on the ternary Ti-Fe-Sb system has revealed that stoichiometric TiFeSb cannot exist as a stable compound,whereas a single-phase TiFe_(1.33)Sb alloy with the half-Heusler-like structure has been synthesized by adding excessive *** this work,we report that TiFeSb can also be stabilized by filling additional Cu to the vacant 4d site of the half-Heusler *** experiments indicate that the TiFe-Cu_(x)Sb(x=0-0.25)samples exhibit a p-type conduction with extremely high carrier concentration((0.5-2.5)×10^(22)cm^(-3)),while these samples attain very large Seebeck coefficients,over 100 mV/K in the whole measured temperature range for the samples with x=*** addition,a logarithmic divergence of the temperature-dependent specific heat capacity(CP/T)is observed at low temperatures,implying the strange-metal behavior of TiFeCu_(x)Sb *** partial filling of the vacant 4d site results in significantly reduced lattice thermal conductivity,leading to the low total thermal conductivity of 2.8 W·m^(-1)·K^(-1)at 823 K for the TiFeCu_(0.20)Sb ***,a dimensionless figure of merit zT of 0.54 at 923 K is realized for TiFeCu_(0.20)Sb,demonstrating that promising thermoelectric materials with intriguing physical properties can be discovered in the composition gap of half-and full-Heusler alloys.

关键词： TiFeSb Thermoelectric materials Heusler alloys Vacancy-filled