The emissions from traditional fossil heavy-duty trucks have become a conspicuous issue worldwide.The electrical road system(ERS)can offer a viable solution for achieving zero CO_(2) emissions and has high energy effi...The emissions from traditional fossil heavy-duty trucks have become a conspicuous issue worldwide.The electrical road system(ERS)can offer a viable solution for achieving zero CO_(2) emissions and has high energy efficiency in long-distance road cargo transport.While many kinds of pantograph structures have been developed for the ERS,their corresponding pantograph-catenary dynamic characteristics under different road conditions have not been investigated.This work performs a numerical study on the dynamics of the pantograph-catenary interaction of an ERS considering different pantograph structures.First,a pantograph-catenary-truck-road model is proposed.The reduced catenary model and reduced-plate model transmission method are used to minimize model scale.Three different types of ERS pantograph structures are considered in the model.After validation,the pantograph-catenary dynamics under the influence of truck-road interactions with complex road roughness and different pantographs are studied and compared.The corresponding vibration transmission mechanism is further focused.The results show that the truck-road interaction has a significant effect on the pantograph-catenary interaction,but the pantograph with only one lower and upper armcan isolate the roll vibrationmotion transmission fromthe truck to the collector head,which has the best dynamic performance and is suggested for use in the ERS.展开更多
Currently,most trains are equipped with dedicated cameras for capturing pantograph videos.Pantographs are core to the high-speed-railway pantograph-catenary system,and their failure directly affects the normal operati...Currently,most trains are equipped with dedicated cameras for capturing pantograph videos.Pantographs are core to the high-speed-railway pantograph-catenary system,and their failure directly affects the normal operation of high-speed trains.However,given the complex and variable real-world operational conditions of high-speed railways,there is no real-time and robust pantograph fault-detection method capable of handling large volumes of surveillance video.Hence,it is of paramount importance to maintain real-time monitoring and analysis of pantographs.Our study presents a real-time intelligent detection technology for identifying faults in high-speed railway pantographs,utilizing a fusion of self-attention and convolution features.We delved into lightweight multi-scale feature-extraction and fault-detection models based on deep learning to detect pantograph anomalies.Compared with traditional methods,this approach achieves high recall and accuracy in pantograph recognition,accurately pinpointing issues like discharge sparks,pantograph horns,and carbon pantograph-slide malfunctions.After experimentation and validation with actual surveillance videos of electric multiple-unit train,our algorithmic model demonstrates real-time,high-accuracy performance even under complex operational conditions.展开更多
Appropriate interaction between pantograph and catenary is imperative for smooth operation of electric trains.Changing heights of overhead lines to accommodate level crossings,overbridges,and tunnels pose significant ...Appropriate interaction between pantograph and catenary is imperative for smooth operation of electric trains.Changing heights of overhead lines to accommodate level crossings,overbridges,and tunnels pose significant challenges in maintaining consistent current collection performance as the pantograph aerodynamic profile,and thus aerodynamic load changes significantly with operational height.This research aims to analyse the global flow characteristics and aerodynamic forces acting on individual components of an HSX pantograph operating in different configurations and orientations,such that the results can be combined with multibody simulations to obtain accurate dynamic insight into contact forces.Specifically,computational fluid dynamics simulations are used to investigate the pantograph component loads in a representative setting,such as that of the recessed cavity on a Class 800 train.From an aerodynamic perspective,this study indicates that the total drag force acting on non-fixed components of the pantograph is larger for the knuckle-leading orientation rather than the knuckle-trailing,although the difference between the two is found to reduce with increasing pantograph extension.Combining the aerodynamic loads acting on individual components with multibody tools allows for realistic dynamic insight into the pantograph behaviour.The results obtained show how considering aerodynamic forces enhance the realism of the models,leading to behaviour of the pantograph-catenary contact forces closely matching that seen in experimental tests.展开更多
Reducing the aerodynamic drag and noise levels of high-speed pantographs is important for promoting environmentally friendly,energy efficient and rapid advances in train technology.Using computational fluid dynamics t...Reducing the aerodynamic drag and noise levels of high-speed pantographs is important for promoting environmentally friendly,energy efficient and rapid advances in train technology.Using 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 pantographs.The results of the study indicate that the panhead,base and insulator are the main contributors to aerodynamic drag and noise in high-speed pantographs.Therefore,a gradual optimization process is implemented to improve the most significant components that cause aerodynamic drag and noise.By optimizing the cross-sectional shape of the strips and insulators,the drag and noise caused by airflow separation and vortex shedding can be reduced.The aerodynamic drag of insulator with circular cross section and strips with rectangular cross section is the largest.Ellipsifying insulators and optimizing the chamfer angle and height of the windward surface of the strips can improve the aerodynamic performance of the pantograph.In addition,the streamlined fairing attached to the base can eliminate the complex flow and shield the radiated noise.In 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.展开更多
A pantograph serves as a vital device for the collection of electricity in trains.However,its aerodynamic resistance can limit the train’s running speed.As installing fairings around the pantograph is known to effect...A pantograph serves as a vital device for the collection of electricity in trains.However,its aerodynamic resistance can limit the train’s running speed.As 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 assessed.In particular,this is accomplished through numerical simulations based on the k-ωShear Stress Transport(SST)two-equation turbulence model.The results indicate that the fairing diminishes the direct impact of high-speed airflow on the pantograph,thereby reducing its aerodynamic resistance.However,it also induces interferences in the flow field around the train,leading to variations in the aerodynamic resistance and lift of train components.It 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.展开更多
The technology of pantograph sinking in the cavity is generally adopted in the new generation of high-speed trains in China for aerodynamic noise reduction in this region. This study takes a high-speed train with a 4-...The technology of pantograph sinking in the cavity is generally adopted in the new generation of high-speed trains in China for aerodynamic noise reduction in this region. This study takes a high-speed train with a 4-car formation and a pantograph as the research object and compares the aerodynamic acoustic performance of two scale models, 1/8 and 1/1, using large eddy simulation and Ffowcs Williams–Hawkings integral equation. It is found that there is no direct scale similarity between their aeroacoustic performance. The 1/1 model airflow is separated at the leading edge of the panhead and reattached to the panhead, and its vortex shedding Strouhal number(St) is 0.17. However, the 1/8 model airflow is separated directly at the leading edge of the panhead, and its St is 0.13. The cavity's vortex shedding frequency is in agreement with that calculated by the Rooster empirical formula. The two scale models exhibit some similar characteristics in distribution of sound source energy, but the energy distribution of the 1/8 model is more concentrated in the middle and lower regions. The contribution rates of their middle and lower regions to the radiated noise in the two models are 27.3% and 87.2%, respectively. The peak frequencies of the radiated noise from the 1/1 model are 307 and 571 Hz. The 307 Hz is consistent with the frequency of panhead vortex shedding, and the 571 Hz is more likely to be the result of the superposition of various components. In contrast, the peak frequencies of the radiated noise from the 1/8 scale model are 280 and 1970 Hz. The 280 Hz comes from the shear layer oscillation between the cavity and the bottom frame, and the 1970 Hz is close to the frequency at which the panhead vortex sheds. This shows that the scaled model results need to be corrected before applying to the full-scale model.展开更多
Aiming to mitigate the aerodynamic lift force imbalance between pantograph strips,which exacerbates wear and affects the current collection performance of the pantograph-catenary system,a study has been conducted to s...Aiming to mitigate the aerodynamic lift force imbalance between pantograph strips,which exacerbates wear and affects the current collection performance of the pantograph-catenary system,a study has been conducted to support the beam deflector optimization using a combination of experimental measurements and computational fluid dynamics(CFD)simulations.The results demonstrate that the size,position,and installation orientation of the wind deflectors significantly influence the amount of force compensation.They also indicate that the front strip deflectors should be installed downwards and the rear strip deflectors upwards,thereby forming a“π”shape.Moreover,the lift force compensation provided by the wind deflectors increases with the size of the deflector.Alternative wind compensation strategies,such as control circuits,are also discussed,putting emphasis on the pros and cons of various pantograph types and wind compensation approaches.展开更多
The paper is aimed at developing an optimized design of the pantograph and catenary system with double pantographs at a speed of 350 km/h for the Wuhan-Guangzhou high-speed railway. First, the pantograph and catenary ...The paper is aimed at developing an optimized design of the pantograph and catenary system with double pantographs at a speed of 350 km/h for the Wuhan-Guangzhou high-speed railway. First, the pantograph and catenary system for the Beijing-Tianjin high-speed railway was analyzed to verify whether its design objective could be fulfilled. It shows that the system is not able to satisfy the requirement of a sustainable running speed of 350 km/h. Then a new scheme for the pantograph and catenary system is proposed through optimization and renovation of the structure and parameters of the pantograph and catenary system, including the suspension type of the catenary, tension of the contact wire, and space between two pantographs. Finally, the dynamic performance of the new system was verified by simulation and line testing. The results show that the new scheme of the pantograph and catenary system for the Wuhan- Guangzhou high-speed railway is acceptable, in which the steady contact between the rear pantograph and the catenary at the space of 200 m can be maintained to ensure the current-collection quality. A current collection with double pantographs at a speed of 350 km/h or higher can be achieved.展开更多
As the unique power entrance,the pantograph-catenary electrical contact system maintains the efficiency and reliability of power transmission for the high-speed train.Along with the fast development of high-speed rail...As the unique power entrance,the pantograph-catenary electrical contact system maintains the efficiency and reliability of power transmission for the high-speed train.Along with the fast development of high-speed railways all over the world,some commercialized lines are built for covering the remote places under harsh environment,especially in China;these environmental elements including wind,sand,rain,thunder,ice and snow need to be considered during the design of the pantograph-catenary system.The pantograph-catenary system includes the pantograph,the contact wire and the interface—pantograph slide.As the key component,this pantograph slide plays a critical role in reliable power transmission under dynamic condition.The fundamental material characteristics of the pantograph slide and contact wire such as electrical conductivity,impact resistance,wear resistance,etc.,directly determine the sliding electrical contact performance of the pantograph-catenary system;meanwhile,different detection methods of the pantograph-catenary system are crucial for the reliability of service and maintenance.In addition,the challenges brought from extreme operational conditions are discussed,taking the Sichuan-Tibet Railway currently under construction as a special example with the high-altitude climate.The outlook for developing the ultra-high-speed train equipped with the novel pantograph-catenary system which can address the harsher operational environment is also involved.This paper has provided a comprehensive review of the high-speed railway pantograph-catenary systems,including its progress,challenges,outlooks in the history and future.展开更多
The significant increase in speed of high-speed train will cause the dynamic contact force of the pantograph-catenary system to fluctuate more severely,which poses a challenge to the study of the pantograph-catenary r...The significant increase in speed of high-speed train will cause the dynamic contact force of the pantograph-catenary system to fluctuate more severely,which poses a challenge to the study of the pantograph-catenary relationship and the design of highspeed pantographs.Good pantograph-catenary coupling quality is the essential condition to ensure safe and efficient operation of high-speed train,stable and reliable current collection,and reduction in the wear of contact wires and pantograph contact strips.Among them,the dynamic parameters of high-speed pantographs are crucial to pantograph-catenary coupling quality.With the reduction of the standard deviation of the pantograph-catenary contact force as the optimization goal,multi-parameter joint optimization designs for the high-speed pantograph with two contact strips at multiple running speeds are proposed.Moreover,combining the sensitivity analysis at the optimal solutions,with the parameters and characteristics of in-service DSA380 highspeed pantograph,the optimization proposal of DSA380 was given.展开更多
In this paper, a deterministic delay differential pantograph equation （DDPE） with an unbounded memory is stochastically perturbed by an Ito-type noise. The contribution of white noise to the oscillatory behaviour of...In this paper, a deterministic delay differential pantograph equation （DDPE） with an unbounded memory is stochastically perturbed by an Ito-type noise. The contribution of white noise to the oscillatory behaviour of the new stochastic delay differential pantograph equation （SDDPE） is investigated. It is established that under certain conditions and with a highly positive probability, the new stochastic delay differential pantograph equation has an oscillatory solution influenced by the presence of the noise. This is not possible with the original deterministic system which has a non-oscillatory solution due to the absence of noise.展开更多
With the continuous increase of train speed,undulations of catenary and vibrations of the pantograph head result in generating pantograph- catenary arc frequently,intensifying the abrasion between pantograph strip and...With the continuous increase of train speed,undulations of catenary and vibrations of the pantograph head result in generating pantograph- catenary arc frequently,intensifying the abrasion between pantograph strip and catenary wire,which has seriously influenced the current collection and safety of electric multi units(EMU). It is necessary to study the pantographcatenary arc in immediately. Some researchers develop a few pantograph- catenary arc testing equipment,which couldn’t really reflect the operating condition of pantograph-catenary system. In this paper,the pantograph-catenary arc test apparatus was developed,which simulated the flexible and straight contact of pantograph strip and catenary wire,based on the coupling relationship between pantograph and catenary. The equipment was used to research the electrical parameters of the pantograph-catenary arc and the dynamic contact resistance.展开更多
Catch arc is the bottleneck of train acceleration. The arc characteristics of pantograph is an important index of the current high-speed train problems, which will seriously affect the normal operation of traction dri...Catch arc is the bottleneck of train acceleration. The arc characteristics of pantograph is an important index of the current high-speed train problems, which will seriously affect the normal operation of traction drive system. The study of the characteristics of the pantograph arc in the process of off-line pantograph can provide some help for improving the quality of the current receiving and the safe operation of the train.展开更多
In this paper,a modeling method for a pantograph-catenary system is put forward to investigate the dynamic contact behavior in space,taking into consideration of the appearance characteristics of the contact surfaces ...In this paper,a modeling method for a pantograph-catenary system is put forward to investigate the dynamic contact behavior in space,taking into consideration of the appearance characteristics of the contact surfaces of the pantograph and catenary.The dynamic performance of the pantograph-catenary system,including contact forces,accelerations,and the corresponding spectra,is analyzed.Furthermore,with the modeling method,the influences of contact wire irregularity and the vibration caused by the front pantograph on the rear pantograph for a pantograph-catenary system with double pantographs are investigated.The results show that the appearance characteristics of the contact surfaces play an important role in the dynamic contact behavior.The appearance characteristics should be considered to reasonably evaluate the dynamic performance of the pantograph-catenary system.展开更多
A crucial system for the operation of high-speed trains is the pantograph catenary interface as it is the sole responsible to deliver electrical power to the train. Being the catenary a stationary system with a long l...A crucial system for the operation of high-speed trains is the pantograph catenary interface as it is the sole responsible to deliver electrical power to the train. Being the catenary a stationary system with a long lifespan it is also less likely to be redesigned and upgraded than the pantographs that fit the train vehicles. This letter proposes an optimization procedure for the improvement of the contact quality between the pantograph and the catenary solely based on the redesign of the pantograph head suspension characteristics. A pantograph model is defined and validated against experimental dynamic characteristics of existing pantographs. An optimization strategy based on the use of a global optimization method, to find the vicinity of the optimal solution, followed by the use of a deterministic optimization algorithm, to fine tune the optimal solution, is applied here. The spring stiffness, damping characteristics and bow mass are the design variables used for the pantograph optimization. The objective of the optimal problem is the minimization of the standard deviation of the contact force history, which is the most important quantity to define the contact quality. The pantograph head suspension characteristics are allowed to vary within technological realistic limits. It is found that current high-speed railway pantographs have a limited potential for mechanical improvements, not exceeding 10% 15% on the decrease of the standard deviation of the contact force. C 2013 The Chinese Society of Theoretical and Applied Mechanics. [doi：10.1063/2.1301306]展开更多
This study investigates the influence of different pantograph parameters and train length on the aerodynamic drag of high-speed train by the delayed detached eddy simulation(DDES) method. The train geometry considered...This study investigates the influence of different pantograph parameters and train length on the aerodynamic drag of high-speed train by the delayed detached eddy simulation(DDES) method. The train geometry considered is the high-speed train with pantographs, and the different versions have 3, 5, 8, 10, 12, 16 and 17 cars. The numerical results are verified by the wind tunnel test with 3.6% difference. The influences of the number of cars and the position, quantity and configuration of pantographs on flow field around high-speed train and wake vortices are analyzed. The aerodynamic drag of middle cars gradually decreases along the flow direction. The aerodynamic drag of pantographs decreases with its backward shift, and that of the first pantograph decreases significantly. As the number of pantographs increases, its effect on the aerodynamic drag decrease of rear cars is more significant. The engineering application equation for the aerodynamic drag of high-speed train with pantographs is proposed. For the 10-car and 17-car train, the differences of total aerodynamic drag between the equation and the simulation results are 1.2% and 0.4%, respectively. The equation generalized in this study could well guide the design phase of high-speed train.展开更多
To study the influence of the pantograph fixing position on aerodynamic characteristics of high-speed trains, the aerodynamic models of high-speed trains with eight cars were established based on the theory of com- pu...To study the influence of the pantograph fixing position on aerodynamic characteristics of high-speed trains, the aerodynamic models of high-speed trains with eight cars were established based on the theory of com- putational fluid dynamics, and eight cases with pantographs fixed on different positions and in different operational orientations were considered. The pantographs were fixed on the front or the rear end of the first middle car or fixed on the front or the rear end of the last middle car. The external flow fields of the high-speed trains were numeri- cally simulated using the software STAR-CCM＋. The results show that the pantograph fixing position has little effect on the aerodynamic drag force of the head car and has a large effect on the aerodynamic drag force of the tail car. The influences of the pantograph fixing position on the aerodynamic lift forces of the head car, tail car and pan- tographs are obvious. Among the eight cases, considering the total aerodynamic drag force of the train and the aerodynamic lift force of the lifted pantograph, when the pantographs are fixed on the rear end of the last middle car and the lifted pantograph is in the knuckle-upstream ori- entation, the aerodynamic performance of the high-speed train is the best.展开更多
Pantograph is a critical component of the high-speed train.It collects power through contact with catenary,which significantly affects the running safety of the train.Pantograph with double collector strips is one com...Pantograph is a critical component of the high-speed train.It collects power through contact with catenary,which significantly affects the running safety of the train.Pantograph with double collector strips is one common type.The aerodynamic performance of the collector strips may affect the current collection of the pantograph.In this study,the aerodynamic performance of the pantograph with double strips is investigated.The numerical results are consistent with the experimental ones.The error in the aerodynamic drag force of the pantograph between numerical and experimental results is less than 5%.Three different conditions of the strips are studied,including the front strip,the rear strip,and the double strips.Results show that the presence of the front strip will affect the lift force of the rear strip,and reduce the resistance of the rear strip under the opening condition.Meanwhile,the rear strip has few effects on the front strip under the opening operation condition.The law of the resistance for the interaction between two strips under the closing condition is similar to the opening one.展开更多
基金supported by the National Natural Science Foundation of China(grant number 12302048,received by author Yan Xu)Yunnan fundamental research projects(grant No.202501AT070321,received by author Yan Xu).
文摘The emissions from traditional fossil heavy-duty trucks have become a conspicuous issue worldwide.The electrical road system(ERS)can offer a viable solution for achieving zero CO_(2) emissions and has high energy efficiency in long-distance road cargo transport.While many kinds of pantograph structures have been developed for the ERS,their corresponding pantograph-catenary dynamic characteristics under different road conditions have not been investigated.This work performs a numerical study on the dynamics of the pantograph-catenary interaction of an ERS considering different pantograph structures.First,a pantograph-catenary-truck-road model is proposed.The reduced catenary model and reduced-plate model transmission method are used to minimize model scale.Three different types of ERS pantograph structures are considered in the model.After validation,the pantograph-catenary dynamics under the influence of truck-road interactions with complex road roughness and different pantographs are studied and compared.The corresponding vibration transmission mechanism is further focused.The results show that the truck-road interaction has a significant effect on the pantograph-catenary interaction,but the pantograph with only one lower and upper armcan isolate the roll vibrationmotion transmission fromthe truck to the collector head,which has the best dynamic performance and is suggested for use in the ERS.
基金supported by the National Key R&D Program of China(No.2022YFB4301102).
文摘Currently,most trains are equipped with dedicated cameras for capturing pantograph videos.Pantographs are core to the high-speed-railway pantograph-catenary system,and their failure directly affects the normal operation of high-speed trains.However,given the complex and variable real-world operational conditions of high-speed railways,there is no real-time and robust pantograph fault-detection method capable of handling large volumes of surveillance video.Hence,it is of paramount importance to maintain real-time monitoring and analysis of pantographs.Our study presents a real-time intelligent detection technology for identifying faults in high-speed railway pantographs,utilizing a fusion of self-attention and convolution features.We delved into lightweight multi-scale feature-extraction and fault-detection models based on deep learning to detect pantograph anomalies.Compared with traditional methods,this approach achieves high recall and accuracy in pantograph recognition,accurately pinpointing issues like discharge sparks,pantograph horns,and carbon pantograph-slide malfunctions.After experimentation and validation with actual surveillance videos of electric multiple-unit train,our algorithmic model demonstrates real-time,high-accuracy performance even under complex operational conditions.
基金support of RSSB to this work via the project RSSB/COF-UOH-49 is greatly appreciated.The authors also acknowledge the support by FCT,through IDMEC,under LAETA,project UIDB/50022/2020.
文摘Appropriate interaction between pantograph and catenary is imperative for smooth operation of electric trains.Changing heights of overhead lines to accommodate level crossings,overbridges,and tunnels pose significant challenges in maintaining consistent current collection performance as the pantograph aerodynamic profile,and thus aerodynamic load changes significantly with operational height.This research aims to analyse the global flow characteristics and aerodynamic forces acting on individual components of an HSX pantograph operating in different configurations and orientations,such that the results can be combined with multibody simulations to obtain accurate dynamic insight into contact forces.Specifically,computational fluid dynamics simulations are used to investigate the pantograph component loads in a representative setting,such as that of the recessed cavity on a Class 800 train.From an aerodynamic perspective,this study indicates that the total drag force acting on non-fixed components of the pantograph is larger for the knuckle-leading orientation rather than the knuckle-trailing,although the difference between the two is found to reduce with increasing pantograph extension.Combining the aerodynamic loads acting on individual components with multibody tools allows for realistic dynamic insight into the pantograph behaviour.The results obtained show how considering aerodynamic forces enhance the realism of the models,leading to behaviour of the pantograph-catenary contact forces closely matching that seen in experimental tests.
基金supported by National Natural Science Foundation of China(12372049)Science and Technology Program of China National Accreditation Service for Confor-mity Assessment(2022CNAS15)+1 种基金Sichuan Science and Technology Program(2023JDRC0062)Independent Project of State Key Laboratory of Rail Transit Vehicle System(2023TPL-T06).
文摘Reducing the aerodynamic drag and noise levels of high-speed pantographs is important for promoting environmentally friendly,energy efficient and rapid advances in train technology.Using 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 pantographs.The results of the study indicate that the panhead,base and insulator are the main contributors to aerodynamic drag and noise in high-speed pantographs.Therefore,a gradual optimization process is implemented to improve the most significant components that cause aerodynamic drag and noise.By optimizing the cross-sectional shape of the strips and insulators,the drag and noise caused by airflow separation and vortex shedding can be reduced.The aerodynamic drag of insulator with circular cross section and strips with rectangular cross section is the largest.Ellipsifying insulators and optimizing the chamfer angle and height of the windward surface of the strips can improve the aerodynamic performance of the pantograph.In addition,the streamlined fairing attached to the base can eliminate the complex flow and shield the radiated noise.In 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.
基金the National Natural Science Foundation of China(12172308,52072319)the Independent Project of State Key Laboratory of Rail Transit Vehicle System(2023TPL-T06).
文摘A pantograph serves as a vital device for the collection of electricity in trains.However,its aerodynamic resistance can limit the train’s running speed.As 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 assessed.In particular,this is accomplished through numerical simulations based on the k-ωShear Stress Transport(SST)two-equation turbulence model.The results indicate that the fairing diminishes the direct impact of high-speed airflow on the pantograph,thereby reducing its aerodynamic resistance.However,it also induces interferences in the flow field around the train,leading to variations in the aerodynamic resistance and lift of train components.It 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.
基金supported by the National Natural Science Foundation of China (No. 52272363)the Key Laboratory of Aerodynamic Noise Control (No. ANCL20200302),Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province。
文摘The technology of pantograph sinking in the cavity is generally adopted in the new generation of high-speed trains in China for aerodynamic noise reduction in this region. This study takes a high-speed train with a 4-car formation and a pantograph as the research object and compares the aerodynamic acoustic performance of two scale models, 1/8 and 1/1, using large eddy simulation and Ffowcs Williams–Hawkings integral equation. It is found that there is no direct scale similarity between their aeroacoustic performance. The 1/1 model airflow is separated at the leading edge of the panhead and reattached to the panhead, and its vortex shedding Strouhal number(St) is 0.17. However, the 1/8 model airflow is separated directly at the leading edge of the panhead, and its St is 0.13. The cavity's vortex shedding frequency is in agreement with that calculated by the Rooster empirical formula. The two scale models exhibit some similar characteristics in distribution of sound source energy, but the energy distribution of the 1/8 model is more concentrated in the middle and lower regions. The contribution rates of their middle and lower regions to the radiated noise in the two models are 27.3% and 87.2%, respectively. The peak frequencies of the radiated noise from the 1/1 model are 307 and 571 Hz. The 307 Hz is consistent with the frequency of panhead vortex shedding, and the 571 Hz is more likely to be the result of the superposition of various components. In contrast, the peak frequencies of the radiated noise from the 1/8 scale model are 280 and 1970 Hz. The 280 Hz comes from the shear layer oscillation between the cavity and the bottom frame, and the 1970 Hz is close to the frequency at which the panhead vortex sheds. This shows that the scaled model results need to be corrected before applying to the full-scale model.
文摘Aiming to mitigate the aerodynamic lift force imbalance between pantograph strips,which exacerbates wear and affects the current collection performance of the pantograph-catenary system,a study has been conducted to support the beam deflector optimization using a combination of experimental measurements and computational fluid dynamics(CFD)simulations.The results demonstrate that the size,position,and installation orientation of the wind deflectors significantly influence the amount of force compensation.They also indicate that the front strip deflectors should be installed downwards and the rear strip deflectors upwards,thereby forming a“π”shape.Moreover,the lift force compensation provided by the wind deflectors increases with the size of the deflector.Alternative wind compensation strategies,such as control circuits,are also discussed,putting emphasis on the pros and cons of various pantograph types and wind compensation approaches.
文摘The paper is aimed at developing an optimized design of the pantograph and catenary system with double pantographs at a speed of 350 km/h for the Wuhan-Guangzhou high-speed railway. First, the pantograph and catenary system for the Beijing-Tianjin high-speed railway was analyzed to verify whether its design objective could be fulfilled. It shows that the system is not able to satisfy the requirement of a sustainable running speed of 350 km/h. Then a new scheme for the pantograph and catenary system is proposed through optimization and renovation of the structure and parameters of the pantograph and catenary system, including the suspension type of the catenary, tension of the contact wire, and space between two pantographs. Finally, the dynamic performance of the new system was verified by simulation and line testing. The results show that the new scheme of the pantograph and catenary system for the Wuhan- Guangzhou high-speed railway is acceptable, in which the steady contact between the rear pantograph and the catenary at the space of 200 m can be maintained to ensure the current-collection quality. A current collection with double pantographs at a speed of 350 km/h or higher can be achieved.
基金supported by the National Natural Science Foundation of China(Nos.U19A20105,51837009,51807167,51922090,U1966602 and 52077182)the Scientific and Technological Funds for Young Scientists of Sichuan(No.2019JDJQ0019)。
文摘As the unique power entrance,the pantograph-catenary electrical contact system maintains the efficiency and reliability of power transmission for the high-speed train.Along with the fast development of high-speed railways all over the world,some commercialized lines are built for covering the remote places under harsh environment,especially in China;these environmental elements including wind,sand,rain,thunder,ice and snow need to be considered during the design of the pantograph-catenary system.The pantograph-catenary system includes the pantograph,the contact wire and the interface—pantograph slide.As the key component,this pantograph slide plays a critical role in reliable power transmission under dynamic condition.The fundamental material characteristics of the pantograph slide and contact wire such as electrical conductivity,impact resistance,wear resistance,etc.,directly determine the sliding electrical contact performance of the pantograph-catenary system;meanwhile,different detection methods of the pantograph-catenary system are crucial for the reliability of service and maintenance.In addition,the challenges brought from extreme operational conditions are discussed,taking the Sichuan-Tibet Railway currently under construction as a special example with the high-altitude climate.The outlook for developing the ultra-high-speed train equipped with the novel pantograph-catenary system which can address the harsher operational environment is also involved.This paper has provided a comprehensive review of the high-speed railway pantograph-catenary systems,including its progress,challenges,outlooks in the history and future.
基金the National Natural Science Foundation of China(Grant No.11672297)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB22020200).
文摘The significant increase in speed of high-speed train will cause the dynamic contact force of the pantograph-catenary system to fluctuate more severely,which poses a challenge to the study of the pantograph-catenary relationship and the design of highspeed pantographs.Good pantograph-catenary coupling quality is the essential condition to ensure safe and efficient operation of high-speed train,stable and reliable current collection,and reduction in the wear of contact wires and pantograph contact strips.Among them,the dynamic parameters of high-speed pantographs are crucial to pantograph-catenary coupling quality.With the reduction of the standard deviation of the pantograph-catenary contact force as the optimization goal,multi-parameter joint optimization designs for the high-speed pantograph with two contact strips at multiple running speeds are proposed.Moreover,combining the sensitivity analysis at the optimal solutions,with the parameters and characteristics of in-service DSA380 highspeed pantograph,the optimization proposal of DSA380 was given.
文摘In this paper, a deterministic delay differential pantograph equation （DDPE） with an unbounded memory is stochastically perturbed by an Ito-type noise. The contribution of white noise to the oscillatory behaviour of the new stochastic delay differential pantograph equation （SDDPE） is investigated. It is established that under certain conditions and with a highly positive probability, the new stochastic delay differential pantograph equation has an oscillatory solution influenced by the presence of the noise. This is not possible with the original deterministic system which has a non-oscillatory solution due to the absence of noise.
基金supporting program of the National Science Foundation for Distinguished Young Scholars of China(Project No.51325704)the State Key Program of National Natural Science of China(Project No.U1234202)。
文摘With the continuous increase of train speed,undulations of catenary and vibrations of the pantograph head result in generating pantograph- catenary arc frequently,intensifying the abrasion between pantograph strip and catenary wire,which has seriously influenced the current collection and safety of electric multi units(EMU). It is necessary to study the pantographcatenary arc in immediately. Some researchers develop a few pantograph- catenary arc testing equipment,which couldn’t really reflect the operating condition of pantograph-catenary system. In this paper,the pantograph-catenary arc test apparatus was developed,which simulated the flexible and straight contact of pantograph strip and catenary wire,based on the coupling relationship between pantograph and catenary. The equipment was used to research the electrical parameters of the pantograph-catenary arc and the dynamic contact resistance.
文摘Catch arc is the bottleneck of train acceleration. The arc characteristics of pantograph is an important index of the current high-speed train problems, which will seriously affect the normal operation of traction drive system. The study of the characteristics of the pantograph arc in the process of off-line pantograph can provide some help for improving the quality of the current receiving and the safe operation of the train.
基金Project supported by the National Natural Science Foundation of China (No.51075341)the National Basic Research Program (973) of China (No.2011CB711105)
文摘In this paper,a modeling method for a pantograph-catenary system is put forward to investigate the dynamic contact behavior in space,taking into consideration of the appearance characteristics of the contact surfaces of the pantograph and catenary.The dynamic performance of the pantograph-catenary system,including contact forces,accelerations,and the corresponding spectra,is analyzed.Furthermore,with the modeling method,the influences of contact wire irregularity and the vibration caused by the front pantograph on the rear pantograph for a pantograph-catenary system with double pantographs are investigated.The results show that the appearance characteristics of the contact surfaces play an important role in the dynamic contact behavior.The appearance characteristics should be considered to reasonably evaluate the dynamic performance of the pantograph-catenary system.
基金supported by the projects SMARTRACKfunded by FCT with the contract PTDC/EMEPME/101419/2008 and PANTOTRAIN+1 种基金funded by the EC with the contract SC8-GA-2009-234015led by UNIFE
文摘A crucial system for the operation of high-speed trains is the pantograph catenary interface as it is the sole responsible to deliver electrical power to the train. Being the catenary a stationary system with a long lifespan it is also less likely to be redesigned and upgraded than the pantographs that fit the train vehicles. This letter proposes an optimization procedure for the improvement of the contact quality between the pantograph and the catenary solely based on the redesign of the pantograph head suspension characteristics. A pantograph model is defined and validated against experimental dynamic characteristics of existing pantographs. An optimization strategy based on the use of a global optimization method, to find the vicinity of the optimal solution, followed by the use of a deterministic optimization algorithm, to fine tune the optimal solution, is applied here. The spring stiffness, damping characteristics and bow mass are the design variables used for the pantograph optimization. The objective of the optimal problem is the minimization of the standard deviation of the contact force history, which is the most important quantity to define the contact quality. The pantograph head suspension characteristics are allowed to vary within technological realistic limits. It is found that current high-speed railway pantographs have a limited potential for mechanical improvements, not exceeding 10% 15% on the decrease of the standard deviation of the contact force. C 2013 The Chinese Society of Theoretical and Applied Mechanics. [doi：10.1063/2.1301306]
基金Projects(2018YFB1201801-4,2018YFB1201804-2)supported by National Key R&D Program of China。
文摘This study investigates the influence of different pantograph parameters and train length on the aerodynamic drag of high-speed train by the delayed detached eddy simulation(DDES) method. The train geometry considered is the high-speed train with pantographs, and the different versions have 3, 5, 8, 10, 12, 16 and 17 cars. The numerical results are verified by the wind tunnel test with 3.6% difference. The influences of the number of cars and the position, quantity and configuration of pantographs on flow field around high-speed train and wake vortices are analyzed. The aerodynamic drag of middle cars gradually decreases along the flow direction. The aerodynamic drag of pantographs decreases with its backward shift, and that of the first pantograph decreases significantly. As the number of pantographs increases, its effect on the aerodynamic drag decrease of rear cars is more significant. The engineering application equation for the aerodynamic drag of high-speed train with pantographs is proposed. For the 10-car and 17-car train, the differences of total aerodynamic drag between the equation and the simulation results are 1.2% and 0.4%, respectively. The equation generalized in this study could well guide the design phase of high-speed train.
基金supported by the High-Speed Railway Basic Research Fund Key Project of China(Grant No.U1234208)the National Natural Science Foundation of China(Grant Nos.51475394 and 51605397)
文摘To study the influence of the pantograph fixing position on aerodynamic characteristics of high-speed trains, the aerodynamic models of high-speed trains with eight cars were established based on the theory of com- putational fluid dynamics, and eight cases with pantographs fixed on different positions and in different operational orientations were considered. The pantographs were fixed on the front or the rear end of the first middle car or fixed on the front or the rear end of the last middle car. The external flow fields of the high-speed trains were numeri- cally simulated using the software STAR-CCM＋. The results show that the pantograph fixing position has little effect on the aerodynamic drag force of the head car and has a large effect on the aerodynamic drag force of the tail car. The influences of the pantograph fixing position on the aerodynamic lift forces of the head car, tail car and pan- tographs are obvious. Among the eight cases, considering the total aerodynamic drag force of the train and the aerodynamic lift force of the lifted pantograph, when the pantographs are fixed on the rear end of the last middle car and the lifted pantograph is in the knuckle-upstream ori- entation, the aerodynamic performance of the high-speed train is the best.
基金supported by Sichuan Science and Technology Program(No.2019YJ0227)China Postdoctoral Science Foundation(No.2019M663550)+1 种基金Self-determined Project of State Key Laboratory of Traction Power(2019TPL_T02)the National Key Research and Development Program of China(2018YFF0215602).
文摘Pantograph is a critical component of the high-speed train.It collects power through contact with catenary,which significantly affects the running safety of the train.Pantograph with double collector strips is one common type.The aerodynamic performance of the collector strips may affect the current collection of the pantograph.In this study,the aerodynamic performance of the pantograph with double strips is investigated.The numerical results are consistent with the experimental ones.The error in the aerodynamic drag force of the pantograph between numerical and experimental results is less than 5%.Three different conditions of the strips are studied,including the front strip,the rear strip,and the double strips.Results show that the presence of the front strip will affect the lift force of the rear strip,and reduce the resistance of the rear strip under the opening condition.Meanwhile,the rear strip has few effects on the front strip under the opening operation condition.The law of the resistance for the interaction between two strips under the closing condition is similar to the opening one.
