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Effect of Streamlined Nose Length on the Aerodynamic Performance of a 800 km/h Evacuated Tube Train 被引量:13
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作者 Xiaohan Zhang Yao Jiang Tian Li 《Fluid Dynamics & Materials Processing》 EI 2020年第1期67-76,共10页
The aerodynamic resistance of a train running in the open air limits the maximum speed that can be attained by the train.For this reason,evacuated tube trains(ETT)are being considered as valid alternatives to be imple... The aerodynamic resistance of a train running in the open air limits the maximum speed that can be attained by the train.For this reason,evacuated tube trains(ETT)are being considered as valid alternatives to be implemented in the future.The atmosphere in the tube,the so-called blocking ratio and the length of the streamlined nose are the key factors affecting the aerodynamic performances of these trains.In the present work,we investigate evacuated tube trains with different lengths of the streamline nose on the basis of computational fluid dynamics(CFD).The three-dimensional steady compressible Navier-Stokes equations are solved.The running speed of the ETT is 800 km/h and the blocking ratio is 0.2.Results show that with the increase of the streamlined nose length,the aerodynamic drag and lift forces of the head car decrease gradually,and the drag and lift forces of the middle car change slightly.For the tail car,the drag force decreases,whereas the absolute value of the lift force increases.At a speed of 800 km/h,a slight shock wave appears at the rear of the tail car,which affects the aerodynamic forces acting on the train. 展开更多
关键词 Evacuated tube train RESISTANCE aerodynamic performance streamlined nose
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Aerodynamic Design of a Subsonic Evacuated Tube Train System 被引量:5
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作者 Tian Li Xiaohan Zhang +1 位作者 Yao Jiang Weihua Zhang 《Fluid Dynamics & Materials Processing》 EI 2020年第1期121-130,共10页
The so-called Evacuated Tube Train(ETT)is currently being proposed as a high-speed transportation system potentially competitive with airplane transportation.Aerodynamic resistance is one of the most crucial factors f... The so-called Evacuated Tube Train(ETT)is currently being proposed as a high-speed transportation system potentially competitive with airplane transportation.Aerodynamic resistance is one of the most crucial factors for the successful design of an ETT.In the present work,a three-dimensional concept ETT model has been elaborated.The aerodynamic characteristics of the subsonic ETT have been numerically simulated under different conditions.The train’s running speed varies from 600 km/h up to 1200 km/h,and the blockage ratio is in the range between 0.1 and 0.3.As the blocking ratio and running speed increase,the resistance of the head car increases greatly,while the resistance of the middle car changes slightly.The aerodynamic resistance of the tail car is affected by the shock wave emerging in the wake flow.Two different design criteria for the maximum allowed aerodynamic resistance are proposed for aerodynamic parameter matching.With an increase in the blockage ratio and running speed,the atmospheric pressure in the tube should be decreased to achieve a balance. 展开更多
关键词 Evacuated tube train aerodynamic resistance blockage ratio shock wave
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Aerodynamic simulation of evacuated tube maglev trains with different streamlined designs 被引量:12
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作者 Xuyong CHEN Lifeng ZHAO +1 位作者 Jiaqing MA Yuansen LIU 《Journal of Modern Transportation》 2012年第2期115-120,共6页
Based on the Navier-Stokes (N-S) equations of incompressible viscous fluids and the standard k-ε turbu- lence model with assumptions of steady state and two dimensional conditions, a simulation of the aerodynamic d... Based on the Navier-Stokes (N-S) equations of incompressible viscous fluids and the standard k-ε turbu- lence model with assumptions of steady state and two dimensional conditions, a simulation of the aerodynamic drag on a maglev train in an evacuated tube was made with ANSYS/FLOTRAN software under different vacuum pressures, blockage ratios, and shapes of train head and tail. The pressure flow fields of the evacuated tube maglev train under different vacuum pressures were analyzed, and then compared under the same blockage ratio condition. The results show that the environmental pressure of 1 000 Pa in the tube is the best to achieve the effect of aerodynamic drag reduction, and there are no obvious differences in the aerodynamic drag reduction among different streamline head shapes. Overall, the blunt-shape tail and the blockage ratio of 0.25 are more efficient for drag reduction of the train at the tube pressure of 1 000 Pa. 展开更多
关键词 aerodynamic drag evacuated tube maglev train blockage ratio train head and tail
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The approach to calculate the aerodynamic drag of maglev train in the evacuated tube 被引量:10
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作者 Jiaqing Ma Dajing Zhou +2 位作者 Lifeng Zhao Yong Zhang Yong Zhao 《Journal of Modern Transportation》 2013年第3期200-208,共9页
In order to study the relationships between the aerodynamic drag of maglev and other factors in the evacuated tube, the formula of aerodynamic drag was deduced based on the basic equations of aerodynamics and then the... In order to study the relationships between the aerodynamic drag of maglev and other factors in the evacuated tube, the formula of aerodynamic drag was deduced based on the basic equations of aerodynamics and then the calculated result was confirmed at a low speed on an experimental system developed by Superconductivity and New Energy R&D Center of South Jiaotong University. With regard to this system a high temperature superconducting magnetic levitation vehicle was motivated by a linear induction motor (LIM) fixed on the permanent magnetic guideway. When the vehicle reached an expected speed, the LIM was stopped. Then the damped speed was recorded and used to calculate the experimental drag. The two results show the approximately same relationship between the aerodynamic drag on the maglev and the other factors such as the pressure in the tube, the velocity of the maglev and the blockage ratio. Thus, the pressure, the velocity, and the blockage ratio are viewed as the three important factors that contribute to the energy loss in the evacuated tube transportation. 展开更多
关键词 Evacuated tube Maglev train Aerodynamic drag Pressure in the tube
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An Aerothermal Study of Influence of Blockage Ratio on a Supersonic Tube Train System 被引量:5
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作者 SUI Yang NIU Jiqiang +4 位作者 YUAN Yanping YU Qiujun CAO Xiaoling WU Dan YANG Xiaofeng 《Journal of Thermal Science》 SCIE EI CAS CSCD 2022年第2期529-540,共12页
Evacuated tube transportation is an important development direction for the high-speed transportation technology of the future.However,a train running at supersonic speed in a closed tube can create an unstable aeroth... Evacuated tube transportation is an important development direction for the high-speed transportation technology of the future.However,a train running at supersonic speed in a closed tube can create an unstable aerothermal phenomenon,causing the temperature to rise sharply inside the tube and endangering the safe operation of trains and equipment.The blockage ratio is one of the key factors affecting the aerodynamic characteristics in the tube.In this paper,a 2 D axisymmetric model and Delayed Detached Eddy Simulation(DDES)based on the Shear Stress Transport(SST)k-ωturbulence model are used to study the aerothermal environment in the tube.The calculation method used in this paper was verified by a wind tunnel experiment.The aerothermal phenomenon and distribution of the flow field in the tube with different blockage ratios were compared and analysed.The results show that the aerothermal environment is significantly affected by the blockage ratio.A choking limit formed in the flow field will aggravate the aerodynamic phenomenon as the blockage ratio increases,which further deteriorates the aerothermal environment of the tube.Moreover,the existence of the choking limit,shock wave,and Mach disk make the flow field in the tube more complicated. 展开更多
关键词 tube train aerothermal environment blockage ratio choking limit numerical simulation
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Numerical study on the influence of initial ambient temperature on the aerodynamic heating in the tube train system 被引量:13
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作者 Shijie Bao Xiao Hu +3 位作者 Jukun Wang Tianhao Ma Yingyu Rao Zigang Deng 《Advances in Aerodynamics》 2020年第1期579-596,共18页
The evacuated tube transportation has great potential in the future because of its advantages of energy saving and environmental protection.The train runs in the closed tube at ultra-high speed.The heat quantity gener... The evacuated tube transportation has great potential in the future because of its advantages of energy saving and environmental protection.The train runs in the closed tube at ultra-high speed.The heat quantity generated by aerodynamic heating is not easy to spread to external environment and then accumulates in the tube,inducing the ambient temperature in the tube to rise gradually.In this paper,a three-dimensional geometric model and the Shear Stress Transport(SST)κ-ωturbulence model are used to study the influence of initial ambient temperature on the structure of the flow field in the tube.Simulation results show that when the train runs at transonic speed,the supersonic flow region with low temperature and low-pressure is produced in the wake.The structure of the flow field of the wake will change with the initial ambient temperature.And the higher the initial ambient temperature is,the shorter the low temperature region in the wake will be.The larger temperature difference caused by the low temperature region may increase the temperature stress of the tube and affect the equipment inside the tube.Consequently,the temperature inside the tube can be maintained at a reasonable value to reduce the influence of the low temperature region in the wake on the system. 展开更多
关键词 tube train Initial ambient temperature Aerodynamic heating Numerical simulation
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