scholarly journals Numerical simulation and analysis of aerodynamic drag on a subsonic train in evacuated tube transportation

2012 ◽  
Vol 20 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Yaoping Zhang
Keyword(s):  
Numerical Simulation ◽  
Aerodynamic Drag ◽  
Evacuated Tube Transportation ◽  
Evacuated Tube

Explicit Formula for Estimating Aerodynamic Drag on Trains Running in Evacuated Tube Transportation

2013 ◽  
Vol 307 ◽  
pp. 156-160
Author(s):  
Yao Ping Zhang
Keyword(s):  
Explicit Formula ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Research Work ◽  
Maglev Train ◽  
Isaac Newton ◽  
Fluent Software ◽  
Evacuated Tube Transportation ◽  
Theory Research ◽  
Evacuated Tube

Because of reducing aerodynamic drag, the maglev train could run at a high-speed in the partial vacuum tube. Scientists of some conutries such as U.S., Swiss and China, have started the research work on high-speed tube trains. In this situation, evacuated tube transportation aerodynamics becomes an important theory research aspect, in which the main study content is how to calculate aerodynamic drag. Based on the explicit formula for estimating aerodynamic drag on moving body in an infinite boundary surroundings put up by Isaac Newton, the evacuated tube surroundings is analyzed and the explicit formula with blockage ratio as an independent variable for estimating aerodynamic drag acted on trains running in the evacuated tube which is a finite space is deduced. With the calculation case, compared with the results came out from the explicit formula got in this paper and the results got by Fluent software, it was found that those results are closed. Thus, the explicit formula created in this paper for conveniently estimating aerodynamic drag based on trains running in evacuated tube transportation is credible.

Influence of Engine Cabin Simplification on Aerodynamic Characteristics of Car

2014 ◽  
Vol 1042 ◽  
pp. 188-193 ◽  
Author(s):  
Xing Jun Hu ◽  
Jing Chang
Keyword(s):  
Numerical Simulation ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
Thin Plates ◽  
Average Thickness ◽  
Two Dimensional ◽  
Engine Cooling ◽  
Aerodynamic Drag Coefficient ◽  
Simulation Results ◽  
The Impact

In order to analyze the impact of engine cabin parts on aerodynamic characteristics, the related parts are divided into three categories except the engine cooling components: front thin plates (average thickness of 2mm), bottom-suspension and interior panels. The aerodynamic drag coefficient (Cd) were obtained upon the combination schemes consisting of the three types of parts by numerical simulation. Results show that Cd by simulation is closer to the test value gained by the wind tunnel experiment when front thin plates were simplified to the two-dimensional interface with zero thickness. The error is only 5.23%. Meanwhile this scheme reduces grid numbers, thus decreasing the calculating time. As the front thin plates can guide the flow, there is no difference on the Cd values gained from the model with or without bottom-suspension or interior panels when the engine cabin contains the front thin plates; while only both bottom-suspension and interior panels are removed, the Cd value can be reduced when the cabin doesn’t contain the front thin plates.

Two Application Issues of High Temperature Superconducting Maglev in the Evacuated Tube Transportation

2011 ◽  
Vol 71-78 ◽  
pp. 4389-4393 ◽  
Author(s):  
Yao Ping Zhang ◽  
Jian Yue Yu ◽  
Yong Zhao ◽  
Ben Lin Liu
Keyword(s):  
High Temperature ◽  
Liquid Nitrogen ◽  
High Reliability ◽  
Relief Valve ◽  
High Temperature Superconducting ◽  
Energy Consuming ◽  
Evacuated Tube Transportation ◽  
Evacuated Tube ◽  
High Temperature Superconducting Maglev ◽  
Stability Energy

Based on some special merits such as self-stability, energy-consuming-efficiency, less pollution, high reliability, and so on, high temperature superconducting maglev (HTSM) is one of the promising potential technologies among present Maglev technologies for the future evacuated tube transportation (ETT). In this paper, the possibility, the merits, and the demerits of the applications of HTSM in ETT system are investigated. Especially, two application issues, liquid nitrogen vessel on the vehicle and isolated gate set in ETT, are discussed and solutions are suggested. On the first issue, this paper suggests to install a pressure relief valve on the sealed liquid nitrogen vessel so as to reduce the liquid nitrogen vaporization in the vacuum tube. As for the second issue, this paper recommends to use HTSM permanent magnet (PM) track structure with a streamline separated gap between the surface of track and the bottom of liquid nitrogen vessel. Those guideway structure could fit to the isolation gate setting in ETT.

Aerodynamic Simulation of Evacuated Tube Transport Trains With Suction at Tail

2014 ◽  
Author(s):  
Brijesh Kumar Pandey ◽  
Sujay Kumar Mukherjea
Keyword(s):  
Turbulence Modeling ◽  
Aerodynamic Drag ◽  
Ambient Pressure ◽  
Navier Stokes ◽  
Geometrical Shape ◽  
Two Dimensional Flow ◽  
Reduction Effect ◽  
Evacuated Tube Transport ◽  
Evacuated Tube ◽  
Additional Reduction

Steady Navier-Stokes (N-S) equations for two dimensional flow using standard k-ε turbulence modeling was solved with the help of FLUENT 14 software to simulate the flow around a train in an evacuated tunnel. Suction mechanism at the rear end was applied to study the additional reduction effect of the aerodynamic drag on the vehicle. It was observed that coefficient of drag was decreasing with the increase of suction speed. Similar investigations have also been performed by taking different shapes of the head and tail of the vehicle at the same blockage ratio under different pressures of evacuation. It was found that with the decrease of ambient pressure the aerodynamic drag reduced for any geometrical shape. Investigations have also been performed on the wake structure with respect to wake size.

Numerical Simulation of Evacuated Tube Solar Water Heaters

2012 ◽  
Author(s):  
Michele Pinelli ◽  
Alessio Suman ◽  
Michele Vanti
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Circulation Rate ◽  
Heat Distribution ◽  
Solar Water ◽  
Water Heaters ◽  
Reference Parameters ◽  
Solar Water Heaters ◽  
Evacuated Tube ◽  
Rayleigh Numbers

This paper evaluates the characteristics of water-in-glass evacuated tube solar water heaters including assessment of the circulation rate through single ended tubes. A numerical model of the fluid flow inside a single ended evacuated tube has been developed assuming no interaction between adjacent tubes in the collector array. The numerical model is firstly validated by means of literature data. Then, the performance in terms of circulation mass flow rate in different heat flux condition and at different inclination angle of the collector are evaluated. Moreover, a sensitivity analysis on the effect of the assumptions of different reference parameters and of the choice of the values of the fluid thermophysical properties is carried out and a quantitative analysis of the expected uncertainty is presented. Finally, an extension of previous literature correlations in terms of non-dimensional Reynolds and Rayleigh numbers is proposed. Regarding heating boundary conditions, the circumferential heat distribution was found to be an important parameter influencing the flow structure and circulation rate through the tube.

Numerical Research of Thermal-Pressure Coupling Effect on Blockage Ratio in the Evacuated Tude Transportation System

2013 ◽  
Vol 561 ◽  
pp. 454-459 ◽  
Author(s):  
Qing Ling Li ◽  
Wen Guang Jia ◽  
Chen Guang Dong ◽  
Rui Xiang Duan
Keyword(s):  
Coupling Effect ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Aerodynamic Heating ◽  
Blockage Ratio ◽  
Thermal Pressure ◽  
Navier Stokes Equation ◽  
Coupling Equations ◽  
Evacuated Tube Transportation ◽  
Evacuated Tube

According to the three-dimensional mathematical model and physical model of evacuated tube transportation(ETT) system, thermal-pressure coupling equations based on viscous fluid Navier-Stokes equation and k- ε turbulence model are established for the first time. The numerical simulation is carried out to investigate the inherent laws for different blockage ratios of ETT system. The simulation results show that: when the speed of the train and the pressure of the system are constants, in the temperature field, the aerodynamic heating is getting more as the blockage ratio increases, and its trend grows exponential. In the pressure field, with the increase of the blockage ratio, the stagnation pressure is gradually increased, but the growth is getting slower; vortex region pressure reduces gradually, and has accelerated the decreasing trend; the pressure difference between the head and the end of the train is linear increment.

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