Aerodynamic Simulation of Evacuated Tube Transport Trains With Suction at Tail

Pandey, Brijesh; Mukherjea, S. K.

doi:10.1115/imece2014-37904

Cited by 7 publications

(4 citation statements)

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“…In designing of a Hyperloop system, aerodynamic limitations such as drag become critical issues. Drag is one of the most important parameters in the analysis of objects moving at very high speed, especially within confined tubes [4,5]. Lower drag in a Hyperloop system not only drastically reduces construction and operation cost, but also minimizes the energy load of propulsion system.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Aerodynamic Characteristics of Hyperloop System

Kang

Ham

et al. 2019

Energies

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The Hyperloop system is a new concept that allows a train to travel through a near-vacuum tunnel at transonic speeds. Aerodynamic drag is one of the most important factors in analyzing such systems. The blockage ratio (BR), pod speed/length, tube pressure, and temperature affect the aerodynamic drag, but the specific relationships between the drag and these parameters have not yet been comprehensively examined. In this study, we investigated the flow phenomena of a Hyperloop system, focusing on the effects of changes in the above parameters. Two-dimensional axisymmetric simulations were performed in a large parameter space covering various BR values (0.25, 0.36), pod lengths (10.75–86 m), pod speeds (50–350 m/s), tube pressures (~100–1000 Pa), and tube temperatures (275–325 K). As BR increased, the pressure drag was significantly affected. This is because of the smaller critical Mach number for a larger BR. As the pod length increased, the total drag and pressure drag did not change significantly, but there was a considerable influence on the friction drag. As the pod speed increased, strong shock waves occurred near the end of the pod. At this point, the flows around the pod were severely choked at both BR values, and the ratio of the pressure drag to the total drag converged to its saturation level. At tube pressures above 500 Pa, the friction drag increased significantly under the rapidly increased turbulence intensity near the pod surface. High tube temperatures increase the speed of sound, and this reduces the Mach number for the same pod speed, consequently delaying the onset of choking and reducing the aerodynamic drag. The results presented in this study are applicable to the fundamental design of the proposed Hyperloop system.

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Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Aerodynamic Characteristics of Hyperloop System

Kang

Ham

et al. 2019

Energies

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“…ii. Pandey and Mukherjea [32] stated that for Mach number (M) < 0.3 the assumption was taken that the flow inside the tube is incompressible. For M>0.3 the flow inside the tube was compressible.…”

Section: Basic Assumptionsmentioning

confidence: 99%

CFD Simulation on Aerodynamic Performance of Hyperloop Vehicle

Murty

Pabsetti

Bhoje

et al. 2023

ARFMTS

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Aerodynamic drag is one of the most opposing factors for ground vehicle. This becomes even more difficult while travelling through a tunnel. The Evacuated- Tube Trains (ETTs) or Hyperloop’s are a new concept of ground transportation presently being developed by many different companies. The main purpose of an Hyperloop can be displayed as a cheaper medium of ground transport, which could allow its consumers to propagate to different places at a cheaper and faster rate compared to the present day locomotives and road transport. Passengers can travel at over 700 mph in floating capsules that swoop along within gigantic low-pressure tubes that are either below or above surface. This study analyses the Hyperloop designs using Computational Fluid Dynamics software ANSYS FLUENT. The effects of operating speed, Capsule shape and internal tube pressure have been studied in this paper. The flow inside the tube is considered as turbulent and incompressible. The software simulation results show the significant effects of inside pressure and operating speed on the aerodynamic drag of the capsule. Study with different shapes for the Capsule’s front and rear end suggest the most optimum shape for least aerodynamic drag.

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“…Conventional trains inside tunnels, ETTs, and hyperloops all involve the analysis of moving objects at high speeds within a confined space. In this environment, two main sources provoke drag [10,11]. One of them is the choking of the flow when the local Mach number reaches its critical level.…”

Section: Introductionmentioning

confidence: 99%

CFD Simulation of a Hyperloop Capsule Inside a Low-Pressure Environment Using an Aerodynamic Compressor as Propulsion and Drag Reduction Method

Lluesma-Rodríguez

González²,

Hoyas

2021

Applied Sciences

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One of the most restrictive conditions in ground transportation at high speeds is aerodynamic drag. This is even more problematic when running inside a tunnel, where compressible phenomena such as wave propagation, shock waves, or flow blocking can happen. Considering Evacuated-Tube Trains (ETTs) or hyperloops, these effects appear during the whole route, as they always operate in a closed environment. Then, one of the concerns is the size of the tunnel, as it directly affects the cost of the infrastructure. When the tube size decreases with a constant section of the vehicle, the power consumption increases exponentially, as the Kantrowitz limit is surpassed. This can be mitigated when adding a compressor to the vehicle as a means of propulsion. The turbomachinery increases the pressure of part of the air faced by the vehicle, thus delaying the critical conditions on surrounding flow. With tunnels using a blockage ratio of 0.5 or higher, the reported reduction in the power consumption is 70%. Additionally, the induced pressure in front of the capsule became a negligible effect. The analysis of the flow shows that the compressor can remove the shock waves downstream and thus allows operation above the Kantrowitz limit. Actually, for a vehicle speed of 700 km/h, the case without a compressor reaches critical conditions at a blockage ratio of 0.18, which is a tunnel even smaller than those used for High-Speed Rails (0.23). When aerodynamic propulsion is used, sonic Mach numbers are reached above a blockage ratio of 0.5. A direct effect is that cases with turbomachinery can operate in tunnels with blockage ratios even 2.8 times higher than the non-compressor cases, enabling a considerable reduction in the size of the tunnel without affecting the performance. This work, after conducting bibliographic research, presents the geometry, mesh, and setup. Later, results for the flow without compressor are shown. Finally, it is discussed how the addition of the compressor improves the flow behavior and power consumption of the case.

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Aerodynamic Simulation of Evacuated Tube Transport Trains With Suction at Tail

Cited by 7 publications

References 0 publications

Numerical Analysis of Aerodynamic Characteristics of Hyperloop System

Numerical Analysis of Aerodynamic Characteristics of Hyperloop System

CFD Simulation on Aerodynamic Performance of Hyperloop Vehicle

CFD Simulation of a Hyperloop Capsule Inside a Low-Pressure Environment Using an Aerodynamic Compressor as Propulsion and Drag Reduction Method

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