Special Issue "Hyperloop and Associated Technologies"

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "Energy Fundamentals and Conversion".

Deadline for manuscript submissions: closed (20 December 2020).

Special Issue Editor

Dr. Adonios Karpetis
E-Mail Website
Guest Editor
Department of Aerospace Engineering, Texas A&M University, College Station, TX 778453-3141, USA
Interests: combustion; hyperloop; high-speed combustion/propulsion; modeling, simulation and optimization of energy systems; laser diagnostics for reacting flows; turbulent flames; space weather; supersonic flames

Special Issue Information

Dear colleagues,

The Hyperloop concept exploded in the public perception in 2015, after SpaceX inaugurated the eponymous design competition. The concept, which can be described succinctly as a sonic train that travels in an evacuated tube, was envisioned in a white paper written by Elon Musk in 2013. In the span of the few last years, since the first design competition that was held at the Texas A&M University in 2016, a number of academic institutions and industrial concerns proposed and constructed different Hyperloop designs, with the actual prototype implementation currently in its early stages.

For the Hyperloop concept to become a competitive mode of transportation at distances of 1000 km, the friction associated with all aspects of the problem must be minimized, as follows: contact friction wherever applicable, shear stress in the boundary layers surrounding the device, wave drag due to ensuing shocks, electromagnetic drag when magnetic levitation is used, and all other present sources of drag must be suppressed in order to minimize the level of required propulsive power. Hyperloop, then, introduces novel problems in areas of aerodynamics and fluid mechanics, turbomachinery, tribology, electromagnetism, power generation and battery management, dynamics and controls, propulsion and locomotion, and ergonomics, to name some of the more obvious ones.

Contributions are solicited in this Special Issue of Energies on all topics relevant to the Hyperloop concept as well as its associated technologies. All aspects, from academic research to specific, narrow topics with relevance to the concept, to the design and trade-off studies that examine the broader issues of its implementation, are necessary before Hyperloop becomes the “fifth mode of transportation” in the future; the Special Issue should reflect the same synergy.

Dr. Adonios Karpetis
Guest Editor

Manuscript Submission Information

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Keywords

  • hyperloop
  • levitation
  • electromagnetic suspension
  • transonic transport
  • high-speed rail
  • air bearings
  • maglev
  • Kantrowitz limit
  • wave drag

Published Papers (8 papers)

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Research

Open AccessArticle
Concepts of Hyperloop Wireless Communication at 1200 km/h: 5G, Wi-Fi, Propagation, Doppler and Handover
Energies 2021, 14(4), 983; https://doi.org/10.3390/en14040983 - 13 Feb 2021
Viewed by 413
Abstract
The new generation of capsules that circulate through vacuum tubes at speeds up to 1200 km/h, which is being developed, demands communication systems that can operate at these speeds with high capacity and quality of service. Currently, the two technologies available are the [...] Read more.
The new generation of capsules that circulate through vacuum tubes at speeds up to 1200 km/h, which is being developed, demands communication systems that can operate at these speeds with high capacity and quality of service. Currently, the two technologies available are the new generation of 802.11ax networks and 5G NR. Using these technologies at such high speeds in a confined environment requires a careful study and design of the configuration of the network and optimization of the physical interface. This paper describes the requirements for critical and business communications, proposing a WLAN and 5G network design based on the analysis of the propagation characteristics and constraints of vacuum tubes and using propagation measurements and simulations made in similar environments at frequencies of 2.5/5.7/24 GHz. These measurements and simulations show that propagation losses in this environment are low (4–5 dB/100 m), as a consequence of the guided propagation, so that the use of bands is preferred. Finally, considering the propagation constraints and requirements of a Hyperloop system, a complete wireless communication system is proposed using two networks with 802.11 and 5G technology. Full article
(This article belongs to the Special Issue Hyperloop and Associated Technologies)
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Open AccessArticle
Mitigating the Piston Effect in High-Speed Hyperloop Transportation: A Study on the Use of Aerofoils
Energies 2021, 14(2), 464; https://doi.org/10.3390/en14020464 - 16 Jan 2021
Viewed by 482
Abstract
The Hyperloop is a concept for the high-speed ground transportation of passengers traveling in pods at transonic speeds in a partially evacuated tube. It consists of a low-pressure tube with capsules traveling at both low and high speeds throughout the length of the [...] Read more.
The Hyperloop is a concept for the high-speed ground transportation of passengers traveling in pods at transonic speeds in a partially evacuated tube. It consists of a low-pressure tube with capsules traveling at both low and high speeds throughout the length of the tube. When a high-speed system travels through a low-pressure tube with a constrained diameter such as in the case of the Hyperloop, it becomes an aerodynamically challenging problem. Airflow tends to get choked at the constrained areas around the pod, creating a high-pressure region at the front of the pod, a phenomenon referred to as the “piston effect.” Papers exploring potential solutions for the piston effect are scarce. In this study, using the Reynolds-Average Navier–Stokes (RANS) technique for three-dimensional computational analysis, the aerodynamic performance of a Hyperloop pod inside a vacuum tube is studied. Further, aerofoil-shaped fins are added to the aeroshell as a potential way to mitigate the piston effect. The results show that the addition of fins helps in reducing the drag and eddy currents while providing a positive lift to the pod. Further, these fins are found to be effective in reducing the pressure build-up at the front of the pod. Full article
(This article belongs to the Special Issue Hyperloop and Associated Technologies)
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Open AccessArticle
Displacements of the Levitation Systems in the Vehicle Hyperloop
Energies 2020, 13(24), 6595; https://doi.org/10.3390/en13246595 - 14 Dec 2020
Viewed by 415
Abstract
The paper will present a mathematical model for the guideway as a continuous system, followed by a moving force coming from the capsule and the capsule as a discrete system. The theoretical problem selected for analysis comes from a group of technical problems, [...] Read more.
The paper will present a mathematical model for the guideway as a continuous system, followed by a moving force coming from the capsule and the capsule as a discrete system. The theoretical problem selected for analysis comes from a group of technical problems, which solve the dynamics of systems subjected to moving loads. Dynamic reactions in the system are described by a system of coupled partial and ordinary differential equations. Their solution was obtained using approximate numerical methods. The article concerns the analysis of Hyperloop vehicle guideway displacement in the occurrence of magnetic levitation phenomenon, which appears when starting, driving and braking the vehicle. The analysis was carried out using a numerical, three-dimensional model of the guideway. The results of the analysis are illustrated with calculation examples. The displacement of the guideway and magnet elements was determined by simulations. The simulations were conducted using MBS software. The presented results refer to the movements of the capsule of Hyperloop vehicles. Full article
(This article belongs to the Special Issue Hyperloop and Associated Technologies)
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Open AccessArticle
A Concept of Integration of a Vactrain Underground Station with the Solidarity Transport Hub Poland
Energies 2020, 13(21), 5737; https://doi.org/10.3390/en13215737 - 02 Nov 2020
Cited by 1 | Viewed by 672
Abstract
This paper provides an analysis of a designed underground station infrastructure for vacuum tube high-speed trains for the planned mega transport hub in Poland. The potential of integrating the infrastructure of the station building with sealed low-pressure tubes system is analyzed. The Solidarity [...] Read more.
This paper provides an analysis of a designed underground station infrastructure for vacuum tube high-speed trains for the planned mega transport hub in Poland. The potential of integrating the infrastructure of the station building with sealed low-pressure tubes system is analyzed. The Solidarity Transport Hub Poland is a planned mega hub to be located in Baranów Municipality, Poland, which is comprised of an airport, an airport city, a road, and railway infrastructure. It is to be integrated with the first route of vactrains in Poland. The aim of this paper is to design a hyperloop station building adequate for the advanced technology of low-pressure high-speed trains. Designing a hyperloop station is not trivial, due to technological aspects which have not been hitherto present in airport or railway planning and design, such as low-pressure zones or airlocks which determine possible passenger paths and evacuation roads. Both the mega airport and Polish hyperloop are in the planning stage, therefore, in this paper, available models and designs of the hyperloop station building and infrastructure are used in order to formulate recommendations for further development and identify critical issues related to the safety and reduction of passenger transit time. The main contribution of this paper is a model of the hyperloop station building which respects the principles of spatial planning and safety standards. Full article
(This article belongs to the Special Issue Hyperloop and Associated Technologies)
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Open AccessArticle
Design Model of Null-Flux Coil Electrodynamic Suspension for the Hyperloop
Energies 2020, 13(19), 5075; https://doi.org/10.3390/en13195075 - 28 Sep 2020
Viewed by 573
Abstract
The Hyperloop has been developed using various technologies to reach a maximum speed of 1200 km/h. Such technologies include magnetic levitation technologies that are suitable for subsonic driving. In the Hyperloop, the null-flux electrodynamic suspension (EDS) system and superconducting magnets (SCMs) can perform [...] Read more.
The Hyperloop has been developed using various technologies to reach a maximum speed of 1200 km/h. Such technologies include magnetic levitation technologies that are suitable for subsonic driving. In the Hyperloop, the null-flux electrodynamic suspension (EDS) system and superconducting magnets (SCMs) can perform stable levitation without control during high-speed driving. Although an EDS device can be accurately analyzed using numerical analysis methods, such as the 3D finite element method (FEM) or dynamic circuitry theory, its 3D configurations make it difficult to use in various design analyses. This paper presents a new design model that fast analyzes and compares many designs of null-flux EDS devices for the Hyperloop system. For a fast and effective evaluation of various levitation coil shapes and arrangements, the computational process of the induced electromotive force and the coupling effect were simplified using a 2D rectangular coil loop, and the induced current and force equations were written as closed-form solutions using the Fourier analysis. Also, levitation coils were designed, and their characteristics were analyzed and compared with each other. To validate the proposed model, the analyzed force responses for various driving conditions and the changed performance trend by design variables were compared with analyzed FEM results. Full article
(This article belongs to the Special Issue Hyperloop and Associated Technologies)
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Open AccessArticle
Concepts on Train-to-Ground Wireless Communication System for Hyperloop: Channel, Network Architecture, and Resource Management
Energies 2020, 13(17), 4309; https://doi.org/10.3390/en13174309 - 20 Aug 2020
Viewed by 678
Abstract
Hyperloop is envisioned as a novel transportation way with merits of ultra-high velocity and great traveling comforts. In this paper, we present some concepts on the key technologies dedicated to the train-to-ground communication system based on some prevailing fifth-generation communication (5G) technologies from [...] Read more.
Hyperloop is envisioned as a novel transportation way with merits of ultra-high velocity and great traveling comforts. In this paper, we present some concepts on the key technologies dedicated to the train-to-ground communication system based on some prevailing fifth-generation communication (5G) technologies from three aspects: wireless channel, network architecture, and resource management. First, we characterize the wireless channel of the distributed antenna system (DAS) using the propagation-graph channel modelling theory. Simulation reveals that a drastic Doppler shift variation appears when crossing the trackside antenna. Hence, the leaky waveguide system is a promising way to provide a stable receiving signal. In this regard, the radio coverage is briefly estimated. Second, a cloud architecture is utilized to integrate several successive trackside leaky waveguides into a logical cell to reduce the handover frequency. Moreover, based on a many-to-many mapping relationship between distributed units (DUs) and centralized units (CUs), a novel access network architecture is proposed to reduce the inevitable handover cost by using the graph theory. Simulation results show that this scheme can yield a low handover cost. Then, with regards to the ultra-reliable and low latency communication (uRLLC) traffic, a physical resource block (PRB) multiplexing scheme considering the latency requirements of each traffic type is exploited. Simulation presents that this scheme can maximize the throughput of non-critical mission communication services while guaranteeing the requirements of uRLLC traffic. Finally, in terms of the non-critical mission communication services, two cache-based resource management strategies are proposed to boost the throughput and reduce the midhaul link burden by pre-fetching and post-uploading schemes. Simulation demonstrates that the cache-based schemes can boost the throughput dramatically. Full article
(This article belongs to the Special Issue Hyperloop and Associated Technologies)
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Open AccessArticle
Sub-Sonic Linear Synchronous Motors Using Superconducting Magnets for the Hyperloop
Energies 2019, 12(24), 4611; https://doi.org/10.3390/en12244611 - 04 Dec 2019
Cited by 6 | Viewed by 1196
Abstract
Sub-sonic linear synchronous motors (LSMs) with high-temperature superconducting (HTS) magnets, which aim to accelerate to a velocity of 1200 km/h in the near-vacuum tubes of 0.001 atm for the Hyperloop, are newly introduced in this paper. By the virtue of the combination of [...] Read more.
Sub-sonic linear synchronous motors (LSMs) with high-temperature superconducting (HTS) magnets, which aim to accelerate to a velocity of 1200 km/h in the near-vacuum tubes of 0.001 atm for the Hyperloop, are newly introduced in this paper. By the virtue of the combination of LSMs and electrodynamic suspensions (EDSs) with HTS magnets, a large air-gap of 24 cm, low magnetic resistance forces of below 2 kN, and the efficient as well as practical design of propulsion power supply systems of around 10 MVA could be guaranteed at a sub-sonic velocity. The characteristics of the proposed LSMs with HTS magnets, in addition, are widely analyzed with theories and simulation results. Optimal design methods for LSMs and inverters, which account for more than half of the total construction cost, are introduced with design guidelines and examples for the commercialization version of the Hyperloop. At the end of the paper, in order to verify the proposed design models of the sub-sonic LSMs, two different test-beds—i.e., 6 m long static and 20 m long dynamic propulsion test-beds—are fabricated, and it is found that the experimental results are well matched with proposed design models as well as simulation results; therefore, the design methods constitute guidelines for the design of sub-sonic LSMs for the Hyperloop. Full article
(This article belongs to the Special Issue Hyperloop and Associated Technologies)
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Open AccessArticle
Levitation Methods for Use in the Hyperloop High-Speed Transportation System
Energies 2019, 12(21), 4190; https://doi.org/10.3390/en12214190 - 02 Nov 2019
Cited by 6 | Viewed by 1465
Abstract
The Hyperloop system offers the promise of transportation over distances of 1000 km or more, at speeds approaching the speed of sound, without the complexity and cost of high-speed trains or commercial aviation. Two crucial technological issues must be addressed before a practical [...] Read more.
The Hyperloop system offers the promise of transportation over distances of 1000 km or more, at speeds approaching the speed of sound, without the complexity and cost of high-speed trains or commercial aviation. Two crucial technological issues must be addressed before a practical system can become operational: air resistance, and contact/levitation friction must both be minimized in order to minimize power requirements and system size. The present work addresses the second issue by estimating the power requirements for each of the three major modes of Hyperloop operation: rolling wheels, sliding air bearings, and levitating magnetic suspension systems. The salient features of each approach are examined using simple theories and a comparison is made of power consumption necessary in each case. Full article
(This article belongs to the Special Issue Hyperloop and Associated Technologies)
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