Numerical study on the impact of Mach number on the coupling effect of aerodynamic heating and aerodynamic pressure caused by a tube train

Enhancing resilience of DC microgrids with model predictive control based hybrid energy storage system

Numerical study on wave phenomena produced by the super high-speed evacuated tube maglev train

In this paper, we built a high-temperature superconducting (HTS) maglev vehicle-bridge coupled system model by Universal Mechanism (UM) software, and analyzed the vertical dynamics. The UM model is composed of two parts, the train subsystem involved three vehicles, and the flexible bridge with simple-supports. In the UM modeling system, the expression of levitation force and the parameters related to the maglev vehicle-bridge were indispensable. The levitation force of maglev vehicle was described by an exponential analytical expression simplified by the experimental results of four YBCO bulks above a Halbach permanent magnetic guideway. The parameters related to the maglev vehicle-bridge are based on experimental prototype. Based on the UM model, the vertical dynamic was simulated and analyzed with different bridge spans under different operating velocities. This subject is a basic study for understanding the unique dynamic characteristic of the HTS maglev vehicle-bridge system. The simulation results provided reference for the further design of the HTS maglev vehicle-bridge coupled system in different speed ranges.

Dynamic Simulation of the HTS Maglev Vehicle-Bridge Coupled System Based on Levitation Force Experiment

This paper discusses the traction performance of a single-side linear induction motor and a single-side coreless Halbach permanent magnet linear synchronous motor (PM-LSM) for the mid- and low-speed maglev train Based on a typical mid- and low-speed maglev transit system, the overall performance of the two kinds of propulsion motors was analyzed by the finite element method By comparing the performance of the single-side coreless Halbach PM-LSM at different magnetization direction of the PMs of the Halbach array, the optimal angle between the magnetization direction of two adjacent PMs was found In order to achieve the higher propulsion efficiency of the single-side coreless Halbach PM-LSM, various cross-sectional shapes of the conductor were analyzed The analytical results indicate that the coreless Halbach PM-LSM is more suitable for the mid- and low-speed maglev train in urban rail transit system

Study on High Efficiency Permanent Magnet Linear Synchronous Motor for Maglev

As a bellwether transportation mode, albeit with hot controversy, evacuated tube transport (ETT) can dramatically reduce air friction, and incorporating Maglev technology could also thoroughly eliminate wheel-rail friction. It is not difficult to imagine that incorporation of these two technologies could establish an innovative transportation system, with particular advantages in terms of high speed, safety, energy saving, and environmental protection. The integration of these two technologies has been a great challenge, however, due to the composite technology. To realize this revolutionary idea, we have successfully developed the first proof-of-principle prototype of a 45-m-long high-temperature superconducting Maglev evacuated tube transport (HTS Maglev-ETT) test system, called the “Super-Maglev,” based on the passive self-stable HTS Maglev conceived in our group in 2000. The system mainly consists of three parts: an HTS Maglev-vehicle-guideway coupling system with 1-t load capability at a levitation gap of 10 mm, a 45-m-long racetrack-type evacuated tube with a 2-m-diameter circular cross section pumped by a hybrid air extraction system, and a 3-m linear induction motor to provide sectional propulsion. The system can achieve a pressure as low as 2.9 kPa in the tube. Experiments show that air drag on the vehicle is greatly reduced at that low air pressure, and a maximum speed of 50 km/h was recorded on the 6-m-diameter test guideway. Theoretically, the reduction of the aerodynamic consumed power could reach as high as to 90% under 10 kPa. This “Super-Maglev” strongly demonstrates the feasibility and potential merits of the HTS Maglev-ETT transportation concept.

A High-Temperature Superconducting Maglev-Evacuated Tube Transport (HTS Maglev-ETT) Test System

The permanent magnet guideway (PMG) is very important for the performance of the high temperature superconducting (HTS) system in terms of electromagnetic force and operational stability. The dynamic response characteristics of a HTS maglev model levitating on two types of PMG, which are the normal PMG with iron flux concentration and Halbach-type PMG, were investigated by experiments. The dynamic signals for different field-cooling heights (FCHs) and loading/unloading processes were acquired and analyzed by a vibration analyzer and laser displacement sensors. The resonant frequency, stiffness and levitation height of the model were discussed. It was found that the maglev model on the Halbach-type PMG has higher resonant frequency and higher vertical stiffness compared with the normal PMG. However, the low lateral stiffness of the model on the Halbach-type PMG indicates poor lateral stability. Besides, the Halbach-type PMG has better loading capacity than the normal PMG. These results are helpful to design a suitable PMG for the HTS system in practical applications.

Dynamic response characteristics of high temperature superconducting maglev systems: Comparison between Halbach-type and normal permanent magnet guideways

Dynamic response characteristics of the high-temperature superconducting maglev system under lateral eccentric distance

With the development of high temperature superconducting (HTS) maglev stepping in a key period of test line applications, the test and analysis of the dynamic operation parameters become more and more crucial. In this paper, the dynamic operating characteristics of single-cryostat and multicryostat levitation systems were comparatively studied on a 45-m-long permanent magnet guideway test line with different working conditions. Vibration acceleration signals of three levitation systems (a single cryostat, a bogie with two cryostats, and a car with four cryostats) were measured in the running experiments. The vibration characteristics were analyzed in both time domain and frequency domain. Results show that the multicryostat levitation system has better dynamic performance of stiffness than those of the single-cryostat system. The experimental data also indicates a positive correlation between the stability of the HTS maglev vehicle and the number of the cryostat. This work is helpful to understand the essential characteristics of HTS maglev vehicle system, and will be beneficial to the future design.

Dynamic Vibration Characteristics of HTS Levitation Systems Operating on a Permanent Magnet Guideway Test Line

In the high temperature superconducting maglev-evacuated tube transport (HTS Maglev-ETT) system, the air drag is the most principal resistance to the speed improvement and energy conservation. Considering the aerodynamic performance of the HTS Maglev-ETT system has great significance in practical application. As the first step, we experimentally explored the influence of velocity, blockage ratio and airshaft on the air drag of a running maglev vehicle at atmospheric pressure (95.6 kPa in Chengdu), coupled with the simulation by using the ANSYS-FLUENT software. The results preliminarily confirmed the feasibility of the aerodynamic experiments on the HTS maglev-ETT test system, as the drag is proportional to the blockage ratio and the square of velocity respectively. Moreover, airshafts are suggested to be added in the future design of the HTS Maglev-ETT system, aimed at its good relief on the air drag displayed in the experiment and simulation.

https://www.dpi-proceedings.com/index.php/dtetr/article/download/15646/15157

Bo Wang

Papers

A High-Temperature Superconducting Maglev-Evacuated Tube Transport (HTS Maglev-ETT) Test System

Dynamic response characteristics of high temperature superconducting maglev systems: Comparison between Halbach-type and normal permanent magnet guideways

Dynamic response characteristics of the high-temperature superconducting maglev system under lateral eccentric distance

Dynamic Vibration Characteristics of HTS Levitation Systems Operating on a Permanent Magnet Guideway Test Line

Preliminary Study of Aerodynamic Characteristics of High Temperature Superconducting Maglev-Evacuated Tube Transport System