Electromagnetic drag forces between HTS magnet and tube infrastructure for hyperloop

Maglevs are typically accelerated using electromagnetic propulsion and levitation. High-temperature superconducting (HTS) magnets along with electrodynamic suspension (EDS) and linear synchronous motors are one of the best options for Hyperloop. However, the strong magnetic fields generated by HTS magnets on the pods inevitably interact with the magnetic and conductive structures in the vacuum tubes, along with the tube itself, while the pods move through the tubes. This interaction is observed as a drag force on the pods, significantly reducing the propulsion efficiency. This study comprehensively analyzes the electromagnetic drag force (EDF) generated by HTS magnets on pods, which accounts for most of the drag forces faced by Hyperloop. Theoretical analysis and 3D FEA simulations are performed to analyze the propulsion forces with HTS magnets and all the drag forces on the pods. The EDF generated by AISI 1010 steel rebars in concrete guideways is even greater than the designed propulsion forces of 40 kN. Consequently, high-manganese (Hi-Mn) steel and insulated steel rebars are adopted and analyzed using 3D FEA simulations. The EDFs generated by the AISI 1010 steel and Hi-Mn steel vacuum tubes are determined by varying the distance between the HTS magnets and tubes at 50 and 1200 km/h, respectively; a minimum distance of 0.75 m is determined by a drag force below 8 kN within their operating velocities. Lastly, the total EDFs of the AISI 1010 steel and Hi-Mn steel tubes with EDS rails are obtained through the optimal design of rebars and tubes. The simulation results show that the total EDFs can be significantly reduced to below 10 kN (approximately 25% of the designed propulsion force after the levitation of pods).