Helium damping characteristics of rotating superconducting rotor

Abstract

The superconducting rotor magnetic levitation device can be used to make an angular velocity sensor, and the high-speed rotating superconducting rotor is the basis for achieving high-precision measurement of the superconducting rotor magnetic levitation device. The heat loss and radial mass eccentricity of the superconducting rotor can cause thermal quenching and resonance in the driving process, which is unfavorable to the driving process of the superconducting rotor. Therefore, it is necessary to maintain a certain quantity of helium gas in the superconducting cavity in the driving process, to transfer the heat generated by the driving process and avoid its resonance. But helium gas also has a drag torque on the rotating superconducting rotor, affecting the driving process of the superconducting rotor. Based on this, the drag torque of the helium on the rotating superconducting rotor is studied. Firstly, the Van der Waals equation is introduced to analyze the properties of low-temperature helium, and a method of studying the drag effect of low-temperature helium on the rotating superconducting rotor is proposed based on Reynolds law and Stoke’s first problem. Then, an experiment on superconducting rotor speed attenuation is conducted to verify the proposed analysis method. Based on the finite element method, the driving electromagnetic structure and driving torque of the superconducting rotor are analyzed. Finally, the influence of helium on the driving process of the superconducting rotor is investigated, including critical driving speed, acceleration time of the superconducting rotor, and frictional heat of the helium on the superconducting rotor. The research results further enrich the study of the drag torque of low-temperature gases on rotating superconductors, providing a reference for further optimizing the driving process of superconducting rotors.