Operation and Improvement of Liquid Nitrogen Pumps with Radial High- Temperature Superconductor Bearings

Abstract

This paper reviews the advantages of replacing the mechanical bearings of low-temperature pumps by radial high-temperature superconductor (HTS) bearings. Radial HTS bearings have the advantage of being non-abrasive, so that the working life is increased significantly. In this article, two types of liquid nitrogen pump with radial HTS bearings are proposed. To reduce heat leakage, one pump uses a permanent magnet (PM) coupling and the other uses a long hollow pipe coupling. Successful stable operation of these two pumps means that radial HTS bearings have the potential to be applied in liquid nitrogen pumps. Test results show that the flow rate is influenced mainly by rotational speed but not by the coupling component. Further designs of the two types of pump for practical applications are described, and their characteristics are analyzed: the pump with a PM coupling has lower heat leakage, whereas the pump with a long hollow pipe coupling can solve the force creep problem of the HTS bearing. The design of the pump with a long hollow pipe coupling is based on the pump that is already in practical use, and therefore has greater feasibility for practical applications. Finally, improvements of the liquid nitrogen pump by improving the structure of the pump and the performance of the radial HTS bearing are discussed.

Fluid Characteristics Analysis of the Lubricating Oil Film and the Wear Experiment Investigation of the Sliding Bearing

“…In order to improve the reliability of the sliding bearings, it is necessary to fully grasp the relationship between the fluid characteristics of the bearing oil film and bearing wear, while also exploring the distribution of the lubricating oil film and the wear of the bearing under high-speed rotation. Therefore, theoretical calculations and experiments with bearings are needed as well [6][7][8].…”

Influence of cooling temperature on load-carrying performance of a radial HTS magnetic bearing

“…High temperature superconducting (HTS) magnetic bearing can operate in the harsh environment of low temperature and negative pressure with low loss and self-stability. Therefore, it has been gradually applied in flywheel energy storage [1], cryogenic liquid pump [2], cold compressor [3] and some other cryogenic rotating machinery. At the same time, the HTS levitation system is a complex multiphysical field coupling system [4].…”

Analysis and testing of a superconducting maglev submersible cryogenic liquid pump

“…The cryogenic fluid medium of CLPs can provide an inherent cooling environment for SCs, so as to eliminate the use of dedicated refrigeration systems. In the literatures reporting the superconducting CLP, research work is focussed on the following aspects: SMBs for CLP [11][12][13][14], superconducting motors for CLP [15,16], and novel structure of superconducting CLPs [17,18]. Even so, most of these studies are at the stage of the conceptional design and experimental tests.…”