Static and Dynamic Characteristics of Superconducting Magnetic Force and Hydrostatic Fluid Film Force Compound Bearings

This paper took the new generation of liquid rocket engine turbo pump as the application prospect. In order to resolve the status that the reliability of the mechanical contact type bearings can't be guaranteed, the YBCO superconducting circular pad was introduced with the basis of existing fluid lubrication thrust bearings, and a kind of thrust bearing composited by superconducting magnetic force and hydrostatic fluid film force was proposed. This compound bearing was constituted of six superconducting circular pads and six liquid circular thrust pads with orifice restrictor, which were uniformly and alternately arranged on the bearing seat. With the support of cryogenic medium (such as liquid hydrogen and oxygen) in the rocket turbine pump, the recombination of superconductive repulsive force and liquid hydrostatic pressure was realized. Because of the weak coupling property between hydrostatic pressure and superconducting magnetic force, the bearing characteristics of the compound bearing were analyzed based on the decoupled analysis method. The performance of composite bearing was obtained by superposition with separated bearing characteristics of superconducting bearing and fluid bearing. The influence of structure parameters on the bearing capacity and stiffness were studied, e.g. throttle diameter, fluid cavity diameter. Around the designed working point, the carrying capacity of superconducting thrust pads and fluid lubrication thrust pads were almost equal, and the stiffness of the latter was 300 times higher than the former. The theoretical result shows that this compound bearing can avoid the contact friction in the start and stop process of turbo pump, but also maintain a high stiffness in the working stage to resist impact load. The research of this paper has reference value for the design of high reliability shafting structure of high speed rocket turbine pump.