利用火箭发动机涡轮泵机械密封所处的低温工况，设计静环上嵌有圆形YBCO超导块材的机械密封结构。该机械密封在工作时静环和动环之间同时产生动压液膜力和超导磁斥力，可增大机械密封端面的轴向承载力，避免小间隙下的磨损。利用超导磁力计算模型和磁斥力检测系统，从理论和试验2个角度研究YBCO块材超导磁力大小随间隙的变化；建立含超导磁力的机械密封性能计算模型，对导磁液复合机械密封的承载力、泄漏量、膜厚和摩擦阻力矩等进行计算仿真。研究结果表明：YBCO超导导块可在间隙为5~30 μm时为机械密封提供784~896 N的超导磁力；在转速为10 000~35 000 r/min时，受超导磁力的影响，机械密封的承载力平均增大了896 N，泄漏量平均增大了0.72 mL/s，膜厚平均增加了2.8 μm，摩擦阻力矩平均降低了0.47 N·m。承载力和膜厚的增大以及摩擦阻力矩的降低，有助于减小机械密封在极端工况下因启动和停止而产生的磨损，提高了其寿命。
A mechanical seal with circular YBCO superconducting blocks embedded in the static ring was designed,utilizing the low temperature condition of the rocket engine turbine pump mechanical seal.This mechanical seal generates both dynamic pressure liquid membrane force and superconducting magnetic repulsion force between the static and dynamic rings during operation,which can increase the axial bearing capacity of the mechanical seal face and avoid wear under small gaps.Based on the superconducting magnetic force calculation model and magnetic repulsive force detection system,the variation of superconducting magnetic force of YBCO block with gaps was studied theoretically and experimentally.The calculation model of the mechanical seal performance with superconducting magnetic force was established,and the opening force,leakage,film thickness and friction resistance moment of the magnetic fluid composite mechanical seal were simulated.The results show that the designed YBCO superconducting block can provide 784 N to 896 N superconducting magnetic force for the mechanical seal at a gap from 5 μm to 30 μm.At the speeds from 10 000 r/min to 35 000 r/min, the opening force of the mechanical seal with superconducting magnetic force increases by 896 N on average,the leakage increases by 0.72 mL/s on average,the film thickness increases by 2.8 μm on average,and the friction resistance torque decreases by 0.47 N·m on average.The increase in bearing capacity and film thickness,as well as the decrease in friction resistance moment,helps to reduce the wear of mechanical seals caused by starting and stopping under extreme working conditions,thereby improving their lifespan.
WANG Xiaoli, SHANG Xuemei, LIU Xi, BAI Lifeng, ZHAO Weigang, JIA Qian. Simulation Study on Mechanical Seal Performance of Turbo Pump with Superconducting Magnetic Force and Liquid Film Force[J]. Lubrication Engineering,2023,48(10):8-13.