Abstract: In order to solve the problems of lubricant oil leakage at the shaft end of crankcase on large marine diesel engines, the leakage behavior of labyrinth seals under gas-liquid two-phase conditions was studied by numerical simulation and experiments. In order to reveal the sealing mechanism and leakage law of labyrinth seals in gas-liquid two-phase environments, the flow field in labyrinth seals was calculated by using FLUENT, and the DPM was used to analyze the escape behavior of oil droplets. The sealing structure and the working conditions were built based on a test rig, and the oil leakage rate was measured under different rotating speeds, the functions of different structural features of the shaft end seals were studied, and finally two effective improvement measures were given. The results show that the staggered labyrinth structure may significantly reduce the air leakage compared with the straight labyrinth. The outward transport on liquid phase by air are greatly weaken by adding staggered labyrinth. In addition, the oil leakage may be significantly reduced by appropriately using labyrinth structure to return oil.

Key words: labyrinth seal, two-phase flow, discrete phase model(DPM), staggered labyrinth

摘要： 为解决大型船用柴油机曲轴箱轴端漏油问题，通过仿真和试验对气液两相条件下迷宫密封的泄漏行为开展研究。基于FLUENT软件进行迷宫密封流场仿真，利用离散相模型开展油滴逃逸行为分析，揭示迷宫密封在气液两相环境中的密封机理和泄漏规律。在试验器上模拟了曲轴箱密封的实际结构和工况条件，测量了不同转速条件下的漏油速率，研究了密封装置中的不同结构特征的功能作用，最终提出了两种改进措施并验证了措施的有效性。研究结果表明：交错迷宫结构与直通型迷宫结构相比可以更显著地减少空气泄漏，增加交错迷宫结构可大幅减少空气对液相介质的向外输运，此外，合理利用迷宫结构进行回油亦能显著减少滑油泄漏。

关键词: 迷宫密封, 两相流, 离散相模型, 交错迷宫