Experimental and Dynamic Simulation Study on Rotational Lubrication of Labyrinth Seal for Shield Machine
The main drive sealing system of the shield machine is prone to muck invasion under harsh working condi-tions,leading to seal failure.However,current research on the invasion of muck into the seal is insufficient,and research on the lubrication of the main drive seal are limited to reduced-scale model experiments and simulation methods,lacking real machine tests and simulation.By establishing a φ2 m-class main drive seal lubrication test bench and constructing a full-scale grid model,the flow and diffusion of dynamically rotating EP2 grease in the labyrinth seal chamber under various fac-tors such as different rotation speeds,seal types,and eccentricity,were explored through experimental methods.A full-scale test bench grid model was constructed,and the sliding mesh method was used to simulate the rotation and diffusion of EP2 in the labyrinth seal chamber.The experimental results were compared to verify the accuracy of numerical simulation.The experimental results show that the arc length of EP2 grease diffusion increases with the increase of rotation speed and ec-centricity,but compared with eccentricity,the impact of the main drive rotation speed on the grease diffusion arc length is smaller.Under the same eccentricity and main drive rotation speed,the sealing performance of the staggered labyrinth seal is better than that of the straight-through labyrinth seal.According to industry experience,when the single mouth grease in-jection volume is set to 3.4 mL/min,only a small amount of EP2 adheres to the inner and outer cylinder walls in the laby-rinth seal chamber,with the rest being empty cavities.And it is difficult for EP2 to flow out from the top of the labyrinth seal chamber.Under the interaction of viscous force,gravity,and centrifugal force,EP2 cannot flow out evenly,resulting in a lack of grease lubrication in the upper part of the labyrinth seal,which leads to the failure of the labyrinth seal due to the invasion of muck.
shield tunneling machinelabyrinth sealedgrease flowsliding grid methodlip seal
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