Numerical Simulation For Labyrinth Seal Compressor Using Dynamic Mesh Technique

Having the merits of simpleness, convenience and reliability, labyrinth seals have been widely used in dynamic machine, such as aero engine, steam turbine, compressor, and so on. As a non-contacting seal, there is no contact friction and no lubrication during the work process. But it has the disadvantage of leakage, which directly affects the efficiency of the machine. The leakage has significant effect on the flow field changes and different structure of the straight type labyrinth seal. So analysis the internal flow field and design the rational labyrinth structure are significant to improve the efficiency of the machine.The 2-D mathematical models of piston and cylinder are built on the basis of the structure of labyrinth seal of 4K-80 MG straight-through type labyrinth compressor. Finally, the structure is improved significantly by studying on the unsteady analyze about the inner flow field and perfecting the theory of labyrinth seal. On the basis of absorbing predecessors’ research results, in this paper, the main research work is as follows:Firstly, the theory which is about straight-through type labyrinth compressor is summarized by studying on the research status review and the application of labyrinth seal.Secondly, according to the physical model and computational fluid dynamic model of labyrinth compressor, the computation method which is used to simulate the inner flow field of straight-through type labyrinth compressor is built based on the simulation software Fluent. It will provide an efficient tool to the parameters design of labyrinth seal.Thirdly, a UDF program which could control the motion of piston in the air cylinder is designed, according to the actual motion of piston and dynamic grid technique of unsteady analysis. This achieves the aim of observing the change rule of labyrinth inner flow field and air in the air cylinder. The dynamic grid technique has advantages on analyzing seal of straight-through type labyrinth compressor through comparison between unsteady method and steady method.Finally, a reasonable structure of labyrinth seal is achieved by analyzing the influences of different structures on the basis of making further study on the parameters witch influence the seal ability. The leakage rate will be lowered and the work efficiency will be improved significantly, which provides a reliable basis for engineering practice.