Theoretical Research On The Principles Of Seal In Labyrinth Piston Compressors

Having the merits of simpleness, convenience and reliability, labyrinth seals have been widely used in dynamic machine, such as aeroengine, compressor, steam turbine, and so on. However, as a non-contacting seal, labyrinth seals have the disadvantage of leakage, which directly affects the efficiency of dynamic machine. Since the performance of labyrinth seals is determined by the energy wastage during the flow process, it is very important to study the seal mechanism to decrease the leakage.The straight type labyrinth seal used in the labyrinth piston compressor is modeled in this paper. On the basis of the previous investigation fruits, the further research is made to perfect the theory of labyrinth seals and offer basis for the design of labyrinths and labyrinth piston compressors.The main objections of the investigation are as followings:Firstly, the current research on the mechanism of labyrinth piston compressors and labyrinth seals in recent years is summarized, and related theories of straight type labyrinth seals are emphatically introduced. Secondly, the geometrical model and numerical model of straight type labyrinths are set up. With the CFD software of FLUENT, computation method of simulating the inner flow field is established in order to provide a valid tool.Thirdly, the relationships between the characteristics of flow and the configuration parameters are discussed, and therefore the performance of seals is analyzed. In addition, the steady mechanism of seals and the suggestions to enhance the seal effectiveness are presented.Then, by combining orthogonal experimental method with numerical simulation, the key factors of affecting the leakage and the optimization of configuration of labyrinth seals are obtained from range analysis and variance analysis, and a mathematical model of the relationship between the discharge coefficient and the geometric parameters, which can be a reliable reference to design labyrinths, is established by multiplying linear regression.Finally, because of the periodical change of the inlet state parameters in labyrinth piston compressors, the mechanism of seals in the transient condition, which is valuable for the methods to design the labyrinth piston, is researched according to the investigation of the steady state case.