Influence of labyrint sealing parameters in the low pressure turbine on stage efficiency

In the article, the estimated efficiency of the low-pressure turbine stage of the turbine engine with various versions of the labyrinth seal design is performed. For the study, the structural elements most influenced by the efficiency of the processes occurring in the labyrinth seal, such as: radial clearance, the number of combs, the step between the combs were selected. During the study, the results were obtained, on the basis of which the following conclusions can be drawn. The application of mathematical model of the turbine stage, was made by software AutoGrid 5, that made possible to evaluate that change of radial gap between the combs and hab for given boundary conditions has no significant impact on the labyrinth seal located from 0,0018 mm to 0,0073 mm. At the same time as the design is changed to increase the efficiency of the stage by reducing leakage through the seal, the laboriousness of manufacturing the labyrinth seal can in some cases increase (the increase in the number of combs leads to a proportional increase in the time for processing additional combs), while in others it decreases or stays at the same level. For example, it is possible to implement a more efficient version of a labyrinth seal with a smaller number of combs, increasing the distance between the combs. What leads to a reduction in costs, including in production due to fewer operations and a reduce the number of damaged parts [1]. Also, the change in parameters such as the pitch between the combs, the radial clearance, can be limited by the design of the turbine itself, without allowing the various designs to be fully realized. Thus, CFD calculation allows to model an effective design of compaction in a given geometric volume.