Numerical investigations of flow structure in gas turbine shroud gap

[摘要] The structure of the flow in the labyrinth sealing of an axial gas turbine was investigated by means of numerical simulations. Additionally, the flow structure for two- and three-dimensional axisymmetric models was compared. The porous disc as a model for the pressure drop relevant to the obtained in the cascade was proposed and tested. Several flow structure features existing in the sealing cavities are investigated: vortical structure and separation bubble on the rib and the correlation between the pressure drop and the clearance size. The carried out investigations indicate that the innovation aimed at decreasing the leakage flow through implementation of the flow control devices is possible. Furthermore the comparison between 2D and 3D models shows good agreement, thus application of less demanding 2D model introduces negligible differences. It is shown that the proposed porous disc model applied to mimic pressure drop in cascade can be effectively used for rotor blade sealing simulations.

[发布机构] Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Fiszera 14, Gdask; 80-952, Poland^1;Gdansk University of Technology, Narutowicza 11/12, Gdask; 80-233, Poland^2

[效力级别] 力学 [学科分类] 力学，机械学

[关键词] Axisymmetric models;Flow control devices;Labyrinth sealing;Leakage flow;Numerical investigations;Separation bubble;Structure features;Vortical structures