Investigation of a Straight Through Labyrinth Seal with an Air-Curtain using Computational Fluid Dynamics and 1D Modelling

Labyrinth seals are essential components in gas turbine engines, designed to minimize leakage by creating a tortuous flow path. These seals are capable of operating effectively under conditions of high rotational speed and high temperature, and with the presence of “Air-Curtain” sealing is enhanced. This effect involves the injection of high-pressure air into the seal pockets, which further creates a barrier that enhances the sealing process at the expense of additional air flow. Present study investigates the “Air-Curtain” effect on a straight-through labyrinth seal. Rig tests and respective numerical simulations using ANSYS Fluent are conducted to serve as a baseline validation study. For finding the optimal position of the “Air-Curtain’s” inside tooth pocket, various cases with varying the seal pressure ratio (PRseal) and fixed Air-Curtain flow rate (%Wjet) are tried and determined through 2D axisymmetric CFD simulations. Furthermore, a sensitivity analysis comprises of 45 cases for different PRseal, %Wjet, and inlet swirl ratio (XK) is conducted and examined the impact of the Air-Curtain’s in-pocket position and angle on sealing effectiveness, identifying the most effective configuration for 3D modelling. Finally, the integration of the seal into the Altair Flow Simulator (FS) for 1D analyses is explored to simplify design evaluations and reduce computational costs.