Investigation of Leakage and Windage Heating of the Counter-Rotating Labyrinth Seal on Various Rotation Speed and Clearance

Abstract Vaneless counter-rotating configurations are known to improve aero-engine thrust-to-weight ratios; however, the sealing behavior of labyrinth seals under counter-rotating conditions has not been thoroughly investigated. Existing studies focus solely on stationary or single-rotating conditions. This work employs three-dimensional computational fluid dynamics (CFD) simulations with the standard k–ε turbulence model to analyze the effects of independent rotations of the tooth-wall and land-wall in a straight-through labyrinth seal, considering variations in seal clearance and rotational speed. Rotational effects are characterized using two dimensionless parameters: the relative comprehensive rotational speed (vrc) and the rotational speed ratio (θ). In the high-speed region (vrc > 1), the counter-rotation condition (θ≈−1) reduces leakage by over 20% and results in the most severe windage heating. Conversely, In the low-speed region (vrc < 1), tooth-wall-dominated rotation (θ≈0) leads to a slight leakage increase of up to 0.63%. The influence of tooth-wall rotation is further amplified with increased seal clearance. Notably, a counter-rotating labyrinth seal with a 0.58 mm clearance at 10,000 rpm achieves sealing performance comparable to a single-rotating seal with a 0.5 mm clearance. This finding suggests that counter-rotating designs can permit larger clearances (CL) than conventional single-rotation configurations.