Multi-objective Optimization Study on Parameters of a Novel Labyrinth-fingertip Composite Seal Structure Based on Taguchi Design

Abstract

This paper proposes a labyrinth-finger seal designed for high-pressure differential and high-speed operating machinery, with an emphasis on its thermal-fluid behavior and multi-objective optimization. A two-dimensional axisymmetric numerical model is established. In this model, the upstream labyrinth teeth are simulated using conventional flow modeling, and the downstream finger section is modeled as a porous medium and solved with the RNG k-ε turbulence model. Frictional heat generation at the contact interface between the finger boot and rotor is incorporated. Leakage rate and peak temperature are adopted as evaluation metrics. Single-factor sensitivity analysis is first conducted to identify the dominant geometric parameters, specifically, tooth radial clearance, rear shield protection height, and number of finger plates. Subsequently, an L25 orthogonal array based on the Taguchi method is constructed to perform multi-objective optimization of six key factors. Results indicate that within the pressure differential range of 0.10–0.50 MPa and rotational speeds of 9,000–21,000 r/min, the optimized configuration achieves a leakage reduction of approximately 50% and a peak temperature decrease of 6–10 K. Flow field analysis revealed that leakage suppression arises from a synergistic mechanism: throttling energy dissipation at the labyrinth teeth combined with compliant flow restriction at the fingertip. Validation against published experimental data yields deviations within 10%, confirming the effectiveness of the combined CFD-Taguchi optimization approach. This methodology offers practical guidance for the engineering design of high‑performance composite seals.