Synergistic Tip Clearance Optimization for Fuel Cell Centrifugal Compressors: Integrating Blade Deformation and Rotordynamics

Abstract

Tip clearance is a critical determinant of aerodynamic performance in fuel cell centrifugal compressors supported by gas foil bearings. Traditional designs typically employ overly conservative clearances to mitigate rubbing risks, which induces substantial leakage losses and compromises efficiency. This study proposes a synergistic optimization methodology that integrates multi-physics blade deformation with comprehensive rotor dynamics. First, fluid-structure interaction (FSI) simulations were conducted to quantify blade deformations under coupled aerodynamic, thermal, and centrifugal loads. Second, the rotor's radial and axial displacements were characterized across the full operational speed range, accounting for the non-linear stiffness of foil bearings. Quantitative analysis reveals that rotor dynamics are the predominant driver of clearance variations, contributing 44.31% of the total deviation. Based on these insights, the tip clearances were optimized from a uniform 0.3 mm to 0.28 mm for the first stage and 0.25 mm for the second stage. Experimental validation demonstrates that the optimized compressor operates safely without interference, achieving a 1.2% enhancement in isentropic efficiency (from 69% to 70.2%) and a 2.4% increase in peak pressure ratio. This integrated approach provides a robust framework for high-efficiency compressor design in hydrogen fuel cell applications.