How do you evaluate and improve turbomachinery component efficiency?

Efficiency is evaluated using: Isentropic efficiency (actual work / ideal isentropic work) for compressors and turbines; Polytropic efficiency (accounts for stage-by-stage losses, better for comparing different pressure ratios). Improvement strategies: Blade aerodynamic optimization (3D airfoil design, lean, sweep, bow), Tip clearance reduction (abradable seals, active clearance control), Surface finish improvement (reduces boundary layer losses), Reduced leakage (improved seals, shroud design), Flow path optimization (blade count, aspect ratio, solidity), and Advanced materials enabling tighter tolerances. Modern compressors achieve 90%+ polytropic efficiency, turbines 88-92%. Each 1% efficiency improvement reduces fuel burn by ~0.5%.