Parametric optimization of variable lead curves for screw rotors in twin-screw air compressors

Twin-screw air compressors are widely used in industry for their stability, reliability, and high efficiency. Optimizing rotor lead curves is essential for improving compressor performance, with multi-stage variable lead designs offering enhanced chamber volume control, better gas sealing, and reduced internal leakage. This study investigates the design and performance of multi-stage variable lead curves under identical rotor profiles, helical section lengths, and wrap angles. The lead curve is divided into suction, compression, and discharge segments, with reference angles derived from constant-lead conditions to define design parameters. Lead parameters are normalized using constant lead values and wrap angles, and a predictive model is developed by combining radial basis function approximation, uniform experimental design, and ISIGHT. Global optimization is performed in Mathematica using a least-squares method. The optimized designs are validated through geometric analysis and evaluation of volumetric and isentropic efficiencies at different rotational speeds. The results provide practical guidance for optimizing three-segment rotor lead curves in twin-screw air compressors to enhance compressor performance.