CFD Investigation of Cavitation Effects on High-Speed Propeller Performance

Cavitation represents a critical phenomenon affecting the performance, durability, and acoustic signature of high-speed propellers. This study extends a previous non-cavitating analysis of the same propeller by investigating cavitation onset, evolution and performance change for a 140 mm diameter, three-blade fixed-pitch high-speed propeller. The Rayleigh-Plesset cavitation model, implemented in ANSYS CFX 24.2 within a two-phase Eulerian framework coupled with SST turbulence closure, was used to simulate 72 operational combinations spanning six advance velocities (0–10 m/s) and twelve rotational speeds (300–3600 RPM), with nine representative cases analyzed in detail. Results show that onset thresholds are strongly velocity-dependent: at zero advance velocity (bollard-pull condition, v = 0 m/s) cavitation inception occurs between 1800 and 2000 RPM, whereas at high advance velocity (v = 10 m/s) localized tip-vortex cavitation appears at rotational speeds as low as 300 RPM despite a nominally favourable global cavitation number (σ = 1.96), demonstrating that the global cavitation number alone cannot predict the onset of cavitation. Cavitation consistently initiates at blade tip leading edges, evolving from attached sheet cavitation to supercavitation with vapor fractions exceeding 95% at maximum conditions. At the critical design point, propulsive efficiency reaches η = 38.6% (T = 244.04 N, Q = 12.08 Nm). A direct comparison with the non-cavitating baseline reveals that this effect is regime-dependent: cavitation reduces predicted thrust by 7–11% under bollard pull conditions (v = 0 m/s, 1800–3600 RPM), partially attributable to active-blade-area loss; at moderate advance velocities (v = 2–6 m/s) the two predictions nearly coincide, while at high advance ratio (v = 8–10 m/s) cavitating thrust matches or exceeds the non-cavitating prediction, by up to 88% at v = 10 m/s and 3600 RPM. These findings define indicative operational envelopes, identify blade tip protection as essential for erosion mitigation and provide practical design guidance for high-speed propellers in fast vessels, rescue craft and autonomous surface vehicles.