Flow characteristics of tip leakage vortex cavitation ofducted propeller under different cavitation conditions

Abstract

ObjectivesThis study aims to investigate the effects of the development of tip leakage vortex (TLV) cavitations on the core characteristics of vortices. MethodsThe numerical simulation associated with the SST k-ω turbulence model and Zwart-Gerber-Belamri (ZGB) cavitation model is used to solve the cavitating flow of the TLV of a ducted propeller under different cavitation conditions. Based on the reliable numerical simulation, the development of the TLV cavitation and the evolution of its core characteristics are studied according to the vapor volume fraction iso-surface and Q criterion. ResultsThe results show that the area of the tip leakage cavitation expands with the development of the TLV cavitation. The TLV cavitation twists near the trailing edge of the tip leakage cavitation under specific conditions. The performance of the ducted propeller is greatly affected by the continuous decrease in the cavitation number. The development of the cavitation makes the TLV gradually flow away from the blade suction surface, increasing the complexity of the velocity distribution at the TLV core center. When the cavitation number σ is 1.488, the continuous development of the cavitation significantly reduces the intensity of the TLV. With the development of the TLV, its ability to absorb the circumferential vorticity from the inner wall weakens, and the turbulent kinetic energy from the tip gap is gradually transported to the vortex center. ConclusionsThe proposed method and results of this study can provide valuable references for the performance prediction of hydraulic rotating machinery and control methods for TLV cavitations.

Keywords

• ducted propeller
• tip leakage vortex (tlv)
• cavitation
• numerical simulation