Numerical investigation on hydrodynamic performance of a novel shaftless rim-driven counter-rotating thruster considering gap fluid. (January 2022)

• Record Type: Journal Article
• Authors: Jiang, Han; Ouyang, Wu; Sheng, Chenxing; Lan, Jiafen; Bucknall, Richard
• Is Part Of: Applied ocean research. Volume 118(2022)
• Publication Date: 2022-01
• Subjects: Shaftless rim-driven thruster -- Counter-rotating propeller -- Hydrodynamic performance -- Gap fluid -- Friction torque; Ocean engineering -- Periodicals; 620.416205
• DOI: 10.1016/j.apor.2021.102967
• Languages: English
• ISSNs: 0141-1187

Abstract

Highlights: A novel counter-rotating shaftless rim-driven thruster (CRP-RDT) is proposed, and the hydrodynamic performance analysis is determined. Three simulation models for the hydrodynamic performance of the CRP-RDT are established to figure out whether the motor stator/rotor gap should be considered. The flow distribution characteristics of the gap fluid friction force and the gap flow channel are studied. The thrust coefficient, torque coefficient and the maximum efficiency value of the CRP-RDT are all greater than those of the single propeller RDT. Abstract: Shaftless rim-driven thruster (RDT) has recently become the research focus for marine propulsion, primarily due to low vibration, low noise, and energy saving as its advantage. This study is based on CFD theory and used the Ansys-Fluent software to examine the hydrodynamic performance of a novel rim-driven counter-rotating thruster (RDCRT). It takes a No.19A+Ka4-70 duct propeller and a 20 kW RDT as examples, as it verifies the feasibility of the simulation method. It establishes three geometric models for RDCRT's hydrodynamic performance to determine whether it is necessary to consider the motor stator/rotor gap. It examines the flow distribution characteristics of the gap fluid friction force and flow channel and investigates the gap's influence on the hydrodynamic performance. Relevant case studies indicate that, when considering the gap, the calculation outcomes of the simulation model are between the stationary model and the rotational model of the rotor inner wall when ignoring the gap. In the Forward and Aft regions, the total frictional power of the gap channel correspondingly accounts for 1.7% and 1.35% of the rated power. Additionally, compared to situations with a gap, the pressure coefficient of the inner surface of the Forward and Aft rim without a gap is more significant. Thus, the hydrodynamic simulation model should not ignore the gap. For the RDCRT, the thrust coefficient, the torque coefficient, and the maximum efficiency value are more significant than those of the single-propeller RDT, hence validating its advantages.