Hydrodynamic performance of a rim-driven thruster improved with gap geometry adjustment

Lin, Jianfeng; Yao, Huadong; Wang, Chao; Su, Yumin; Yang, Chun

doi:10.1080/19942060.2023.2183902

Cited by 12 publications

(12 citation statements)

References 24 publications

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“…The influence of the number of blades, in addition to being a result of optimization activities [12], was investigated in [16]. Lin et al [17] studied the flow, the so-called "RIM effect", in the annulus between stator and rotor, and its influence, in terms of parasitic torque, on the global performance of the system. They also investigated the role of the annulus shape on the overall propulsive efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…In any case, with the partial exception of Cao et al [15] and Lin et al [17], very few studies have been proposed on the evolution of the vortical trailing wake of RIMdriven thrusters, so important from the point of view of radiated noise. Cao et al [15] correlated some characteristics of the trailing wake of the propellers with their blade loading distributions.…”

Section: Introductionmentioning

confidence: 99%

“…They showed, for the cases under investigation, the occurrence of merging of root vortices and the sudden appearance of more intense tip vortices far in the wake. Lin et al [17] visualized the vortical structures shed by RIM-driven thrusters. As in the calculations of [15], however, the spatial discretization as well as the employed numerical schemes were not adequate for accurate prediction of these features since the focus of their study was not explicitly on the wake dynamics.…”

Section: Introductionmentioning

confidence: 99%

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A Study on the Wake Evolution of a Set of RIM-Driven Thrusters

Gaggero

2023

JMSE

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In the current paper, high-fidelity improved delayed detached-eddy simulations (IDDES) using the OpenFOAM library are employed to characterize the performances and the wake dynamics of RIM-driven thrusters. Despite their relatively old conception, this type of propulsors has gained attention only recently thanks to innovative manufacturing technologies and materials, which finally have made possible their practical implementation. Fostered by stringent regulations on radiated noise and emissions enforced in protected areas, they are also replacing conventional thrusters and main propulsors. By mitigating the tip vortex cavitation and, more in general, by reducing the strength of tip vortices, indeed, these propulsors may grant a reduction in the induced pressure pulses and of the radiated noise without excessively sacrificing the efficiency of the equivalent ducted propellers they replace. To provide proof of this, three different RIM-driven thrusters (one four-bladed, two six-bladed) are analyzed and compared to a reference decelerating ducted propeller delivering the same thrust at identical functioning conditions. The evolution of the trailing wakes of the propulsors, the role of the leakage vortex, and the nozzle wake destabilizing effects, are highlighted, and the superior performances of RIM-driven thrusters, in terms of less intense tip vortices, are discussed. Near-field pressure pulses, as a measure of the radiated noise, are compared, showing a reduction in the sound pressure levels of the selected RIM propulsors up to 15 dB (non-cavitating case) with respect to the reference ducted propeller.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Study on the Wake Evolution of a Set of RIM-Driven Thrusters

Gaggero

2023

JMSE

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“…2 The earliest original geometry of RDT was proposed in a novel patent approximately 80 years ago. 3 Compared to shafting-driven propellers, the ingenious design outperforms the RDT as follows: 4 (i) The compact arrangement saves cabin rooms and is helpful for flexible installation. (ii) The higher motor efficiency is due to the broadband torque transmission through the magnetic field.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, they proposed that a proper fillet at the corner of the gap could reduce the torque loss, and their numerical and experimental data on torque loss agreed well. Lin et al 4 used the OpenFOAM solver to determine how the shape of the gap affects the hydrodynamics of RDT and concluded that the efficiency could be improved by shortening the gap length. yþ over the S surfaces has an impact on the distribution of the tangential velocity in the gap.…”

Section: Introductionmentioning

confidence: 99%

Improved efficiency with concave cavities on S3 surface of a rim-driven thruster

Li,

Yao,

Wang

et al. 2023

Physics of Fluids

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Rim-driven thrusters (RDT) are of great interest for the development of integrated electric motors for underwater vehicles. Gap flow is one of the most prominent flow characteristics and plays an important role in the hydrodynamic performance of RDT. In this study, the rim in a carefully designed RDT was modified with several concave cavities defined by four parameters, and their influence on hydrodynamics was carefully calculated and analyzed. The simulations were performed using the k-ω shear stress transport turbulence model by solving the unsteady Reynolds-averaged Navier–Stokes equations. The numerical method was verified using a popular combination. The numerical results showed that the concave cavities on the rim improve the propulsive efficiency of RDT by a maximum of 3.52%. The increase in the propulsive efficiency is directly associated with the parameters of the concave cavities. Nevertheless, the flow in the gap has a negligible effect on the main flow field through the RDT. According to the numerical analysis, the different pressure integrals at the front and back surfaces of the concave cavities are the main reason for the improvement of the propulsive efficiency. The modification of the rim is helpful and practical for the hydrodynamic optimization of the RDT.

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