• International Journal of Naval Architecture and Ocean Engineering
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• 제8권1호
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• pp.110-116
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• 2016

In this study an attempt has been made to study the hydrodynamic performance of pumpjet propulsor. Numerical investigation based on the Reynolds Averaged NaviereStokes (RANS) computational fluid dynamics (CFD) method has been carried out. The structured grid and SST ${\kappa}-{\omega}$ turbulence model have been applied. The numerical simulations of open water performance of marine propeller E779A are carried out with different advance ratios to verify the numerical simulation method. Results show that the thrust and the torque are in good agreements with experimental data. The grid independent inspection is applied to verify accuracy of numerical simulation grid. The numerical predictions of hydrodynamic performance of pumpjet propulsor are carried out with different advance ratios. Results indicate that the rotor provides the main thrust of propulsor and the balance performance of propulsor is generally satisfactory. Additionally, the curve of propulsor efficiency is in good agreement with experimental data. Furthermore, the pressure distributions around rotor and stator blades are reasonable. Beyond that, the existence of tip clearance accounts for the appearance of tip vortex that leads to a further loss in efficiency and a probability of cavitation phenomenon.

• 제어로봇시스템학회논문지
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• 제10권11호
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• pp.981-990
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• 2004

Specialized propulsors for naval applications have numerous opportunities in terms of research, design and fabrication of an appropriate propulsor. One of the most important components of any propulsor is the actuator that provides the mode of locomotion. Ionomeric electro-active polymer may offer an attractive solution for locomotion of small propulsors. A common ionomeric electro-active polymer, ionic Polymer-Metal Composites (IPHCs) give large true bending deformations under low driving voltages, operate in aqueous environments, are capable of transduction and are relatively well understood. IPMC fabrication and operation are presented to further elucidate the use of the material for a propulsor. Various materials, including IPMCs, are investigated and a simplified propulsor model is explored.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.341-346
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• 2010

In this paper, viscous flow calculation of pump-jet that is used as underwater propulsor was made by using RANS equation. For the validation, calculation for DTRC4119 marine propeller was made and reasonable agreements were obtained between the present results and the experiment. An unstructured overset mesh technique is used for analysis of relative motion between rotor and stator in pump-jet propulsor. Results for pump-jet propulsor were compared with computational results of another researcher.

• Journal of Ship and Ocean Technology
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• 제8권1호
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• pp.31-41
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• 2004

A ducted marine propulsor has been widely used for the thruster of underwater vehicles for protecting collision damage, increasing propulsive efficiency, and reducing cavitation. Since a single-stage ducted propulsor contains a set of rotor and stator inside an annular duct, the numerical analysis becomes extremely complex and computationally expensive. However, the accurate prediction of viscous flow past a ducted marine propulsor is essential for determining hydrodynamic forces and the propulsive performances. To analyze a ducted propulsor having rotor-stator Interaction, the present work has solved 3D incompressible RANS equations on the sliding multiblocked grid. The flow of a single stage turbine flow was simulated for code validation and time averaged pressure coefficients were compared with experiments. Good agreement was obtained. The hydrodynamic performance coefficients were also computed.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권3호
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• pp.219-227
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• 2016

Numerical simulation based on the Reynolds Averaged Naviere-Stokes (RANS) Computational Fluid Dynamics (CFD) method had been carried out with the commercial code ANSYS CFX. The structured grid and SST $k-{\omega}$ turbulence model had been adopted. The impact of non-condensable gas (NCG) on cavitation performance had been introduced into the Schnerr and Sauer cavitation model. The numerical investigation of cavitating flow of marine propeller E779A was carried out with different advance ratios and cavitation numbers to verify the numerical simulation method. Tip clearance effects on the performance of pumpjet propulsor had been investigated. Results showed that the structure and characteristics of the tip leakage vortex and the efficiency of the propulsor dropped more sharply with the increase of the tip clearance size. Furthermore, the numerical simulation of tip clearance cavitation of pumpjet propulsor had been presented with different rotational speed and tip clearance size. The mechanism of tip clearance cavitation causing a further loss of the efficiency had been studied. The influence of rotational speed and tip clearance size on tip clearance cavitation had been investigated.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권3호
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• pp.307-317
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• 2018

In this study, numerical investigations of the tip clearance flow characteristics of a pumpjet propulsor based on Computational Fluid Dynamics (CFD) method have been presented. The Zwart-Gerber-Belamri (Z-G-B) cavitation model based on Reynolds Averaged Navier-Stokes (RANS) method is employed. The structured gird is applied. The formation and development of the tip clearance flows has been investigated and presented. The structure of the tip leakage vortex has been shown. The radial distributions of different velocity components with different Span along the axial direction have been carried out to present the influence of the tip clearance flow on the main flow. In addition, the influences of the tip clearance size on the pumpjet propulsor performance, including the impact on the velocity flow fields and the cavitation characteristic, have been presented.

• Smart Structures and Systems
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• 제20권4호
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• pp.499-508
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• 2017

The ionic polymer-metal composite (IPMC) is an electroactive polymer material and has a promising potential as actuators for propulsion and locomotion in underwater systems. In this paper a physics based model is used to analyse the actuation dynamics of the IPMC propulsor. Moreover, proportional-integral (PI) controller is used for position control of the tip displacement of IPMC propulsor. PI parameter tuning is performed using particle swarm optimization (PSO) algorithm. Several performance indices have been used as an objective function to optimize the error of the system. Finally, the best tuning method is found out by comparing the results under various performance indices.

• 대한조선학회논문집
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• 제59권3호
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• pp.149-156
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• 2022

In order to study the open-water test and analysis techniques for pumpjet propulsors in the Large Cavitation Tunnel (LCT), at the Korea Research Institute of Ships and Ocean Engineering, a set of test equipment was designed and manufactured. The pumpjet propulsor is composed of rotor, stator and duct resulting in the strong interaction between the components. A ring-shaped sensor was developed to measure the thrust and torque for duct and stator. The test equipment including the pumpjet is installed on an existing POW dynamometer in the reverse direction. The results from the reverse POW test setup were validated against those from the conventional POW test setup in the Towing Tank (TT) as well as in the LCT. The pumpjet open-water test was conducted at the Reynolds number of around 1.0×106, at which the obtained experimental data became stable in the Reynolds number effect test. The open-water test for the rotor (rotor-only) was conducted to study whether the duct and stator should be considered as a part of the hull or the propulsor. On the basis of the test results, it was shown that the duct and stator could be included in the propulsor. The total thrust, combined thrust of rotor, duct, and stator was used for the pumpjet open-water test analysis. As the whole pumpjet is defined as a propulsor, it is thought that the self-propulsion test and analysis could be conducted in the same way as that of the conventional propeller.

• 대한조선학회논문집
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• 제59권5호
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• pp.271-279
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• 2022

In order to study the self-propulsion test and analysis techniques for the submerged body with pumpjet propulsors in the Large Cavitation Tunnel (LCT), at the Korea Research Institute of Ships and Ocean Engineering, a set of test equipment was designed and manufactured. The pumpjet propulsor is composed of rotor, stator and duct which results in the strong interaction between the components. To measure the thrust and torque for duct and stator, a ring-shaped sensor was applied. The test equipment including pumpjet is installed on the stern of the submerged body. As the whole pumpjet including duct and stator was considered as the propulsor from pumpjet open-water test, the self-propulsion test was conducted in the same way. The total thrust, combined thrust of rotor, duct and stator was used for the pumpjet self-propulsion test analysis. Accordingly, the self-propulsion test and analysis were conducted in the same way as those of the conventional propeller. The full-scale performances of the pumpjet propulsor were compared with those of the reference propeller. On the basis of the present study, it is thought that the pumpjet propulsor would be designed optimally.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권2호
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• pp.287-301
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• 2013

The present paper deals with the problems of yaw angle effects on podded propulsor performance. The study aims at providing insights on characteristics of podded propulsors in azimuthing condition. In this regard, a wide numerical simulation that concerned yaw angle effect measurement on podded propeller performance was performed. The Reynolds-Averaged Navier Stokes (RANS) based solver is used in order to study the variations of hydrodynamic characteristics of podded propulsor at various angles. At first, the propeller is analyzed in open water condition in absence of pod and strut. Next flow around pod and strut are simulated without effect of propellers. Finally, the whole unit is studied in zero yaw angle and azimuthing condition. Structured and unstructured mesh techniques are used for single propeller and podded propulsor. The performance curves of the propeller obtained by numerical method are compared and verified by the experimental results. The characteristic parameters including the torque and thrust of the propeller, the axial force and side force of unit are presented as function of velocity advance ratio and yaw angle. The results shows that the propeller thrust, torque and podded unit forces in azimuthing condition depend on velocity advance ratio and yaw angle.