• 대한조선학회논문집
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• 제41권6호
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• pp.15-23
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• 2004

In order to investigate efficiency and flowfield charateristics of the intake-diffuser for the ship waterjet propulsion, new experimental verification technology was set up in the cavitation tunnel. 1-hole and 5-hole pilot tubes were designed and manufactured to measure the pressure and velocity distributions at intake-diffuser entrance and impeller inlet. The calibration of the 5-hole pilot tubes is conducted at the cavitation tunnel The cavitation inception occurs at the intake lip, and the occurrence position depends on IVR (Inlet Velocity Ratio) condition. The present experimental device will be applied sufficiently for the development of the design and performance improvement technologies.

• 대한조선학회논문집
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• 제41권6호
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• pp.8-14
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• 2004

The numerical analysis of a waterjet propulsion system was performed to provide detail understanding of complicated flow phenomena including interactions of intake duct, rotor, stator, and contracted discharge nozzle. The incompressible RANS equations were solved on moving multiblocked grid system. To handle interface boundary between rotor and stator, the sliding multiblock method was applied. The numerical results were compared with experiments and good agreement was obtained. The complicated viscous flow features of the waterjet, such as secondary flow inside the intake duct, the recovery of axial flow by the role of the stator, and tip and hub vortex, etc. were well analyzed by the present simulation. The performance of thrust and torque was also predicted.

• 대한조선학회논문집
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• 제41권5호
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• pp.21-27
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• 2004

A waterjet propulsion system has many advantages compared with a conventional screw propeller especially for amphibious military vehicles because of a good maneuverability at low speed, good operating ability at shallow water, high thrust at low speed to aid maneuverability and exit from water, etc. Especially, compact design is important for the tracked-vehicle because of buoyancy in water and available space inside the tracked vehicle. The experiment is parametrically performed for various impeller diameters for more compact design. The experimental results are analyzed according to the ITTC 1996 standard analysis method as well as the conventional propulsive factor analysis method. The full-scale effective and delivered power of the tracked-vehicle are evaluated according to the variation of impeller diameter. This paper emphasized the effect of impeller diameter on the performance of waterjet system.

• 대한조선학회논문집
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• 제42권6호
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• pp.575-582
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• 2005

• Journal of Ship and Ocean Technology
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• 제4권4호
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• pp.34-44
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• 2000

This paper deals with the sea trial results of a fast craft with the hybrid supported type hul form. waterjet propulsion system and motion control system. The hybrid-type container ship operable in the sea with a wave height of y6 m, a speed of 50 knots and a payload of 1,500 tons were designed. A 1/8 scale 10 m- long test craft was constructed and tested in open seas. The hydrodynamic performance such as speed, turning, motion control in waves and waterjet thrush was analyzed.

• 대한조선학회논문집
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• 제41권5호
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• pp.14-20
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• 2004

The aim of this paper is to analyze the steady performance of POD-type waterjet system by panel method. A surface panel method is applied to the present analysis. To analyze the compound propulsor. analysis program has been developed based on a perturbation potential method. The developed code has been validated by comparing the experimental data of shrouded propeller. The validated code has been applied to the POD-type waterjet system which can be used for the propulsion of amphibious vehicle. The computed results have been compared with experimental results. which shows a good agreement between them.

• 해양환경안전학회지
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• 제24권6호
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• pp.810-817
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• 2018

우리나라에서 다랑어 선망어업은 국내 원양산업 중 업종별 생산량 1위의 업종으로, 1980년대 중 후반부터 연구가 지속적으로 수행되어왔으며, 기술의 현대화 연구가 활발히 진행되어왔다. 하지만, 어선에 탑재되는 보조작업선들은 원양어업에서 중요한 역할을 맡고 있음에도 관련 연구가 미흡한 실정이다. 이에 본 연구에서는 보조작업선들 중 네트보트의 추진기를 프로펠러에서 워터제트 형태로 변경하고, 그에 따른 선형 변환을 통한 선체 부가저항 감소 및 운항성능을 향상하고자 하였다. 이를 위해 전산수치해석을 통해서 선박의 유체성능 변화를 계산하였으며, 또한 기존 선형 및 추진기 변화 선형에 대해 모형선 수조시험을 수행하여 속도별 저항성능 비교를 수행하였다. 수치해석 및 1/7의 축소모형의 수조시험 결과, 기존의 네트보트 대비 45~58 % 저항성능이 크게 향상되었으며, 이는 철망 제거에 의한 단순 침수표면적 및 선형개선에 의한 저항성능 향상을 확인하였다.

• 한국군사과학기술학회지
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• 제24권1호
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• pp.84-98
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• 2021

The hydrodynamic characteristics of amphibious assault vehicles are investigated using commercial CFD code, STAR-CCM+. Resistance performances of a displacement-type vehicle and a semi-planing type vehicle are analyzed in calm water. The self-propelled model is also computed for the semi-planing type vehicle. All computations are performed using an overset mesh system and a RANS based flow-solver coupled with a two-degree of freedom equations of motion. A moving reference frame is applied to simulate revolutions of impeller blades for a waterjet propulsion system. Grid dependency tests are performed to evaluate discretization errors for the mesh systems. The numerical analysis results are compared with the experimental results obtained from model tests. It is shown that RANS is capable of investigating the resistance and self-propulsion characteristics of high-speed amphibious assault vehicles. It is also found that a fully covered side skirt, which is covering tracks, reduces resistance and stern trim, besides increasing propulsive efficiency.

• 대한조선학회논문집
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• 제36권2호
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• pp.9-21
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• 1999

물분사 추진장치(waterjet)는 현재 고속선의 추진기로 폭넓게 사용되고 있으나, 입구면(inlet) 형상에 따른 효율 문제와 제작상의 어려움으로 인해 제작사는 한정되어 있다. 입구면 형상 설계에 있어서 가장 중요한 문제는 효율에 크게 영향을 주는 공동(cavitation) 발생을 최소화하는 것이다. 본 논문에서는 포텐셜 유동해석에 의해 공동발생이 최소화되는 최적 형상을 찾기 위해, 평접형(flush type) 이차원 물분사 추진장치의 입추면 형상을 수치계산 모델로 택하여 이차원 단면으로 가정하고, 유동해석을 수행하였다. 형상 파라미터의 변화를 통해 얻어진 다양한 입구면 형상에 대해 수치계산을 수행하여, 공동 발생에 미치는 입구면 형상의 영향을 조사하였고, 이를 바탕으로 최적 형상을 얻을 수 있는 형상해석 기법을 확립하였다. 또한 주어진 입구면 주위의 압력분포를 입력자료로 하여 입구면 형상이 찾아지도록 하는 형상 설계법을 확립하였다. 입구면의 형상 해석 및 형상 설계시 이용한 포텐셜 유동해석은 최근 공동문제 해석에 적용되어 좋은 결과를 주고 있는 포텐셜을 기저로 한 패널법[1,2]을 적용하였다. 형상 해석을 수행하여 얻어진 결과와 Kashiwadani[3,4]의 결과를 비교하여 근사한 결과를 얻은 것으로 본 논문의 형상 해석 기법의 우수성을 알 수 있었다. 형상 해석 결과로 얻어진 압력분포를 입력자료로 하여 입구면의 lip과 ramp에 대한 형상 설계를 수행한 결과 모두 만족스러운 결과를 얻었다.

• 항공우주시스템공학회지
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• 제5권2호
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• pp.27-32
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• 2011

The purpose of this study was to suggest 10 kinds of case and perform Mixed-flow pump optimum design and performance analysis depending on the shape of the impeller for suitable to water jet propulsion system. H20 was applied to the material properties, to analysis conditions for water jet axial impeller 1000 rpm given analysis was performed. Interpretation for each case as a result of speed, pressure, flow rate, calculate the thrust at the Inlet Angle $30^{\circ}$ and Outlet Angle $30^{\circ}$ could see a persistence of optimal performance.