• The KSFM Journal of Fluid Machinery
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• v.6 no.2 s.19
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• pp.41-46
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• 2003

The hydraulic design optimization and performance analysis of mixed-flow pumps for waterjet marine vehicle propulsion has been carried out using mean streamline analysis and three-dimensional computational fluid dynamics (CFD) code. In the present study, the conceptual design optimization has been formulated with a non-linear objective function to minimize the fluid dynamic losses, and then the commercial CFD code was incorporated to allow for detailed flow dynamic phenomena in the pump system. Newly designed mixed-flow model pump has been tested in the laboratory. Predicted performance curves by the CFD code agree very well with experimental data for a newly designed mixed-flow pump over the normal operating conditions. The design and prediction method presented herein can be used efficiently as a unified hydraulic design process of mired-flow pumps for waterjet marine vehicle propulsion.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.126-126
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• 2017

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.16-20
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• 2003

Recently, The fast change of fishing boat fishery surrounding environment is connected by request of fan shape development that meet in restructuring of existing fishing boat fishery and new community, economical surrounding. In southern sea district along the coast work and district along the coast fishing bats that sail to exposed propeller fishing net, rope etc.. cold real condition that accident is increasing every year. This study is thing which analyze main performance of minuteness water jet type district along the coast fishing boat through model examination to propeller protection tunnel sticking district along the coast fishing boat that correct existing stem shape for marine accident prevention of district along the coast fishing boat in viewpoint such as ideal and examines.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.139-142
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• 2003

레피어 직기는 1,000rpm 이상의 워터제트와 에어제트 직기의 생산성에 미치지는 못하지만 제직 범위가 넓고 다양한 색사 사용이 가능하다는 장점으로 인해 고급직물을 생산하기 위해 오늘날에도 폭넓게 사용되고 있다. 현재는 외국 선진국뿐만 아니라 국내에서도 레피어직기는 제트직기와 더불어 주력개발기종 중의 하나이다. 근래 레피어직기의 개발방향은 고속화에 주력하고 있다. 레피어를 고속화하기 위한 시도는 위입구동부, 바디침기구, 개구부, 송출부 및 권취부 등 전반적으로 검토되어야 하지만 본 연구에서는 바디침기구의 고속화를 위해 바디침기구의 구동원이 되는 구동캠의 성능향상에 목적을 두고 수행되었다. (중략)

• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.10
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• pp.48-53
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• 2019

A water jet propeller is a key component that generates propulsion during the start of a naval vessel. When failure or breakage occurs, the vessel cannot operate. Recently, a flow analysis and structural analysis were conducted to understand the cause of damage to a bolt on a water jet. In particular, the stress and strain acting on the fastening bolt (impeller shaft and tail shaft) were examined to determine the extent of misalignment between the impeller shaft and the tail shaft of the water jet propeller. The study determined that stress and strain were concentrated on the impeller shaft and the tail shaft bolt. The alignment of the propeller impeller shaft and the tail shaft increased significantly in response to the tail shaft bolt. Failure of the tail shaft bolt fastening can lead to misalignment between the impeller shaft and the tail shaft.

• Journal of Korea Fishing Vessel Association
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• v.61
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• pp.9-13
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• 1995

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.922-927
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• 2004

Abrasive waterjet (AWJ) cutting is an emerging technology for precision cutting of difficult-to-machining materials with the distinct advantages of no thermal effect, high machinability, high flexibility and small cutting forces. This paper investigated theoretical and experimental cutting characteristics associated with abrasive waterjet cutting of quartz GE214. It is shown that the proper variations of several cutting parameters such as waterjet pressure, cutting speed and cutting depth improve the roughness on workpiece surfaces produced by AWJ cutting. From the experimental results by AWJ cutting of quartz GE214, the optimal cutting conditions to improve the surface roughness were proposed and discussed.

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.72-72
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• 2018

• Journal of the Society of Naval Architects of Korea
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• v.60 no.3
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• pp.165-174
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• 2023

Unmanned Surface Vehicle (USV)'s berthing and unberthing is the most difficult maneuvering tasks and have the highest risk of accidents. In this paper, we designed a berthing/unberthing control algorithm given human joystick command for an USV equipped with a waterjet and a bow thruster. The berthing and unberthing maneuvers are performed remotely by a joystick operator at the Ground Control Center (GCC) where the status of USV and environmental situation can be monitored. We interpret the human joystick commands into USV's desired speed, yaw rate, and heading angle commands. next, we developed a control algorithm for the desired target values of MIMO actuators (engine speed, bucket step, nozzle angle, and bow thruster state) to follow the interpreted commands. The validity of the control algorithm is confirmed through simulations and sea trials at Gwang Am port.