• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.400-406
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• 2017

The model used in this study was reversed to analyze the cause of excessive damage that occurred inside the rotating system and pipe system of a centrifugal-type seawater pump on a ship. For this purpose, internal flow analysis on a cooling seawater pump was performed using CFD. As a result, the shape and boundary conditions of the target pump were set by reverse engineering, and pump efficiency at a design operating point of $125m^3/h$ was calculated as 85.3 % with a head of 32.0 m. The maximum efficiency point of the target pump was estimated to be 86.2 % at $150m^3/h$, but this differed from the actual operating point. At $112.5m^3/h$, which was the lowest flow point, flow was unstable due to the characteristics of the low flow point and analysis convergence was not good. The purpose of this study was to clarify the cause of ongoing cavitation in seawater pumps and piping systems in operation. Future research will be needed to clarify causes for pipe systems in the future by performing calculations for the total piping system of an inlet and outlet, in addition to measuring the flow rate of each branch pipe.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.677-687
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• 2017

Aircraft can often be exposed to a variety of environments and vibrations such as engine, hydraulic pump, aerodynamic force. These may cause cracking and destruction of the mechanical structure and sub-components by high-cycle fatigue. The axial piston type pump which is usually applied to the aircraft hydraulic pump can be necessarily accompanied by the fluid pulsation by continuous rotation of the axial piston. The fatigue crack was identified at the dampener fitting welding zone to prevent vibration damping during the running of aircraft equipped with this type of pulsation hydraulic pump. In order to understand the root cause of this matter, fracture and component analyses were carried out and also integral type dampener fitting was applied to prevent recurrence of the crack as a subject of design improvements. Structural integrity stress analysis, fatigue analysis, qualification test and aircraft system equipped test was conducted to verify the design validity in application to integral type dampener fitting. The test results were sufficiently satisfactory with the demand lifetime of the material from the various types of test as conducted and the subject of design improvement in this study could be objectively evaluated that shall be applied to the operational aircraft.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.1
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• pp.195-201
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• 2010

In this paper, a cooling system of high-power propulsion motor with Energy Saving System(ESS) is described. Normally, the cooling system for ship consists of fresh water pump, sea water pump, 3-way valve and cooler. In the cooling system, F.W(Fresh Water) and S.W(Sea Water) pump is operated on rated rpm, and the 3-way valve is controlled for preventing over-cooling. So, the consumption power of pump's motor is changed according to a sea water temperature. In the proposed cooling system, F.W. pump and S.W pump is controlled by inverter, and it is can be reduced the consumption power. Also, it is proved with simulation.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.4
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• pp.395-403
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• 2020

In this paper, the performance characteristics of the impeller and volute in the 2 vane pump were investigated using response surface method (RSM) with commercial computation fluid dynamics (CFD) code. Design variables were defined with the impeller blade angle and volute area distribution. The objective functions were defined as the total head, total efficiency and solid material size of the 2 vane pump. The design optimization of the design variables was determined using the RSM. The numerical results for the reference and optimum models were compared and discussed in this work.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.58-64
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• 2006

This work focuses on reducing the noise and vibration levels of an LPi fuel pump, which are generated from the dynamic motions of pump elements and non-uniform flow of fuel. The noise and vibration levels increase as the revolution speed of the cam goes up. The fuel pump consists of five cavity cells, plungers and diaphragms, which are driven by the cam. The optimal design of the cam profile is performed to decrease the accelerations of moving Parts and to obtain a smooth hydraulic force through a dynamic analysis of a cam-plunger mechanism. The cam-Plunger with a cavity is modeled as a 2 degrees of freedom system having non-linear contacts, the cam profile being represented in terms of Fourier series in order to determine the optimal shape of the cam. From the optimized cam Profile, the acceleration of the diaphragm is reduced in $78\%$, the hydraulic force becoming smoother in case that the hydraulic force is rapidly dropped.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.15-19
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• 2006

유출지하수나 지표수를 열원으로 하는 지열히트펌프의 Pond Loop형 열교환기를 개발하기 위하여 미국에서 상용화된 Slim-Jim 열교환기와 본 연구에서 자체설계, 제작한 Pond-loop type의 열교환기를 유동이 없는 유출수조 내에서 수조온도가 변화함에 따라 일정한 열교환기 입구온도를 유지하면서 열전달량의 변화를 측정하였다. 그 결과 유출수를 Heat Source로 사용하는 경우 Slim-Jim에서는 $8,000{\sim}11,000 kcal/hr$의 열량이 전달되었고, 자체 제작한 열교환기에서는 $11,000{\sim}16,000kcal/hr$의 열량이 전달되었다. 유출수를 Heat Sink로 사용할 경우 Slim-Jim에서는 $2,500{\sim}7,000 kcal/h$의 열량이 전달되었고, 자체제작한 열교환기의 경우, $6,800{\sim}14,00 kcal/hr$의 열량이 전달되었다. 측정된 열전달량을 바탕으로 총괄열전달계수를 구한 결과 Slim-Jim 열교환기의 경우 $210{\sim}340 kcal/hr\;m^2{\circ}C$, 자체개발한 열교환기의 경우 $350{\sim}590 kcal/hr\;m^2{\circ}C$로 나타나 자체 개발한 열교환기의 열전달 성능이 비교적 우수함을 입증하였다.

• Journal of the Korea Convergence Society
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• v.8 no.10
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• pp.185-191
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• 2017

Recently, for such reasons as its inexpensive price and eco-friendliness, LNG has been under the limelight as an alternative fuel for vessels and is expected to grow rapidly in the industry. However, the technology level of domestic shipbuilders in manufacturing the cryogenic pump designed to supply LNG for vessels is so low that design and manufacturing technology of core parts are in urgent need. Therefore, this study describes the stepwise development procedure of cryogenic submerged centrifugal pump for ship LNG supply system. And it aims to suggest practical and specific development methods of the pump by approaching the characteristics of each step and major development items from the standpoint of engineering and management.

• Journal of the Korea Convergence Society
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• v.9 no.7
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• pp.199-203
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• 2018

Because of emission control of greenhouse gas, shipbuilders, especially those in Korea, are pushing forward to introduce eco-friendly ship-building technology utilizing LNG. However, Technical skills of domestic shipbuilders in manufacturing the cryogenic pump designed to supply LNG for vessels are so low that technical skills for design and manufacturing of core parts are in urgent need. Therefore, This study described about the Rotor as a core part of cryogenic submerged centrifugal pump for ship LNG supply system. We wish to utilize for the basic data to develop the technology for the Rotor as deducing the optimal outcome with the experimental and the analytical methods in material selection.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.6
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• pp.428-434
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• 2015

The objective of the present study is to analyze the results of the trial-test for the full-scale driving pump, which is arranged in the LCT (Large Cavitation Tunnel). Firstly, the reasons of selecting the final design pump are introduced in terms of the performance analysis in model tests. The trial-test items for the full-scale driving pump are measurements of output current/voltage at the inverter of the main motor and the flow velocity in the LCT test section. The test results show the increase in flow rate of about 10.7% and the decrease in pump head of about 26%, compared with those of final design-pump specification. The motor power has the margin of about 22%. The performance analysis for the full-scale pump is conducted using the commercial code (CFX-10). The delivered power calculated with CFX-10 shows good agreement with that extracted from the full-scale pump test. It is found that CFX-10 is useful to analyze a full-scale pump.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.1
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• pp.30-37
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• 2010

In order to control the weight balance of the waterjet propulsion ship, the pump's weight needed to be decreased. We reduced length of pump hub, overall length of pump and chord length of impeller and stator. To keep pump efficiency and cavitation performance similar to the $1^{st}$design pump, optimum design and experiment were conducted. This paper describes experimental method and numerical analysis for pump design. At the blade design stage, performance analysis of the pump is conducted using commercial CFD codes ($BladeGen^+$,CFX-10). Required performance and cavitation characteristics of the design pumps were measured and observed using the stand-alone test apparatus. The weight of the pump was successfully decreased through a series of pump design processes composed of blade design, performance analysis and model test.