• Journal of Advanced Marine Engineering and Technology
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• 제40권3호
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• pp.185-190
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• 2016

선박이 고출력화, 초대형화 됨에 따라 대형저속 2행정 엔진을 탑재한 선박에서 축계배치의 잘못에 기인하는 주기관 선미측 베어링과, 선미관 후부 베어링의 손상이 증가하는 경향이 있다. 또한 고출력화에 의한 추진축의 강성은 증가한 반면에 선체는 고장력 후판을 사용하므로 이전의 선체보다 훨씬 더 쉽게 변형하는 실정이다. 이는 기존의 선박보다 더욱 정교한 축계배치가 요구됨을 의미한다. 본 연구에서는 열팽창 효과, 감도지수를 이용한 중간축 베어링의 최적위치 선정 및 베어링의 강성을 고려하여, 베어링의 하중 분석 및 영향 계수를 분석함으로서 축계 배치가 이론적으로 최적이 되는 것을 검토하였다. 이를 위하여 축계 배치 계산시 대형 엔진 제조사의 엔진 거치기준을 참조하고, 한국선급 및 DnV 선급의 축계 배치 프로그램을 이용하여 검토하고 그 신뢰성을 검증하였다.

• 해양환경안전학회지
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• 제14권1호
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• pp.83-87
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• 2008

산유국으로부터 에너지 독립을 하고 대기오염방지를 위한 배기배출물을 저감시키기 위하여 대체연료에 많은 관심을 가지고 있다. 폐유나 새로운 식물성 기름과 동물성 기름으로부터 생성할 수 있는 바이오디젤유가 압축점화기관인 디젤기관에 구조적인 변화없이 사용될 수 있다. 이 논문에서는 4행정 직접분사식 디젤기관을 이용하여 순수 디젤유와 바이오디젤 혼합유(바이오디젤 10% 및 20% 함유)의 연료소비율과 배기배출물에 미치는 영향을 제시했으며, 특히 실험에 사용된 바이오디젤 연료는 우리 실험실에서 유채유로부터 직접 생산되었다. 이 연구 결과 바이오디젤 혼합유가 디젤유 보다 연료소비율과 질소산화물은 약간 증가 되었고 일산화탄소와 매연은 상당히 감소되었다.

• 한국항해항만학회지
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• 제39권6호
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• pp.457-463
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• 2015

가스터빈 기관은 우주항공, 발전 플랜트뿐만 아니라 해상운송 분야에 사용되는 원동기로서 매우 중요한 역할을 하고 있다. 그러나 그 구조가 복잡하고 연소과정에서 시간지연 요소가 포함되어 있어 가스터빈 기관을 잘 제어할려면 정교한 수학적 모델링이 필요하다. 본 논문에서는 가스터빈 기관의 주요 구성품인 가스발생기, PLA 액추에이터, 미터링 밸브에 대한 모델링 기법을 설명한다. 또한, 가스터빈 기관의 시운전 데이터를 기초로 몇 가지 정상상태 때의 동작점에서 서브모델을 구하고, 각 서브모델에 대해 비선형 비례적분미분 제어기를 설계하여 기관의 속도를 제어하는 방법을 제안한다. 제안하는 비선형 제어기는 비선형 함수로 구현되는 3가지 이득을 사용한다. 비선형 제어기의 파라미터는 제어시스템의 목적함수를 최소화하는 관점에서 실수코딩 유전자알고리즘으로 동조한다. 제안한 방법은 가스터빈 기관에 적용하고 시뮬레이션을 실시하여 그 유효성을 확인한다.

• 한국정밀공학회지
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• 제29권2호
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• pp.139-146
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• 2012

A multi-tasking machine tool for large scale marine engine crankshafts has been developed together with design technologies for its special devices. Since work pieces, that is, crankshafts to be machined are big and heavy; weight of over 100 tons, length of 10 m long, and diameter of over 3.5 m, several special purpose core devices are necessarily developed such as PTD (Pin Turning Device) for machining eccentric pin parts, face place and steady rest for chucking and resting heavy work pieces. PTD is a unique special purpose device of open-and-close ring typed structure equipped with revolving ring spindle for machining eccentric pins apart from journal. In order to achieve high rigidity of the machine tool, structural design optimization using TMSA (Taguch Method based Sequential Algorithm) has been completed with FEM structural analysis, and a hydrostatic bearing system for the PTD has been developed with theoretical hydrostatic analysis.

• Journal of Advanced Marine Engineering and Technology
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• 제39권6호
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• pp.599-603
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• 2015

탄소배출과 관련된 선박규제가 강화되면서 효율향상에 대한 많은 연구가 진행되고 있다. 이러한 기술들은 현존선에 적용이 어려우며 많은 비용이 소요된다. 본 논문은 기존의 선박에 우선적용이 가능한 연료유 이송시스템에 관한 것으로 저장탱크의 구조를 개선하였으며 이를 계산적으로 분석하였다. 저장탱크의 격벽을 설치하고 격벽에 마련된 홀 위치의 변경 및 격벽을 교차하여 이중으로 설치한 경우에 대하여 계산을 수행하였다. 이중 격벽의 경우가 에너지 손실을 최소화 하면서 효율적으로 연료를 이송하는 결과를 나타내었다.

• Journal of Advanced Marine Engineering and Technology
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• 제24권3호
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• pp.52-57
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• 2000

This study intends to reduce the weight of structure without changing the dynamic characteristics. At first, the Vibration analysis by the Substructure Synthesis Method and FFM using the ANSYS are performed for the engine speed converter to confirm the reliability of the analyzing tools. Weight minimization is performed by the Sensitivity Analysis and the Optimum Structural Modification. To decrease the converter weight ideally, the parts with low sensitivity are to be cut mainly, and the changing quantity of the natural frequency by the cut is to be recovered by the weight modification of the parts with high sensitivity. As the unique mathematical solution for the homogeneous problem(i.e. 0 object function problem) does not exist, the converter is redesigned with much thinner initial thickness. The goal of this study is to recover the dynamic characteristics of redesigned structure to those of the original one. To say in the other words, the modified structure has the same dynamic characteristics and the more lighter weight to compare with the original one.

• 한국해양공학회지
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• 제23권3호
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• pp.46-52
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• 2009

Nowadays, many components in automobile, aircraft, offshore structure and industry require lightness and high strength. However, since developments of advanced materials have limitations, it mainly is applying to method of surface hardening. This study offered research about camshaft that is one among engine important component. The material used in this study is 0.53% carbon steel as structure material of camshaft, splineshaft, coupling, pulley, driveshaft et cetera. Camshaft is processed using mainly carbon steel, and receives wear and fatigue by special quality high speed of parts. Therefore, camshaft need surface hardening to improve camshaft's fatigue life and increase durability of engine. This study compare to residual stress and martensite microstructure created by high frequency induction treatment, and these results lead to the conclusion of fatigue crack growth characteristics.

• 동력기계공학회지
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• 제9권4호
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• pp.65-70
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• 2005

A liquid storage rectangular tank structures are used in many fields of civil, mechanical and marine engineering. Especially, Ship structures have many tanks in contact with inner or outer fluid, like ballast, fuel and cargo tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these thin walled tanks in contact with fluid near engine propeller are strongly affected by added mass of containing fluid. Therefore it is essentially important to estimate the added mass effect to predict vibration of the tank structures. Many authors have studied vibration of cylindrical and rectangular tanks structures containing fluid. Few research on dynamic interaction among tank walls through fluid are reported in the vibration of rectangular tanks recently. In case of rectangular tanks, structural coupling between adjacent panels and effect of vibration modes of multiple panels on added mass have to be considered. In the present paper, coupling effect between panels of tank structure on added mass of containing fluid, the effect of structural constraint between panels on each vibration mode for fluid region have investigated numerically and experimentally.

• 대한조선학회논문집
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• 제41권6호
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• pp.120-125
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• 2004

There are very few numbers of 115K FPP (Fixed Pitch Propulsion) Tankers for the Baltic ice class IA because the minimum power requirement of FMA (Finish- Swedish Maritime Association) needs quite large engine power and the 40 m Beam is out of calculation range of FMA minimum power requirements. The shipyard has no choice except to increase the engine power to satisfy FMA minimum power requirement Rule. And the operation cost, efficiency of hullform and its building cost are not good from the ship owners' point of view To solve this problem, the experience of ice breaking tanker development and the ice tank test results were adopted. The main idea to reduce the ice resistance is by reducing waterline angle at design load waterline. The reason behind the main idea is to reduce the ice-clearing force. Two hull forms were developed to satisfy Baltic Ice class IA. Two ice tank tests and one towing tank test was performed at MARC (Kvaener-Masa Arctic Research Center) and SSMB (Samsung Ship Model Basin) facilities, respectively. The purpose of these tests was to verify the performance in ice and open water respectively The hull form 2 shows less speed loss compared to Hull form 1 in open water operation but hull form 2 shows very good ice clearing ability. finally the Hull Form 2 satisfying Baltic ice class IA. The merit of this hull form is to use the same engine capacity and no major design changes in hull form and other related designs But the hull structure has to be changed according to the ice class grade. The difference in two hull form development methods, ice model test methods and analysis methods of ice model test will be described in this paper.

• Journal of Advanced Marine Engineering and Technology
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• 제30권3호
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• pp.351-358
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• 2006

The capability of high pressure injection with small fuel quantify at all engine operating conditions is one of the main feature in common rail fuel injection system, which is used in small and light-duty Diesel engine. The key parameter for the better atomized fuel sprays and multiple injections of this common rail fuel injection control, that can be freely selected irrespective of the engine speed and load is the mechanism controlling the needle energizing and movement in high pressure Diesel injector. In the electro-hydraulic injector, the injection nozzle is being opened and closed by movement of the injector's needle which is balanced by pressure between the nozzle seat and the needle control chamber. This study describes the macroscopic spray structure characteristics of the common rail Diesel injectors with different electric driving method i.e. the solenoid-driven and piezo-driven type. The macroscopic spray characteristics such as spray tip speed. spray tip penetration and spray cone angle were investigated by the high speed spray, which is measured by the back diffusion light illumination method with optical system for the high speed temporal photography in a constant volume chamber pressurized by nitrogen gas. As the results, the prototype piezo-driven injector system was designed and fabricated for the first time in domestic case and the effect of injector's needle response driven by different drive type was compared between the solenoid and piezo-driven injector It was found therefore. that the piezo-driven injector showed faster needle response and had better needle control capability by altering the electric input value than the solenoid-driven injector.