• Journal of Advanced Marine Engineering and Technology
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• 제40권5호
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• pp.429-436
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• 2016

Currently, many studies on green ships are under way. Fuel cell (FC) ships are of interest as future low-emission, fuel-efficient vessels. In this paper, a hybrid power management system for an FC ship was designed. The system consists of an FC, a battery, a unidirectional DC/DC converter, a bidirectional DC/DC converter, a filter, an inverter, and a propulsion component. To design the system, we analyze electric sources and converters, and create PLECS models of hybrid power management system. Then, we check the cold start sequence and perform a simulation to understand the characteristics of the hybrid power management system in an FC ship.

• Journal of Advanced Marine Engineering and Technology
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• 제33권4호
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• pp.484-496
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• 2009

The strengthened regulations for atmospheric emissions from ships like MARPOL Annex VI have caused a necessity of new, alternative power system in ships for the low pollutant emissions and the high energy efficiency. This paper attempts to investigate the configuration of SOFC/GT hybrid power system for LNG tanker taking into account the safety and to analyze the influence of design parameters on the system performance. The simulation results provide the basic data for the design and efficiency improvement of SOFC/GT hybrid system and indicate the guidelines for the safe system operation.

• International Journal of Naval Architecture and Ocean Engineering
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• 제2권4호
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• pp.211-216
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• 2010

Recently a Wide Chord Tip (WCT) propeller has been developed and applied to a commercial ship by STX Offshore & Shipbuilding. It is reported that the WCT propeller significantly reduces pressure fluctuations and also ship's noise and vibration. On the sea trial, vibration magnitude in the accommodations at NCR was measured at 0.9mm/sec which is only 10% of international allowable magnitude of vibration (9mm/sec). In this paper, a design method for increasing performance of the marine propellers including the WCT propeller is suggested. It is described to maximize the performance of the propeller by adjusting expanded areas of the propeller blade. Results show that efficiency can be increased up to over 2% through the suggested design method.

• 해양환경안전학회지
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• 제20권3호
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• pp.296-303
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• 2014

The Axiom propeller is a unique 3 bladed propeller and it enables to generate the same amount of thrust going ahead as it does going astern because of its 's' type skew-symmetric blade section. A earlier variant of the design (Axiom I propeller) performed a low propeller efficiency, maximum 35 % efficiency, and further blade outline design was carried out to achieve a higher efficiency. The optimized new blade outline (Axiom II propeller) has more conventional Kaplan geometry shape than Axiom I propeller. Model tests of open water performance and propeller cavitation for both propellers were conducted at Emerson Cavitation Tunnel in order to compare their performances. Experiment results revealed that Axiom II propeller provides a maximum 53 % efficiency and provides better efficiency and cavitation performance over the Axiom I propeller under similar conditions.

• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.76-83
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• 2005

Membrane type LNG Carriers are characterized by their special structures such as trunk deck above upper deck. It is necessary to introduce an appropriate structure arrangement taking into account transition of the trunk deck to the upper deck or deckhouse in fore and aft parts. The transition area at aft part -from trunk deck to the deckhouse - is to be specially considered because of high longitudinal stresses applied at the area. This study has been carried out to tackle the transitional structure problem in design stage This paper deals with not only mesh size of FE models for scantling evaluation and fatigue assessment but also technical issues regarding fatigue assessment.

• 한국기계가공학회지
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• 제18권4호
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• pp.48-55
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• 2019

With recent rapid increases in the power generation capacity of offshore wind power generators, reliable structural analysis of the large-scale infrastructure needed to install wind power generators at sea is required. Therefore, technology for heavy marine equipment such as barges and excavation equipment is needed. Under submarine conditions, rock drilling technology to install the substructure for offshore wind pile excavation is a very important factor in supporting a wind farm safely under dynamic loads over periods of at least 20 years. After investigating the marine environment and on-site ground excavation for the Saemangeum offshore wind farm, in this study we suggest.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 추계학술대회
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• pp.676-678
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• 2021

본 논문은 해상 및 산업용 IoT 서비스를 위한 에지 기기의 설계에 대해 설명한다. 에지 기기는 IoT 센싱 데이터를 수집하여 외부 망을 전달하는 역할만을 수행하도록 설계되었고, 통신 방식은 사용 LoRa와 LTE Cat.M1을 적용하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 Asia Navigation Conference
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• pp.184-190
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• 2006

It is requested to be evaluated whether environmental change in marine traffic passage by maintenance work affect ship handling, safety, when re-design of traffic passage is planned. In the maintenance work, it is also important to evaluate the change of risk and also benefits. However, in a current evaluation index, it is difficult to evaluate the benefit. The recently developed safety index that is led by employing the Unsafe Ship-handling situations model (US-model) is able to estimate risk level of marine accident in a process of a ship handling. We have already reported the relation of the ratio of 10-3 in harbors (Yokohama, Kobe, and Osaka in Japan) [1]. In this study, we acquired the relation of the ratio between the US value and the marine accident at a narrow waterway; Kurushima Strait in Japan, using a ship handling simulator. And we experimented to estimate a marine accident reduction achieved by the maintenance work of the altered shape of passage.

• 대한기계학회논문집A
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• 제40권1호
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• pp.121-128
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• 2016

본 연구는 선박용 프로펠러 주물 생산을 위한 후란주형 설계 및 가공 시스템을 개발하였다. 대형 선박용 프로펠러는 시멘트 혹은 후란 소재로 상형 및 하형 주형을 제작하고, 주조를 통해 소재를 제작한다. 이후 주물소재에 대한 일련의 기계가공 및 사상을 거쳐 제품을 완성한다. 기존 후란주형은 수작업을 통한 조형을 통해 제작되므로 세부 공정이 많아질뿐더러, 상당한 소재여유가 존재함으로써 기계가공 및 사상 공수가 증가한다. 이에 따라 후란주형의 제작 정밀도를 향상하고, 생산과정의 표준화 및 생산성 향상을 위해 설계 소프트웨어 및 6축 로봇을 이용한 후란주형 제작 시스템을 개발하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권9호
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• pp.1075-1080
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• 2014

본 연구는 5MW급 해상풍력 하부구조물개발에 있어 설계에 필요한 다양한 해양환경 조건에 대하여 높은 안정성 확보가 요구되는 해상용 풍력발전 하부구조물과 관련, 구조물의 설계방법을 제시하고 그 안정성을 고찰하여 관련 기술 분야에 기여함을 목표로 한다. 특히, 5MW급 해상풍력발전 시스템에 대해 시험영역에서 큰 바람의 방향이 지속되고 있는 동안에 동시에 발달된 파도의 계산에 대한 정보를 제공한다. 그러므로 바람의 영역과 접근하는 파동 행열간의 관련성을 검토하여 강도, 방향 그리고 시간의 이동성을 계산할 수 있음을 확인하였다. 쇄파에서의 국부적인 압력분포를 물리적인 모델링과 수치적 모델링을 통해 조사하는 것이 가능하다. 해상 풍력 에너지 변환장치의 지지구조물들에 대해 최근 적용된 구조 및 피로에 대한 평가는 일반 설계규칙에 근거했다. 5MW 해상풍력 하부구조물은 제약조건이 많아 단일구조로 취급하는데 이는 생산에서 높은 안전계수를 고려해야함을 의미한다.