• Title/Summary/Keyword: Marine transport

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Design of Marine Transport Facilitie's Anti-Fouling System of Wave Power Generation (해양교통시설물의 파력발전 방오장치 설계)

  • Kim, Ji-Yoon;Jo, Kwan-Jun;Han, Sung-Hun;Oh, Jin-Seok
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2011.06a
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    • pp.192-192
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    • 2011
  • For the safety of vessels sailing Marine Transport Facility announces sea route, reefs or shallow water. Photovoltaic, independent power system, installation in the general Marine Transport Facilities to be used in the marine lantern. Due to install of communications, controls, power consumption inceases. And the weather of cloudy day or rainy, generation of electricity is decrease. Recently, power system of marine facility using a hybrid generation system, photovoltaic generation system and wave power generation system. But increase of adhered shellfish inside the water column, is the cause of the reduction of efficiency. So study was conducted to Single channel AFS(Anti-Fouling system). In this paper we offer the Multi channel AFS for Marine Transport Facility and have simulated. Improve the accuracy of the research, we using the result of anode, in the experiment were actually in the buoy, is based on simulation. The experimental results is shown every anode's, in the Marine Transport Facility, ionization was conducted identically.

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Characteristics of Fluid Flow and Heat Transfer in a Fluidized Heat Exchanger with Circulating Solid Particles

  • Ahn, Soo-Whan;Lee, Byung-Chang;Kim, Won-Cheol;Bae, Myung-Whan;Lee, Yoon-Pyo
    • Journal of Mechanical Science and Technology
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    • v.16 no.9
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    • pp.1175-1182
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    • 2002
  • The commercial viability of heat exchanger is mainly dependent on its long-term fouling characteristic because the fouling increases the pressure loss and degrades the thermal performance of a heat exchanger. An experimental study was performed to investigate the characteristics of fluid flow and heat transfer in a fluidized bed heat exchanger with circulating various solid particles. The present work showed that the higher densities of particles had higher drag force coefficients, and the increases in heat transfer were in the order of sand, copper, steel, aluminum, and glass below Reynolds number of 5,000.

Thermal-Hydraulic Analysis of Pipeline Transport System for Marine Geological Storage of Carbon Dioxide (이산화탄소 해양지중저장 처리를 위한 파이프라인 수송시스템의 열-유동 해석)

  • Huh, Cheol;Kang, Seong-Gil;Hong, Sup;Choi, Jong-Su;Baek, Jong-Hwa
    • Journal of Ocean Engineering and Technology
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    • v.22 no.6
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    • pp.88-94
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    • 2008
  • The concentration of atmospheric carbon dioxide (CO2), which is one of the major greenhouse gases, continues to rise with the increase in fossil fuel consumption. In order to mitigate global warming the amount of CO2 discharge to the atmosphere must be reduced. Carbon dioxide capture and storage (CCS) technology is now regarded as one of the most promising options. To complete the carbon cycle in a CCS system, a huge amount of captured CO2 from major point sources such as power plantsshould be transported for storage into the marine or ground geological structures. Since 2005, we have developed technologies for marine geological storage of CO2,including possible storage site surveys and basic design of CO2 transport and storage process. In this paper, the design parameters which will be useful to construct on-shore and off-shore CO2 transport systems are deduced and analyzed. To carry out this parametric study, we suggested variations in thedesign parameters such as flow rate, diameter, temperature and pressure, based on a hypothetical scenario. We also studied the fluid flow behavior and thermal characteristics in a pipeline transport system.

Applications of the Sediment-Transport Path Model to the Tidal Flats of Garolim Bay, West Coast of Korea

  • Shin, Dong-Hyeok;Yi, Hi-Il;Han, Sang-Joon;Oh, Jae-Kyung;Won, Joong-Sun
    • International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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    • v.23 no.1
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    • pp.39-51
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    • 1995
  • Bidirectional transport trend using the sediment-transport path model was identified in the two areas, sand ridge area and tidal mudflat in Garolim Bay, which is located in the mid-western coast of Korean Peninsular. This model exhibits the two-dimensional view of clear sediment transport trend based on data of changes in sediment statistics such as mean, sorting, and skewness, Garolim Bay was selected to test for the sediment-transport path model developed by McLaren and Bowles [1985]. Line-S, a typical tidal mudflat and representative of the Garolim Bay tidal flats, is well tested by this model, showing a clear seasonal change and coarsening-trend seaward (case C). This indicates that strong ebb currents carried relatively coarser sediments seaward with respect to high energy regime. Seasonally, this energy regime slowly decreases toward the summer in contrast with an increase of energy regime of flood tides, carrying coarser sediments landward (case C) in the summer. However, the Line-D area does not show consistent transport trend with respect to time-series. Separated and scattered events show fining trend landward (case B) in the sand ridge itself. The finining-trend (case B) either seaward and landward is not chiefly important in both the entire Line-D area and sand ridge itself. Also, the coarsening-Trend (case C) landward is not significant in the sand ridge itself. Consequently, in reality, the selection of suitable and representative locations are very important to fit with this model.

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A Study on Temporal-Spatial Water Exchange Characteristics in Gamak Bay using a Method for Calculating Residence Time and Flushing Time (체류시간과 교체시간 계산을 통한 가막만의 시·공간적 해수교환 특성 연구)

  • Kim, Jin Ho;Lee, Won Chan;Hong, Sok Jin;Park, Jung Hyun;Kim, Chung Sook;Jung, Woo Sung;Kim, Dong-Myung
    • Journal of Environmental Science International
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    • v.25 no.8
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    • pp.1087-1095
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    • 2016
  • The concepts of residence time and flushing time can be used to explain the exchange and transport of water or materials in a coastal sea. The application of these transport time scales are widespread in biological, hydrological, and geochemical studies. The water quality of the system crucially depends on the residence time and flushing time of a particle in the system. In this study, the residence and flushing time in Gamak Bay were calculated using the numerical model, EFDC, which includes a particle tracking module. The average residence time was 55 days in the inner bay, and the flushing time for Gamak Bay was about 44.8 days, according to the simulation. This means that it takes about 2 months for land and aquaculture generated particles to be transported out of Gamak Bay, which can lead to substances accumulating in the bay. These results show the relationships between the transport time scale and physical the properties of the embayment. The findings of this study will improves understanding of the water and material transport processes in Gamak Bay and will be important when assessing the potential impact of coastal development on water quality conditions.

Contributions of Emissions and Atmospheric Physical and Chemical Processes to High PM2.5 Concentrations on Jeju Island During Spring 2018 (2018년 봄철 제주지역 고농도 PM2.5에 대한 배출량 및 물리·화학적 공정 기여도 분석)

  • Baek, Joo-Yeol;Song, Sang-Keun;Han, Seung-Beom;Cho, Seong-Bin
    • Journal of Environmental Science International
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    • v.31 no.7
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    • pp.637-652
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    • 2022
  • In this study, the contributions of emissions (foreign and domestic) and atmospheric physical and chemical processes to PM2.5 concentrations were evaluated during a high PM2.5 episode (March 24-26, 2018) observed on the Jeju Island in the spring of 2018. These analyses were performed using the community multi-scale air quality (CMAQ) modeling system using the brute-force method and integrated process rate (IPR) analysis, respectively. The contributions of domestic emissions from South Korea (41-45%) to PM2.5 on the Jeju Island were lower than those (81-89%) of long-range transport (LRT) from China. The substantial contribution of LRT was also confirmed in conjunction with the air mass trajectory analysis, indicating that the frequency of airflow from China (58-62% of all trajectories) was higher than from other regions (28-32%) (e.g., South Korea). These results imply that compared to domestic emissions, emissions from China have a stronger impact than domestic emissions on the high PM2.5 concentrations in the study area. From the IPR analysis, horizontal transport contributed substantially to PM2.5 concentrations were dominant in most of the areas of the Jeju Island during the high PM2.5 episode, while the aerosol process and vertical transport in the southern areas largely contributed to higher PM2.5 concentrations.

A new cavitation model considering inter-bubble action

  • Shi, Yazhen;Luo, Kai;Chen, Xiaopeng;Li, Daijin;Jia, Laibing
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.13 no.1
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    • pp.566-574
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    • 2021
  • The process of cavitation involves generation, growth, coalescence, and collapse of small bubbles and is tremendously influenced by bubble-bubble interactions. To understand these interactions, a new cavitation model based on the transport equation is proposed herein. The modified Rayleigh-Plesset equation is analyzed to determine the bubble growth rate by assuming equal-sized spherical bubble clouds. The source term in the transport equation is then derived according to the bubble growth rate with the bubble-bubble interaction. The proposed model is validated by various test simulations, including microscopic bubble cloud evolution as well as macroscopical two- and three-dimensional cavitating flows. Compared with previous models, namely the Kunz and Zwart cavitation models, the newly proposed model does not require adjustable parameters and generally results in better predictions both microscopic and macroscopical cases. This model is more physical.