著者

尾崎 雅彦 南浦 純一 北島 良則 溝上 宗二 竹内 和久 畠中 勝則

出版者

公益社団法人日本船舶海洋工学会

雑誌

日本造船学会論文集 (ISSN:05148499)

巻号頁・発行日

no.187, pp.185-192, 2000-06

被引用文献数

3

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Ocean sequestration of the captured CO_2 from fossil fuel burning is a possible option to mitigate the increase of CO_2 concentration in the atmosphere. It can isolate huge amount of CO_2 from the atmosphere for long time in relatively low cost, if it is acceptable from the viewpoint of the oceanic environmental impact. The dissolution type treated in this paper is based on the idea that CO_2 dissolved and sufficiently diluted in seawater does no more harms than slightly increasing the concentration of CO_2 already contained in the seawater. The concept of CO_2 dispersion in the ocean depths by ship is a promising implementation for the efficient dilution. That is, liquefied CO_2 is delivered by ship to the site and injected into ocean depths of 1,000 to 2,500m with a suspended and towed pipe by a slowly moving ship. The constant movement of releasing point of CO_2 causes no stagnation and accumulation of CO_2 in seawater. The released CO_2 will form plenty of droplets, and then they rise gently due to the buoyancy, while reducing in the size to disappear by dissolution in the ambient seawater. Since the turbulent diffusion in the intermediate ocean is dominant horizontally, use of the vertical journey of CO_2 droplets will be very effective for the initial dilution. Thus, authors have good prospects for the dilution ratio of one to a hundred thousands in a couple of hours after injection on an engineering realistic scale, by means that the initial size of droplets is controlled. Drop formations from a fixed nozzle are investigated referring the common knowledge on textbooks. And the possibility of generating relatively large size of droplets from a moving nozzle is experimentally studied. As a result, it is found that the horizontal nozzle towed by the slowly moving ship is promising for the control of the drop formations in a realistic scale .

著者

溝上 宗二 黒岩 良太

出版者

公益社団法人 日本船舶海洋工学会

雑誌

日本船舶海洋工学会論文集 (ISSN:18803717)

巻号頁・発行日

vol.29, pp.1-9, 2019 (Released:2019-09-25)

参考文献数

13

被引用文献数

2

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The authors verified an energy saving effect of an air lubrication system for the domestic service ferry which was one of slender body ships. The energy saving effect was evaluated by the engine output reduction rate of system ON and OFF at speed-trial test. As the result, a net energy saving effect of about 3.7% was confirmed.After that, long-term voyage monitoring had been conducted since the ship was in service. At the same time, monitoring had been conducted about same type of sister ship without air lubrication system, in service on the same route.The investigation result of the energy saving effect by comparison of fuel consumption of both ships, a net effect of about 3.13% was confirmed. According to these results, the effectiveness of an air lubrication system for slender body ships was proved; therefore, scope of an air lubrication system as energy saving system of ships had expanded.

著者

柏木 正 杉本 健 上田 武志 山崎 啓市 東濱 清 木村 校優 山下 力蔵 伊東 章雄 溝上 宗二

出版者

公益社団法人日本船舶海洋工学会

雑誌

関西造船協会論文集 (ISSN:13467727)

巻号頁・発行日

no.241, pp.67-82, 2004-03-25

被引用文献数

4

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A prediction and analysis system for the performance of a ship in real seas is proposed and constructed, with EUT (Enhanced Unified Theory) adopted as the main calculation method. The proposed system can compute the frequency-domain response functions of the wave-induced ship motions, the distribution of the pressure and global wave loads, the relative wave height, and etc. In addition, the added resistance, wave-induced steady lateral force and yaw moment can be predicted, including effects of the bow wave diffraction, the forward speed and 3-D interactions in a rational manner. By using these results and a wave spectrum representing real irregular seas, the short-term prediction of linear responses, the averaged added resistance, and the resultant speed loss of a ship in irregular waves can be calculated with the present system. Good performance of the system is demonstrated with some comparisons to experimental results and some applications to the speed correction in the speed trial and the prediction of the speed loss in actual voyages.