マリンエンジニアリング
Online ISSN : 1884-3778
Print ISSN : 1346-1427
ISSN-L : 1346-1427
44 巻 , 5 号
選択された号の論文の29件中1~29を表示しています
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  • 桑島 隆志, 伊丹 良治
    2009 年 44 巻 5 号 p. 782-786
    発行日: 2009年
    公開日: 2012/10/25
    ジャーナル フリー
    The propulsion efficiency of a ship is affected by the fouling of the propeller and ship's hull surface. Fouled surfaces decrease the propulsion efficiency of a ship, and consequently main engine fuel consumption; this increase is due to the torque-rich condition of the main engine.It is well understood that the coating on a propeller and on a hull can protect the propeller and hull surfaces from fouling. It enables us to maintain the service speed of the ship over long periods. Marine engineers check also periodically note the rpm margin of engine output. In the T.S KAIGI-MARU, three kinds of surface treatment were applied during dry docking and over three years. To determine the most effective treatment, three different kinds were employed, for maintaining high propulsion efficiency. The data was then collected for the rpm margin.In this paper, the fouled conditions of the propeller and hull surfaces were estimated by analyzing the rpm margin, so in order to find the optimum Dry Dock Time.
  • 岩野 淳一, 廣岡 秀昭, 近藤 健介, 志垣 富雄, 小山 健夫, 濱田 和光, 高橋 寿和, 梶山 勝徳, 藤原 崇
    2009 年 44 巻 5 号 p. 787-792
    発行日: 2009年
    公開日: 2012/10/25
    ジャーナル フリー
    The governor has been the key component in the operation of the stable-heat engine since the invention of Stevenson's "Rocket". However, concerning the operational management of the marine diesel engine, doubts have been expressed as to whether it is required. Under seagoing conditions and against the always-changing resistance of the ocean, we do continually control the volume of the fuel-oil supply, so as to maintain constant engine speed. On the other hand, this leads to the doubt as to whether harder operations are forced onto marine diesel engines. This project was to return to the starting point and reconsider the definition of the governor's purpose. We focused attention on the idea that it might be better - in terms of both fuel-oil consumption and engine load - to maintain a stable ignition pressure within each cylinder, and then allow the engine's revolutions to vary, somewhat. We stopped the former practice of micro-controlling the amount of fuel oil supplied. We then changed fuel-oil supply comparatively slowly. And although engine speeds vary, the average engine speed remains generally as before. This paper introduces the basic research results gathered from container vessels in the development of a "fuel save mode" control system, one built around the new governor.
論文
  • 西村 龍夫, 川原 秀夫, 畑岡 完
    2009 年 44 巻 5 号 p. 793-800
    発行日: 2009年
    公開日: 2012/10/25
    ジャーナル フリー
    With lift flames in a diffusion combustor, there is partially premixed combustion at the base of the flame, and the flames have various flame characteristics, such as extinction and re-ignition phenomena. Elucidating those combustion mechanisms is also useful and interesting from the standpoint of discussing flame stability. In this research, we have examined the characteristics of lift flames observed in a bluff body combustor, and the effects which the behavior of annular air flow have on these flame characteristics. The results showed that there is a hysteresis phenomenon whereby the flame configuration varies under the same conditions during an increase and decrease of the fuel flow velocity. It was found that the range where this phenomenon occurs varies greatly depending on the flow velocity of the annular air. In addition, when the flow velocity of the fuel was fixed and the flow velocity of annular air was changed, the bifurcation phenomenon in the flame form was observed.
  • Tran Hong Ha, 西田 修身, 藤田 浩嗣, 原野 亘
    2009 年 44 巻 5 号 p. 801-807
    発行日: 2009年
    公開日: 2012/10/25
    ジャーナル フリー
    ディーゼル機関の排ガス中の微粒子(DPM)を取り除くために静電噴霧スクラバーを排ガス処理に適用した.このスクラバーがDPMや大気汚染物質を処理する効果を実験的に研究した.噴霧水とDPMとをそれぞれ反対の極性に高度に帯電させることによって,0.1から2.5μmの微粒子を高い効率で除去することが可能である.同時に,酸性物質や腐食性ガスも従来のスクラバーと同程度に除去される.DPMの捕集効率は,DPMの粒子径,噴霧粒子径,帯電力および機関負荷に依存する.無帯電噴霧,または帯電噴霧と比べて,水とDPM両方の粒子を帯電させた本方法では,高い微粒子捕集効率が得られ,排ガス処理装置として有効に作用する.
  • Tran Hong Ha, 西田 修身, 藤田 浩嗣, 原野 亘
    2009 年 44 巻 5 号 p. 808-815
    発行日: 2009年
    公開日: 2012/10/25
    ジャーナル フリー
    本研究はディーゼル微粒子を静電水スクラバーにて集める数学的モデルである.本モデルはガス流体のモーメンタム,水粒子径並びに電場を考慮している.作動パラメーターにはスクラバー内のガス流,水流,微粒子の集塵能力を考慮している.微粒子と水滴への荷電が増すほど粒子集塵力が増す.スクラバー入口,出口での粒子捕集能力を求めることができ,計算と実験の良い一致を得ることができた.
  • 齋藤 年正
    2009 年 44 巻 5 号 p. 816-823
    発行日: 2009年
    公開日: 2012/10/25
    ジャーナル フリー
    Numerical calculations were performed in the investigation of the elasto-hydrodynamic lubrication characteristics of a stern tube bearing; several main characteristic values were determined. When the stern tube bearings are not parallel to the propeller shaft, the magnitude of the maximum oil film pressure, generated in the bearing, increases significantly. The magnitude of the maximum oil film pressure generated is greatly affected by the attitude angle of the shaft. As the attitude angle of the shaft is varied between 90 and 180 degrees, the maximum oil film pressure gradually increases. If the eccentricity at the centre of the bearing, and the angle of the shaft centre relative to the bearing's centre, and the attitude angle of the shaft can be determined, then it is possible to quantitatively determine the maximum oil film pressure. This, by taking the elastic deformation of the bearing into account, as described in this paper.
  • 西岡 俊久, 廣岡 佑亮, 元 瑛俊, 周 广勤, 藤本 岳洋
    2009 年 44 巻 5 号 p. 824-829
    発行日: 2009年
    公開日: 2012/10/25
    ジャーナル フリー
    Generally, crack shape which exists in a three-dimensional structure, can be approximated as part of an elliptical crack. High precision evaluations of the stress intensity factor are necessary for the prediction of growth, and unstable fracture of the crack, in such a structure. However, it is difficult to obtain the high precision stress intensity factor if element subdivision is not made fine. This, in the singularity vicinity; such as a crack front. In general, numerical methods for analysis, use such as the Finite Element Method or Boundary Element Method. Also, using general numerical method for analysis, the calculation time becomes very large, to analyze interference problem of the crack group, requiring complicated element subdivision. By using Finite Element-Alternating Method, it is possible to obtain the solution with good accuracy and without completely modeling the crack.In this study, we evaluated by this method, the interference degree between a surface crack and the oil hole in the crank shaft.
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