Study on the Application of Micro-Bubble Drag Reduction Technique in ship Model

• Main Authors: Yu-Ming Wang, 王郁銘
• Other Authors: 蔡進發
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/41623831312779277096

碩士 === 臺灣大學 === 工程科學及海洋工程學研究所 === 98 === Energy saving and carbon reduction is one of the most important research in the world. With more than 80% of international trade in goods being carried by sea, reducing the resistance and raising the efficiency of ship propulsion is a great contribution to Energy saving and carbon reduction. The major target of the research is to develop the most promising and cleaning micro-bubble drag reduction technique in ship model. It is expected to develop a micro-bubble drag reduction technique which can be applied to the full scale ship. There are three micro-bubble generated methods used in this research. It includes pinhole, air/water mixer and porous plates. The pinhole method was not used in the drag reduction test because the air injected by pinhole is accumulated and form large bubble. The air/water mixer and aluminum porous plates were used to reduce the drag of flat-plate in towing tank. The drag reduction rate of aluminum porous plates was better than air/water mixer as shown from the test results. The 31.6% drag reduction was obtained by the micro-bubble generated by Aluminum porous plates when the model velocity is 3.6m/s. Thus the aluminum porous plates have been selected to apply on the ship model to verify the drag reduction effect. There are three aluminum porous plates have been installed on a flat bottom of ship model. The best drag reduction rate of 7.2% was found in this test. For better micro-bubble coverage, the bulb bow injector was set up on the ship model. The 9.6% drag reduction was obtained when both of bulb bow injector and aluminum porous plates operated at the same time. The test results prove that the better micro-bubble coverage bring the better drag reduction rate.