| Trimaran is one of high performance ships investigated during the past 20 years. It has already been applied in many fields. Because the trimaran has a fast speed, most trimarans use waterjet propulsion, waterjet propels the ship by the inverse thrust through sucking water from the bottom and then ejecting water away from the stern. Because of its excellent performance in propulsion and anti-cavitation, it has become the most propulsion of high-speed ships and warships. And how to improve the efficiency of waterjet propulsion has become a study emphasis of research institutions, because of its structure is more complex than propeller’s, and there are many factors that influence efficiency of propulsion and restraining each other. Therefore, how to design and select relevant parameters of water jet propulsion system is a challenges in the field of water jet propulsion research.The research object in this thesis is an aluminum-alloy high-speed trimaran with 120-meter and waterjet propulsion. The main content is discussed as follows:1. Introducing the development history and research status of trimaran and waterjet propulsion. And discussing the theory and structure of water jet propulsion.2. Establishing 3D model of the 120-meter aluminum alloy high-speed trimaran and waterjet propulsion mechanism. Analyzing the flow field and obtain resistance prediction of trimaran by simulation of naked hull and hull equipped with waterjet device using CFD method. According to the ship obstacle under different speeds, the required flow rate Q is calculated. And the reason of obstacle increasing is concluded.3. Using parameterized modeling method to design seven different flow optimization schemes.4. Establishing 3D model of impeller, then calculated the schemes under different rotation. Researching the change of flow field, and analyzing the flow field within the pump features and factors affecting propulsive efficiency. |
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