| Summary: | 碩士 === 國立臺灣海洋大學 === 系統工程暨造船學系 === 98 === A new type 4-blades CLT propeller with area ratio of 0.785 is designed, and the new-foil section is adopted for its blade and end-plate design. The intersection between the propeller tip and endplate is modified to a round radius with 2 times maximal thickness at tip. The open water test of the propeller is carried out in NTOU medium-sized cavitation tunnel for the boat speed operated between 28 to 40 knots at inclined shaft 8° and 10°. Whether the thrust breakdown at low cavitation number and at inclined shaft condition can be improved due to the fact that the pressure side of the CLT propeller contributes more thrust than the suction side and that the sections at the tip generate more thrust than those of conventional propellers, will be investigated in this paper.
From the results of the experiment, it is shown that the efficiency of the CLT propeller is good for all cavitation numbers. The thrust breakdown of the CLT propeller at low cavitation number has been improved in comparison with cupped propeller. Futhermore, the fluid separation from the upper surface of end-plate to the suction side of propeller tip has also been improved. However, the angle of attack of the end-plate is still high when blade rotates to upper position at inclined shaft condition.
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