| 摘要 |
PURPOSE:To prevent the occurrence of erosion in a blade root part of a boss section by arranging a pressurized water outlet port in the upstream side part of the blade against the blade root part of the boss section having a propeller blade structure and arranging a pressurized water intake port in other part of the boss section so as to communicate with each other through a conduit arranged in the boss section. CONSTITUTION:A water jet propulsion marine vessel 10 has a water jet duct 13 in the rear part of its hull. The water jet duct 13 has a water intake port 14 and a water outlet port 15, and in the middle of those, a stationary blade 16 is employed fixedly, and at the same time a moving blade 17 is employed so as to rotate freely. The moving blade 17 is rotated with the rotation of an engine 12 through an output shaft 18, and produces jet inside of the duct 13. Here, in the moving blade 17, a pressurized water outlet port 31 is arranged in the upstream side part of the blade against the blade root part 17C of a boss section 17A fixed to an output shaft 18 and at the same time a pressurized water intake port 32 is arranged in the downstream side edge surface of the blade of the boss section 17A so that the outlet port 31 and the intake port 32 can communicate with each other through a dented conduit 33 arranged in the boss section 17A. By means of this, water pressure acting on the blade root part can be set so as not to fall below cavitation appearing pressure. |
