Nozzle apparatus for propelling craft

Abstract

Abstract PURPOSE: To facilitate the production of a nozzle and improve the propelling efficiency of a screw, in a nozzle surrounding a screw propeller, by locating the blade tip of the propeller in front of the boundary line between the front inner surface and the rear inner surface of the nozzle. CONSTITUTION: The intersecting point P between the propeller axis central line 4 and the central line 17 of the nozzle outer surface is arranged in front of the propeller center 0, while the intersecting point Q between the propeller axis central line 4 and the central line 18 of the nozzle rear inner surface is arranged in the rear of the propeller center 0. The blade tip of a screw propeller 2 is located in front of the boundary line 22 between the front inner surface and the rear inner surface of the nozzle. The nozzle inner surfaces 20a and 20b in front of the boundary line 22 are constituted so as to be axially symmetric with respect to the propeller axis central line 4. The nozzle inner surfaces 19a and 19b in the rear of the boundary line 22 are constituted so as to be axially symmetric with respect to the nozzle rear inner surface central line 18. Moreover, the nozzle outer surfaces 21a and 21b are constituted so as to be axially symmetric with respect to the nozzle outer surface central line 17. Thereby, production is facilitated, and the gap between the blade tip of the propeller 2 and the inner surface of the nozzle 12 will not change in the circumferential direction. Accordingly, cavitation hardly occurs, so that a nozzle performance of high propelling efficiency can be obtained. COPYRIGHT: (C)1982,JPO&Japio

Inventors

• 👤 Kinya Tamura

Bibliographic Details