Method for reducing vessels stern semi-balance suspension rudder blade surface cavitation

Abstract

The invention relates to a method reducing cavitation on the surface of a half-balanced suspension rudder leaf at the tail of a ship. The method adopts the measures in the area of the half-balanced suspension rudder leaf which is easy to be cavitated: (1) the right angle at the riverside position at the lower edge of the rudder leaf is changed into fillet; (2) a guide fin is additionally added atthe vertical rudder from the lower edge of the rudder leaf to the midpoint of the central line of the oar shaft; (3) a guide bar is additionally added nearby the frontage of the connection between a rubber bearing and the rudder leaf. After adopting the method of the invention, the change of the linetype of the tangential plane of the rear rudder is flat, and the vortex cavitation of a prop can still keep vortex cavitation when floats to the lower edge of the rudder leaf and does not cavitate the rudder leaf at the position; when the rudder angle turns to a certain angle, the prop vortex cavitation floated to the position does not change the performance owning to the demulcent change of pressure field; meanwhile, with the wake flow continuing to drift to the rear of the ship, the added guide bar can reduce the water flux flowing to the clearance and leads the water flow to stably slide by; meanwhile, the unavoidable cavitation is guided out of the surface of the rudder surface, thus relieving the cavitation phenomenon at the position.

Description

technical field [0001] The invention relates to anticorrosion of ships, in particular to a method for reducing and eliminating cavitation on the surface of rudder blades of semi-balanced suspended rudders at the tail of ships. The most important object is the rudders of large high-speed container ships. Background technique [0002] With the rapid development of the international shipping industry, people's demand for ultra-large container ships is increasing day by day. In the past 20 years, the power of a single ship has increased from 30MKW to 70MKW, while the draft of the ship has basically remained unchanged. Increased power but inconvenient draft maintenance greatly increases the load on the propeller, and the trailing flow field changes drastically behind the ship, which increases the risk of cavitation of propeller blades and attachments (such as rudders, shrouds, shaft brackets, etc.) . [0003] In recent years, very obvious denudation caused by cavitation has bee...

AI Technical Summary

Problems solved by technology

Increased power but inconvenient draft maintenance greatly increases the load on the propeller, and the trailing flow field changes drastically behind the ship, which increases the risk of cavitation of propeller blades and attachments (such as rudders, shrouds, shaft brackets, etc.)

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