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

A surface cavitation and semi-balanced technology, which is applied in directions such as rudder steering and steering, can solve the problems of inconvenient draft maintenance, increased propeller load, and drastic changes in wake field, etc., and achieve the effect of reducing cavitation and reducing water flow

Active Publication Date: 2008-05-28
HUDONG ZHONGHUA SHIPBUILDINGGROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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.)

Method used

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

Examples

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Embodiment Construction

[0026] Next, we take the rudder cavitation model test of a semi-balanced suspended rudder of a 5000TEU class container ship as an example, and describe in detail the method of reducing the cavitation phenomenon on the surface of the rudder blade of the semi-balanced suspended rudder at the stern of the ship. The test was carried out in a cavitation water tank of a ship transportation science research institute.

[0027] See Fig. 2, Fig. 2 is the schematic diagram of the measures taken by the present invention for the cavitation phenomenon at the lower edge of the semi-balanced suspension rudder blade. 1 in the figure is the rudder bearing, and what 2 represents is the rudder blade. The method of the present invention is to change the right angle of the lower edge of the conventional rudder blade into a circular arc, as indicated by the arrow in the figure, the circular arc makes the water flow smoothly transition and reduces the cavitation phenomenon caused by the propeller ti...

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Abstract

The invention relates to a method reducing cavitation on the surface of a half-balanced suspension rudder leaf at the tail of the 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 at the 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 the rubber supporting 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...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B63H25/38
Inventor 左德权陈晓莹
Owner HUDONG ZHONGHUA SHIPBUILDINGGROUP
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