Frictional resistance reducing vessel and a method of reducing frictional resistance of a hull

Abstract

The object of the present invention is to provide a frictional resistance reducing vessel and method of reducing the frictional resistance of a hull that are able to effectively conserve energy consumed during operation by reducing frictional resistance at a low level of energy consumption. In the present invention, a negative pressure region (51), which is at low pressure relative to a gaseous space, is formed in the water accompanying operation of a hull (30), and together with bubbles being guided to this negative pressure region (51) in the water from the gaseous space, the state of this negative pressure region (51) is changed based on changes in vessel velocity.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to a frictional resistance reducing vessel that reduces the frictional resistance of the hull, and more particularly, to improving the total energy efficiency by efficiently releasing bubbles into the water.[0003] 2. Description of the Prior Art[0004] A method has been proposed in the prior art for the purpose of conserving energy consumed during operation of marine vessels and so forth that consisted of reducing frictional resistance between the hull and the water by feeding a gas into the water and juxtaposition of a large number of microbubbles in the vicinity of the surface of the hull shell plate (submerged surface).[0005] Technologies for generating microbubbles in water are proposed in Japanese Unexamined Patent Application, First Publication No. 50-83992, Japanese Unexamined Patent Application, First Publication 53-136289, Japanese Unexamined Patent Application, First Publication 60-139586, Japanese Unexami...

AI Technical Summary

Benefits of technology

[0010] (1) to effectively conserve energy consumption during operation by reducing frictional resistance with a low level of energy consumption;

[0011] (2) to effectively reduce frictional resistance by efficiently mixing bubbles into the water;

[0021] In addition, the present invention is characterized by being a frictional resistance reducing vessel that reduces the frictional resistance of a hull by releasing bubbles onto the submerged surface of a hull; provided with a negative pressure forming portion arranged protruding from the submerged surface so that cavitation occurs in the water behind it due to the relative flow of water with respect to the hull during operation; a discharge outlet provided behind the negative pressure forming portion; and, a flow path of which one end is open to a gaseous space and the other end is open into the water via said discharge outlet.

[0022] In addition, the present invention is characterized by being a frictional resistance reducing vessel that reduces the frictional resistance of a hull by releasing bubbles onto the submerged surface of a hull; provided with an indentation formed so as to be recessed from the submerged surface; a negative pressure forming member, which together with being supported to as to rotate freely inside this indentation, forms a negative pressure region in the water at a low pressure relative to a gaseous space by having at least a portion protrude from the submerged surface; a flow path for guiding air from the gaseous space to the negative pressure region in the water, one end of which being open to the gaseous space, and the other end being open into said indentation; and, an angle adjusting mechanism for causing at least a portion of the negative pressure forming member to protrude in a prescribed state from the submerged surface that supports the negative pressure forming member and adjusts the angle of the negative pressure forming member.

[0023] In addition, the present invention is characterized by being a frictional resistance reducing vessel that reduces the frictional resistance of a hull by releasing bubbles onto the submerged surface of a hull; provided with an indentation provided in the submerged surface; a flow path of which one end is open to the atmosphere and the other end is open to the inside of said indentation; a wing body having a wing that is arranged within said indentation; and, a positioning mechanism that supports said wing body in a prescribed direction while allowing to move freely and positions the wing at a prescribed position; said positioning mechanism positioning the wing so that the inside of the indentation is open relative to the flow of water and results in negative pressure relative to the atmosphere during reduction of frictional resistance.

Problems solved by technology

However, in the case of blowing a gas into water using such an apparatus, since a new motive power is required to operate the apparatus, the amount of motive power conserved during operation as a result of reduction by microbubbles ends up being lost.

At locations of comparatively large water depths, such as the bottom of a large ship, in particular, it is necessary to pressurize the gas to a high pressure corresponding to the water pressure (hydrostatic pressure) when blowing the gas into the water, thereby resulting in the consumption of a large amount of energy.

In addition, in the installation of the apparatus in the hull, huge costs are incurred, such as equipment costs and installation costs.

Moreover, since the composition of the apparatus is comparatively complex, the apparatus is expensive and its maintenance and inspection are not easy.

Images