RU2690642C1 - Forward end of ship hull - Google Patents

Abstract

FIELD: shipbuilding.SUBSTANCE: invention relates to shipbuilding, particularly, to design of entrance lines of ship hull. Proposed hull comprises ship fairing. Fairing is installed at least on one third of ship length and is made of separate sections arranged in pairs symmetrically to ship longitudinal axis, together forming semi-cylinder. Each section is fixed on an axis parallel to longitudinal axis of ship, with possibility of independent rotation and displacement under deck.EFFECT: ruled out capture of ship bow by wave, which increases safety of seamanship.1 cl, 2 dwg

Description

The invention relates to the field of shipbuilding, in particular to the design of the contours of the nasal tip of the hull.

Known design of the front part of the vessel of the pushing type (RU 2374120, IPC W63B 1/06, published on November 27, 2009) with transverse symmetry about the central axis, with the hull forming lines increasing in width from the baseline. Bottom is flat or has deadrise and goes into the bottom with a given bottom radius. From the bottom to the specified height, the lines forming are slightly inclined outwards. At the level of the tank deck, the shape of the line inclined outwardly stops and passes upward in the form of a curved line back towards the central axis.

This design has the following disadvantages:

- the vessel has a large sail;

- the wheelhouse is removed from the engine room, which complicates the laying of cable routes;

- poor conditions of habitability;

- hitting the waves can knock out the windows in the wheelhouse and damage the navigation equipment;

- at high wave heights they can overlap through the superstructure, while the flat surfaces of the deck will contribute to the seizure of the vessel’s nose by a wave [Burakovsky EP, Burakovsky P.Е. Some problems of ensuring the general strength of vessels in emergency situations // Proceedings of the Krylov State Research Center - Vol. 82 (366), 2014. — pp. 21-30];

- bad germination on the wave, because due to the slimness of the waterline, the ship crashes into the wave, and it twists over the bow and to the side, with the result that the bow of the ship can be caught in a wave, which will lead to the death of the ship.

Known fore end of the vessel, containing the stem, bulb fitting, bottom, deck, forecastle and bulwarks (Barabanov N.V. The design of the hull of sea-going ships. L., Shipbuilding, 1981. - 552 p., P. 181-189, figure 44) .

This design has a significant drawback in the ability to capture the nasal tip of the wave, as a result of which both the vessel may overturn and its hull may collapse due to the flat surfaces of the deck and the superstructure of the tank [Burakovsky EP, Burakovsky P.Ye. Some problems of ensuring the general strength of vessels in emergency situations // Proceedings of the Krylov State Research Center - Vol. 82 (366), 2014 — pp. 21-30]. Capturing the nasal tip with a wave means that when the deck is heavily flooded, it works submerged like a wing flowing around a fluid flow, which results in a resultant pressure force on flat surfaces, which is determined by the angle of attack and the velocity of the incoming fluid. This wrap is unstable, with the result that the resultant can at any time move away from the center plane and cause a strong roll or tipping of the vessel, or cause the hull to collapse if there is no offset of the resultant plane.

The bow end of the hull, equipped with a fairing (CN 105480384, IPC В63В 17/00, publ. 13.04.2016) was adopted as the closest analogue.

A significant disadvantage of this design is that the fairing can be installed only on a small length of the body in the nasal tip. Increasing the length of this fairing is associated with the fact that it will make it impossible to perform loading and unloading and production operations on the deck of the vessel, as well as significantly worsen the review of the master, which will lead to the occurrence of navigation accidents. With a small length of the fairing, it will reduce the loads acting on the deck of the vessel, only at low wave heights. However, more than a third of the vessel’s length can be submerged in the developed roughness, as a result of which this fairing will be ineffective and the bow of the vessel at high wavelengths will be caught by the wave, which will lead to the vessel tipping over or destruction of its hull.

The invention solves the problem of improving the safety of navigation, excluding the seizure by the wave of the nasal tip of the vessel, by creating optimal conditions for the flow around the nasal tip of the vessel for at least one third of its length when immersed in a wave in storm conditions, by reducing the resultant pressure forces and preventing the force from shifting in side of the center plane, while maintaining the usable deck area under normal operating conditions.

To obtain the required technical result, it is proposed to install the fairing in the bow end of the hull containing the deck finder at least one third of the length of the ship and make of separate sections, which should be arranged in pairs symmetrically to the longitudinal axis of the ship, together forming a half-cylinder. Each section is proposed to be fixed on an axis parallel to the longitudinal axis of the vessel, with the possibility of independent rotation and movement under the deck.

In the proposed technical solution, in the storm conditions, the fairing sections are installed above the deck at a length not less than one third of the vessel's length, as a result of which the fluid flow acts on the deck fairing, and not on the flat surface of the deck, thereby reducing the hydrodynamic force acting on the bow end, and the possibility of the displacement of this force in the direction of the diametral plane, thereby eliminating the tipping of the vessel.

On the attached graphic materials depicted:

in fig. 1 - a general view of the nasal tip of the vessel;

in fig. 2 shows section A-A in FIG. one.

The following materials are used on the graphic materials:

1 - deck;

2 - fairing section;

3 - axis of the fairing section.

The design of the bow of the hull contains the deck 1 and section of the fairing 2, mounted on the axes of the section of the fairing 3.

The nasal tip of the vessel operates as follows. When the vessel is moving under conditions of strong oncoming disturbance, the bow end can be periodically submerged in water, which leads to the appearance of a complex flow around deck 1 and causes the danger of a wave being caught by the vessel’s bow. In the proposed design, when a danger arises that a nasal tip of the vessel is captured by the wave of the section of the fairing 2, they are transferred to a position in which they form a convex cylindrical surface above the deck 1 of the vessel. In this case, when the bow end of the vessel is immersed in a wave, the fluid flow acts on the section of the fairing 2 from the convex side, thereby reducing the resultant pressure forces and eliminating the possibility of displacing this force away from the vessel’s median plane. This allows you to significantly reduce the load acting on the deck 1 of the vessel in the bow when it is wrapped. In the design of the closest analogue for the unimpeded use of deck space and maintaining a review to the navigator, the fairing can only be installed at a small length of the hull, so its effect on the hydrodynamic force acting on the deck of the vessel when it flows around will be insignificant. In addition, when immersed in the wave structure of the closest analogue, water will be poured into the cavity between the fairing and the deck, which will correspond to the flow of a concave surface fluid flow and further increase the load on the nasal tip, even compared to the flat surface of the deck .

The increase in the length of the fairing in the design of the nearest analogue is associated with blocking of the deck and the inability to carry out loading and unloading and production operations. In addition, in this case, the area of the boatmaster’s view is significantly limited, which can lead to emergencies, especially when maneuvering in ports, as well as when driving in areas with intensive navigation. In the proposed design, under normal operating conditions of the vessel, not related to the effect of developed waves on the bow, the section of the fairing 2 is removed under deck 1 by turning the section of the fairing 3 relative to the axes. This avoids the above disadvantages of the closest analogue to values at which it could have a significant impact on the magnitude of the hydrodynamic loads acting on the deck of the ship during its flow.

Thus, the force acting on the nasal tip of the structure of the closest analogue and the proposed structure can be estimated using (Kuchling X. Physics Handbook: Trans. From it. 2nd ed. - M .: Mir, 1985. - 520 p. ). Thus, a force acting on a body in a fluid flow

where C is a coefficient depending on the shape of the body, the Reynolds number (for the plate C, the _layer is 1.11, for the cylinder C, the _cylinder is 0.4);

S is the area of the largest cross section of the body in a plane perpendicular to the direction of flow;

ρ is the density of the liquid;

V is the velocity of the fluid flow incident on the body.

Since the parameters S, V, ρ are equal for the construction of the closest analogue and the proposed construction, the ratio of the forces acting on them during flow past the nasal tip is equal to the ratio of the coefficients C _layer and C _cylinder , i.e.

where F _b.a. - force acting on the structure of the closest analogue in the flow past the nasal tip;

F _pk - the force acting on the proposed design when wrapped around the nasal tip.

Thus, the proposed design, without cluttering up the deck of the vessel and not limiting the navigator’s field of view under normal operating conditions, makes it possible to reduce the hydrodynamic force acting on the bow of the vessel when it is wrapped under conditions of a stormy sea compared to the nearest analogue structure, which allows you to avoid the capture of the nasal tip of the vessel by the wave and its death, and, consequently, increase the safety of navigation.

Claims (1)

The bow end of the hull containing a deck fairing, characterized in that the fairing is installed at least one third of the length of the vessel and made of separate sections arranged in pairs symmetrically to the longitudinal axis of the vessel, together forming a half-cylinder, each section being fixed on an axis parallel to the longitudinal axis of the vessel, with the possibility of independent rotation and movement under the deck.

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