RU2248302C1 - Marine propulsion plant of "steering nozzle" type - Google Patents

Abstract

FIELD: shipbuilding; marine propulsion plants of "steering nozzle" type.

SUBSTANCE: proposed propulsion plant of "steering nozzle" type includes one or two propellers with transmission located in streamlined casing; blades of at least one propeller are movably secured in hub for motion relative to plane of propeller disk and turning around axis passing through blade root and displacement along this axis. Axis along which blade turns and/or shifts is perpendicular to propeller disk; axis relative to which blade turns is parallel to propeller disk and is located in its plane. Each blade of propeller may turn through angle of ±10 deg and turning unit is provided with blade position retainer.

EFFECT: improved service characteristics; reduction of disturbances in the course of maneuvering and reversing; reduction of transversal force arising on operating propeller.

6 cl, 3 dwg

Description

The invention relates to the field of shipbuilding, in particular to ship propulsion systems of the type "rotary column".

Known propulsion system of a ship of the type "rotary column" containing a propeller with a mechanical transmission, including horizontal and vertical lines of drive shafts located in a streamlined hull and a vertical strut of the rotary column (see the book A.D. Hoffmann "Propulsion-steering complex and maneuvering ship ". Shipbuilding. Leningrad. 1988, p. 17).

Also known is the propulsion system of a ship of the "rotary column" type, containing a propeller with an electric transmission, including an electric motor with a horizontal drive screw, placed in a streamlined casing (see the magazine "Navigator", International Maritime Journal No. 2/94, p. 8, photo - propulsion type "Azipod").

The disadvantage of these marine propulsion systems is the increased level of vibration of the propeller when turning the unit for maneuvering.

The closest technical solution to the claimed one, adopted as a prototype of the invention, is a rotary column propulsion system containing two coaxial propellers of a fixed pitch of opposite rotation with a mechanical transmission located in a streamlined casing (see the journal "Navigator", International Maritime Journal No. 2/94, pp. 8-26, 27. Weikkola weights “Counter-rotation propellers developed by Aquamaster increase the safety of tankers”).

The disadvantage of this prototype is the increased level of vibration of the propellers when turning the column to maneuver the vessel or ensure its reversal. When the column is rotated, the propellers find themselves in a strongly oblique flow, which causes the appearance of periodic hydrodynamic forces on the propellers, which cause the vibration of the "rotary column" type propulsion as a whole. The greatest hydrodynamic loads, which are the cause of increased vibration of the propellers, occur in the transition to reverse in the reverse jet mode (see the Handbook on the theory of the ship, vol. 1. Shipbuilding. Leningrad. 1985, p. 723). The increased vibration level of the propulsion system makes it necessary to limit the angle of rotation of the column or the speed of its shifting, reduce the speed during maneuvering and reduce the speed of rotation of the propellers. The increased level of vibration reduces the reliability of the propulsion system and affects the habitability of the vessel. The limitation of maneuvering parameters leads to an increase in the probability of a collision of vessels, i.e. is the reason for the decrease in safety of navigation. In addition, fixed-pitch propellers in non-design modes do not allow the full power of the power plant to be used and work with reduced hydrodynamic efficiency due to the presence of residual flow swirling behind the propellers (this drawback is valid when driving from a diesel power plant and can only be eliminated by using variable-pitch propellers) .

Another reason that worsens the performance of the columns is due to the fact that when it is shifted at full speed, a transverse force arises, which prevents the column from turning and, therefore, leads to the need to increase the power of the steering machine. The emergence of a significant transverse force due to the mowing of the flow relative to the column when it is rotated.

The proposed technical solution is aimed at improving the operational characteristics of the ship propulsion system of the "rotary column" type, namely: reducing the disturbing forces of a hydrodynamic nature that arise on the propeller blades during the maneuvering of the vessel and its reversal; reduction of the transverse force arising on the working screw when the column is rotated, and, thereby, reducing the power of the drive ensuring its transfer.

Reducing the disturbing forces of a hydrodynamic nature will lead to a decrease in the vibration of the propulsion system, improve the habitability of the vessel, as well as the characteristics of controllability and maneuverability (by eliminating restrictions on the angle of rotation of the column and the speed of its rotation). In addition, in non-design modes, even with a diesel drive, a propulsion system with a movable blade mount on the hub uses the full power of the engine and eliminates the need for adjustable pitch propellers.

The specified technical result is achieved by the fact that in a ship propulsion system of the "rotary column" type, containing one or two propellers with a gear located in a streamlined casing, the blades of at least one screw are fixed in the hub movably with the possibility of moving them relative to the plane of the propeller disk by turning around an axis passing through the root of the blade, and (or) their displacement along this axis; the axis relative to which the blade rotates and (or) moves, perpendicular to the propeller disk; the axis relative to which the blade rotates is parallel to the plane of the propeller disk and is located in the plane of the propeller disk; each propeller blade is mounted rotatable by an angle of ± 10 °; grooves are made in the hub in the plane of the propeller disk, in which the root parts of the propeller blades and the knot of rotation and (or) displacement of the blades with a damper are placed; the rotation and (or) displacement unit of the blade is equipped with a blade position lock.

The invention is illustrated by the drawing, figure 1 schematically shows a side view of a ship propulsion system of the type "rotary column"; figure 2 and 3 - mounting options for the aft parts of the blades in the hub of the screw (increased).

An example of a specific implementation of the claimed technical solution is a ship propulsion system of the "rotary column" type, comprising a streamlined waterproof casing 1 with a mechanical transmission including a hollow shaft 2, in the inner cavity of which a shaft 3 is located. A hub 4 of the rear propeller is fixed on the shaft 3, in which grooves are made 5. In the grooves 5 are placed the root parts 6 of the blades 7, which are mounted movably relative to the hub 4, and the aft part of the blade 7 is movably mounted on the hub 4. The root part 6 of the blade 7 can be movably fixed on the shaft 8, located at an angle to the propeller disk (close to or equal to the step angle of the root section of the blade), rigidly fixed in the groove 5 and passing through the hole 9, which is made in the root part 6, while in the groove 5 between the root part 6 and the hub 4 are placed a damper 10, and between the bottom of the groove 5 and the root part 6 is the position lock of the blade 11 (see figure 2), or the root part 6 of the blade 7 can be rigidly mounted on the shaft 8, which is movably fixed, for example, in bearings 12, while An additional damper 13 is mounted between the shaft 8 and the hub 4. A shaft 14 of the front propeller screw 14 is fixed to the shaft 2, on which blades 15 are fixed, which can be fixedly mounted relative to the specified hub 14 or movably. When the blades 15 are movably mounted, their root parts 16 are fixed similarly to the root parts 6 of the blades 7 of the rear propeller. The blades 7 and 15 of the rear propeller and the front propeller are respectively mounted rotatably at an angle of ± 10 °.

Ship propulsion system operates as follows. A marine engine (not shown in the drawing) through a mechanical transmission (electric feed is possible), including a hollow shaft 2 and a shaft 3 drives the propellers into rotation. At extremely low revolutions, the blades 7 and 15 are kept from turning around the shaft 8 by force of weight by the position lock of the blade 11 (for example, friction type). Centrifugal and hydrodynamic moments relative to shaft 8 act on the blade 7 rotating in the composition of the rear propeller, due to centrifugal and hydrodynamic forces. The action of the moments is opposite, and the relative movement of the blade 7 in the direction opposite to its rotation together with the propeller corresponds to an increase in the moment from the centrifugal force and a decrease in the moment from the hydrodynamic force, since the centrifugal force shoulder increases while the blade pitch decreases. When the blade 7 is deflected in the opposite direction, the opposite picture is observed. Thus, the position of the blade 7 on the hub 4 is determined by the equality of acting mutually opposite moments. Moreover, depending on the operating mode of the propulsion system (relative propeller treads), the position of the blade 7 on the hub 4 will be different. This leads to a change in the geometric characteristics of the blade and, accordingly, hydrodynamic, ensuring compliance with the screw characteristics of the propulsor and the external characteristics of the engine, eliminating the need to use adjustable pitch propellers for this purpose (which is especially difficult for a ship rotary column propulsion system with coaxial propellers opposite rotation).

When the propulsion system is rotated to maneuver the vessel, the propellers are in a strongly oblique flow, as a result of which variable hydrodynamic loads occur on each blade, the blade begins to oscillate, forming an oscillatory system, where inertial forces act as restoring forces, and variables act as disturbing forces hydrodynamic loads. The frequency of natural vibrations depends on the geometry of the blades and their mass characteristics. Analysis of the frequencies of natural vibrations showed that they are less than the frequency of rotation of the propeller shaft. As a result, with respect to disturbing hydrodynamic loads, each blade oscillates in a resonance mode so that the variable hydrodynamic forces are largely compensated by inertial forces and are not transmitted to the hub. Due to the fact that the shaft 8 is located at an angle to the propeller disk, the variable hydrodynamic forces are compensated not only in the plane of the propeller disk, but also in the plane perpendicular to it.

In the reversal mode of the vessel, the variable hydrodynamic forces are so great that additional technical measures are required to compensate for them, namely: the use of a damper 10, which reduces the vibration component along the shaft 8. The use of fastening mobility is useful not only in terms of reducing the variable load transmitted to the column body, but also to reduce the lateral force that prevents the rotation of the column due to the oblique flow on the propulsion. As you know, these transverse forces on conventional propellers are formed as a result of the addition of the variable hydrodynamic forces and moments acting on the blades due to the bevel of the flow. On the blades that oscillate in the resonance mode, the variable forces will be largely compensated by the inertia of the blade itself and the mass of fluid attached to it, so that as a result the transverse hydrodynamic force and moment become smaller (see P.M. Kortunov, L.I. Vishnevsky. Abstracts Krylov readings of 1999. On the mechanism of the appearance of shear force during operation of a screw with movable fastening of the blades in an oblique flow)

Thus, the claimed ship propulsion system of the type "rotary column" allows you to reduce the variable hydrodynamic forces on the propellers, provides coordination of the screw characteristics and the external characteristics of the engines (diesel) in a wide range of loads, reducing the drive power of the steering machine, as well as improving the controllability of the vessel, its maneuverable and reverse characteristics.

Claims (6)

1. A ship propulsion system of the “rotary column” type, comprising one or two propellers with a gear located in a streamlined casing, characterized in that the blades of at least one propeller are movably fixed in the hub with the possibility of moving them relative to the plane of the propeller disk by rotation around an axis passing through the root of the blade, and their displacement along this axis. 2. Ship propulsion system according to claim 1, characterized in that the axis relative to which the blade rotates and / or moves is perpendicular to the propeller disk. 3. Ship propulsion system according to claim 1, characterized in that the axis relative to which the blade rotates is parallel to the plane of the propeller disk and is located in the plane of the propeller disk. 4. Ship propulsion system according to claims 1 and 3, characterized in that each propeller blade is rotatably mounted at an angle of ± 10 °. 5. The ship propulsion system according to claim 1, characterized in that in the hub in the plane of the propeller disk, grooves are made in which the root parts of the propeller blades and the rotation and / or displacement unit of the blades with a damper are located. 6. Ship propulsion system according to claim 5, characterized in that the blade rotation unit is equipped with a blade position lock.

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