CN103910056A - Novel efficient rudder - Google Patents

Abstract

The invention provides a novel efficient rudder. The novel efficient rudder comprises a rudder blade, a rudderstock and a rudder bearing. The rudder blade is fixedly connected with the rudderstock through a flange, the rudderstock is connected with a rudder power mechanism in a ship through the rudder bearing, the surface of the rudder blade is roughened, the outer surface of the rudder blade is provided with one or various of pits, grooves and texture structures for reducing frictional drag of the rudder blade. The rudder blade of a sternpost rudder can effectively reduce frictional drag and viscous drag of the sternpost rudder in the water. Besides, without additional devices, the novel efficient rudder is economic and practical and capable of increasing ship navigation speed on the premise of not increasing cost and capable of reducing energy consumption under the condition of same navigational speed, and the purpose of energy conservation and emission reduction is achieved.

Description

A new type of high-efficiency rudder

technical field

The invention relates to a direction control device on a ship, more specifically, to a new high-efficiency rudder.

Background technique

Ship resistance is divided into frictional resistance, viscous resistance and wave-making resistance according to the physical essence. Frictional resistance and viscous resistance are produced by friction and viscosity between the submerged part of the hull and the fluid, while the stern rudder is A part that must work under the water surface, the fluid will inevitably produce frictional resistance and viscous resistance on the surface of the rudder. The resistance of a ship's single rudder accounts for 1%-2% of the bare hull resistance, and the double rudder accounts for 3%-5% of the resistance of the bare hull. Therefore, the reduction of rudder resistance can make it easier for the ship to achieve higher navigation under the rated main engine power. speed.

In order to achieve this goal, people have made many efforts in various aspects. At present, the main method is to design the cross section of the rudder blade into a streamlined or airfoil shape, and make the surface of the rudder blade as smooth as possible to reduce its damage in water. resistance. However, when the ship is sailing, the magnitude of Re can reach 105, which is far greater than the requirement of Re=60 for boundary layer separation. layer, which is close to the surface of the rudder blade, and there is a flow region with a large velocity gradient and curl along the normal direction of the rudder blade surface. Viscous stress is resistance to the water body in the boundary layer, so as the water body flows backward along the object surface, the water body in the boundary layer will gradually slow down and pressurize. Due to the continuum of water flow, the boundary layer thickens to allow more low-velocity water to flow at the same time. Therefore, there is an adverse pressure gradient in the boundary layer, and the flow will further decelerate under the action of the adverse pressure gradient. In the end, the kinetic energy of the water body in the entire boundary layer is not enough to maintain the flow downstream for a long time, so that its velocity somewhere on the surface of the object It will be opposite to the velocity direction of the potential flow, that is, a countercurrent will occur. This countercurrent will push the boundary layer into the potential flow, causing the boundary layer to suddenly thicken or separate. The separation of the boundary layer will increase the resistance, especially because the pressure difference of the water body before and after the rudder blade increases, so that the pressure difference resistance becomes larger. Even streamlined or airfoil-shaped rudder blades still cannot solve the problem of increased drag caused by boundary layer separation.

Contents of the invention

The technical problem to be solved by the present invention is to provide a new type of high-efficiency rudder. The rudder blades of this rudder can effectively reduce the frictional resistance and viscous resistance of the stern rudder in water, and do not need to install additional equipment. It is economical, practical, and On the premise of not increasing the cost, the speed of the ship can be increased, or the energy consumption can be reduced at the same speed, so as to achieve the goal of energy saving and emission reduction.

Correspondingly, the present invention solves the above-mentioned technical problems by roughening the surface of the rudder blade. This new high-efficiency rudder includes a rudder blade, a rudder stock and a rudder bearing. The rudder blade is fixedly connected to the rudder stock through a flange, and the rudder stock The rudder bearing is connected with the rudder power mechanism installed in the ship, and the outer surface of the rudder blade is provided with one or more combinations of pits, grooves and texture structures for reducing the frictional resistance of the rudder blade. The texture structure may be a grid-like texture structure formed by interlacing oblique lines. The depth of the dimples can range from 10 mm to 50 mm, and the area ratio of dimples, grooves and texture structures on the surface of the rudder blade ranges from 10% to 60%.

These pits can be one or more combinations of circular pits, oval pits, polygonal pits, scale-shaped pits, and irregular-shaped pits, and there can be multiple arrangements. For example, the pits can be a plurality of circular pits of the same shape, aligned vertically and horizontally, criss-crossed or irregularly arranged on the outer surface of the rudder blade; Vertically and horizontally aligned, crisscrossed or irregularly arranged; it can also be a plurality of polygonal dimples of the same shape (polygons can include triangles, rectangles, pentagons, etc.), on the outer surface of the rudder blade, vertically and horizontally aligned, crisscrossed or Irregular arrangement. The same arrangement also applies to scale-shaped and irregular-shaped pits.

In addition to single-shaped pits, it can also be a combination of various forms of pits, such as a mixed distribution of circular and polygonal pits, aligned vertically and horizontally on the outer surface of the rudder blade, criss-crossed or irregularly arranged, the same mixed distribution and arrangements are also available for dimple combinations of circles and ovals, circles and polygons, circles and scales, circles and irregular shapes, or pairs of ovals, polygons, scales and irregular shapes , even circular pits, elliptical pits, polygonal pits, scale-shaped pits, irregular-shaped pits in three, four or even five mixed combinations, the arrangement of these mixed combinations can also be The outer surfaces of the rudder blades are neatly aligned vertically and horizontally, criss-crossed or irregularly arranged.

The grooves can be linear grooves or curved grooves, arranged parallel to each other, or mixed linear and curved grooves, arranged in parallel, or arranged in the form of grooves and pits arranged at intervals.

The surface of the rudder blade may adopt a single dimple, groove or texture structure, or a dimple and groove, dimple and texture structure, texture structure and groove or a mixed combination of dimple, groove and texture structure.

The boundary layer when the surface of the rudder blade moves in the water body, according to the Reynolds number of the local flow field, the fluid in the boundary layer can be divided into laminar flow or turbulent flow. The flow in the boundary layer of smooth rudder blade surface is usually laminar, while the flow in the boundary layer of rough rudder blade is turbulent flow. The turbulent boundary layer is less affected by the adverse pressure gradient, so the separation point of the boundary layer on the surface of the rough rudder blade is relatively behind, and its viscous resistance is lower than that of the smooth rudder blade, and the pressure difference resistance can be even greater. The magnitude decreases.

Compared with the prior art, the present invention is beneficial in that: the stern rudder can effectively push back the boundary separation point and reduce resistance. Usually, when the ship is sailing, the Reynolds number Re can reach more than 105, which is far larger Due to the requirement of Re=60 for boundary layer separation, when the ship is sailing normally, the boundary layer separation phenomenon will occur, and the drag reduction structure on the ship can play a role in delaying the boundary layer separation point, reducing the pressure on the rudder blade. The viscous resistance and frictional resistance reduce the energy consumption of the ship when sailing.

Description of drawings

Fig. 1 is a schematic structural view of a specific embodiment of the present invention;

Fig. 2 is a histogram of the change of the resistance on the rudder blade with the speed of the ship;

Fig. 3 is the structural representation of specific embodiment two;

Fig. 4 is a schematic structural diagram of the third embodiment.

Detailed ways

The present invention will be further described below according to specific embodiments and accompanying drawings.

The new high-efficiency rudder shown in Figure 1 includes rudder blade 1, rudder stock 2 and rudder support. Rudder blade 1 is fixedly connected to rudder stock 2 through a flange, and rudder stock 2 is connected to the rudder power mechanism installed in the ship through the rudder support. In connection, the outer surface of the rudder blade 1 is provided with a circular dimple 3 for reducing the frictional resistance of the rudder blade. The depth of the dimples 3 is 30mm, and they are aligned vertically and horizontally on the outer surface of the rudder blade 1, and the area ratio of the dimples 3 on the surface of the rudder blade is 25%.

Due to traditional habits, people think that the smoother the frictional resistance of the surface, the inventor of the present invention has overcome the traditional technical prejudice---a rough surface will increase the frictional resistance, and the surface of the rudder blade 1 will be roughened, resulting in The turbulent boundary layer delays the boundary separation point and advances the turning point, and has achieved good results in reducing the resistance of the rudder blade, and has been confirmed in experiments.

In the experiment, a streamlined rudder with a wing length of 2m and a chord length of 1m was taken as the experimental object. One of the rudder blades had a smooth surface, and the other rudder had multiple rudder blades with a diameter of 30mm arranged vertically and horizontally. The circular dimples are tested at different liquid flow rates (simulated ship speeds), and the following results can be obtained:

Table 1-1 Variation of resistance with speed of rudder blade with smooth surface

Speed (m/s) R(N) 10 278.5631 15 308.6234 20 365.2085 22.5 506.2598 25 722.4245

Table 1-2 The resistance of the rudder blade with 30mm dimples on the surface changes with the speed

Speed (m/s) R(N) 10 258.3625 15 284.5882 20 327.5363 22.5 473.461 25 678.5431

It can be seen from Table 1-1, 1-2 and Figure 2 that as the flow velocity increases, the resistance of the rudder blade with 30mm dimples on the surface and the rudder blade of the traditional smooth outer plate increase correspondingly, but the traditional smooth outer plate The suffered resistance of the rudder blade is bigger than this specific embodiment all the time.

Therefore, it can be concluded that setting 30 mm dimples on the surface of the rudder blade can significantly reduce the resistance of the rudder blade, optimize the performance of the rudder blade, and achieve the expected effect.

In specific implementation, the depth of the pit 3 can be selected within the range of 10-50mm, and the depth of the pit 3 is 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm for testing, and all can obtain ideal The technical effect of improving the lift-to-drag ratio.

In addition, the shape of the pit 3 can also be in the form of one or more groups of circular pits, elliptical pits, polygonal pits and irregular pits, and can be arranged regularly or irregularly. After testing Both can obtain the ideal technical effect of improving the lift-to-drag ratio.

The area ratio of dimples on the surface of the rudder blade is between 10% and 60%, and 10%, 20%, 30%, 45%, 50%, 55%, and 60% are used for testing, and the results are all very satisfactory.

In addition to the regular circular concave holes, several parallel grooves 4 can also be set on the surface of the rudder blade 2, as shown in the second embodiment of Figure 3. The depth of these grooves is 30mm, parallel to the surface of the rudder blade. Edge settings.

The specific embodiment 3 shown in FIG. 4 differs from the specific embodiment 1 only in that the rudder blade 2 is provided with a grid-like texture structure 5 composed of interlaced oblique lines. The texture structure is 10mm deep and the total area ratio is 30%.

The above embodiments are for the purpose of understanding the present invention, and are not intended to limit the present invention. Those of ordinary skill in the related art can also make various changes or shapes on the basis of the technical solution described in the claims, such as grooves Wave-shaped grooves, zigzag-shaped grooves or irregular-shaped grooves can be used, and these changes or modifications should be understood as still belonging to the protection scope of the present invention.

Claims (10)

1. a new and effective rudder, comprise rudder blade, rudder stock and rudder bearer, rudder blade is fixedly connected with rudder stock by flange, rudder stock is connected with the rudder actuating unit being arranged in boats and ships by rudder bearer, it is characterized in that: the outside face of described rudder blade is provided with for reducing one or more combinations in the pit of the suffered resistance of rudder blade, groove and texture structure.

2. new and effective rudder according to claim 1, is characterized in that: described pit is one or more combinations in circular pit, oblong pits, polygon pit, fish scale shape pit, irregularly shaped pit.

3. new and effective rudder according to claim 2, is characterized in that: the quantity of described pit has multiple, and in the outside face of the rudder blade proper alignment of aliging in length and breadth.

4. new and effective rudder according to claim 2, is characterized in that: the quantity of described pit has multiple, and in the outside face criss-cross arrangement of rudder blade.

5. new and effective rudder according to claim 2, is characterized in that: the quantity of described pit has multiple, and in the outside face irregular alignment of rudder blade.

6. according to the new and effective rudder described in claim 1 to 5 any one, it is characterized in that: the degree of depth of described pit is 10mm～50mm.

7. new and effective rudder according to claim 6, is characterized in that: the area occupation ratio of described pit is 10%～60%.

8. new and effective rudder according to claim 1, is characterized in that: described groove is linear pattern groove and/or shaped form groove.

9. new and effective rudder according to claim 2, is characterized in that: the degree of depth of described groove is 10mm～50mm.

10. new and effective rudder according to claim 1, is characterized in that: described texture structure is latticed texture structure.