Hub vortex eliminating mechanism for ship propeller

Abstract

The invention provides a hub vortex eliminating mechanism for a ship thruster, and relates to the technical field of ship thrusters, the hub vortex eliminating mechanism comprises a pod, and a propeller is arranged in the middle of the right end of the pod; a hub vortex eliminating assembly is arranged at the left end of the nacelle and comprises a flow guide pipe, the flow guide pipe is located in the middle of the left end of the nacelle, the flow guide pipe and the nacelle are connected through multiple sets of flow guide blades, and the number and the angle of the flow guide blades are arranged according to flow field distribution of hub vortexes; the bottoms of the multiple groups of guide vanes are fixedly mounted on the outer surface of the pod, and the tail ends of the multiple groups of guide vanes are connected with the inner side surface of the guide pipe; the flow guide pipe and the multiple groups of flow guide blades are fixed by welding; and the blade sections of the guide blades are wing-shaped. By arranging the hub vortex eliminating assembly, circumferential vortexes appearing near the hub part can be fully eliminated, and by means of the circumferential energy of the vortexes to be dissipated, the axial energy is increased, the axial thrust is improved, and the efficiency of the propeller is improved.

Description

Technical Field

[0001] The invention relates to the technical field of ship propellers, and in particular to a hub vortex elimination mechanism for ship propellers. Background Art

[0002] Traditional ship propulsion is a type of long-shaft propeller, which can only generate axial thrust for ship propulsion. In order to achieve the maneuverability of the ship, the rudder is installed behind the propeller, and the ship is turned by rotating the rudder blades. In recent years, the application of full-turn propellers has become more and more common. Through the bevel gear transmission mechanism, the propeller can rotate 360 ​​degrees around the propeller's rotation axis in the horizontal plane. It has the ability to propel and control the ship at the same time. Not only that, the thrust of traditional long-shaft propellers is lower when they are reversed than when they are forward. The full-turn propeller can rotate 180 degrees and still generate thrust approximately equal to that of the forward rotation, which has a better effect on emergency braking and reversing conditions.

[0003] Since the full-rotation propeller is a propulsion device that is driven by a bevel gear system, it has a lower shell with a large wet surface area. The suction effect of the propeller rotation will generate a certain resistance to the lower shell, thereby affecting the propulsion efficiency of the entire propeller. Figure 6 ), the propeller accelerates the flow field in front of the blade (to the left of the blade) through rotational motion, consuming energy to generate thrust, and the axial flow velocity on the left is converted into axial velocity and circumferential velocity, flowing behind the blade (to the right of the blade). Since there is no secondary acceleration device at the rear, the energy of the circumferential velocity is dissipated, thereby reducing efficiency; at the same time, at the outflow end close to the lower shell (the contraction section of the sphere on the far right of the figure), the axial flow velocity becomes slow due to the wall effect, and even backflow occurs, which also increases the loss.

[0004] In order to solve the above problems, we propose a hub vortex elimination mechanism for a ship propeller to solve the above problems. Summary of the invention

[0005] In order to solve the problems in the background technology, the present invention provides a hub vortex elimination mechanism for a ship propeller.

[0006] To achieve the above object, the technical solution adopted by the present invention is: A hub vortex elimination mechanism for a ship propeller comprises a pod, wherein a propeller is arranged in the middle of the right end of the pod; a hub vortex elimination assembly is arranged at the left end of the pod, comprising a guide pipe, wherein the guide pipe is located in the middle of the left end of the pod, and the guide pipe is connected to the pod via a plurality of groups of guide blades, wherein the number and angle of the guide blades are arranged according to the flow field distribution of the hub vortex.

[0007] Preferably, the bottoms of the multiple groups of guide blades are fixedly mounted on the outer surface of the pod, and the ends of the multiple groups of guide blades are connected to the inner side surface of the guide pipe.

[0008] Preferably, the guide pipe and the multiple groups of guide blades are fixed by welding.

[0009] Preferably, the guide vane has an airfoil-shaped blade cross-section and an arch line is provided on its surface.

[0010] Preferably, the flow guide pipe is configured as an annular structure.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The present invention, by providing a hub vortex elimination component, can fully eliminate the circumferential vortex appearing near the hub, utilize the circumferential energy of the vortex that is about to be dissipated, realize the increase of axial energy, improve the axial thrust, and enhance the efficiency of the propeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a left side view of the guide pipe and the guide vane in the present invention; Figure 3 Schematic diagram of the airfoil structure of the guide vane in the present invention; Figure 4 It is a schematic diagram of the flow guiding by the guide vane in the present invention; Figure 5 It is a side sectional structural diagram of the flow guide pipe in the present invention; Figure 6 It is a structural schematic diagram of the prior art mentioned in the background technology.

[0013] In the figure: 1. nacelle; 2. propeller; 3. guide duct; 4. guide vane. DETAILED DESCRIPTION

[0014] The technical solution in the embodiment of the present application is to solve the problems of the above-mentioned background technology, and the overall idea is as follows: Example: Refer to Figure 1-Figure 6 As shown, a hub vortex elimination mechanism for a ship propeller of this embodiment includes a pod 1, and a propeller 2 is arranged in the middle of the right end of the pod 1.

[0015] A hub vortex elimination assembly is provided at the left end of the pod 1, including a guide duct 3. The guide duct 3 is located in the middle of the left end of the pod 1. The guide duct 3 is connected to the pod 1 through multiple groups of guide blades 4. The number and angle of the guide blades 4 are arranged according to the flow field distribution of the hub vortex.

[0016] The bottoms of the multiple groups of guide blades 4 are fixedly mounted on the outer surface of the pod 1 , and the ends of the multiple groups of guide blades 4 are connected to the inner side surface of the guide pipe 3 .

[0017] In some examples, the guide tube 3 and the plurality of guide vanes 4 are fixed by welding.

[0018] In some examples, the blade cross-section of the guide vane 4 is airfoil-shaped, and an arch line is arranged on its surface, and the arch line needs to be designed according to the flow field distribution; the tangent directions of the arch line at the inlet end and the outlet end correspond to the direction of the acceleration flow V1 and the direction of the axial outflow V2, respectively, thereby achieving a drainage effect and effectively eliminating the hub vortex; since the distribution of the hub vortex on the inlet surface is uneven, the circumferential distribution number and angle of the guide vane 4 and the radial arch line distribution are all different, which depends entirely on the distribution of the flow field at the inlet end, that is, where the hub vortex is serious, the guide vanes 4 are densely distributed and the blade cross-section arch angle is large.

[0019] Specific reference Figure 3 As shown, for the guide vane 4, the upper and lower profiles are both real machinable surfaces, and the arch line is a line synthesized by the upper and lower profiles shrinking inward at equal distances at the same time, that is, AC=BC.

[0020] Assuming that the profile shrinks into an arch line, drainage should be performed according to the arch line. Figure 4 As shown; According to the Coanda effect of the fluid, the arch line guides the water flow to change direction; Inflow velocity: ; Outflow speed: ; and and The direction is consistent with the tangent direction of the arch line A and B points, that is, it goes downstream; So the guide blade 4 is becomes conducive to the rotation of propeller 2 (Improve propeller 2 efficiency); Hub vortex elimination is to become , through the above calculation, the correct arch line can be obtained, so as to carry out drainage; consider If the value exceeds the threshold, it means that the circumferential energy is high and a guide vane is needed. , forming a matrix, Radial: ; Take the average value of each column as the main basis for the circumferential distribution of guide vane 4.

[0021] In some examples, the cross-section of the guide tube 3 is also airfoil-shaped, which is an accelerating duct. The guide tube 3 has two technical effects: first, it accelerates the axial flow to form a positive thrust, which is superimposed on the positive thrust of the propeller to improve the propulsion efficiency; second, it increases the structural strength. Since the guide blades 4 are relatively thin, without the guide tube 3, the guide blades 4 may vibrate or even be damaged in the flow field. Adding the guide tube 3 can increase the structural strength of the entire hub vortex elimination assembly, making it safer and more reliable.

[0022] Specific reference Figure 5 As shown, assuming that the flow velocity on the inlet surface is ,area , outflow velocity ,area According to the law of conservation of mass, ,because ,so , because the outside of the guide tube 3 is full of The velocity field, and the velocity distribution in the flow guide tube 3 is Flow rate , according to Bernoulli's equation, , forming force , since the flow guide pipe 3 is distributed in an annular symmetric manner, Offset each other to form thrust .

[0023] The working principle of the present invention is: The fluid moves from right to left, first flowing in axial direction Passing through the propeller 2, the fluid absorbs the energy of the propeller 2 and generates an accelerated flow. The accelerated flow can be decomposed into the axial velocity in the axial-circumferential plane. and circumferential speed , the fluid moves to the hub vortex elimination assembly, and the circumferential velocity flows around the guide vane 4 section. The guide vane 4 converts the circumferential velocity The flow is directed to the point where the circumferential velocity approaches zero and the axial velocity The hub vortex elimination assembly can fully eliminate the circumferential vortex appearing near the hub, and use the circumferential energy of the vortex that is about to be dissipated to increase the axial energy, thereby increasing the axial thrust and improving the efficiency of the propeller.

[0024] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A hub vortex elimination mechanism for a ship propeller, characterized in that: It comprises a pod (1), wherein a propeller (2) is arranged at the middle of the right end of the pod (1); A hub vortex elimination assembly is provided at the left end of the pod (1), comprising a guide pipe (3), the guide pipe (3) being located at the middle of the left end of the pod (1), the guide pipe (3) being connected to the pod (1) via a plurality of groups of guide blades (4), the number and angle of the guide blades (4) being arranged according to the flow field distribution of the hub vortex.

2. A hub vortex elimination mechanism for a ship propeller according to claim 1, characterized in that: The bottoms of the multiple groups of guide blades (4) are fixedly mounted on the outer surface of the pod (1), and the ends of the multiple groups of guide blades (4) are connected to the inner side surface of the guide pipe (3).

3. A hub vortex elimination mechanism for a ship propeller according to claim 2, characterized in that: The guide pipe (3) and the multiple groups of guide blades (4) are fixed by welding.

4. A hub vortex elimination mechanism for a ship propeller according to claim 3, characterized in that: The blade cross-section of the guide blade (4) is in the shape of an airfoil, and an camber line is provided on its surface.

5. The hub vortex elimination mechanism for a ship propeller according to claim 4, characterized in that: The flow guide pipe (3) is configured as a ring structure.

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