Hydrodynamic energy-saving device for pump-jet propeller

Abstract

The invention relates to a hydrodynamic energy-saving device for a pump-jet propeller, comprising: a rotor blade which is a main output component and is used for receiving energy and outputting thrust; the front stator blade is a static part and is mainly used for improving the inflow of the rotor blade and improving the efficiency of the rotor blade; the guide pipe is a static part, is mainly used for integrating a flow field and can be used for providing additional thrust, and the appropriate guide pipe wing type can also be used for improving the cavitation performance of the rotor; the hub cap fin blades rotate along with the rotor blades, so that hub vortex energy loss of the propeller hub of the pump-jet propeller can be reduced, a low-pressure area behind the propeller hub is eliminated, and the hydrodynamic performance is improved; and the propeller hub is used for fixedly connecting the rotor blades and the hub cap fin blades. According to the hydrodynamic energy-saving device for the pump jet propeller, the flow field behind a hub can be improved, the thrust of the propeller can be increased, the torque of rotor blades can be reduced, and the purpose of improving the hydrodynamic performance is achieved.

Description

Technical Field

[0001] The present invention relates to the field of underwater vehicle propulsion and energy saving and noise reduction, and in particular to a hydrodynamic energy-saving device for a pump-jet propulsion device. Background Art

[0002] The pump-jet propeller is a new type of special propeller, mainly used in underwater navigation bodies. Its main structure is the external duct, the stator blades used to connect the duct and the hub, the rotor blades, and the hub supporting the propeller. The propulsion method of the pump-jet propeller is mainly to change the pressure distribution of the flow field around the propeller through the rotation of the rotor blades, thereby generating a pressure difference and further generating thrust.

[0003] In order to further improve the hydrodynamic performance of pump-jet propulsion, most current methods of improvement are to change the components of the pump-jet propulsion itself. For example, grooves are engraved on the pump-jet duct or propeller hub, the shape of the duct trailing edge is changed, and the inflow or wake field is improved in a bionic way, thereby improving the hydrodynamic performance of the pump-jet. However, these hydrodynamic improvement methods have the following disadvantages:

[0004] 1. Pump-jet propulsion has many parts, and shark skin bionic drag reduction will increase the complexity of its tail flow field. Especially under high speed conditions, the complex tail vortex structure will sharply increase the unsteady force, thus generating a lot of noise. And under extreme conditions, the original energy-saving effect will disappear or even produce negative optimization.

[0005] 2. The current methods of improving pump-jet propulsion are very complicated. For example, adding a groove structure to the duct, changing the trailing edge of the duct to a serrated shape, and changing the propulsion mode of the pump-jet propulsion are relatively large modifications to the prototype pump-jet propulsion, which require complex processing and are difficult to implement.

[0006] In summary, in order to further improve the propulsion efficiency of the pump-jet propulsion while ensuring the low noise performance of the pump-jet propulsion, this paper proposes to add the hub cap fin blade to the hub of the pump-jet propulsion to form an energy-saving device for the pump-jet propulsion. The energy-saving device is not only simple in structure, easy to manufacture and install, but also has good hydrodynamic energy-saving performance, can reduce the vibration and noise of the rotor blades, and improve the stealth performance of the navigation body. Summary of the invention

[0007] Due to the above shortcomings in current technology, the present invention provides a hydrodynamic energy-saving device for a pump-jet propulsion system, which can further improve the hydrodynamic performance of the pump-jet propulsion system under different working conditions, reduce the excitation force and noise of the pump-jet propulsion system, and improve the stealth performance of the underwater vehicle.

[0008] A hydrodynamic energy-saving device for a pump-jet propeller, comprising rotor blades, stator blades, a hub, a hub cap, fin blades, and a duct;

[0009] A plurality of stator blades evenly distributed in the circumferential direction are fixedly arranged on the surface of the inner cavity of the duct near the inlet; a hub is provided in the center of the inner cavity of the duct, and a plurality of rotor blades and hub cap fin blades evenly distributed in the circumferential direction are fixedly arranged on the surface of the hub; the hub cap fin blades are located in the rear flow field area of ​​the rotor blades, close to the hub cap, and are used to ensure that the hub cap fin blades recover the energy of the wake flow field and the hub vortex.

[0010] Furthermore, the rotor blades and the hub cap fin blades are moving parts, and the stator blades and the duct blades are stationary parts.

[0011] The model is built with the propeller disk of the stator blade as the origin. The coordinates of the hub cap fin blade can be expressed as:

[0012]

[0013] The corresponding coordinates in the coordinate system o-xyz are:

[0014]

[0015] Where dis1 is the distance between the hub cap fin blade and the stator blade and dis2 is the distance between the rotor blade and the stator blade, yb and yf represent the shape values ​​of the dorsal fin surface of the hub cap fin blade, β represents the pitch angle of the hub cap fin blade, s represents the chord length at different radius positions of the hub cap fin blade, and c1 represents the distance from the point of the hub cap fin blade to the guide edge.

[0016] Furthermore, the number of the hub cap fin blades is consistent with that of the rotor blades, and the diameter of the hub cap fin blades does not exceed one third of the diameter of the rotor blades and is not less than one fifth of the diameter of the rotor blades.

[0017] Furthermore, the pitch angle of the boss cap fin blade is opposite to the pitch angle of the rotor blade.

[0018] Furthermore, the number of stator blades is greater than the number of rotor blades.

[0019] Furthermore, the number of stator blades is an odd number.

[0020] Furthermore, the cross-section of the duct is an airfoil cross-section, which is used to improve the incoming flow field of the rotor blades and play a role in rectification.

[0021] Furthermore, when the duct is made of sound-absorbing material, the noise performance of the propulsion system can be improved.

[0022] The beneficial effects of the present invention are:

[0023] 1. Since the hub cap fin blades have a certain pitch angle, and the pitch angle is opposite to that of the rotor blades, the hub cap fin blades can also generate thrust and drag, and the lift can reduce the torque in the rotation direction of the rotor blades;

[0024] 2. Since the hub cap fin blades are close to the hub cap, the flow field at the tail of the pump-jet propulsor can be improved well, and the hub vortex can be broken up while recovering the energy of the rotor blade tail vortex. Although the thrust generated by the hub cap fin blades is limited or even does not generate thrust, due to their influence, the thrust of the hub and rotor blades can be increased and the torque of the pump-jet propulsor can be reduced, thereby improving the efficiency of the pump-jet propulsor by 2% to 5%. The improvement effect is related to the installation angle, diameter, and spacing between the fins and rotor blades of the hub cap fin blades. In particular, the diameter of the hub cap fin blades, a suitable hub cap fin blade diameter can achieve higher energy-saving effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a front cross-sectional view of a hydrodynamic energy-saving device for a pump-jet propulsion system.

[0026] Figure 2 The present invention is a side sectional view of a hydrodynamic energy-saving device for a pump-jet propulsion system.

[0027] Explanation of reference numerals: 1 - rotor blade, 2 - stator blade, 3 - hub, 4 - hub cap fin blade, 5 - duct. DETAILED DESCRIPTION

[0028] In order to further understand the present invention, the present invention is described in detail below with reference to the accompanying drawings and examples.

[0029] The rotor blade 1 is mounted on the hub 3, which is connected to the transmission shaft. The shaft provides a rotation speed, and the hub 3 transfers energy to the rotor blade 1. The rotation of the rotor blade 1 changes the flow field around the rotor blade 1, so that there is a pressure difference between the back and front of the propeller, thereby providing thrust; the stator blade 2 connects the duct and the hub, is used to support the duct, and can improve the incoming flow of the rotor blade 1 and improve the efficiency of the rotor blade 1; the hub 3 is mainly used to transfer rotational energy and support rotating parts and stator blades 2; the hub cap fin blade 4 is basically equivalent to the small rotor blade 1 in structure, but the rotation direction is opposite to that of the rotor blade 1. In this way, when the rotor blade 1 rotates synchronously, it can absorb the tail vortex energy of the rotor blade 1, and untie the hub vortex generated by the hub, restore the low pressure area of ​​the hub, and generate additional thrust. In addition, the torque of the rotor blade 1 can also be reduced, thereby improving the efficiency of the propulsion system. Since the hub cap fin blade 4 changes the tail vortex structure of the propeller system, it can even improve the unsteady force of the pump-jet propeller and further improve the noise performance of the pump-jet propeller. Due to its airfoil profile, the duct 5 can also provide a certain thrust for the propulsion system in the flow field. In addition, since its inlet diameter is large and the rotor blade 1 is at a smaller diameter position, its contraction structure will increase the inflow velocity near the rotor blade 1, thereby improving the thrust performance of the rotor blade 1, and it can shield hydrodynamic noise to a certain extent. The effect is better when the duct material is made of sound-absorbing material. In addition, the duct is located at the outermost side of the propulsion system, and can also protect the core rotating component, the rotor blade 1.

[0030] It can be known from the above technical scheme that the hydrodynamic energy-saving device for the pump-jet propulsion provided in the above embodiment of the present invention utilizes the coupling effect of multiple energy-saving devices to make up for the shortcomings of another energy-saving device. Through the mutual induction effect of the stator blades 2, the hub cap fin blades 4, and the duct 5, the stator blades 2 are pre-rotated, the hub cap fin blades 4 recover the tail vortex energy, and the duct 5 is rectified. They change the flow field of the rotor blades 1 in three different ways, thereby improving the working flow field of the rotor blades 1, thereby improving the thrust and efficiency of the overall propulsion device. In addition, by improving the material of the closed duct, the noise generated by the rotation of the propeller can be absorbed, thereby improving the noise performance of the propeller.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hydrodynamic energy-saving device for a pump-jet propulsion system, characterized in that: It comprises rotor blades (1), stator blades (2), a hub (3), a hub cap fin blade (4), and a duct (5); A plurality of stator blades (2) are fixedly provided near the inlet on the inner surface of the duct (5) and are evenly distributed in the circumferential direction; a hub (3) is provided at the center of the inner surface of the duct (5); a plurality of rotor blades (3) and hub cap fin blades (4) are fixedly provided on the surface of the hub (3) and are evenly distributed in the circumferential direction; the hub cap fin blades (4) are located in the rear flow field area of ​​the rotor blades (1) and are close to the hub cap, so as to ensure that the hub cap fin blades (4) recover the energy of the wake flow field and the hub vortex of the hub (3).

2. A hydrodynamic energy-saving device for a pump-jet propulsion system according to claim 1, characterized in that: The rotor blades (1) and the hub cap fin blades (4) are moving parts, the stator blades (2) and the duct blades (5) are stationary parts, and the model is built with the propeller disk surface of the stator blade (2) as the origin. The coordinates of the hub cap fin blades (4) can be expressed as: The corresponding coordinates in the coordinate system o-xyz are: Wherein dis1 is the distance between the hub cap fin blade (4) and the stator blade (2), dis2 is the distance between the rotor blade (1) and the stator blade (2), yb and yf respectively represent the profile values ​​of the dorsal fin surface of the hub cap fin blade (4), β represents the pitch angle of the hub cap fin blade (4), s represents the chord length of the hub cap fin blade (4) at different radial positions, and c1 represents the distance from the point of the hub cap fin blade (4) to the guide edge.

3. A hydrodynamic energy-saving device for a pump-jet propulsion system according to claim 2, characterized in that: The number of the hub cap fin blades (4) is consistent with that of the rotor blades (1), and the diameter of the hub cap fin blades (4) is no more than one third of the diameter of the rotor blades (1) and no less than one fifth of the diameter of the rotor blades (1).

4. The hydrodynamic energy-saving device for a pump-jet propulsion system according to claim 2, characterized in that: The pitch angle of the hub cap fin blade (4) is opposite to the pitch angle of the rotor blade (1).

5. The hydrodynamic energy-saving device for a pump-jet propulsion system according to claim 2, characterized in that: The number of the stator blades (2) is greater than the number of the rotor blades (1).

6. The hydrodynamic energy-saving device for a pump-jet propulsion system according to claim 2, characterized in that: The number of the stator blades (2) is an odd number.

7. The hydrodynamic energy-saving device for a pump-jet propulsion system according to claim 1, characterized in that: The cross section of the duct (5) is an airfoil cross section, which is used to improve the incoming flow field of the rotor blades (1) and play a role in rectifying the flow.

8. The hydrodynamic energy-saving device for a pump-jet propulsion system according to claim 7, characterized in that: When the duct (5) is made of sound-absorbing material, the noise performance of the propulsion system can be improved.

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