A high-efficiency, low-noise water jet propulsion pump

Abstract

This invention discloses a high-efficiency, low-noise waterjet propulsion pump, belonging to the field of marine engineering technology. The propulsion pump includes a shroud, a nozzle, a drive shaft, a drive shaft casing, a hub, an impeller, and a guide vane. The shroud and nozzle are connected, and the drive shaft and hub are coaxially connected and supported by the drive shaft casing inside the shroud and nozzle. The impeller and guide vane are fixed to the hub. The inner surface of the constricted nozzle at the rear of the impeller and guide vane has recesses, which are evenly distributed on the inner surface. This invention can reduce the flow resistance of the waterjet propulsion pump and improve propulsion efficiency.

Description

Technical Field

[0001] This invention relates to a waterjet propulsion pump, specifically a waterjet propulsion pump that can reduce resistance and noise, belonging to the field of marine engineering technology. Background Technology

[0002] To ensure propulsion efficiency, the waterjet propulsion pumps used in amphibious vehicles, ships, vessels, and boats are designed to minimize or avoid cavitation. Their structural design has remained largely unchanged for many years, resulting in minimal improvements in propulsion efficiency. The main problems include:

[0003] (a) Noise and resistance in the inlet section

[0004] When the water jet propulsion pump uses a curved section at the bottom of the vehicle body to enter the water before the impeller inlet, the water flow in the curved section is very turbulent. The direction of the flow velocity in the ocean flow field is not completely consistent with the direction of the water flow at the pump inlet. In particular, when the seawater flows over the drive shaft liner, vortices will be generated at the rear of the liner. These places will form noise sources and generate a certain amount of power consumption, reducing propulsion efficiency.

[0005] (b) Resistance in the outlet section

[0006] The nozzle outlet section of the waterjet propulsion pump is constricted to facilitate the generation of high-speed water flow and propulsion. However, the contact between the high-speed flowing water column and the inner surface of the constricted outlet of the waterjet propulsion pump creates resistance, reducing the pump's propulsion efficiency. Summary of the Invention

[0007] In view of this, the present invention provides a high-efficiency, low-noise waterjet propulsion pump that can reduce the flow resistance of the waterjet propulsion pump and improve the propulsion efficiency.

[0008] A high-efficiency, low-noise water jet propulsion pump includes a shroud, a nozzle, a drive shaft, a drive shaft guard, a hub, an impeller, and a guide vane. The shroud and nozzle are connected together, and the drive shaft and hub are coaxially connected and supported inside the shroud and nozzle by the drive shaft guard. The impeller and guide vane are fixed on the hub. The inner surface of the constricted nozzle at the tail end of the nozzle, corresponding to the rear of the impeller and guide vane, has recesses that are evenly distributed on the inner surface.

[0009] Furthermore, the pit is circular in shape.

[0010] Furthermore, biomimetic grooves are formed on both sides of the outer circumference of the drive shaft guard in the direction of flow, and the grooves are formed at a certain angle to the axis of the drive shaft guard.

[0011] Furthermore, the grooves on both sides of the drive shaft guard are arranged in an equally spaced, staggered pattern.

[0012] Beneficial effects:

[0013] This invention reduces flow resistance by creating a recess on the inner surface of the nozzle outlet at the tail of the water jet propulsion pump, using a semi-circular recess. In addition, grooves are made on both sides of the drive shaft casing to further reduce the flow resistance of the water jet propulsion pump, improve propulsion efficiency, and reduce the operating noise of the water jet propulsion pump. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the water jet propulsion pump of the present invention;

[0015] Figure 2 This is a schematic diagram of the nozzle structure;

[0016] Figure 3 This is a schematic diagram of the drive shaft protective tube.

[0017] Figure 4 for Figure 3 AA section view;

[0018] Figure 5 for Figure 3 BB cross-sectional view.

[0019] Among them, 1-diffuser, 2-nozzle, 3-drive shaft, 4-drive shaft protector, 5-hub, 6-impeller, 7-guide impeller, 8-pit, 9-groove. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] This invention provides a high-efficiency, low-noise water jet propulsion pump, as shown in the attached figure. Figure 1 As shown, the propulsion pump includes a guide vane 1, a nozzle 2, a drive shaft 3, a drive shaft protective tube 4, a hub 5, an impeller 6, and a guide vane 7. The guide vane 1 and nozzle 2, when connected, form a mounting cavity for the drive shaft 3 and hub 5. To better illustrate the connection relationships between the components within the mounting cavity, an appendix is ​​attached. Figure 1 The draft shield 1 and nozzle 2 have been subjected to perspective treatment. The drive shaft 3 and hub 5 are coaxially connected and supported and fixed inside the draft shield 1 and nozzle 2 by the drive shaft guard tube 4. The impeller 6 and guide vane 7 are fixed on the hub 5. The inner surface of the constricted nozzle tail end corresponding to the rear of the impeller and guide vane has a circular recess 8 for drag reduction, as shown in the attached diagram. Figure 2 As shown, the circular pits 8 are evenly distributed on the inner surface. (See attached image.) Figure 3-5 As shown, biomimetic grooves 9 are formed on both sides of the drive shaft guard tube 4 in the direction of flow. The groove direction of the grooves 9 forms an angle of 30-60° with the axis of the drive shaft guard tube, and the grooves 9 on both sides are arranged in an equally spaced staggered manner.

[0022] Bionic research has shown that non-smooth surfaces—specifically, pitted surface structures—are another way to reduce drag, and this research has also been developed. Bearman and Harvey studied the effect of non-smooth surfaces on the drag of flow around a cylinder, and experimentally concluded that semi-circular pits can reduce the drag of flow around a cylinder within a selected Reynolds number range.

[0023] Furthermore, research by scholars both domestically and internationally has shown that biomimetic grooves on the boundary layer surface of objects in fluids can significantly reduce flow resistance and noise. Figure 3 The drive shaft protective tube shown has a cylindrical cross-section, which will generate a certain resistance to the water flow in the pipe. In order to reduce the resistance of the drive shaft protective tube, biomimetic grooves are opened on both sides of the protective tube in the direction of flow to further reduce the inlet resistance.

[0024] When the water jet flows at high speed through the constriction port at the tail of the water pump, a large number of microbubbles are generated at the contact surface between the high-speed water jet and the pump tail port due to the presence of pits. Due to the presence of this microbubble boundary layer, the resistance of the pump tail port to the water jet jet is reduced. Under underwater conditions, it can also reduce the interaction between the water jet jet and the water area at the tail of the vehicle (or other watercraft), improve propulsion efficiency, and at the same time achieve drag reduction and noise reduction through microbubbles.

[0025] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-efficiency, low-noise water jet propulsion pump, comprising a shroud, a nozzle, a drive shaft, a drive shaft housing, a hub, an impeller, and a guide vane; the shroud and nozzle are connected, the drive shaft and hub are coaxially connected and supported by the drive shaft housing inside the shroud and nozzle, and the impeller and guide vane are fixed to the hub, characterized in that, The inner surface of the constricted nozzle at the tail end of the nozzle corresponding to the rear of the impeller and guide impeller has a recess, which is evenly distributed on the inner surface; the recess is circular in shape; biomimetic grooves are formed on both sides of the outer circumference of the drive shaft guard in the direction of flow, and the grooves are formed at a certain angle to the axis of the drive shaft guard.

2. The high-efficiency, low-noise waterjet propulsion pump as described in claim 1, characterized in that, The grooves on both sides of the drive shaft guard are arranged in an equally spaced, staggered pattern.

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