Vibration-reducing and efficiency-improving micro-baffle structure of water-jet propulsion pump

Abstract

A hub surface of a guide vane body of the water-jet propulsion pump is a hemispheroid, guide vane body blades are distributed on the guide vane body, the sides, close to the plane of the hemispheroid, of the guide vane body blades are roots of the guide vane body blades, and the bone surfaces of the guide vane body blades of the water-jet propulsion pump are taken as reference surfaces S; the front side of the guide vane body blade is a pressure face C, the back face of the guide vane body blade is a suction face A, the back face of the micro-baffle structure is a suction face B, one side of the micro-baffle structure is connected with the pressure face of the guide vane body blade, and the other side of the micro-baffle structure extends to the outer edge of the guide vane body blade after being bent. Development of the wake at the root of the impeller in a guide vane body channel is limited, the guide vane body transverse vortex intensity caused by the transverse pressure gradient is restrained, the structure is simple, the efficiency of the water-jet propeller can be improved, and the dynamic flow excitation force of the water-jet propeller can be reduced.

Description

Technical Field

[0001] The invention relates to a micro-baffle structure for reducing vibration and increasing efficiency of a water jet propulsion pump in terms of hydrodynamic performance, and belongs to the technical field of ship engineering. Background Art

[0002] Water jet propulsion uses the reaction force generated by high-speed jet flow to propel the ship forward. It has the characteristics of high efficiency at high speed, low vibration and noise level, good maneuverability, and strong anti-cavitation performance. It is widely used in high-performance ships. The propulsion pump is the core working component of the water jet propulsion and the main source of propeller vibration and noise. It includes a rotating impeller and a stationary guide vane body. The water flow is pressurized in the impeller, enters the guide vane body after the outflow, and is sprayed out after being rectified by the guide vane body. The impeller and the guide vane body are both composed of blades, forming a centrally symmetrical blade channel. After the wake at the root of the impeller blade enters the guide vane body, it is affected by the lateral pressure gradient of the channel and develops a strong dynamic vortex, which enhances the dynamic flow excitation of the propeller and affects the efficiency of the propeller.

[0003] In the ideal hydraulic model of the propulsion pump, the water flow is usually designed to enter the guide vane body without relative circumferential velocity. In the actual water jet propulsion pump, the impeller has a certain thickness along the edge, especially near the hub. The rounding of the blade root significantly increases the thickness, forming a strong root wake. After entering the downstream guide vane body, the wake has a circumferential motion form. Under the influence of the lateral pressure gradient in the guide vane body, a strong dynamic vortex is developed, which significantly enhances the propeller flow excitation and affects the propeller efficiency. The current water jet propulsion pump does not take control measures for the impeller root wake. Summary of the invention

[0004] The technical problem to be solved by the present invention is: how to reduce vibration and increase efficiency of a water jet propulsion pump, in terms of vibration performance, so as to reduce the amplitude of dynamic flow excitation force of the water jet propulsion device and improve the propulsion device efficiency.

[0005] In order to solve the above problems, the present invention provides a micro-baffle structure for reducing vibration and increasing efficiency of a water jet pump. The hub surface of the guide vane body of the water jet pump is a hemisphere, and guide vane blades are distributed on the guide vane body. The side of the guide vane blade close to the hemispherical plane is the root of the guide vane blade. The bone surface of the guide vane blade of the water jet pump is taken as the reference plane S, the front side of the guide vane blade is the pressure surface C, the back side of the guide vane blade is the suction surface A, and the back side of the micro-baffle structure is the suction surface B. One side of the micro-baffle structure is connected to the pressure surface of the guide vane blade, and the other side is bent and extended to the outer edge of the guide vane blade.

[0006] Preferably, the suction surface B of the micro-baffle structure is parallel to the suction surface A of the guide vane body blade.

[0007] Preferably, there is a guide vane channel between two adjacent guide vane blades, the spacing between each guide vane channel is the same, the projection angle of the guide vane channel on the hub surface of the guide vane body is the guide vane channel angle θ, that is, the number of guide vane blades is n, then θ=360° / n=36°.

[0008] More preferably, the micro-baffle structure is located between two adjacent vane blades, the micro-baffle structure is connected to the pressure surface of one of the vane blades, and the projection angle between the edge of the micro-baffle structure and the root of the other vane blade on the hub surface of the vane is 0.6-0.75θ. Since the impeller wake moves from the suction surface to the pressure surface in the vane channel, in order to suppress the development of this movement, the micro-baffle structure is arranged closer to the suction surface of the vane blade.

[0009] Preferably, a projection angle α of the side walls of the micro-baffle structure on the hub surface of the guide vane body is not greater than 1°.

[0010] Preferably, the distance from the outer edge of the micro-baffle structure to the hub surface of the guide vane body is a height H, which is 5% of the diameter of the hub surface of the guide vane body.

[0011] Preferably, the outer edge of the micro-baffle structure is chamfered.

[0012] More preferably, the outer edge of the micro-baffle structure is a rounded structure.

[0013] Preferably, the outer edge of the micro-baffle structure adopts an airfoil configuration. After the basic configuration of the baffle is established, in order to improve the circumferential flow suppression effect of the channel, it is necessary to further optimize the configuration of the baffle edge, chamfer each edge, round the leading edge of the suction surface side of the baffle blade near the guide vane body, or adopt an airfoil configuration to form the pressure surface and suction surface of the baffle, and make the suction surface of the baffle face the suction surface of the guide vane body, and the pressure surface of the baffle face the pressure surface of the guide vane body, so as to strengthen the suppression of the lateral vortex in the channel.

[0014] Preferably, the water jet pump is an axial flow water jet pump or a mixed flow water jet pump.

[0015] The present invention is placed in the guide vane channel, which can block the circumferential movement of the impeller root wake in the guide vane channel, inhibit the development of channel vortex, reduce the dynamic flow excitation of the propeller, and improve the propeller efficiency.

[0016] The present invention provides a guide vane micro-baffle structure for controlling the impeller root wake, limiting the development of the impeller root wake in the guide vane channel, suppressing the lateral vortex intensity of the guide vane caused by the lateral pressure gradient, having a simple structure, and being able to improve the efficiency of a water jet propulsion system and reduce the dynamic flow excitation of the water jet propulsion system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 ,2 A schematic diagram of a reference surface of a micro-baffle structure provided by the present invention;

[0018] Figure 3 A schematic diagram of the placement position of the micro-baffle structure provided by the present invention;

[0019] Figure 4 A schematic diagram of the installation structure of the micro-baffle structure provided by the present invention;

[0020] Figure 5 , 6 This is a data comparison chart before and after installing the micro-baffle structure. DETAILED DESCRIPTION

[0021] In order to make the present invention more clearly understood, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0022] Example

[0023] like Figure 1-4 As shown, a micro-baffle structure for reducing vibration and increasing efficiency of a water jet pump provided by the present invention, the hub surface of the guide vane body of the water jet pump is a hemisphere, guide vane blades are distributed on the guide vane body, the side of the guide vane blade close to the hemisphere plane is the root of the guide vane blade, the bone surface of the guide vane blade of the water jet pump is the reference plane S, the front side of the guide vane blade is the pressure surface C, the back side of the guide vane blade is the suction surface A, the back side of the micro-baffle structure is the suction surface B, one side of the micro-baffle structure is connected to the pressure surface of the guide vane blade, and the other side is bent and extended to the outer edge of the guide vane blade.

[0024] The suction surface B of the micro baffle structure is parallel to the suction surface A of the guide vane body blade.

[0025] There is a guide vane channel between two adjacent guide vane blades, and the spacing between each guide vane channel is the same. The projection angle of the guide vane channel on the hub surface of the guide vane body is the guide vane channel angle θ, that is, the number of guide vane blades is n, then θ = 360° / n = 36°. The micro-baffle structure is located between two adjacent guide vane blades, and the micro-baffle structure is connected to the pressure surface of one of the guide vane blades. The edge of the micro-baffle structure and the root of the other guide vane blade are projected at an angle of 0.6 to 0.75θ on the hub surface of the guide vane body. Since the impeller wake moves from the suction surface to the pressure surface in the guide vane channel, in order to suppress the development of this movement, the micro-baffle structure is set closer to the suction surface of the guide vane blade.

[0026] The projection angle α of the side walls of the micro baffle structure on the hub surface of the guide vane body is 1°.

[0027] The distance from the outer edge of the micro-baffle structure to the hub surface of the guide vane body is a height H, which is 5% of the diameter of the hub surface of the guide vane body.

[0028] After the basic configuration of the baffle is established, in order to improve the circumferential flow suppression effect of the channel, it is necessary to further optimize the configuration of the baffle edge, chamfer each edge, and make the leading edge of the baffle on the suction side of the blade near the guide vane body a chamfered structure β, or adopt an airfoil configuration to form the pressure side and suction side of the baffle, and make the suction side of the baffle opposite to the suction side of the guide vane body, and the pressure side of the baffle opposite to the pressure side of the guide vane body, so as to enhance the suppression of lateral vortex in the channel.

[0029] Water jet propulsion with rear guide vanes can be Figure 2 The micro-baffle structure is constructed by the schematic method in the figure. The present invention can be applied to various types of water jet pumps with rear guide vanes, including axial flow water jet pumps, mixed flow water jet pumps, etc.

[0030] The dynamic flow excitation spectrum of the water jet propulsion pump when the above-mentioned micro-baffle structure is installed and not installed is as follows Figure 5 The propulsion efficiency of the water jet propulsion pump when the above-mentioned micro-baffle structure is installed and when it is not installed is shown in Figure 6 shown.

Claims

1. A micro-baffle structure for reducing vibration and increasing efficiency of a water jet pump, wherein the hub surface of the guide vane body of the water jet pump is a hemispherical body, guide vane body blades are distributed on the guide vane body, and the side of the guide vane body blade close to the hemispherical plane is the root of the guide vane body blade, characterized in that: The skeleton surface of the guide vane blade of the water jet propulsion pump is taken as the reference plane S, the front side of the guide vane blade is the pressure surface C, the back side of the guide vane blade is the suction surface A, the back side of the micro-baffle structure is the suction surface B, one side of the micro-baffle structure is connected to the pressure surface of the guide vane blade, and the other side is bent and extended to the outer edge of the guide vane blade.

2. The micro-baffle structure for reducing vibration and increasing efficiency of a water jet propulsion pump as claimed in claim 1, characterized in that: The suction surface B of the micro baffle structure is parallel to the suction surface A of the guide vane body blade.

3. The micro-baffle structure for reducing vibration and increasing efficiency of a water jet propulsion pump as claimed in claim 1, characterized in that: There is a guide vane channel between two adjacent guide vane blades. The spacing between each guide vane channel is the same. The projection angle of the guide vane channel on the hub surface of the guide vane body is θ, that is, the number of guide vane blades is n, then θ=360° / n=36°.

4. The micro-baffle structure for reducing vibration and increasing efficiency of a water jet propulsion pump as claimed in claim 3, characterized in that: The micro baffle structure is located between two adjacent guide vane blades, connected to the pressure surface of one of the guide vane blades, and the projection angle between the edge of the micro baffle structure and the root of the other guide vane blade on the hub surface of the guide vane body is 0.6-0.75θ.

5. The micro-baffle structure for reducing vibration and increasing efficiency of a water jet propulsion pump as claimed in claim 1, characterized in that: The projection angle α of the side walls of the micro baffle structure on the hub surface of the guide vane body is not greater than 1°.

6. The micro-baffle structure for reducing vibration and increasing efficiency of a water jet propulsion pump as claimed in claim 1, characterized in that: The distance from the outer edge of the micro-baffle structure to the hub surface of the guide vane body is a height H, which is 5% of the diameter of the hub surface of the guide vane body.

7. The micro-baffle structure for reducing vibration and increasing efficiency of a water jet propulsion pump as claimed in claim 1, characterized in that: The outer edge of the micro baffle structure is chamfered.

8. The micro-baffle structure for reducing vibration and increasing efficiency of a water jet propulsion pump as claimed in claim 7, characterized in that: The outer edge of the micro baffle structure is a rounded structure.

9. The micro-baffle structure for reducing vibration and increasing efficiency of a water jet propulsion pump as claimed in claim 1, characterized in that: The outer edge of the micro-baffle structure adopts an airfoil configuration.

10. The micro-baffle structure for reducing vibration and increasing efficiency of a water jet propulsion pump as claimed in claim 1, characterized in that: The water jet propulsion pump is an axial flow water jet propulsion pump or a mixed flow water jet propulsion pump.

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