A micro baffle structure for vibration reduction and efficiency improvement of a water jet propelling pump

Abstract

The application discloses a micro baffle structure for reducing vibration and increasing efficiency of a water jet propeller pump, wherein a hub surface of a guide vane body of the water jet propeller pump is a semi-sphere, the guide vane body is provided with guide vane body blades, a side of the guide vane body blades close to the semi-sphere plane is a root of the guide vane body blades, a bone surface of the guide vane body blades is a reference surface S, a front side of the guide vane body blades is a pressure surface C, a back surface of the guide vane body blades is a suction surface A, a back surface of the micro baffle structure is a suction surface B, one side of the micro baffle structure is connected with the suction surface A of the guide vane body blades, and the other side of the micro baffle structure is bent and extends to an outer edge of the guide vane body blades. The application limits the development of a rotor root wake in a guide vane body channel, suppresses the intensity of guide vane body transverse vortex flow caused by a transverse pressure gradient, has a simple structure, and can improve the efficiency of the water jet propeller and reduce the dynamic flow excitation force of the water jet propeller.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of micro baffle structures of water jet propeller vibration reduction and efficiency improvement in water dynamic performance, belong to ship engineering technical field. BACKGROUND

[0002] Water jet propeller utilizes the reaction force generated by high-speed jet to push the ship forward, with high efficiency at high speed, low vibration and noise level, good maneuverability, strong anti-cavitation performance and other characteristics, widely used in high-performance ships. Propulsion pump is the core working component of water jet propeller, and is also the main source of propeller vibration and noise. It includes rotating impeller and stationary guide vane body. Water flow is pressurized in the impeller, and after outflow, it enters the guide vane body and is sprayed after being rectified by the guide vane body. The impeller and guide vane body are composed of blades, forming a center-symmetric blade passage. The wake at the root of the impeller blade enters the guide vane body and is affected by the transverse pressure gradient, developing into a strong dynamic vortex, enhancing the dynamic flow-induced force of the propeller and affecting 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 actual water jet propeller pump, the impeller has a certain thickness, especially near the hub, the blade root is rounded, which significantly increases the thickness, forming a strong root trail. The trail enters the downstream guide vane body and has a circumferential motion form, which is affected by the transverse pressure gradient in the guide vane body and develops into a strong dynamic vortex, significantly enhancing the flow-induced force of the propeller and affecting the efficiency of the propeller. The current water jet propeller pump does not take control measures for the root trail of the impeller. SUMMARY

[0004] The technical problem to be solved by the present application is how to reduce the vibration and improve the efficiency of the water jet propeller pump, and to reduce the amplitude of the dynamic flow-induced force of the water jet propeller and improve the efficiency of the propeller in terms of vibration performance.

[0005] To solve the above problems, the present application provides a micro baffle structure for reducing vibration and improving efficiency of water jet propeller pump. The hub surface of the guide vane body of the water jet propeller pump is a hemisphere, and the guide vane body has guide vane body blades distributed thereon. The side of the guide vane body blade close to the plane of the hemisphere is the root of the guide vane body blade. The bone surface of the guide vane body blade is taken as the reference surface S, the front side of the guide vane body blade is the pressure surface C, the back of the guide vane body blade is the suction surface A, the back of the micro baffle structure is the suction surface B, one side of the micro baffle structure is connected with the suction surface A of the guide vane body blade, and the other side is bent to extend towards the outer edge of the guide vane body 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, the adjacent two guide vane bodies are connected by a guide vane channel, the distance of 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, the guide vane body has n guide vane blades, and θ = 360° / n.

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

[0009] Preferably, the projection angle α of the two 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 establishing the basic configuration of the baffle, in order to improve the suppression effect of the circumferential flow in the channel, the edge of the baffle is further optimized, the edges are chamfered, the leading edge near the suction surface of the guide vane body is rounded, or an airfoil configuration is adopted to form the pressure surface and the suction surface of the baffle, and the suction surface of the baffle is opposite to the suction surface of the guide vane body, and the pressure surface of the baffle is opposite to the pressure surface of the guide vane body, so as to strengthen the suppression of the transverse vortex in the channel.

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

[0015] The micro baffle structure of the guide vane body provided by the application can block the circumferential movement of the impeller root wake in the guide vane channel, suppress the development of the vortex in the channel, reduce the dynamic flow excitation force of the propeller, and improve the efficiency of the propeller.

[0016] The micro baffle structure of the guide vane body provided by the application can block the circumferential movement of the impeller root wake in the guide vane channel, suppress the development of the vortex in the channel, reduce the dynamic flow excitation force of the propeller, and improve the efficiency of the propeller. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 ,2 A schematic diagram of the reference plane of the microbaffle structure provided by the present invention;

[0018] Figure 3 A schematic diagram showing the placement of the microbaffle structure provided by the present invention;

[0019] Figure 4 This is a schematic diagram of the installation structure of the micro baffle structure provided by the present invention;

[0020] Figure 5 , 6 This is a comparison chart of data before and after the installation of the micro-baffle structure. Detailed Implementation

[0021] To make the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0022] Example

[0023] like Figures 1-4 As shown, this invention provides a micro-baffle structure for vibration reduction and efficiency enhancement of a water jet propulsion pump. The hub surface of the guide vane of the water jet propulsion pump is a hemisphere, and guide vane blades are distributed on the guide vane. The side of the guide vane blade closest to the plane of the hemisphere is the root of the guide vane blade. Taking the rib surface of the guide vane blade of the water jet propulsion pump as the reference surface 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 suction surface A of the guide vane blade, and the other side is bent and extends 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 blade.

[0025] The guide vane body has channels between adjacent guide vane blades, with equal spacing between each channel. The projection angle of each channel onto the hub surface of the guide vane body is θ, meaning that if the number of guide vane blades is n, then θ = 360° / n. The micro-baffle structure is located between adjacent guide vane blades and connects to the pressure surface of one of the blades. The projection angle between the edge of the micro-baffle structure and the root of the other blade onto the hub surface is 0.6~0.75θ. Because the impeller wake moves from the suction surface to the pressure surface within the guide vane channels, the micro-baffle structure is positioned closer to the suction surface of the guide vane blades to suppress this movement.

[0026] The projection angle α of the two sidewalls of the microbaffle structure onto the hub surface of the guide vane is 1°.

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

[0028] In order to improve the circumferential flow inhibition effect of the channel, the edge of the baffle is further optimized, the edges are chamfered, the leading edge of the suction surface side of the baffle near the guide vane body is a rounded structure β, or a wing surface configuration is adopted, so as to form the pressure surface and the suction surface of the baffle, and the suction surface of the baffle is opposite to the suction surface of the guide vane body, the pressure surface of the baffle is opposite to the pressure surface of the guide vane body, and the inhibition of the transverse vortex in the channel is strengthened.

[0029] The water jet propeller with the rear guide vane can be constructed into the micro-baffle structure by the schematic method in Figure 2 The present application can be applied to various water jet propeller pumps with rear guide vanes, including axial flow water jet propeller pumps, mixed flow water jet propeller pumps and the like.

[0030] The dynamic flow excitation force spectrum of the water jet propeller pump with the micro-baffle structure and without the micro-baffle structure is shown in Figure 5 The propeller efficiency of the water jet propeller pump with the micro-baffle structure and without the micro-baffle structure is shown in Figure 6 .

Claims

1. A water jet propeller pump vibration reduction and efficiency enhancement micro baffle structure, wherein a hub surface of a guide vane body of the water jet propeller pump is a semi-spherical body, guide vane body blades are distributed on the guide vane body, and a side of the guide vane body blades close to a plane of the semi-spherical body is a root of the guide vane body blades, and the micro baffle structure is characterized in that, The bone surface of the guide vane body blade of the water jet propelling pump is taken as a reference surface S, the front side of the guide vane body blade is a pressure surface C, the back surface of the guide vane body blade is a suction surface A, the back surface of the micro baffle structure is a suction surface B, one side of the micro baffle structure is connected with the suction surface A of the guide vane body blade, and the other side is bent to extend to the outer edge of the guide vane body blade; the suction surface B of the micro baffle structure is parallel to the suction surface A of the guide vane body blade; the adjacent two guide vane body blades are connected by a guide vane body channel, the distance of each guide vane body channel is the same, the projection angle of the guide vane body channel on the hub surface of the guide vane body is θ, the guide vane body channel angle is θ, that is, the number of guide vane body blades is n, and θ = 360° / n; the micro baffle structure is located between the adjacent two guide vane body blades, the micro baffle structure is connected with the pressure surface of one of the guide vane body blades, and the projection angle of the edge of the micro baffle structure and the root of the other guide vane body blade on the hub surface of the guide vane body is 0.6-0.75θ.

2. The water jet propelling pump vibration reduction and performance enhancement micro-baffle structure of claim 1, wherein, The projection angle α of the two side walls of the micro baffle structure on the hub surface of the guide vane body is not greater than 1°.

3. The water jet propelling pump vibration reduction and performance enhancement micro-baffle structure of claim 1, wherein, 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.

4. The water jet propelling pump vibration reduction and performance enhancement micro-baffle structure of claim 1, wherein, The outer edge of the micro baffle structure is chamfered.

5. The water jet propelling pump vibration reduction and performance enhancement micro-baffle structure of claim 4, wherein, The outer edge of the micro baffle structure is a rounded structure.

6. The water jet propelling pump vibration reduction and performance enhancement micro flapper structure in accordance with claim 1, wherein, The outer edge of the micro baffle structure adopts an airfoil configuration.

7. The water jet propelling pump vibration reduction and performance enhancement micro-baffle structure of claim 1, wherein, The water jet propelling pump is an axial flow water jet propelling pump or a mixed flow water jet propelling pump.

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