A low-noise centrifugal pump impeller blade with high flow performance

Abstract

This invention discloses a low-noise centrifugal pump impeller blade with high flow performance, comprising a blade body, a rectifier section at the blade head, and a cut arc with transition curves at both ends on the suction surface of the rectifier section. The trailing edge of the blade body has a sinusoidal wave-shaped trailing edge groove. This invention improves the undesirable flow conditions such as flow separation and backflow at the blade suction surface under low flow conditions by cutting the suction surface to form the rectifier section; it expands the flow area of ​​the centrifugal pump impeller, improving the flow capacity and making the fluid flow within the impeller more stable, allowing the centrifugal pump to operate more efficiently; while enhancing the flow capacity, it largely solves the problems of efficiency reduction, noise, and blade wear caused by eddies, further improving the internal and external characteristics of the centrifugal pump.

Description

Technical Field

[0001] The invention belongs to the technical field of centrifugal pump impellers and relates to a low-noise centrifugal pump impeller blade with high flow performance. Background Art

[0002] The pump is called the heart of modern industry. It is widely used in agriculture, chemical industry, mining and metallurgy, electric power, national defense and military industry, urban municipal administration and other industries. It is the most widely used general-purpose machinery. Its working principle is that the impeller rotates to make the fluid in the pump centrifugal motion to obtain centrifugal force and do work, generate energy and then work. The advantages are simple structure, small size, stable flow, easy to manufacture and maintain, so it is widely used in industry, agriculture, chemical industry and other industries. Its energy consumption is about 3 / 20 of the national power generation.

[0003] Under today's technological background, when operating under low flow conditions, adverse flow states such as vortex and backflow are prone to occur in the flow channel on the suction surface of the centrifugal pump impeller blades. Once the vortex is generated, it will collide with the water flow and induce adverse flows such as vortex and backflow, thereby reducing the working efficiency of the centrifugal pump. At the same time, the collision will also cause problems such as noise and vibration, and there is a possibility of impeller breakage after long-term use. Summary of the invention

[0004] The purpose of the present invention is to provide a low-noise centrifugal pump impeller blade with high flow performance, which solves the problems of poor flow conditions such as flow separation and backflow on the suction surface of the impeller blade of the centrifugal pump under low flow conditions in the prior art.

[0005] The technical solution adopted by the present invention is a low-noise centrifugal pump impeller blade with high flow performance, including a blade body, the head of the blade body is arranged as a straightening section, the suction surface streamline of the straightening section is a cutting arc with transition curves at both ends, the transition curves are transition curve a closer to the head end of the blade body and transition curve b closer to the tail end of the blade body, the transition curve a and the transition curve b are both second-order Bezier curves, the tail edge of the blade body is provided with a trailing edge groove with a sine wave waveform, and the plane where the sine wave of the trailing edge groove is located is the normal plane of the plane where the blade edge is located.

[0006] The present invention is also characterized in that:

[0007] The cutting arc is a minor arc, and the center of the cutting arc coincides with the vertex of the blade body wrap angle.

[0008] The relationship between the radius R of the cutting arc and the diameter D of the centrifugal pump impeller inlet is 0.15 D ≤ R ≤0.2 D .

[0009] The relationship between the length of the transition curve Li and the length of the blade body bone line L is: 0.05 L ≤Li ≤0.15 L , where i=1, 2, i=1 represents transition curve a, and i=2 represents transition curve b.

[0010] The period of the sine wave of the trailing edge groove is 2 to 4.

[0011] The amplitude of the sine wave of the trailing edge groove is 1 / 2 h , the distance between adjacent peaks and troughs is l ,spacing l Length and height of blade body H The relationship is: 0.02 H ≤ l ≤0.04 H , the amplitude h length is: 2 / 3 l ≤ h ≤ l .

[0012] The beneficial effects of the present invention are:

[0013] The present invention provides a low-noise centrifugal pump impeller blade with high flow performance. The impeller is cut on the suction surface of the blade to form a rectifying section, thereby improving the undesirable flow states such as flow separation and backflow on the suction surface of the blade under small flow conditions. When the incoming flow at the inlet of the centrifugal pump impeller passes through the rectifying section of the blade, a small vortex is formed in the concave arc caused by the cutting, and the larger vortex formed by the flow along the original suction surface streamline is broken up, thereby changing the original flow state at the impeller inlet, expanding the flow area of ​​the centrifugal pump impeller flow channel, improving the flow capacity, making the flow of the fluid in the impeller more stable, and the centrifugal pump can operate more efficiently. When the fluid passes through the trailing edge of the blade, shedding and backflow phenomena will occur, and the sinusoidal trailing edge groove can decompose and break up the shedding vortex, so that the shedding vortex in the impeller flow channel under small flow conditions is significantly reduced, while enhancing the flow capacity, to a large extent solving the problems of reduced efficiency, noise and blade wear caused by the vortex, and further improving the internal and external characteristics of the centrifugal pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of a low-noise centrifugal pump impeller blade with high flow performance according to the present invention;

[0015] Figure 2 It is a partial structural schematic diagram of a blade rectifying section of a centrifugal pump impeller with high flow performance and low noise according to the present invention;

[0016] Figure 3 It is a front view of a trailing edge groove of an impeller blade of a low-noise centrifugal pump with high flow performance according to the present invention;

[0017] Figure 4 It is a schematic diagram of the structure of the centrifugal pump impeller blades in the prior art;

[0018] Figure 5 It is a flow line distribution diagram inside the impeller flow channel of a centrifugal pump in the prior art;

[0019] Figure 6 The present invention is applied to the internal streamline distribution diagram of the centrifugal pump impeller flow channel.

[0020] In the figure, 1. impeller body, 2. straightening section, 2-1. cutting arc, 2-2. transition curve a, 2-3. transition curve b, 3. trailing edge groove. DETAILED DESCRIPTION

[0021] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] The present invention provides a low-noise centrifugal pump impeller blade with high flow performance, such as Figure 1 As shown, it includes a blade body 1, the head of the blade body 1 is set as a straightening section 2, the suction surface streamline of the straightening section 2 is a cutting arc 2-1 with transition curves at both ends, and the trailing edge of the blade body 1 is provided with a trailing edge groove 3 with a sine wave waveform.

[0023] like Figure 2 As shown, the cutting arc 2-1 is a minor arc, and the center of the cutting arc 2-1 coincides with the vertex of the angle of the blade body 1. The relationship between the radius R of the cutting arc 2-1 and the diameter D of the centrifugal pump impeller inlet is: 0.15 D ≤ R ≤0.2 D， The cutting of the cutting arc 2-1 occurs over the entire blade height.

[0024] The transition curves are transition curve a2-2 closer to the head end of the blade body 1 and transition curve b2-3 closer to the tail end of the blade body 1. Both transition curve a2-2 and transition curve b2-3 are second-order Bezier curves. The relationship between the length Li of the transition curve and the length L of the bone line of the blade body 1 is: 0.05 L ≤ Li ≤0.15 L , where i=1, 2, i=1 represents transition curve a2-2, and i=2 represents transition curve b2-3.

[0025] The plane where the sine wave of the trailing edge groove 3 is located is the normal plane of the plane where the blade edge is located, and the period of the sine wave of the trailing edge groove 3 is 2 to 4. Figure 3 As shown, the amplitude of the sine wave of the trailing edge groove 3 is 1 / 2 h , the distance between adjacent peaks and troughs is l ,spacing l Length and height of blade body H The relationship is: 0.02 H ≤ l ≤0.04H , the amplitude h length is: 2 / 3 l ≤ h ≤ l .

[0026] The working principle and process of the impeller blades of a low-noise centrifugal pump with high flow performance of the present invention are as follows:

[0027] When working, the centrifugal pump rotates counterclockwise, and the fluid rotates with the blade body 1 and enters the rear cover plate, and the fluid generates centrifugal motion. When running under low flow conditions, a backflow area will appear at the inlet (head end) of the blade body 1 between adjacent blade bodies 1 due to the stall phenomenon, and a shedding vortex will appear at the tail. When the water flows in the rectifying section 2-1 of the blade body 1, a small vortex is formed in the cutting arc 2-1, and the larger vortex in the original flow channel is broken up, changing the original flow state at the impeller inlet, expanding the flow area of ​​the centrifugal pump impeller flow channel, improving the flow capacity, and effectively preventing the phenomenon of unstable flow at the inlet. When the water flows through the outlet (tail end) of the blade body 1, a shedding vortex will be generated. The sinusoidal waveform edge of the trailing edge groove 3 can delay the wake of the previous flow channel of the blade 1 to enter the next flow channel, and is brought into the outlet of the next flow channel with the water flow to form a high-pressure area, which increases the suction surface pressure of the blade body 1, and at the same time plays a role in decomposing and breaking up the shedding vortex, so that the shedding vortex in the impeller flow channel under low flow conditions is significantly reduced.

[0028] In order to verify the flow performance of the low-noise centrifugal pump impeller blade with high flow performance of the present invention, it is compared with the existing centrifugal pump impeller blade. Figure 4 Set the same parameters as follows: Select flow rate Q=15 m 3 / h , speed n=3000 r / min , lift H=17 m Low specific speed centrifugal pump; impeller inlet diameter D1 = 50 mm , impeller outlet diameter D2 =115 mm , blade outlet width b2 = 9.2 mm , blade wrap angle Φ =95°. Under the condition that other geometric structures remain unchanged, the present invention sets the rectifier section 2 and the trailing edge groove 3, and their geometric parameters are set as follows: R =0.2 D ; Li =0.1 L ; l =0.04 H ; h =0.7 l .

[0029] Under the same operating conditions, the flow path streamline distributions of the existing centrifugal pump impeller blades and the centrifugal pump impeller blades of the present invention are respectively Figure 5 and Figure 6 As shown, Figure 5 In the process, there are a lot of vortices at the inlet of the blade head, and a reflow area is formed near the outlet under the original streamline distribution of the blade tail. Especially when running under small flow conditions, the vortex and reflow phenomena are more obvious. Figure 6 Compared to Figure 5 Most of the backflow vortices are broken up, and the vortex at the inlet is significantly improved due to the rectification section. It can be concluded that the centrifugal pump impeller blades of the present application greatly enhance the flow capacity of the impeller and improve the working efficiency of the centrifugal pump.

Claims

1. A low-noise centrifugal pump impeller blade with high flow performance, characterized in that: The invention comprises a blade body (1), wherein the head of the blade body (1) is arranged as a straightening section (2), the suction surface streamline of the straightening section (2) is a cutting arc (2-1) with transition curves arranged at both ends, the transition curves are a transition curve a (2-2) closer to the head end of the blade body (1) and a transition curve b (2-3) closer to the tail end of the blade body (1), the transition curve a (2-2) and the transition curve b (2-3) are both second-order Bezier curves, the cutting arc (2-1) is a minor arc, the center of the cutting arc (2-1) coincides with the vertex of the wrap angle of the blade body (1), and the relationship between the radius R of the cutting arc (2-1) and the diameter D of the centrifugal pump impeller inlet is: 0.15 D ≤ R ≤0.2 D The trailing edge of the blade body (1) is provided with a trailing edge groove (3) having a sine wave waveform, the plane where the sine wave of the trailing edge groove (3) is located is the normal plane of the plane where the blade edge is located, the period of the sine wave of the trailing edge groove (3) is 2 to 4, and the amplitude of the sine wave of the trailing edge groove (3) is 1 / 2 h , the distance between adjacent peaks and troughs is l ,spacing l Length and height of blade body H The relationship is: 0.02 H ≤ l ≤0.04 H , the amplitude h length is: 2 / 3 l ≤ h ≤ l .

2. The low-noise centrifugal pump impeller blade with high flow performance according to claim 1, characterized in that: The relationship between the length Li of the transition curve and the length L of the blade body (1) is: 0.05 L ≤ That ≤0.15 L , where i=1, 2, i=1 represents transition curve a (2-2), and i=2 represents transition curve b (2-3).

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