Impeller and design method

Abstract

The application relates to a kind of impeller and design method, including disc body, the disc body is equipped with multiple main blades, is equipped with splitter blade between adjacent main blades, the back rake angle of main blade is greater than the back rake angle of splitter blade.The application has the advantages of being capable of reducing noise in use.

Description

Technical Field

[0001] This application relates to the technical field of impellers, and in particular to an impeller and a design method thereof. Background Technology

[0002] Traditional centrifugal pump impellers typically employ a 6-10 blade structure, and their hydraulic performance is relatively mature. However, traditional impellers generate significant noise during operation. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, one of the objectives of this application is to provide an impeller and a design method that has the advantage of reducing noise during use.

[0004] The above-mentioned objective of this application is achieved through the following technical solution: An impeller includes a disc body with multiple main blades and a flow divider blade between adjacent main blades. The sweep angle of the main blades is greater than the sweep angle of the flow divider blade.

[0005] In a preferred embodiment, this application can be further configured such that there are multiple diverter blades, and the distance between the inner end of the diverter blade and the center of rotation is 0.6-0.9 times the radius of the disk.

[0006] In a preferred embodiment, the present application may be further configured such that the radius of curvature of the splitter blade is 1.6 to 1.8 times the radius of the disk.

[0007] In a preferred embodiment, this application can be further configured such that the slot angle deviation between adjacent splitter blades is within the range of ±0.5° to 5°.

[0008] In a preferred embodiment, this application can be further configured such that the slot angle deviation between the splitter blades and the main blades is within the range of ±0.5° to 5°.

[0009] In a preferred embodiment, this application may be further configured such that there are multiple diverter blades, and the depths of adjacent diverter blades are not equal.

[0010] In a preferred embodiment, this application may be further configured such that: a plurality of units 1 are formed on the disk body, each unit 1 including one or more main blades and one or more shunt blades.

[0011] In a preferred embodiment, this application may be further configured such that: multiple units II are formed on the disk body, and each unit II includes multiple flow divider blades.

[0012] This application also discloses an impeller design method for designing the aforementioned impeller, comprising the following steps: a step to confirm the number of splitter blades: calculating the range of the number Z of splitter blades when the vortex frequency enters the high-frequency region; a step to confirm the position: determining the position of the splitter blades by using the radius of curvature of the splitter blades and α(r), where α(r) is the sweep angle when the disk radius is r; a step to confirm the depth of the splitter blades: obtaining the pressure difference ΔP(r) on both sides of the splitter blade at radius r, and combining it with the pressure difference distribution at each splitter blade within the impeller to obtain the depth dimensions of the splitter blades at different positions; and an iterative step: using simulation software to iteratively optimize the above parameters to obtain the optimal solution.

[0013] In a preferred example, this application can be further configured to: control the target using a pressure gradient during the position confirmation step. ,in, For pressure coefficient, For the target pressure gradient threshold, Gradient of pressure coefficient; Determine location The upper limit of the pressure gradient at that point; substituting the radius of curvature R(x), ,in: For position Fluid velocity at the location, unit: m / s For position The pressure gradient at the point is expressed in Pa / m. A distribution of the blade curvature radius satisfying the pressure gradient is obtained through CFD iteration. The sweep angle α is calculated by determining the circumferential velocity component of the fluid in the impeller using CFD, and then gradually changing the tangential velocity component along the impeller radius, combined with the formula: ,in: radius The tangential velocity component of the fluid at that location (m / s) radius The radial velocity component of the fluid (m / s) and α(r) are given by the disk radius. The sweep angle at that time.

[0014] The present invention has the following advantages: 1. By varying the curvature or depth of individual split blades, and by setting the angle deviation between adjacent main blades and split blades, the medium pressure gradient is kept stable during impeller rotation. 2. Different depth settings are set between the flow splitters, so that the wake frequency of the longer flow splitter is not equal to that of the shorter flow splitter, thus forming multiple weak peak frequencies and reducing noise; the longer flow splitter extends a larger distance in the radial direction, providing continuous tangential acceleration to the fluid; the shorter flow splitter extends a shorter distance in the radial direction, forming auxiliary flow guidance in the middle section. 3. The structure of the splitter blades exhibiting a regular rhythmic depth can maintain the uniformity of energy input during impeller operation, achieve continuous pressure field transition, and significantly reduce large-scale vortices in the wake structure, thereby improving noise reduction performance and hydraulic stability. 4. By setting the slot angle deviation and different depths between two adjacent split vanes, the rear split vanes are prevented from bearing a larger pressure gradient, thus avoiding the problem of increased noise and loss caused by the phenomenon of "sudden energy addition" in the rear split vanes. 5. By setting different inter-slot angle deviations, the BPF is dispersed, thereby reducing peak noise; 6. Noise reduction and silencing are achieved by refining the vortex by setting flow divider blades. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this application.

[0016] Reference numerals: 1. Disc body; 2. Main blade; 3. Diverter blade. Detailed Implementation

[0017] The present application will be further described in detail below with reference to the accompanying drawings.

[0018] Reference Figure 1 This application discloses an impeller comprising a disc body 1, on which multiple main blades 2 are provided, and diverter blades 3 are provided between adjacent main blades 2. The sweep angle of the main blades 2 is greater than the sweep angle of the diverter blades 3. There are multiple diverter blades 3, and the distance between the inner end of the diverter blade 3 and the center of rotation is 0.6-0.9 times the radius of the disc body 1. The radius of curvature of the diverter blades 3 is 1.6-1.8 times the radius of the disc body 1. The slot angle deviation between adjacent diverter blades 3 is ±(0.5°-5°). The slot angle deviation between the diverter blades 3 and the main blades 2 is ±(0.5°-5°). The depths of adjacent diverter blades 3 are unequal. Multiple unit 1s are formed on the disc body 1, each unit 1 including one or more main blades 2 and one or more diverter blades 3. Multiple unit 2s are formed on the disc body 1, each unit 2 including multiple diverter blades 3. Unit 1 and unit 2 are evenly distributed on the disc body.

[0019] Taking the two adjacent main blades 2 and the counter-rotating branch blades 3 as the first branch blade 3, the second branch blade 3, and so on, as an example, the sweep angle of the front main blade 2 is denoted as α1, and the sweep angle of the branch blades 3 is denoted as α2, α3, and so on. Then α1 > α2, α1 > α3, and so on. Therefore, the above-mentioned slot angle deviation can be understood as α2-α1, α3-α2, etc., which is the sweep angle difference.

[0020] In Unit 1, taking multiple consecutive blades (here, the blades can be either main blades 2 or branch blades 3) as an example, each consisting of one main blade 2 and multiple branch blades 3, the main blade 2 and the branch blades 3 form a structure with a regular rhythm. The sweep angle of the multiple branch blades 3 is smaller than that of the main blade 2, and the slot angle deviation range between adjacent branch blades 3 is ±(0.5°~5°). The slot angle deviation range between the branch blades 3 and the main blade 2 is also ±(0.5°~5°). In Unit 2, the depths of the consecutive branch blades 3 exhibit a pattern of short-long-short or long-short-long, etc. If there are multiple branch blades in Unit 2, the depths of the three branch blades in a single Unit 2 exhibit a pattern of short-long-short. That is, in Unit 1, the relevant parameters of the branch blades 3 and the relevant parameters of the main blades 2 are both regular, and in Unit 2, the relevant parameters of the multiple branch blades 3 are also regular. In other embodiments, the relevant parameters of the branch blades 3 and the relevant parameters of the main blades 2 in Unit 1 may be irregular, and the relevant parameters of the multiple branch blades 3 in Unit 2 may also be irregular.

[0021] This invention also discloses an impeller design method for designing the aforementioned impeller, comprising the following steps: a step to confirm the number of splitter blades 3: calculating the range of the number Z of splitter blades 3 when the vortex frequency enters the high-frequency region; a step to confirm the position: determining the position of the splitter blades 3 by using the radius of curvature of the splitter blades 3 and α(r), where α(r) is the sweep angle when the radius of the disk 1 is r; a step to confirm the depth of the splitter blades 3: obtaining the pressure difference ΔP(r) on both sides of the splitter blades 3 at radius r, and combining it with the pressure difference distribution at each splitter blade 3 within the impeller to obtain the depth dimensions of the splitter blades 3 at different positions; and an iterative step: using simulation software to iteratively optimize the above parameters to obtain the optimal solution.

[0022] More specifically, the above design steps can be further broken down as follows: S10: Determine the number of splitter blades Z; S11: Set the target noise frequency band, such as 1-4kHz; S12: Given the rotor speed, the vortex frequency is:

[0023] in, vortex frequency (Hz) is the rotor rotation frequency (Hz, converted from speed), and k is the correction value (a constant, usually taken as 1 or 2). The range of the number of shunting blades Z is calculated to bring the vortex frequency into the high-frequency region (e.g., greater than 2 kHz); S20: Calculate the radius of curvature of the splitter blade; S21: Target control using pressure gradient:

[0024] in, For pressure coefficient, For the target pressure gradient threshold, The gradient of the pressure coefficient; Determine location The upper limit of the pressure gradient at any point (between two adjacent blades).

[0025] S22: Substitute the radius of curvature R(x), unit: m:

[0026] in: For position Fluid velocity at the location (unit: m / s) For position Pressure gradient at a point (unit: Pa / m); A distribution of the curvature radius of the splitter blades that satisfies the pressure gradient is obtained through CFD (Computational Fluid Dynamics) iteration.

[0027] S30: Calculate the sweep angle α; S31: First, based on the Euler equation:

[0028] in, The fluid's circumferential velocity (unit: m / s) For the circumferential velocity component of the fluid (unit: m / s) Head (unit: m) Acceleration due to gravity (unit: m / s²) 2 ); The circumferential velocity component of the fluid in the impeller was determined using CFD.

[0029] S32: Then, along the impeller radius direction, gradually change the tangential velocity component, combining the formula:

[0030] in: radius Tangential velocity component of the fluid (unit: m / s) radius The radial velocity component of the fluid (unit: m / s), α(r) is the radius of the disk. The sweep angle at that time (unit: rad, converted to °). The position of the splitter blades is determined by the radius of curvature and α(r).

[0031] S40: Calculate the depth h(r) of the splitter blade, in meters; Due to pressure difference The depth of the splitter blades is calculated as follows:

[0032] in: radius Pressure difference across the flow divider blades (unit: Pa) 2 is the proportionality coefficient (unit: (This is determined by the structural form of the splitter blades). By combining the pressure difference distribution at each flow divider blade within the impeller, the depth dimensions of the flow divider blades at different locations are obtained; S50: Iterative optimization; The optimal solution was obtained by iteratively optimizing the above parameters using simulation software. The implementation principle of this embodiment is as follows: by setting diverter blades between the main blades, noise can be effectively reduced during operation.

[0033] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method of impeller design, characterized by: For designing an impeller, the impeller includes a disk body with multiple main blades and shunt blades between adjacent main blades. The sweep angle of the main blades is greater than the sweep angle of the shunt blades. The design method includes the following steps: shunt blade number confirmation step: calculate the range of the number Z of shunt blades when the vortex frequency enters the high-frequency region. Position confirmation steps: The position of the splitter blade is determined by the radius of curvature of the splitter blade and α(r), where α(r) is the sweep angle when the disk radius is r; Steps for confirming the depth of the splitter blade: Obtain the pressure difference ΔP(r) on both sides of the splitter blade at radius r, and combine it with the pressure difference distribution at each splitter blade in the impeller to obtain the depth dimension of the splitter blade at different positions; Iteration steps: Iterate and optimize the above parameters using simulation software to obtain the optimal solution.

2. The impeller design method according to claim 1, characterized in that: In the location confirmation step, the target is controlled using a pressure gradient: in, For pressure coefficient, For the target pressure gradient threshold, Gradient of pressure coefficient; Determine location Upper limit of pressure gradient at the point; substitute the radius of curvature R(x) , in: For position Fluid velocity at the location, unit: m / s For position The pressure gradient at the point is expressed in Pa / m. A distribution of the blade curvature radius satisfying the pressure gradient is obtained through CFD iteration. The sweep angle α is calculated by determining the circumferential velocity component of the fluid in the impeller using CFD, and then gradually changing the tangential velocity component along the impeller radius, combined with the formula: in: radius The tangential velocity component of the fluid, in m / s. radius The radial velocity component of the fluid, in m / s. α ( r (where the radius of the disk is...) The sweep angle at that time.

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