Design method of multi-blade centrifugal fan blade profile, blade and multi-blade centrifugal fan

Abstract

The application provides a design method of a multi-wing centrifugal fan blade profile, a blade and a multi-wing centrifugal fan, and the method comprises the following steps: determining the leading and trailing edge lines of the blade; taking the leading and trailing edge lines as constraint guide lines, and connecting multiple two-dimensional airfoils of the blade one by one by using a preset drawing method to obtain a three-dimensional airfoil of the blade; the blade comprises multiple two-dimensional airfoils, and the inclination angle of each two-dimensional airfoil gradually increases from the rear disc side to the front disc side, and the inclination angle is the included angle between the leading and trailing end connecting line of the two-dimensional airfoil and the rear disc. In the embodiment of the application, the blade of the multi-wing centrifugal fan is divided into different regions according to the airflow flow characteristics, different airfoil designs are performed on different regions, the blade promotes the airflow flow, the doing function of the blade on the airflow is enhanced, and the efficiency of the fan is improved.

Description

Technical Field

[0001] This invention relates to the field of centrifugal fan blade technology, and more specifically, to a design method for a multi-blade centrifugal fan blade profile, a blade, and a multi-blade centrifugal fan. Background Technology

[0002] Multi-blade centrifugal fans are widely used in household appliances, such as the internal air ducts of air conditioners, fresh air systems, and dehumidifiers. A multi-blade centrifugal fan generally consists of an impeller, casing, collector, motor, and transmission components. The impeller typically consists of a disc, multiple blades, a cover, and a shaft disc.

[0003] Traditional centrifugal fan blades employ a two-dimensional design, obtained by stretching a two-dimensional airfoil section. All sections of the blade have the same airfoil shape, which cannot effectively utilize the impeller's performance, resulting in low fan efficiency. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a design method for a multi-blade centrifugal fan blade. The method includes: determining the leading and trailing edge lines of the blade; using the leading and trailing edge lines as constraint guide lines, connecting multiple two-dimensional airfoils of the blade one by one using a preset drawing method to obtain a three-dimensional airfoil of the blade; the blade includes multiple two-dimensional airfoils, and the tilt angle of each two-dimensional airfoil gradually increases from the rear plate side to the front plate side, wherein the tilt angle is the angle between the line connecting the front and rear ends of the two-dimensional airfoil and the rear plate.

[0005] The multi-blade centrifugal fan blade design method provided in this invention divides the blades into regions according to the airflow characteristics, and different airfoil designs are applied to different regions. This makes the blades promote airflow, enhance the blades' ability to perform work on the airflow, and improve the efficiency of the fan.

[0006] Optionally, the method further includes: establishing each of the two-dimensional airfoils based on a two-segment contour curve modeling method.

[0007] In this embodiment of the invention, the airfoil is established based on a two-segment profile curve modeling method. This method is simple to model and can increase the flexibility of adjusting the profile geometry of the centrifugal fan blade.

[0008] Optionally, the pressure and suction surfaces of the two-dimensional airfoil employ parameterized B-spline curves of the same order and the same parameter node vector. The equation of the parameterized B-spline curve is as follows:

[0009]

[0010] In the formula, d i (i=0,1,2…,n) are the control vertices of the control polygon, and the broken line formed by connecting them in sequence is the B-spline control polygon; For the vertex d i B-spline mixture function;

[0011] The recursive method for the mixing function is defined as follows:

[0012]

[0013] In the formula, k is the power of the B-spline; the subscript i is the index; u i For nodes.

[0014] The embodiments of the present invention provide a specific modeling method that can increase the flexibility of adjusting the airfoil profile geometry of centrifugal fan blades.

[0015] This invention provides a blade for a multi-blade centrifugal fan, the blade comprising a front section, a middle section, and a rear section; each of the front section, the middle section, and the rear section includes at least one two-dimensional airfoil; the tilt angle of the two-dimensional airfoils of the front section, the middle section, and the rear section gradually increases from the rear plate side to the front plate side, and two adjacent two-dimensional airfoils are connected by drawing to obtain a three-dimensional airfoil.

[0016] The multi-blade centrifugal fan blades provided in this embodiment of the invention are divided into regions according to the airflow characteristics, and different airfoil designs are used in different regions. This makes the blades promote airflow, enhance the blades' ability to do work on the airflow, and thus improve the efficiency of the fan.

[0017] Optionally, the tilt angle of each of the airfoils in the rear section is zero; the tilt angle of the airfoil in the middle section is smaller than the tilt angle of the airfoil in the front section, and the tilt angles of each of the airfoils in the middle section and each of the airfoils in the front section gradually increase from the rear plate side to the front plate side.

[0018] The embodiments of the present invention provide the tilt angle variation trend of the airfoil in different regions, which adapts to the airflow state inside the centrifugal fan and can enhance the blade's work capacity for airflow.

[0019] Optionally, the tilt angle of each airfoil in the middle section ranges from 16° to 33°.

[0020] The embodiments of the present invention provide a range of values ​​for the tilt angle of the airfoil in the middle section, which can adapt to the airflow state inside the centrifugal fan and enhance the blade's ability to perform work on the airflow.

[0021] Optionally, each of the airfoils is established based on a two-segment profile curve modeling method.

[0022] In this embodiment of the invention, the airfoil is established based on a two-segment profile curve modeling method. This method is simple to model and can increase the flexibility of adjusting the profile geometry of the centrifugal fan blade.

[0023] Optionally, the pressure and suction surfaces of the two-dimensional airfoil employ parameterized B-spline curves of the same order and the same parameter node vector. The equation of the parameterized B-spline curve is as follows:

[0024]

[0025] In the formula, d i (i=0,1,2…,n) are the control vertices of the control polygon, and the broken line formed by connecting them in sequence is the B-spline control polygon; For the vertex d i B-spline mixture function;

[0026] The recursive method for the mixing function is defined as follows:

[0027]

[0028] In the formula, k is the power of the B-spline; the subscript i is the index; u i For nodes.

[0029] The embodiments of the present invention provide specific modeling methods that can increase the flexibility of adjusting the airfoil profile geometry of centrifugal fan blades.

[0030] Optionally, the trailing edge of the front section is provided with a cutting notch.

[0031] In this embodiment of the invention, the trailing edge of the blade is cut at the leading end of the blade, which can reduce the obstruction and loss of the blade to the inlet airflow.

[0032] This invention provides a multi-blade centrifugal fan, including the blades of any of the above-described multi-blade centrifugal fans.

[0033] The multi-blade centrifugal fan of the present invention can achieve the same technical effect as the blades of the aforementioned multi-blade centrifugal fan. Attached Figure Description

[0034] Figure 1 A schematic diagram of the airflow inside the centrifugal fan is shown;

[0035] Figure 2 A schematic diagram of a traditional centrifugal fan blade design is shown.

[0036] Figure 3 A schematic flowchart of a design method for a multi-blade centrifugal fan blade profile according to an embodiment of the present invention is shown;

[0037] Figure 4 A schematic diagram of the centrifugal fan blade profile provided in an embodiment of the present invention is shown;

[0038] Figure 5This diagram illustrates a three-dimensional model drawing provided in an embodiment of the present invention.

[0039] Figure 6 This illustrates a schematic diagram of airfoil drawing provided in an embodiment of the present invention;

[0040] Figure 7 A schematic diagram of the wind turbine assembly provided in an embodiment of the present invention is shown;

[0041] Figure 8 A schematic diagram of the structure of the multi-blade centrifugal fan provided in an embodiment of the present invention is shown. Detailed Implementation

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0043] This invention provides a multi-blade centrifugal fan, whose blades are designed according to airflow characteristics to enhance their ability to influence airflow. The two-dimensional airfoil is modeled using a two-segment curve method, which is simple to model and increases the flexibility of adjusting the airfoil profile geometry of the centrifugal fan blades.

[0044] Specifically, the blades of the aforementioned multi-blade centrifugal fan are divided into regions according to the characteristics of airflow, with different airfoil designs in different regions, so that the blades promote airflow and enhance the blades' ability to perform work on the airflow.

[0045] Figure 1 The diagram shows the airflow inside a centrifugal fan. Unlike the flow characteristics of an axial fan, the gas in a centrifugal fan first enters the impeller axially. Then, as the fan flows past the impeller, the gas becomes radial. Finally, under the action of centrifugal force, the gas is compressed and thrown towards the outer edge of the impeller.

[0046] Specifically, the airflow characteristics differ across the blade as it flows from the front disc to the rear disc. In this embodiment, the blade can be divided into three sections: the front section, the middle section, and the rear section. The front section, located near the front disc (i.e., the fan inlet), primarily flows along the motor axis as the airflow begins to enter the fan. The middle section represents a transition from axial to radial flow, exhibiting an inclined flow. The rear section, near the rear disc, primarily flows radially towards the impeller. Figure 1 The upper middle section is the front plate, and the lower middle section is the rear plate. From top to bottom, they are the front section, middle section, and rear section.

[0047] Figure 2The diagram illustrates a traditional centrifugal fan blade design. Traditional centrifugal fan blades are a two-dimensional design, where all cross-sections of the blade have the same airfoil shape (installation angle, outlet angle, inlet angle, etc.). This is because the blade is formed by stretching a single two-dimensional airfoil cross-section. This design cannot effectively utilize the impeller's performance. Figure 2 Section 1-7 and its corresponding airfoil 1-7 are shown in the figure.

[0048] Figure 3 A schematic flowchart illustrating a design method for a multi-blade centrifugal fan blade profile according to an embodiment of the present invention is shown. The method includes the following steps:

[0049] S302, determine the leading and trailing edge lines of the blade.

[0050] When modeling, the positions of the front and rear edges need to be determined first.

[0051] S304, using the aforementioned leading and trailing edge lines as constraint guide lines, connect the multiple two-dimensional airfoils of the blade one by one using a preset drawing method to obtain the three-dimensional airfoil of the blade.

[0052] The method of connecting multiple two-dimensional airfoils of the blade one by one using a preset drawing method can be achieved by using the creo boundary blending command to connect each two-dimensional airfoil one by one. Specifically, the blade includes multiple two-dimensional airfoils, and the tilt angle of each two-dimensional airfoil gradually increases from the rear disk side to the front disk side. This tilt angle is the angle between the line connecting the front and rear ends of the two-dimensional airfoil and the rear disk.

[0053] Considering that the airflow direction in the front section is mainly along the axis of the motor, the airflow direction in the middle section is inclined, and the airflow direction in the rear section is mainly in the radial direction of the impeller, the tilt angle of the above-mentioned two-dimensional airfoils gradually increases from the rear disk side to the front disk side. For example, the tilt angle of each airfoil in the rear section is zero, the tilt angle of the airfoil in the middle section is smaller than the tilt angle of the airfoil in the front section, and the tilt angle of each airfoil in the middle section and each airfoil in the front section gradually increases from the rear disk side to the front disk side.

[0054] The multi-blade centrifugal fan blade design method provided in this invention divides the blades into regions according to the airflow characteristics, and different airfoil designs are applied to different regions. This makes the blades promote airflow, enhance the blades' ability to perform work on the airflow, and improve the efficiency of the fan.

[0055] Furthermore, the above method also includes: establishing each two-dimensional airfoil based on a two-segment profile curve modeling method. In this embodiment, the airfoil is established based on a two-segment profile curve modeling method, which is simple to model and can increase the flexibility of adjusting the profile geometry of the centrifugal fan blade.

[0056] This invention provides a blade for a multi-blade centrifugal fan, the blade comprising a front section, a middle section, and a rear section.

[0057] The front section is close to the front disk, and the rear section is close to the rear disk. The front, middle and rear sections each include at least one two-dimensional airfoil. The tilt angle of the two-dimensional airfoil in the front, middle and rear sections gradually increases from the rear disk side to the front disk side. The two adjacent two-dimensional airfoils are connected by drawing to obtain a three-dimensional airfoil.

[0058] The multi-blade centrifugal fan blades provided in this embodiment of the invention are divided into regions according to the airflow characteristics, and different airfoil designs are used in different regions. This makes the blades promote airflow, enhance the blades' ability to do work on the airflow, and thus improve the efficiency of the fan.

[0059] For example, the tilt angle of each airfoil in the rear section is zero; the tilt angle of the airfoil in the middle section is greater than that of the airfoil in the front section, and the tilt angles of each airfoil in the middle section and the airfoil in the front section gradually increase from the rear plate side to the front plate side. This embodiment provides the tilt angle variation trend of the airfoil in different regions, which adapts to the airflow state inside the centrifugal fan and can enhance the blade's work capacity for airflow.

[0060] Optionally, the inclination angle of each airfoil in the middle section ranges from 16° to 33°.

[0061] Optionally, each airfoil is established based on a two-segment profile curve modeling method.

[0062] Optionally, a notch is provided on the trailing edge of the leading section of the blade. Cutting the trailing edge of the blade at the leading section can reduce the obstruction and loss of the blade to the inlet airflow.

[0063] Figure 4 A schematic diagram of the centrifugal fan blade profile provided in an embodiment of the present invention is shown. Figure 4 As shown, let the angle between the line connecting the front and rear ends of the airfoil and the rear plate be the tilt angle, denoted as β. Different airfoil tilt angles are set for the front, middle, and rear sections. Figure 4 The left side is the tail edge line, and the right side is the leading edge line.

[0064] For example, the length of the front section L1 accounts for about 30% of the total blade length L, that is, L1 / L=30%, while the middle section and the rear section account for 55% (=L2 / L) and 15% (=L3 / L), respectively.

[0065] In the rear section, since the airflow direction is mainly radial to the impeller, the line connecting the front and rear ends of the airfoil is set parallel to the rear disk, i.e., the tilt angle β is 0°. Airfoils in this section share the same characteristics, including airfoils 8, 9, and 10.

[0066] In the mid-section, the airfoils have different tilt angles β, ranging from 16° to 33°, with the tilt angle gradually increasing from the rear plate to the front plate. Apart from the different tilt angles, the airfoils in this section share the same characteristics, including airfoils 3 through 7.

[0067] In the leading edge section, the blades are cut to reduce obstruction and loss of airflow at the inlet. The airfoils have large canard angles, including airfoil 1 and airfoil 2.

[0068] Figure 5 The diagram illustrates a three-dimensional model drawing provided by an embodiment of the present invention. During modeling, the positions of the leading and trailing edge lines can be determined first. Then, the leading and trailing edge lines are used as constraint guide lines, and the various airfoils are connected one by one using the creo boundary blending command to obtain the three-dimensional airfoil.

[0069] Figure 6 A schematic diagram of airfoil drawing provided by an embodiment of the present invention is shown. Optionally, in this embodiment, the airfoil is modeled based on a two-segment profile curve method, with control points for the pressure surface being P0, P1, P2, ..., Pn, and control points for the suction surface being Q0, Q1, Q2, ..., Qn. The pressure and suction surfaces use parameterized B-spline curves of the same degree and the same parameter node vector. To achieve G1 continuity of the two curves at the leading edge, adjacent control points need to satisfy:

[0070]

[0071] In the formula, K1 is the proportionality coefficient, which can be any non-zero real number.

[0072] The equation of the B-spline curve is as follows:

[0073]

[0074] In the formula, d i (i=0,1,2…,n) are the control vertices of the control polygon, and the broken line formed by connecting them in sequence is the B-spline control polygon; For the vertex d i B-spline basis functions (mixture functions).

[0075] The recursive method for mixed functions is defined as follows:

[0076]

[0077] In the formula: k is the power of the B-spline; subscript i is the index; u i For nodes.

[0078] Figure 7 A schematic diagram of a wind turbine blade assembly provided in an embodiment of the present invention is shown. Figure 7The impeller is composed of multiple blades arranged in a circular ring.

[0079] Figure 8 A schematic diagram of the structure of a multi-blade centrifugal fan provided in an embodiment of the present invention is shown. Figure 8 The diagram shows the upper volute 81, impeller 82, motor 83, and lower volute 84.

[0080] The fan efficiency of this embodiment is higher: by combining the airflow characteristics inside the centrifugal fan and setting the tilt angle of the two-dimensional airfoil, the fan's work capacity can be improved; the airfoil design of this embodiment is simpler: the airfoil is based on a two-segment contour curve modeling method, which makes modeling simple.

[0081] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by computer-controlled devices. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the above method embodiments. The storage medium can be a memory, a disk, an optical disk, etc.

[0082] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

[0083] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0084] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Regarding the multi-blade centrifugal fan blade design apparatus and air conditioner disclosed in the embodiments, since they correspond to the multi-blade centrifugal fan blade design method disclosed in the above embodiments, the description is relatively simple, and relevant parts can be referred to the method section.

[0085] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for designing the blade profile of a multi-blade centrifugal fan, characterized in that, The method includes: Determine the leading and trailing edges of the blade; Using the leading and trailing edge lines as constraint guide lines, the multiple two-dimensional airfoils of the blade are connected one by one using a preset drawing method to obtain the three-dimensional airfoil of the blade; the blade includes multiple two-dimensional airfoils, and the tilt angle of each two-dimensional airfoil gradually increases from the rear disk side to the front disk side, and the tilt angle is the angle between the line connecting the front and rear ends of the two-dimensional airfoil and the rear disk.

2. The method as described in claim 1, characterized in that, The method further includes: Based on the two-segment contour curve modeling method, the two-dimensional airfoils described are established.

3. The method as described in claim 2, characterized in that, The pressure and suction surfaces of the two-dimensional airfoil employ parameterized B-spline curves of the same order and the same parameter node vectors. The equations of the parameterized B-spline curves are as follows: In the formula, d i (i=0,1,2…,n) are the control vertices of the control polygon, and the broken line formed by connecting them in sequence is the B-spline control polygon; For the vertex d i B-spline mixture function; The recursive method for the mixing function is defined as follows: In the formula, k is the power of the B-spline; the subscript i is the index; u i For nodes.

4. A blade for a multi-blade centrifugal fan, characterized in that, The blade includes a front section, a middle section, and a rear section; The front section, the middle section, and the rear section each include at least one two-dimensional airfoil; The tilt angles of the two-dimensional airfoils in the front section, the middle section, and the rear section gradually increase from the rear disk side to the front disk side. Two adjacent two-dimensional airfoils are connected by drawing to obtain a three-dimensional airfoil. The tilt angle is the angle between the line connecting the front and rear ends of the two-dimensional airfoil and the rear disk.

5. The blade as described in claim 4, characterized in that, The tilt angle of each of the airfoils in the rear section is zero; The tilt angle of the airfoil in the middle section is smaller than that of the airfoil in the front section, and the tilt angles of each airfoil in the middle section and each airfoil in the front section gradually increase from the rear disc side to the front disc side.

6. The blade as described in claim 5, characterized in that, The tilt angle of each airfoil in the middle section ranges from 16° to 33°.

7. The blade as described in claim 4, characterized in that, Each airfoil is established based on a two-segment profile curve modeling method.

8. The blade as described in claim 4, characterized in that, The pressure and suction surfaces of the two-dimensional airfoil employ parameterized B-spline curves of the same order and the same parameter node vectors. The equations of the parameterized B-spline curves are as follows: In the formula, d i (i=0,1,2…,n) are the control vertices of the control polygon, and the broken line formed by connecting them in sequence is the B-spline control polygon; For the vertex d i B-spline mixture function; The recursive method for the mixing function is defined as follows: In the formula, k is the power of the B-spline; the subscript i is the index; u i For nodes.

9. The blade as described in claim 4, characterized in that, The trailing edge of the front section is provided with a cutting opening.

10. A multi-blade centrifugal fan, characterized in that, Includes the blades of the multi-blade centrifugal fan as described in any one of claims 4-9.

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