A backward plate-type three-dimensional flow vane volute-less centrifugal fan

Abstract

A backward plate-type three-dimensional flow vane volute-less centrifugal fan, comprising a rear wheel disc, vanes, and a front wheel disc connected coaxially. The surface of the vanes belongs to a three-dimensional space curved surface. The vanes include a rear blade root, a front blade root, an inlet edge, an outlet edge, a pressure surface, and a suction surface. Along the Z-axis direction, several cross-sections are taken between the middle of the rear blade root and the middle of the front blade root. The cross-sections are cross-sections obtained by obliquely dividing the vanes along the direction fitting the back surface of the rear wheel disc. Among them, the two cross-sections at the ends respectively capture the rear blade root and the front blade root, and the inlet angles and outlet angles of each cross-section are respectively optimized. The vane flow channel design in this application can minimize the aerodynamic loss and noise level, ensure that the air flow reaches the best state under the rated working conditions, raise the static pressure efficiency of the impeller to an almost unprecedented height. At the same time, the plate-type vane fan has the advantages of low processing and manufacturing difficulty, low processing cost, and high working efficiency.

Description

Technical Field

[0001] This application relates to the field of fan technology and its applications, and particularly to a backward plate-type three-dimensional flow blade volute-less centrifugal fan. Background Art

[0002] The backward volute-less centrifugal fan is a general-purpose fan that is increasingly preferred and widely used. It is widely used in different industrial and civil fields, such as for the cooling units of EMUs, HVAC units, fresh air units, air supply systems, etc. Compared with traditional volute fans, the volute-less type has many advantages such as simple structure, convenient layout, and easy installation and maintenance.

[0003] In the prior art, the backward volute-less centrifugal fan mainly consists of an impeller, an air inlet, and a motor. The impeller is the core component of the fan, which generates air flow through rotation. The air inlet is used to guide the air flow direction, and the motor provides power for the fan. Generally, the volute-less centrifugal fan adopts a plate-type single arc blade design. Since the blade cross-section is a single arc shape, it has the characteristic of convenient processing and manufacturing. However, the blade shape of the plate-type blade does not conform to the flow characteristics of the complex air flow inside the impeller, resulting in an increase in air flow loss and aerodynamic noise, and a decrease in the fan efficiency. To improve the efficiency and reduce the noise, some volute-less centrifugal fans adopt two-dimensional or even three-dimensional blade airfoil designs, that is, the cross-section of the blade is an airfoil design. By adjusting the shape and angle of the airfoil, the air flow in the impeller can be affected, and relatively high efficiency can be achieved. However, the impeller with an airfoil cross-section will inevitably lead to an increase in manufacturing difficulty and production cost.

[0004] Therefore, there is an urgent need for a new type of volute-less centrifugal fan with an easy-to-process structure, low processing cost, and high working efficiency. Summary of the Invention

[0005] The purpose of this application is to provide a backward plate-type three-dimensional flow blade volute-less centrifugal fan to solve the problems of high processing and manufacturing difficulty, high processing cost, and low working efficiency in the prior art.

[0006] The embodiments of this application can be realized by the following technical solutions:

[0007] A backward plate-type three-dimensional flow blade volute-less centrifugal fan includes a rear wheel disc, blades, and a front wheel disc. The blades are connected between the back of the coaxially arranged rear wheel disc and the front wheel disc. The surface of the blades belongs to a three-dimensional space curve. The blades include a rear blade root, a front blade root, an inlet edge, an outlet edge, a pressure surface, and a suction surface. The rear blade root is the curved surface where the blade is connected to the back of the rear wheel disc, and the front blade root is the curved surface where the blade is connected to the back of the front wheel disc;

[0008] Along the Z-axis inlet and outlet direction, several cross-sections are taken between the middle of the rear blade root and the middle of the front blade root. The cross-sections are the cross-sections obtained by obliquely dividing the blade along the direction of fitting to the back surface of the rear wheel disc. Among them, the two cross-sections at the ends respectively capture the rear blade root and the front blade root;

[0009] In each cross-section, the contour line of the pressure surface is the cross-section profile line. The included angle between two tangents made at the end point where the inlet edge is located in the cross-section profile line is denoted as the inlet angle , and the included angle between two tangents made at the end point where the outlet edge is located in the cross-section profile line is denoted as the outlet angle ;

[0010] Along the front-back direction from the front wheel disc to the rear wheel disc, the inlet angle of the cross-section adjacent to the front wheel disc is greater than the inlet angle of the cross-section adjacent to the rear wheel disc , and the inlet angle of the cross-section adjacent to the rear wheel disc is greater than the inlet angle of the cross-section in front of it ; the outlet angle of the cross-section adjacent to the front wheel disc is greater than the outlet angle of the cross-section behind it , and the outlet angle of the cross-section adjacent to the rear wheel disc is greater than the outlet angle of the cross-section in front of it .

[0011] Furthermore, the inlet angle and the outlet angle of each cross-section are respectively made in the following ways,

[0012] On the pressure surface, the end point where the cross-section intersects the inlet edge is denoted as point, and the end point where the cross-section intersects the outlet edge is denoted as point. The intersection line of the cross-section and the pressure surface is the curve NM, denoted as the cross-section profile line. The cross-section profile line makes two tangents at point and point respectively, and are respectively denoted as tangent and tangent;

[0013] Then, a straight line perpendicular to the back surface of the rear wheel disc and intersecting the Z-axis, and the intersection point is located at the center of the center hole end of the rear wheel disc, is denoted as the E-section line. In the cross-section, two perpendicular lines perpendicular to the E-section line direction are respectively made from point and M point. The intersection point of the two perpendicular lines intersecting the E-section line is O. In the plane where is located, a front circle is made with the straight line as the leading edge radius. The tangent of the front circle at is denoted as tangent. Similarly, at In the plane where it is located, with the straight line as the trailing edge radius, a trailing circle is made. The tangent of this trailing circle at is denoted as tangent. The inlet angle is ∠BNA, and the outlet angle is ∠DMG.

[0014] Furthermore, along the Z-axis direction, at least five equally spaced cross-sections are taken between the middle of the trailing blade root and the middle of the leading blade root. Each cross-section is respectively the first cross-section, the second cross-section, the third cross-section, the fourth cross-section, and the fifth cross-section. The inlet angles of each cross-section are successively , , , , , where . The outlet angles of each cross-section are successively , , , , , where , and .

[0015] Furthermore, the value range of the inlet angle of the first cross-section is 7.6° - 15.6°, the value range of the inlet angle of the second cross-section is 4.6° - 12.6°, and the value range of the inlet angle of the fifth cross-section is 12.9° - 20.9°.

[0016] Furthermore, the value range of the inlet angle of the third cross-section is 3.2° - 11.2°, and the value range of the inlet angle of the fourth cross-section is 1.7° - 9.7°.

[0017] Furthermore, the value range of the outlet angle of the first cross-section is 39.3° - 43.3°, and the value range of the outlet angle of the second cross-section is 32.5° - 36.5°.

[0018] Furthermore, the value range of the outlet angle of the fourth cross-section is 29.1° - 33.1°, and the value range of the outlet angle of the fifth cross-section is 30.6° - 34.6°.

[0019] Furthermore, the value range of the outlet angle of the third cross-section is 29.7° - 33.7°.

[0020] Further, a vertical extension line is drawn along the Z-axis direction from point O in any cross-section. The intersection point of this vertical extension line and the cross-sectional profile is H, and the angle ∠HON is denoted as the position angle. , where the position angle of the third cross-section is greater than the position angle of the second cross-section , and the position angle of the third cross-section is greater than the position angle of the fourth cross-section , such that a part of the leading edge of the inlet edge is convex outward.

[0021] Further, the trailing edge of the outlet edge is concave inward, and the chord lengths C of each cross-section are different.

[0022] Further, the outlet edge at the location of the second cross-section is set to be concave inward, that is, the chord length of the second cross-section is less than the chord length of the first cross-section , and the chord length of the second cross-section is less than the chord length of the third cross-section .

[0023] A backward plate-type three-dimensional flow blade volute-less centrifugal fan provided by an embodiment of the present application has at least the following beneficial effects:

[0024] The blades in the present application are structurally improved through the analysis of the internal flow field of the fan impeller. By selecting appropriate blade inlet and outlet angles and chord length dimensions for multiple cross-sections of the blades, the optimal aerodynamic performance is achieved for each cross-section of the blades. The design of the concave trailing edge of the blades makes the flow field on the pressure surface of the blades more uniform, and the impeller efficiency is further improved. Especially in the actual measurement of the A-type intake performance, the measured impeller efficiency can reach up to 82.2%. Description of the Drawings

[0025] Figure 1 is a schematic structural diagram of a backward plate-type three-dimensional flow blade volute-less centrifugal fan of the present application;

[0026] Figure 2 is a side view of the rear wheel disc in the present application;

[0027] Figure 3 is a side view of the front blade disc in the present application;

[0028] Figure 4 is a three-dimensional structural diagram of the blade in the present application;

[0029] Figure 5 is a schematic diagram of the position dimensions of the cross-section intercepted from the blade in the present application;

[0030] Figure 6Schematic diagram of the first cross-section of the blade in this application;

[0031] Figure 7 Schematic diagram of the second cross-section of the blade in this application;

[0032] Figure 8 Schematic diagram of the third cross-section of the blade in this application;

[0033] Figure 9 Schematic diagram of the fourth cross-section of the blade in this application;

[0034] Figure 10 Schematic diagram of the fifth cross-section of the blade in this application;

[0035] Figure 11 Pressure contour maps of the trailing edge of the blade in the outlet region of the centrifugal fan under different profiles;

[0036] Figure 12 Velocity contour map of the rotating surface at the impeller inlet of the centrifugal fan;

[0037] Figure 13 Comparison curve graph of the measured data of the static pressure for each case;

[0038] Figure 14 Comparison curve graph of the measured data of the static pressure efficiency for each case.

[0039] Reference numerals in the figure

[0040] 1 - Rear wheel disc; 11 - Outer edge of the rear wheel disc; 12 - Center hole end; 13 - Transition surface; 2 - Blade; 21 - Rear blade root; 22 - Front blade root; 23 - Inlet edge 23; 24 - Outlet edge 24; 25 - Pressure surface 25; 26 - Suction surface; 3 - Front wheel disc; 31 - Outer edge of the front wheel disc; 32 - Inlet end of the front wheel disc;

[0041] Q1 - First cross-section; Q2 - Second cross-section; Q3 - Third cross-section; Q4 - Fourth cross-section; Q5 - Fifth cross-section. Detailed implementation manners

[0042] Hereinafter, this application will be further described based on preferred implementation manners with reference to the accompanying drawings.

[0043] In addition, for ease of understanding, various components in the drawings are enlarged (thickened) or reduced (thinned), but this is not intended to limit the protection scope of this application.

[0044] Singular forms of words also include plural meanings, and vice versa.

[0045] In the description of the embodiments of the present application, it should be noted that if terms such as "upper", "lower", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the products of the embodiments of the present application are usually placed during use, it is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present application. In addition, in the description of the present application, in order to distinguish different units, the terms "first", "second", etc. are used in this specification, but these are not restricted by the manufacturing order and cannot be construed as indicating or implying relative importance. In the detailed description and claims of the present application, their names may be different.

[0046] The terms used in this specification are for the purpose of describing the embodiments of the present application, but are not intended to limit the present application. It should also be noted that unless otherwise clearly defined and limited, if terms such as "set", "connected", "connected to" are understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be specifically understood.

[0047] As Figures 1 to 4 shown, a backward plate-type three-dimensional flow vane volute-less centrifugal fan includes a rear wheel disc 1, vanes 2, and a front wheel disc 3. The rear wheel disc 1 and the front wheel disc 3 are coaxially arranged, and this axis is denoted as the Z axis. Both ends of the rear wheel disc 1 are respectively open. Among them, one end is the wide-diameter outer edge 11 of the rear wheel disc, and the other end is the narrow-diameter central hole end 12. A smooth transition surface 13 is formed between the outer edge 11 of the rear wheel disc and the central hole end 12. The transition surface 13 is the back surface of the rear wheel disc 1 that is obliquely arranged toward the front wheel disc 3, so that the rear wheel disc 1 is a conical structure.

[0048] In some preferred embodiments, the front wheel disc 3 is a disc-shaped structure that is folded inward. Both ends of the front wheel disc 3 are respectively open. Among them, one end is the large-diameter outer edge 31 of the front wheel disc, and the other end is the small-diameter inlet end 32 of the front wheel disc, which is used to optimize the air flow at the inlet and reduce the flow loss. The vanes 2 are connected between the transition surface 13 of the rear wheel disc 1 and the end where the outer edge 31 of the front wheel disc 3 of the front wheel disc 3 is located. The surface of the vanes 2 belongs to a three-dimensional space curved surface. The number of the vanes 2 is several, and several vanes 2 are arranged along the circumferential direction of the wheel disc.

[0049] For the convenience of description, the direction where the fan rotation axis is located is marked as the Z axis, and the air flow direction is from the negative direction of the Z axis to the positive direction.

[0050] Specifically, the blade 2 includes a rear blade root 21, a front blade root 22, an inlet edge 23, an outlet edge 24, a pressure surface 25, and a suction surface 26. Among them, the curved surface where the blade 2 is connected to the back surface of the rear wheel disc 1 is the rear blade root 21, the curved surface where the blade 2 is connected to the back surface of the front wheel disc 3 is the front blade root 22, the inlet edge 23 is the edge where the air flow enters, the outlet edge 24 is the edge where the air flow exits, the pressure surface 25 is the surface where the blade 2 does work, the edge of the blade 2 adjacent to the rear wheel disc 1 is the trailing edge, the edge of the blade 2 adjacent to the front wheel disc 3 is the leading edge, the trailing edge of the outlet edge 24 is connected to one end of the transition surface 13 adjacent to the outer edge 11 of the rear wheel disc, and the trailing edge of the inlet edge 23 is connected to one end of the transition surface 13 adjacent to the central hole end 12.

[0051] As the blade 2 rotates, the rotating blade 2 sucks air from its center and then throws the air outwards by centrifugal force to form an air flow. Different from general pipe flow, in general pipe flow, the flow velocity is higher at the center and lower near the wall surface. However, in a centrifugal fan, the velocity distribution shows the opposite, with a higher velocity at the edge and the lowest velocity near the center. For example, the wind speed at the leading edge of the inlet edge 23 of the blade 2 is relatively high, and the center velocity is relatively small. The same velocity trend appears in the velocity contour map of the rotating surface at the inlet of the impeller. For such a velocity distribution, this phenomenon should be noted when designing the blade, such as Figure 12 shown, where the red color represents the high-speed area. Therefore, in order to design a blade structure that matches the air flow characteristics in the flow field of a volute-less centrifugal fan, any blade 2 is sectioned along the air flow direction in the flow field of the volute-less centrifugal fan, and the inlet and outlet angles and chord length dimensions of each section are optimized.

[0052] Specifically, along the Z-axis inlet and outlet direction, several sections are taken between the middle of the rear blade root 21 and the middle of the front blade root 22. The section is a cross-section obtained by obliquely dividing the blade 2 along the direction of the back surface of the rear wheel disc 1. Among them, the two end sections respectively capture the rear blade root 21 and the front blade root 22;

[0053] In each section, the contour line of the pressure surface 25 is the section profile line. The included angle between the two tangents drawn at the end point where the inlet edge 23 is located in the section profile line is denoted as the inlet angle , and the included angle between the two tangents drawn at the end point where the outlet edge 24 is located in the section profile line is denoted as the outlet angle .

[0054] Along the front-back direction from the front wheel disc 3 to the rear wheel disc 1, the inlet angle Greater than the inlet angle of the cross-section adjacent to the rear disk 1 , and the inlet angle of the cross-section adjacent to the rear disk 1 is greater than the inlet angle of the cross-section in front of it ; the outlet angle of the cross-section adjacent to the front disk 3 is greater than the outlet angle of the cross-section behind it , and the outlet angle of the cross-section adjacent to the rear disk 1 is greater than the outlet angle of the cross-section in front of it .

[0055] In some preferred embodiments, along the Z-axis direction, five equally spaced cross-sections are taken between the middle of the rear blade root 21 and the middle of the front blade root 22. Each cross-section is respectively the first cross-section Q1, the second cross-section Q2, the third cross-section Q3, the fourth cross-section Q4, and the fifth cross-section Q5. The schematic diagrams of each cross-section are shown in detail in Figures 6 to 10 , where the first cross-section Q1 captures the rear blade root 21, and the second cross-section Q2 captures the front blade root 22, for capturing more cross-sections, and making full use of the airflow in the fan to conduct a detailed design of each cross-section to effectively reduce turbulent dissipation and lower power consumption.‌

[0056] Specifically, taking any cross-section among the equally spaced cross-sections as an example, on the pressure surface 25, the end point where this cross-section intersects the inlet edge 23 is denoted as point, and the end point where the cross-section intersects the outlet edge 24 is denoted as point. The intersection line of the cross-section and the pressure surface is the curve NM, denoted as the cross-section profile line. The cross-section profile line makes two tangent lines at point and point respectively, and they are respectively denoted as tangent line and tangent line.

[0057] Then, make a straight line perpendicular to the transition surface 13 and intersecting the Z-axis, and the intersection point is located at the center of the center hole end 12. Denote this straight line as the E-section line. Inside the cross-section, draw two perpendicular lines from point and M point in the direction perpendicular to the E-section line. The intersection point of the two perpendicular lines and the E-section line is point O. In the plane where is located, make a front circle with the straight-line distance of the straight line as the leading-edge radius. Denote the leading-edge radius as . The tangent line of this front circle at is denoted as tangent line. Similarly, in the plane where is located, make a rear circle with the straight-line distance of the straight line as the trailing-edge radius. Denote the trailing-edge radius as . The tangent line of this rear circle at is denoted as The tangent line, the inlet angle is ∠BNA, and the outlet angle is ∠DMG.

[0058] Among them, the leading edge radii in the first section Q1, the second section Q2, the third section Q3, the fourth section Q4, and the fifth section Q5 are respectively denoted as , , , , , and the trailing edge radii in the first section Q1, the second section Q2, the third section Q3, the fourth section Q4, and the fifth section Q5 are respectively denoted as , , , , .

[0059] In some preferred embodiments, along the axis direction from the rear wheel disc 1 to the front wheel disc 3, at least five equally spaced sections are taken between the middle of the rear blade root 21 and the middle of the front blade root 22. The sectional lines of each section are distributed as Figure 3 shown. The section is the cross-section cut by the blade 2 obliquely extending along the back of the rear wheel disc 1. Along the direction from the rear wheel disc 1 to the front wheel disc 3, each section is respectively the first section Q1, the second section Q2, the third section Q3, the fourth section Q4, and the fifth section Q5. The inlet angles are successively , , , , , where , and the outlet angles are successively , , , , , where , and , so that each section of the blade 2 achieves the optimal aerodynamic performance, reduces the resistance when the air flow passes through the flow channel, and when the air flow flows out of the trailing edge of the blade, a uniform pressure rise is obtained near the outlet edge, thereby improving the work efficiency of the fan.

[0060] In some preferred embodiments, to reduce the air flow loss of the inlet angle , the design of the tangent line should be as consistent as possible with the air flow direction at the inlet edge 23. To achieve this purpose, the position angle To achieve this, however, due to the different air flow fields at different positions, if the same position angle is adopted , it is impossible to efficiently utilize the air flow in the flow field. Therefore, the applicant optimizes the position angles of each cross-section so that the leading edge of the inlet edge 23 is convex.

[0061] Specifically, in any cross-section, a vertical extension line is drawn along the Z-axis direction from point O. The intersection point of the vertical extension line and the cross-section profile is H, and the position angle is ∠HON. Among them, the position angles in the first cross-section Q1, the second cross-section Q2, the third cross-section Q3, the fourth cross-section Q4, and the fifth cross-section Q5 are respectively , , , , . The position angle of the third cross-section Q3 is greater than the position angle of the second cross-section Q2 , and the position angle of the third cross-section Q3 is greater than the position angle of the fourth cross-section Q4 , that is , and , so that part of the leading edge of the inlet edge 23 is convex.

[0062] Furthermore, the trailing edge of the outlet edge 24 is concave. The straight-line distance between point N and point M in the cross-section is the chord line C, and the length of the chord line C is denoted as . Among them, the chord line lengths in the first cross-section Q1, the second cross-section Q2, the third cross-section Q3, the fourth cross-section Q4, and the fifth cross-section Q5 are respectively denoted as , , , , . The lengths of the chord line C in different cross-sections are different, making the flow field on the pressure surface of the blade more uniform and further improving the impeller efficiency.

[0063] The reason for setting the trailing edge of the outlet edge 24 to be concave is that the trailing edge is a high-pressure concentration area. If the trailing edge is set to a smooth contour, it will cause uneven pressure distribution at the trailing edge of each cross-section, as Figure 11 shown. Figure 11 is the pressure nephogram of the trailing edge under different shapes. In Figure 11In order to intuitively reflect the pressure distribution of each part of the blade, different pressures in the blade are marked with different colors. Among them, the area at the end of the trailing edge is the high-pressure area, that is, the red area of the nephogram. It can be seen from the figure that when the trailing edge is straight, the high-pressure area at the outlet is too concentrated, which is not conducive to the impeller doing work. After setting the trailing edge to be concave in the present application, the pressure distribution of the trailing edge concave shape near the outlet edge is more uniform, and each section also obtains a relatively uniform pressure rise at the trailing edge, which is beneficial to improving the impeller efficiency.

[0064] In some preferred embodiments, the outlet edge 24 at the location of the second section Q2 is set to be concave, that is, the chord length of the second section Q2 is less than the chord length of the first section Q1 and the chord length of the second section Q2 is less than the chord length of the third section Q3, so that the pressure distribution of the trailing edge concave shape near the outlet edge is more uniform.

[0065] Considering the static pressure efficiency of the volute-less centrifugal fan is to ensure that the fan can optimize the overall performance of the system while meeting the requirements of air volume and air pressure, reduce energy consumption, thereby improving the energy efficiency and energy-saving level of the entire fan system, reducing carbon emissions, saving operation costs. Therefore, in this field, the static pressure efficiency is mostly used as a main indicator to evaluate the superiority of the volute-less centrifugal fan performance.

[0066] In the present application, through the optimization design of the blade, the static pressure efficiency of each section of the blade basically reaches more than 70%, which can ensure that each area of the blade works efficiently.

[0067] The following gives specific embodiments.

[0068] Embodiment 1:

[0069] Taking the diameter of the outer edge 11 of the rear wheel disc 1 of the rear wheel disc as 598 mm, the diameter of the center hole end 12 as 190 mm, the linear distance between the outer edge 11 of the rear wheel disc and the center hole end 12 along the Z axis as 130 mm, the diameter of the outer edge 31 of the front wheel disc as 659 mm, the diameter of the inlet end 32 of the front wheel disc as 496 mm, and the linear distance from the center hole end 12 along the Z axis to the outer edge 31 of the front wheel disc along the Z axis as 270 mm as an example.

[0070] Taking five equally spaced cross-sections between the middle of the rear blade root 21 and the middle of the front blade root 22 along the axis direction from the rear wheel disc 1 to the front wheel disc 3, each cross-section is respectively the first cross-section Q1, the second cross-section Q2, the third cross-section Q3, the fourth cross-section Q4, and the fifth cross-section Q5. The geometric dimensions of each cross-section are shown in Table 1.1 as follows:

[0071] Table 1.1 Geometric Dimension Parameters of Each Cross-Section

[0072]

[0073] The static pressure and static pressure efficiency data of this fan on the standard fan performance test bench are shown in detail in Figure 13 and Figure 14 .

[0074] Example 2:

[0075] Taking the diameter of the outer edge 11 of the rear wheel disc of the rear wheel disc 1 as 598 mm, the diameter of the center hole end 12 as 190 mm, the linear distance between the outer edge 11 of the rear wheel disc and the center hole end 12 along the Z axis as 130 mm, the diameter of the outer edge 31 of the front wheel disc as 659 mm, the diameter of the inlet end 32 of the front wheel disc as 496 mm, and the linear distance from the center hole end 12 along the Z axis to the outer edge 31 of the front wheel disc along the Z axis is 270 mm as an example.

[0076] Taking five equally spaced cross-sections between the middle of the rear blade root 21 and the middle of the front blade root 22 along the axis direction from the rear wheel disc 1 to the front wheel disc 3, each cross-section is respectively the first cross-section Q1, the second cross-section Q2, the third cross-section Q3, the fourth cross-section Q4, and the fifth cross-section Q5. The geometric dimensions of each cross-section are shown in Table 2.1 as follows:

[0077] Table 2.1 Geometric Dimension Parameters of Each Cross-Section

[0078]

[0079] The static pressure and static pressure efficiency data of this fan on the standard fan performance test bench are shown in detail in Figure 13 and Figure 14 .

[0080] Comparative Example:

[0081] Taking the diameter of the outer edge 11 of the rear wheel disc of the rear wheel disc 1 as 598 mm, the diameter of the center hole end 12 as 190 mm, the linear distance between the outer edge 11 of the rear wheel disc and the center hole end 12 along the Z axis is 130 mm, and the diameter of the outer edge 31 of the front wheel disc is 659 mm, and the diameter of the inlet end 32 of the front wheel disc is 496 mm. Taking the straight-line distance along the Z-axis from the center hole end 12 to the outer edge 31 of the front wheel disc along the Z-axis as 270 mm as an example.

[0082] Along the axis direction from the rear wheel disc 1 to the front wheel disc 3, five equally spaced cross-sections are taken between the middle of the rear blade root 21 and the middle of the front blade root 22. Each cross-section is the first cross-section Q1, the second cross-section Q2, the third cross-section Q3, the fourth cross-section Q4, and the fifth cross-section Q5 respectively. The geometric dimensions of each cross-section are shown in Table 3.1 as follows:

[0083] Table 3.1 Geometric dimension parameters of each cross-section

[0084]

[0085] The static pressure and static pressure efficiency data of this fan on the standard fan performance test bench are shown in detail in Figure 13 and Figure 14 .

[0086] Through Figure 13 and Figure 14 Comparative analysis of the measured data shows that the blade flow channel designs in Embodiment 1 and Embodiment 2 can minimize aerodynamic losses and noise levels, ensure that the air flow reaches the best state under rated conditions, and improve the impeller static pressure efficiency to an almost unprecedented height. According to the design logic, through actual measurement and detection, the maximum static pressure efficiency is as high as 82%. However, compared with Embodiment 1 and Embodiment 2, the maximum value of the impeller static pressure efficiency in the comparative example cannot reach 82%, which is a major breakthrough in this field.

[0087] The specific implementation manners of the present application have been introduced in detail above. For those skilled in the art of this technology, without departing from the principle of the present application, several improvements and modifications can still be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A backward plate-type three-dimensional flow blade centrifugal fan without a volute, comprising a rear wheel disc (1), a blade (2), and a front wheel disc (3), wherein the blade (2) is connected between the back side of the rear wheel disc (1) and the front wheel disc (3) which are coaxially arranged, and the surface of the blade (2) is a three-dimensional curved surface in space, characterized in that: The blade (2) comprises a rear blade root (21), a front blade root (22), an inlet edge (23), an outlet edge (24), a pressure surface (25), and a suction surface (26); the rear blade root (21) is a curved surface connecting the blade (2) and the back surface of the rear wheel disc (1); and the front blade root (22) is a curved surface connecting the blade (2) and the back surface of the front wheel disc (3); Along the inlet and outlet direction of the Z axis, a plurality of cross sections are taken between the middle of the rear blade root (21) and the middle of the front blade root (22), wherein the cross sections are cross sections of the blade (2) divided obliquely along the direction in which the blade (2) is attached to the back surface of the rear wheel disc (1), wherein the two cross sections located at the end portions capture the rear blade root (21) and the front blade root (22) respectively; In each cross section, the contour line of the pressure surface (25) is the cross-sectional profile, and the angle between the two tangent lines at the end point where the inlet edge (23) in the cross-sectional profile is located is recorded as the inlet angle The included angle between the two tangent lines at the end point of the outlet edge (24) in the cross-sectional profile is recorded as the outlet angle ; The inlet angle of the cross section adjacent to the front wheel disc (3) along the front-to-rear direction from the front wheel disc (3) to the rear wheel disc (1) is greater than the inlet angle of the section adjacent to the rear wheel disc (1) , and the inlet angle of the cross section adjacent to the rear wheel disc (1) Greater than the inlet angle of the section in front of it ; The exit angle of the cross section adjacent to the front wheel disc (3) Greater than the exit angle of the section behind it , the exit angle of the section adjacent to the rear wheel disc (1) Greater than the exit angle of the section in front of it ; Inlet angle of each section , exit angle It is made in the following ways respectively: On the pressure surface (25), the end point where the cross section intersects with the inlet edge (23) is marked The endpoint where the cross section intersects with the outlet edge (24) is recorded as The intersection of the cross section and the pressure surface is the curve NM, which is recorded as the cross section line. point, Draw two tangent lines at the points and record them as Tangent, Tangent; A straight line is then drawn perpendicular to the back of the rear wheel disc (1) and intersecting the Z axis, with the intersection point being located at the center of the center hole end (12) of the rear wheel disc (1). The straight line is recorded as the E-section. Draw two perpendicular lines at points M and E, and the intersection of the two perpendicular lines at the E transect is O. In the plane where The front circle is made with the front edge radius. The tangent line at Tangent, similarly, In the plane where The back circle is made with the back edge radius. The tangent line at Tangent, the inlet angle is ∠BNA, and the outlet angle is ∠DMG.

2. The backward plate-type three-dimensional flow blade centrifugal fan without volute according to claim 1, characterized in that: Along the Z axis direction, at least five spaced sections are taken between the middle of the rear blade root (21) and the middle of the front blade root (22), and each section is a first section (Q1), a second section (Q2), a third section (Q3), a fourth section (Q4), and a fifth section (Q5). The inlet angle of each section is In order , , , , ,in, , the outlet angle of each section In order , , , , ,in, ,and .

3. The backward plate-type three-dimensional flow blade centrifugal fan without volute according to claim 2, characterized in that: The inlet angle of the first section (Q1) The value range is 7.6°-15.6°, and the inlet angle of the second section (Q2) The value range is 4.6°-12.6°, and the inlet angle of the fifth section (Q5) is The value range is 12.9°-20.9°.

4. The backward plate-type three-dimensional flow blade centrifugal fan without volute according to claim 2, characterized in that: The inlet angle of the third section (Q3) The value range is 3.2°-11.2°, and the inlet angle of the fourth section (Q4) is The value range is 1.7°-9.7°.

5. The backward plate-type three-dimensional flow blade centrifugal fan without volute according to claim 2, characterized in that: The outlet angle of the first section (Q1) The value range is 39.3°-43.3°, and the outlet angle of the second section (Q2) The value range is 32.5°-36.5°.

6. The backward plate-type three-dimensional flow blade centrifugal fan without volute according to claim 2, characterized in that: The exit angle of the fourth section (Q4) The value range is 29.1°-33.1°, and the outlet angle of the fifth section (Q5) is The value range is 30.6°-34.6°.

7. The backward plate-type three-dimensional flow blade centrifugal fan without volute according to claim 2, characterized in that: The outlet angle of the third section (Q3) The value range is 29.7°-33.7°.

8. The backward plate-type three-dimensional flow blade centrifugal fan without volute according to claim 1, characterized in that: At point O in any cross section, a vertical extension line is drawn along the Z axis. The intersection of the vertical extension line and the cross section line is H, and ∠HON is recorded as the position angle. , where the position angle of the third section (Q3) is Greater than the position angle of the second section (Q2) , and the position angle of the third section (Q3) Greater than the position angle of the fourth section (Q4) , so that a portion of the front edge of the inlet edge (23) is convex.

9. The backward plate-type three-dimensional flow blade centrifugal fan without volute according to claim 2, characterized in that: The trailing edge of the outlet edge (24) is concave, and the chord lengths C of the various cross sections are different.

10. The backward plate-type three-dimensional flow blade centrifugal fan without volute according to claim 9, characterized in that: The outlet edge (24) where the second section (Q2) is located is set to be concave, that is, the chord length of the second section (Q2) is Less than the chord length of the first section (Q1) , and the chord length of the second section (Q2) Less than the chord length of the third section (Q3) .

Images