A design method and structure of a volute wind wheel air duct system

Abstract

The present invention discloses a design method and structure of a volute wind wheel air duct system, including the design of the volute air duct: according to the theoretical design air volume Q n Calculate the opening of the volute air duct#imgabs0# where B is the height of the volute, C v is the theoretical wind speed, with a range of 16-17 m / s; a regular hexagon is constructed with the center of the impeller as the center and a side length of a = γ / 6; the six vertices of the regular hexagon are used as the starting points, each forming an angle of 100 degrees with the six sides of the regular hexagon, and R 1 , R 2 , R 3 , R 4 , R 5 , R 6 Draw 6 line segments for the length; draw spline curves according to the end points of the 6 line segments to form the inner wall surface of the volute curve. The volute air duct designed by the present invention can accurately capture the reasonable Archimedean spiral trajectory points in the wind wheel air duct system with large air volume and large wind pressure, and realize low-load operation without reducing the aerodynamic performance.

Description

Technical Field

[0001] The present invention relates to the field of wind wheel air duct systems, and in particular to a design method and structure of a volute wind wheel air duct system. Background Art

[0002] The conventional volute air duct curve is mainly the Archimedean spiral, and the potential energy of the airflow is collected through the Archimedean spiral air duct. The trajectory parameters of the Archimedean spiral have a great influence on the performance of the wind wheel air duct system. Unreasonable design parameters of the Archimedean spiral will cause problems such as excessive load, abnormal sound or insufficient wind pressure, backflow, and airflow self-circulation. These problems are particularly obvious in the wind wheel air duct system with large air volume and high wind pressure. Summary of the invention

[0003] The purpose of the present invention is to provide a design method and structure of a volute wind wheel air duct system, which can accurately capture reasonable Archimedean spiral trajectory points for a wind wheel air duct system with large air volume, and achieve low-load operation without reducing aerodynamic performance.

[0004] In order to achieve the above object, the solution of the present invention is:

[0005] A design method for a volute wind wheel air duct system, including the design of the volute air duct: according to the theoretical design air volume Q n Calculate the opening of the volute air duct Where B is the height of the volute, C v is the theoretical wind speed, with a range of 16-17 m / s; a regular hexagon is drawn with the center of the impeller as the center and a side length of a = γ / 6; six line segments are drawn with R1, R2, R3, R4, R5, and R6 as the lengths, with the six vertices of the regular hexagon as the starting points, and each of them forms an angle of 100 degrees with the six sides of the regular hexagon, where R1 = R 风轮 +δ1·a, δ1=1.2±0.3, R2=R 风轮 +δ2·a, δ2=3.0±0.3, R3=R 风轮 +δ3·a, δ3=3.2±0.3, R4=R 风轮 +δ4·a, δ4=4.6±0.3, R5=R 风轮 +δ5·a, δ5=5.9±0.3, R6=R 风轮 +δ6·a, δ6=7.8±0.3; a spline curve is drawn according to the end points of the six line segments to form the inner wall surface of the volute curve.

[0006] The design method of the volute wind wheel air duct system also includes the design of the centrifugal fan blade shape: the aerodynamic equation of the centrifugal fan blade is P = ω 2 ·ρ·q v (cos 2α2·r2-cos 2 α1·r1), where P is the output power, ω is the speed, ρ is the air density, q v is the flow rate generated by the fan blade, α2 is the wind outlet angle, α1 is the wind inlet angle, r2 is the outer diameter of the fan blade, and r1 is the inner diameter of the fan blade.

[0007] The value range of the wind inlet angle α1 is 84-90°.

[0008] The value range of the wind outlet angle α2 is 42-50°.

[0009] The invention discloses a structure of a volute wind wheel duct system, which adopts a forward centrifugal wind wheel and an Archimedean spiral wind duct, and establishes a Cartesian rectangular coordinate system with the center of the wind wheel as the origin. The coordinates of point A on the wind duct curve are (107.6±3.5, 29.3±3.5), the coordinates of point B are (84.5±3.5, 83.3±3.5), the coordinates of point C are (-88.1±3.5, 93.5±3.5), the coordinates of point D are (-132.5±3.5, 0±3.5), the coordinates of point E are (-98.8±3.5, -99.0±3.5), and the coordinates of point F are (113.6±3.5, - 113.4±3.5), where the unit of the coordinate values ​​of the above points is mm, point A is the intersection of the dotted line through the origin and the X-axis with an angle of 15° and the curve of the inner wall surface of the air duct, point B is the intersection of the dotted line through the origin and the X-axis with an angle of 45° and the curve of the inner wall surface of the air duct, point C is the intersection of the dotted line through the origin and the Y-axis with an angle of 45° and the curve of the inner wall surface of the air duct, point D is the intersection of the dotted line through the origin and the Y-axis with an angle of 90° and the curve of the inner wall surface of the air duct, point E is the intersection of the dotted line through the origin and the X-axis with an angle of -135° and the curve of the inner wall surface of the air duct, and point F is the intersection of the dotted line through the origin and the X-axis with an angle of -45° and the curve of the inner wall surface of the air duct.

[0010] The tongue radius of the air duct curve is 14.0±2.0 mm.

[0011] In the volute wind wheel air duct system, the diameter of the wind wheel is 192 mm, the value range of the wind wheel inlet angle is 90°±5°, and the value range of the wind wheel outlet angle is 45°±5°, wherein the wind wheel inlet angle is the angle between the inner edge tangent of the wind wheel and the tangent point of the inner edge tangent and the center of the circle, and the wind wheel outlet angle is the angle between the outer edge tangent of the wind wheel and the tangent point of the outer aid tangent and the center of the circle.

[0012] After adopting the above technical scheme, the volute air duct designed by the present invention can accurately capture the reasonable Archimedean spiral trajectory points in the wind wheel air duct system with large air volume and large wind pressure, and realize low-load operation without reducing the aerodynamic performance.

[0013] In addition, the centrifugal fan blade shape designed in the present invention can improve the aerodynamic performance of the wind wheel and achieve high power and high air volume output under low speed conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the design of the volute air duct of a specific embodiment of the present invention;

[0015] Figure 2 A schematic diagram of the design of the centrifugal fan blade profile according to a specific embodiment of the present invention;

[0016] Figure 3 It is a structural schematic diagram of a wind wheel and wind duct system according to a specific embodiment of the present invention; DETAILED DESCRIPTION

[0017] In order to further explain the technical solution of the present invention, the present invention is described in detail below through specific embodiments.

[0018] The present invention is a design method for a volute wind wheel air duct system, which is suitable for wind volumes greater than 80m 3 / h wind wheel duct system, including the design of the volute duct:

[0019] According to the theoretical design air volume Q n Calculate the opening of the volute air duct Where B is the height of the volute, C v is the theoretical wind speed, ranging from 16-17m / s;

[0020] like Figure 1 As shown, a regular hexagon is drawn with the center of the impeller as the center and a side length of a = γ / 6; six line segments are drawn with the six vertices of the regular hexagon as the starting points, forming an angle of 100 degrees with the six sides of the regular hexagon respectively, and with R1, R2, R3, R4, R5, and R6 as the lengths, where R1 = R 风轮 +δ1·a, δ1=1.2±0.3, R2=R 风轮 +δ2·a, δ2=3.0±0.3, R3=R 风轮 +δ3·a, δ3=3.2±0.3, R4=R 风轮 +δ4·a, δ4=4.6±0.3, R5=R 风轮 +δ5·a, δ5=5.9±0.3, R6=R 风轮 +δ6·a, δ6=7.8±0.3; a spline curve is drawn according to the end points of the six line segments (points A, B, C, D, E, and F in the figure) to form the inner wall surface of the volute curve.

[0021] The above-mentioned δ is the extension coefficient, which is the coefficient under the condition of 52dB sound pressure level and the minimum size of the air duct.

[0022] The characteristics of the volute curve designed by the above method are that from point A to point B is the curve section where wind pressure begins to form, and the extension coefficient increases significantly. From point B to point C, the wind pressure is stable, and the extension coefficient does not change much. From point C to point E, the extension coefficient increases steadily, reducing the loss of kinetic energy. From point E to point F is the wind outlet section, where the wind speed is the highest and the extension coefficient increases, converting kinetic energy into pressure energy and reducing energy loss. According to different wind pressure conditions, segmented design is carried out, which is the biggest difference from conventional design methods. After experimental verification, when the wind volume is the same as 130m 3 In a wind wheel duct system with a rated power of 100 kW / h, the volute duct designed with this method can reduce the output power by 2-3W, which can improve the competitiveness of the product's energy efficiency value; under the premise of the same output power, the air volume that can be achieved is greater. The effect achieved is to achieve the minimum energy loss, reduce the load of the motor, and achieve the maximum performance under the same power. The experimental data is as follows:

[0023]

[0024] The present invention also includes the design of the centrifugal fan blade profile:

[0025] The aerodynamic equation of the centrifugal fan blade is P = ω 2 ·ρ·q v (cos 2 α2·r2-cos 2 α1·r1), where P is the output power, ω is the speed, ρ is the air density, q v is the flow rate generated by the fan blade, α2 is the wind outlet angle, α1 is the wind inlet angle, r2 is the outer diameter of the fan blade, and r1 is the inner diameter of the fan blade. Figure 2 The centrifugal fan blade shape is designed to achieve low speed, high wind pressure and high power output.

[0026] According to the aerodynamic equation, cos 2 When α1·r1 is zero, the maximum power can be output, so the inlet angle α1 can output a large power in the range of 84-90°. According to CFD analysis data, the aerodynamic performance is best when the outlet angle α2 is in the range of 42-50°.

[0027] The above method can obtain Figure 3The structure of a volute wind wheel air duct system shown in the figure adopts a forward centrifugal wind wheel and an Archimedean spiral wind duct, and a Cartesian rectangular coordinate system is established with the center of the wind wheel as the origin. The coordinates of point A on the wind duct curve are (107.6±3.5, 29.3±3.5), the coordinates of point B are (84.5±3.5, 83.3±3.5), the coordinates of point C are (-88.1±3.5, 93.5±3.5), the coordinates of point D are (-132.5±3.5, 0±3.5), the coordinates of point E are (-98.8±3.5, -99.0±3.5), and the coordinates of point F are (113.6±3.5, -113.4±3.5), where the coordinate values ​​of the above points are in units of mm, point A is the intersection of the dotted line with an angle of 15° between the origin and the X-axis and the inner wall curve of the duct, point B is the intersection of the dotted line with an angle of 45° between the origin and the X-axis and the inner wall curve of the duct, point C is the intersection of the dotted line with an angle of 45° between the origin and the Y-axis and the inner wall curve of the duct, point D is the intersection of the dotted line with an angle of 90° between the origin and the Y-axis and the inner wall curve of the duct, point E is the intersection of the dotted line with an angle of -135° between the origin and the X-axis and the inner wall curve of the duct, and point F is the intersection of the dotted line with an angle of -45° between the origin and the X-axis and the inner wall curve of the duct. The design of this duct curve is at the critical value of backflow. The advantage of this design is that it can minimize the resistance generated by the duct and reduce the energy loss caused by backflow.

[0028] The radius of the snail tongue of the above air duct curve is 14.0±2.0mm. The radius of the snail tongue should not be too large or too small: the wind speed at the snail tongue is high, and a too large radius of the snail tongue will reduce the wind pressure and cause too little air volume; a too small radius of the snail tongue will cause sharp aerodynamic noise.

[0029] refer to Figure 2 As shown, in the above-mentioned volute wind wheel air duct system, the diameter of the wind wheel is 192 mm, the value range of the wind wheel inlet angle α1 is 90°±5°, and the value range of the wind wheel outlet angle α2 is 45°±5°, wherein the wind wheel inlet angle α1 is the angle between the inner edge tangent of the wind wheel and the tangent point of the inner edge tangent and the center of the circle, and the wind wheel outlet angle α2 is the angle between the outer edge tangent of the wind wheel and the tangent point of the outer aid tangent and the center of the circle.

[0030] Through the above scheme, the volute air duct designed by the present invention can accurately capture the reasonable Archimedean spiral trajectory points in the wind wheel air duct system with large air volume and large wind pressure, and realize low-load operation without reducing the aerodynamic performance.

[0031] In addition, the centrifugal fan blade shape designed in the present invention can improve the aerodynamic performance of the wind wheel and achieve high power and high air volume output under low speed conditions.

[0032] The above embodiments and drawings do not limit the product form and style of the present invention. Any appropriate changes or modifications made by ordinary technicians in the relevant technical field should be deemed to be within the patent scope of the present invention.

Claims

1. A design method for a volute wind wheel air duct system, characterized in that Including the design of volute air duct and centrifugal fan blade: Design air volume based on theory Calculate the opening of the volute air duct ,in is the height of the volute, is the theoretical wind speed, ranging from 16-17m / s; The center of the impeller is the center of the circle and the side length is Make a regular hexagon; take the six vertices of the regular hexagon as the starting point, make an angle of 100 degrees with the six sides of the regular hexagon, and , , , , , Draw 6 line segments for length, where , , , , , , , , , , , , is the radius of the wind wheel; a spline curve is drawn according to the end points of the six line segments to form the inner wall surface of the volute curve; The aerodynamic equation of the centrifugal fan blade is: ,in is the output power, is the rotation speed, is the air density, is the flow rate generated by the fan blades, For the wind angle, is the wind inlet angle, is the outer diameter of the fan blade, is the inner diameter of the fan blade.

2. A method for designing a volute wind wheel air duct system according to claim 1, characterized in that: The wind inlet angle The value range is 84-90°.

3. The design method of a volute wind wheel air duct system according to claim 1, characterized in that: The wind angle The value range is 42-50°.

4. A structure of a volute wind wheel air duct system, using a design method of a volute wind wheel air duct system as claimed in any one of claims 1 to 3, characterized in that: A forward centrifugal wind wheel and an Archimedean spiral wind duct are used, and a Cartesian rectangular coordinate system is established with the center of the wind wheel as the origin. The coordinates of point A on the wind duct curve are (107.6±3.5, 29.3±3.5), the coordinates of point B are (84.5±3.5, 83.3±3.5), the coordinates of point C are (-88.1±3.5, 93.5±3.5), the coordinates of point D are (-132.5±3.5, 0±3.5), the coordinates of point E are (-98.8±3.5, -99.0±3.5), and the coordinates of point F are (113.6±3.5, -113.4±3 .5), where the unit of the coordinate values ​​of the above points is mm, point A is the intersection of the dotted line through the origin and the X-axis with an angle of 15° and the inner wall curve of the duct, point B is the intersection of the dotted line through the origin and the X-axis with an angle of 45° and the inner wall curve of the duct, point C is the intersection of the dotted line through the origin and the Y-axis with an angle of 45° and the inner wall curve of the duct, point D is the intersection of the dotted line through the origin and the Y-axis with an angle of 90° and the inner wall curve of the duct, point E is the intersection of the dotted line through the origin and the X-axis with an angle of -135° and the inner wall curve of the duct, and point F is the intersection of the dotted line through the origin and the X-axis with an angle of -45° and the inner wall curve of the duct.

5. The structure of the volute wind wheel air duct system according to claim 4, characterized in that: The tongue radius of the air duct curve is 14.0±2.0 mm.

6. The structure of the volute wind wheel air duct system according to claim 4, characterized in that: In the volute wind wheel air duct system, the diameter of the wind wheel is 192 mm, the value range of the wind wheel inlet angle is 90°±5°, and the value range of the wind wheel outlet angle is 45°±5°, wherein the wind wheel inlet angle is the angle between the inner edge tangent of the wind wheel and the tangent point of the inner edge tangent and the center of the circle, and the wind wheel outlet angle is the angle between the outer edge tangent of the wind wheel and the tangent point of the outer aid tangent and the center of the circle.

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