Construction method of volute profile, volute, air duct structure and range hood

Abstract

The present invention provides a method for constructing a volute profile, a volute, an air duct structure, and a range hood, relating to the technical field of volute design, including: taking the center O of the impeller as the origin, starting from the starting ray, determining the volute curve S2 through the equation #imgabs0#; where R2 is the radius of the impeller; b2 is the blade outlet width of the impeller; B is the volute thickness; α is the airflow angle after the impeller passage outlet; #imgabs1# is the angle between the line connecting the point on the volute curve S2 and the center O and the starting ray, and #imgabs2#a0, a1, b1, ω are correction and adjustment constant terms, and -10 ≤ a0 ≤ 10, -10 ≤ a1 ≤ 10, a1 ≥ a0, 20 ≤ b1 ≤ 25, 0.2 ≤ ω ≤ 0.5. The equation provided by the present invention locally controls the shape of the volute curve, making the curve have a smooth transition. The volute curve expands outward compared with the original structure, the flow channel becomes larger, the resistance is reduced, and the aerodynamic noise is lowered.

Description

Technical Field

[0001] The present invention relates to the technical field of volute design, and in particular to a method for constructing a volute profile, a volute, an air duct structure, and a range hood. Background Art

[0002] The air duct system of a household range hood mainly consists of a volute assembly, an impeller, a motor assembly, and a check valve component. The volute and the check valve provide a gas flow channel. The reasonable design of the volute profile plays an important role in improving the aerodynamic performance and noise performance of the fan.

[0003] The function of the volute is to direct the gas leaving the impeller to the volute outlet and convert part of the dynamic pressure into static pressure. The flow inside the volute is very complex. While the gas flows along the volute, gas continuously enters the volute from the impeller, that is, the gas mixes while flowing. In addition, the unevenness of the impeller outlet air flow and the influence of gas viscosity make the flow inside the volute more complex. The design of the volute profile is directly related to the flow loss inside the volute. If the volute profile is not reasonably designed, it will also have an adverse impact on the aerodynamic performance of the previous impeller.

[0004] The design of the volute profile mostly adopts conventional logarithmic spiral or equal circulation design methods. For the convenience of design in engineering, four circular arcs are used to draw the volute profile, and the selection of its parameters often relies on a large amount of experience accumulation, and the drawing process is cumbersome. There are problems of large-scale eddy currents and flow dead zones in the volute outlet area where the wind speed is small. The flow separation caused by air flow stall of the blades near this area is also aggravated, the flow channel resistance is large, and the aerodynamic noise is large. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for constructing a volute profile, a volute, an air duct structure, and a range hood to alleviate the technical problems of large-scale eddy currents and flow dead zones existing in the volute outlet area of the existing volute profile, large flow channel resistance, and large aerodynamic noise.

[0006] The method for constructing a volute profile provided by the present invention includes:

[0007] Taking the center O of the impeller as the origin and the starting ray as the starting point, and through the equation determine the volute curve S2;

[0008] In the formula, R2 is the radius of the impeller; b2 is the blade outlet width of the impeller; B is the volute thickness; α is the air flow angle after the impeller passage outlet; is the included angle between the line connecting the point on the volute curve S2 and the center O and the starting ray, and a0, a1, b1, and ω are correction adjustment constant terms, where -10 ≤ a0 ≤ 10, -10 ≤ a1 ≤ 10, a1 ≥ a0, 20 ≤ b1 ≤ 25, and 0.2 ≤ ω ≤ 0.5.

[0009] Further, it includes determining the center O, determining the reference line and the starting placement angle θ0, and determining the starting ray according to the reference line and the starting placement angle θ0;

[0010] The steps for determining the reference line include: drawing a line parallel to the straight line segment L1 of the circular outlet of the check valve through the center O for determination.

[0011] Further, determine the positions of the first point P1, the second point P2, the third point P3, the fourth point P4, the fifth point P5, and the sixth point P6;

[0012] The second point P2 is a point on the volute curve S2, and the angle between the line connecting it to the center O and the reference line is θ1, where θ0 < θ1 < 90°;

[0013] The third point P3 is the intersection point of the starting ray and the volute curve S2;

[0014] Determine the fourth point P4 and the sixth point P6 through the straight line segment L1 of the circular outlet of the check valve, and the midpoint of the line connecting the fourth point P4 and the sixth point P6 is the fifth point P5; the angle between the line connecting the fifth point P5 to the center O and the reference line is θ2, where θ1 < θ2 < 90°;

[0015] Construct the volute tongue curve S1 between the first point P1 and the second point P2; construct the first check valve guiding baseline S3 between the third point P3 and the fourth point P4; determine the second check valve guiding baseline S4 between the sixth point P6 and the first point P1.

[0016] Further, the volute tongue curve S1, the first check valve guiding baseline S3, and the second check valve guiding baseline S4 are all determined by the Bezier curve equation.

[0017] Further, the range of the starting placement angle θ0 satisfies: 0 ≤ θ0 ≤ 45°.

[0018] Further, the starting placement angle θ0 is 40°.

[0019] Further, the angle θ1 between the line connecting the second point P2 to the center O and the reference line is 78°;

[0020] The angle θ2 between the line connecting the fifth point P5 to the center O and the reference line is 82°.

[0021] The volute provided by the present invention includes a volute rear plate, a volute front plate, a volute shroud, and a volute tongue, and the volute shroud and the volute tongue are sequentially connected between the volute rear plate and the volute front plate;

[0022] The inner wall of the volute shroud is formed by the volute curve S2, and the volute curve S2 is determined by the equation ;

[0023] wherein, R2 is the radius of the impeller; b2 is the blade outlet width of the impeller; B is the volute thickness; α is the airflow angle after the impeller passage outlet; is the angle between the line connecting the point on the volute curve S2 and the center O and the starting ray, and a0, a1, b1, ω are correction and adjustment constant terms, and -10 ≤ a0 ≤ 10, -10 ≤ a1 ≤ 10, a1 ≥ a0, 20 ≤ b1 ≤ 25, 0.2 ≤ ω ≤ 0.5.

[0024] The air duct structure provided by the present invention includes a check valve and the volute described above. The check valve is arranged at the outlet of the volute; the check valve includes a first check valve side plate and a second check valve side plate. The first check valve side plate is connected to one end of the volute shroud away from the volute tongue, and the second check valve side plate is connected to one end of the volute tongue away from the volute shroud;

[0025] The inner wall of the first check valve side plate is formed by the first check valve guiding baseline S3, the inner wall of the second check valve side plate is formed by the second check valve guiding baseline S4, and the inner wall of the volute tongue is formed by the volute tongue curve S1;

[0026] The first check valve guiding baseline S3 is a concave curve with respect to the volute curve S2 in the direction towards the second check valve guiding baseline S4, and the second check valve guiding baseline S4 is a convex curve with respect to the volute curve S2 in the direction away from the first check valve guiding baseline S3.

[0027] The range hood provided by the present invention includes the air duct structure described above.

[0028] The method for constructing the volute profile provided by the present invention includes: taking the center O of the impeller as the origin and the starting ray as the starting point, and determining the volute curve S2 through the equation ; wherein, R2 is the radius of the impeller; b2 is the blade outlet width of the impeller; B is the volute thickness; α is the airflow angle after the impeller passage outlet; is the angle between the line connecting the point on the volute curve S2 and the center O and the starting ray, and a0, a1, b1, ω are correction and adjustment constant terms, and -10 ≤ a0 ≤ 10, -10 ≤ a1 ≤ 10, a1 ≥ a0, 20 ≤ b1 ≤ 25, 0.2 ≤ ω ≤ 0.5.

[0029] Compared with the prior art, the shape of the volute curve S2 is locally controlled by the equation provided in the construction method of the volute profile provided by the present invention, which can maintain the smooth transition of the curve. At the same time, the curve in the first quadrant of the volute curve is locally expanded compared with the original structure, the curve in the second quadrant is locally expanded compared with the original structure, and the curve in the fourth quadrant is expanded compared with the original structure. The air flow passage becomes larger, the resistance of the flow passage is reduced, and the aerodynamic noise is reduced.

[0030] The volute provided by the present invention includes a volute rear plate, a volute front plate, a volute shroud and a volute tongue. The volute shroud and the volute tongue are sequentially connected between the volute rear plate and the volute front plate. The inner side wall of the volute shroud is formed by a volute curve S2, and the volute curve S2 is determined by the equation wherein, R2 is the radius of the impeller; b2 is the blade outlet width of the impeller; B is the volute thickness; α is the air flow angle after the impeller passage outlet; is the included angle between the line connecting the point on the volute curve S2 and the center O and the starting ray, and a0, a1, b1, ω are correction and adjustment constant terms, and -10 ≤ a0 ≤ 10, -10 ≤ a1 ≤ 10, a1 ≥ a0, 20 ≤ b1 ≤ 25, 0.2 ≤ ω ≤ 0.5.

[0031] Compared with the existing structure, it is possible to locally control the shape of the spiral line of the volute curve S2, maintain the smooth transition of the curve. At the same time, the volute curve S2 is locally expanded compared with the original structure, the air flow passage becomes larger, the resistance of the gas in the flow passage is reduced, and thus the aerodynamic noise is reduced.

[0032] The air duct structure provided by the present invention includes a check valve and the above-mentioned volute. The check valve is arranged at the outlet of the volute. The check valve includes a first check valve side plate and a second check valve side plate. The first check valve side plate is connected to the end of the volute shroud away from the volute tongue, and the second check valve side plate is connected to the end of the volute tongue away from the volute shroud. The inner side wall of the first check valve side plate is formed by a first check valve guiding baseline S3, the inner side wall of the second check valve side plate is formed by a second check valve guiding baseline S4, the inner side wall of the volute tongue is formed by a volute tongue curve S1. The first check valve guiding baseline S3 is a concave curve facing the second check valve guiding baseline S4 direction with respect to the volute curve S2, and the second check valve guiding baseline S4 is a convex curve away from the first check valve guiding baseline S3 direction with respect to the volute curve S2.

[0033] On the one hand, it makes the connection between the volute and the check valve smoother and more unobstructed, reducing the separation loss of the air flow in the volute caused by the sudden change in curvature, and reducing the aerodynamic noise caused by vortices. On the other hand, the guiding baseline S3 of the first check valve is concave with respect to the volute curve. The concave surface guided by the guiding baseline S3 of the first check valve can decelerate and pressurize the air flow at the volute outlet, inhibit the premature flow separation of the gas from the volute outlet wall surface, and reduce the aerodynamic noise. The guiding baseline S4 of the second check valve is convex with respect to the volute curve. The convex surface guided by the guiding baseline S4 of the second check valve serves to converge the air flow. The combined action of the guiding baseline S3 of the first check valve and the guiding baseline S4 of the second check valve can make the air flow distribution at the check valve outlet uniform, solving the problems of large-scale vortices and flow dead zones in the volute outlet area. In addition, increasing the height of the check valve can make the internal air flow uniform in advance, reducing the problems of turbulent flow and uneven flow velocity distribution at the outlet.

[0034] The range hood provided by the present invention includes the described air duct structure. Therefore, this range hood also has the advantages of the described air duct structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0036] Figure 1 Schematic diagram of the volute profile formed by the method for constructing the volute profile provided in the embodiment of the present invention;

[0037] Figure 2 Comparison schematic diagram of the volute curve and the original curve of the method for constructing the volute profile provided in the embodiment of the present invention;

[0038] Figure 3 Structure diagram of the air duct structure of the side suction air duct provided in the embodiment of the present invention;

[0039] Figure 4 Exploded view of the air duct structure of the side suction air duct provided in the embodiment of the present invention;

[0040] Figure 5 Partial structure diagram of the air duct structure of the side suction air duct provided in the embodiment of the present invention;

[0041] Figure 6 Schematic diagram of the application of the side suction air duct of the air duct structure provided in the embodiment of the present invention;

[0042] Figure 7Schematic linear diagram of the thin air duct of the air duct structure provided by the embodiment of the present invention;

[0043] Figure 8 Structural diagram of the air duct structure to which the thin air duct provided by the embodiment of the present invention is applied;

[0044] Figure 9 Front view of the air duct structure to which the thin air duct provided by the embodiment of the present invention is applied;

[0045] Figure 10 Structural diagram of the application of the thin air duct of the air duct structure provided by the embodiment of the present invention;

[0046] Figure 11 Front view of the application of the thin air duct of the air duct structure provided by the embodiment of the present invention;

[0047] Figure 12 Schematic diagram of the gas flowing in the volute provided by the embodiment of the present invention;

[0048] Figure 13 Field cloud map of the volute outlet area of the original structure;

[0049] Figure 14 Field cloud map of the volute outlet area provided by the embodiment of the present invention;

[0050] Figure 15 Distribution cloud map of the position and intensity of the main noise sources on the surface of the air duct of the original structure;

[0051] Figure 16 Distribution cloud map of the position and intensity of the main noise sources on the surface of the air duct structure provided by the embodiment of the present invention.

[0052] Icon: 100 - check valve; 110 - first check valve side plate; 120 - second check valve side plate; 200 - volute; 210 - volute shroud; 220 - volute tongue; 230 - volute rear plate; 240 - volute front plate; 300 - motor; 400 - impeller;

[0053] S1 - volute tongue curve; S2 - volute curve; S3 - first check valve guiding baseline; S4 - second check valve guiding baseline; L1 - straight line segment of the circular outlet of the check valve. Detailed implementation manners

[0054] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0055] As Figures 1 to 2As shown in the figure, the method for constructing the volute profile provided by the present invention includes: taking the center O of the impeller 400 as the origin, taking the starting ray as the starting point, and passing through the equation to determine the volute curve S2; in the formula, R2 is the radius of the impeller 400; b2 is the blade outlet width of the impeller 400; B is the thickness of the volute 200; α is the airflow angle after the impeller passage outlet; is the angle between the line connecting the point on the volute curve and the center O and the starting ray, and a0, a1, b1, ω are correction and adjustment constant terms, and -10 ≤ a0 ≤ 10, -10 ≤ a1 ≤ 10, a1 ≥ a0, 20 ≤ b1 ≤ 25, 0.2 ≤ ω ≤ 0.5.

[0056] Compared with the prior art, the shape of the volute curve is locally controlled by the equation provided in the method for constructing the volute profile provided by the present invention, which can maintain the smooth transition of the curve. At the same time, the curve in the first quadrant of the volute curve is locally expanded compared with the original structure, the curve in the second quadrant is locally expanded compared with the original structure, and the curve in the fourth quadrant is expanded compared with the original structure. The airflow passage becomes larger, the resistance of the flow passage is reduced, and the aerodynamic noise is reduced.

[0057] It should be noted that as Figure 12 shown is the schematic diagram of the gas flow in the volute 200. Among them, R2 is the impeller radius, that is, the impeller passage outlet radius; c’2 is the impeller passage outlet velocity; c’2u is the circumferential velocity after the impeller passage outlet; c’2m is the radial velocity after the impeller passage outlet; α is the airflow angle after the impeller passage outlet; the airflow angle α after the impeller passage outlet is related to the blade parameters, and its value range is: 0 < α < 90°. In this embodiment, α = 6.2°.

[0058] Furthermore, it includes determining the center O, determining the reference line and the starting installation angle θ0, and determining the starting ray according to the reference line and the starting installation angle θ0; the step of determining the reference line includes: passing through the center O to make a line parallel to the straight line segment of the circular outlet of the check valve 100 to determine.

[0059] Specifically, first determine the center O, that is, the axis of the impeller 400. Then, make the reference line, that is, draw a ray OA parallel to the plane where the upper end face of the check valve 100 is located through the center O to the left. Then determine the starting installation angle θ0, that is, rotate the ray OA clockwise by an angle θ0 to obtain the starting ray OB. Finally, determine the volute curve S2 through the modified logarithmic spiral equation

[0060] Furthermore, determine the positions of the first point P1, the second point P2, the third point P3, the fourth point P4, the fifth point P5 and the sixth point P6; among them, the P3 point is when ​When it is 0 degrees, the intersection of the circle with radius R obtained from the above equation and the starting ray OB. P4 and P6 are determined according to the installation position of the check valve 100 during actual use, that is, the fourth point P4 and the sixth point P6 are determined through the straight line segment of the circular outlet of the check valve 100. P5 is the midpoint of the straight line connection between P4 and P6. The point P2 is the starting point of the volute tongue curve and can be determined by the installation angle θ1 of the volute curve. That is, rotate the reference line OA clockwise by θ1 to form a ray OC, and the intersection of the ray OC and the volute curve S2 is P2. Among them, P1 can be set manually or determined according to the design method in the prior art so that an inward concave volute tongue curve S1 can be formed between P1 and P2.

[0061] In this embodiment, the second point P2 is a point on the volute curve, and the included angle between the connection line between it and the center O and the reference line is θ1, and θ0 < θ1 < 90°; the third point P3 is the intersection of the starting ray and the volute curve S2; the fourth point P4 and the sixth point P6 are determined through the straight line segment L1 of the circular outlet of the check valve, and the midpoint of the straight line connecting the fourth point P4 and the sixth point P6 is the fifth point P5; the included angle between the connection line between the fifth point P5 and the center O and the reference line is θ2, and θ1 < θ2 < 90°.

[0062] Construct a volute tongue curve S1 between the first point P1 and the second point P2; construct a first check valve guiding baseline S3 between the third point P3 and the fourth P4; determine a second check valve guiding baseline S4 between the sixth point P6 and the first point P1.

[0063] Preferably, in this embodiment, the included angle θ1 between the connection line between the second point P2 and the center O and the reference line is 78°; the included angle θ2 between the connection line between the fifth point P5 and the center O and the reference line is 82°.

[0064] Furthermore, the range of the starting installation angle θ0 satisfies: 0 ≤ θ0 ≤ 45°.

[0065] Preferably, the starting installation angle θ0 is 40°.

[0066] Furthermore, the volute tongue curve S1, the first check valve guiding baseline S3 and the second check valve guiding baseline S4 are all determined by the Bezier curve equation.

[0067] Specifically, the section from P1 to P2 is the volute tongue curve S1, which is a Bezier curve. P2 to P3 is the volute curve S2 based on the logarithmic spiral. P3 to P4 is the first check valve guiding baseline S3 based on the Bezier curve. P4 to P6 is the straight line segment L1 of the circular outlet of the check valve. P6 to P1 is the second check valve guiding baseline S4 based on the Bezier curve.

[0068] As Figure 2As shown, compared with the original air duct structure, the overall width and height of the volute 200 are basically the same. The improved volute tongue 220 moves further inward relative to the original volute tongue 220, which helps to improve the gas reflux at the outlet of the impeller 400, increase the outlet static pressure and the fan efficiency; the curve of the first quadrant of the volute curve expands locally compared with the original structure, the curve of the second quadrant expands locally compared with the original structure, and the curve of the fourth quadrant expands compared with the original structure. The air flow channel becomes larger, reducing the flow channel resistance and lowering the aerodynamic noise.

[0069] Specifically, the guiding baseline S3 of the first check valve is a concave curve relative to the volute curve towards the direction of the guiding baseline S4 of the second check valve, and the guiding baseline S4 of the second check valve is a convex curve relative to the volute curve away from the direction of the guiding baseline S3 of the first check valve.

[0070] As Figure 1 shown, points P3 to P4 are the guiding baseline S3 of the first check valve based on the Bezier curve, points P6 to P1 are the guiding baseline S4 of the second check valve based on the Bezier curve. The deflection angle of the midpoint P5 of the outlet of the check valve 100 from the center of the volute 200 is θ2, and its angle range is θ0 < θ2 < 90°, and θ2 > θ1. In this example, it is 82°.

[0071] The guiding baseline S3 of the first check valve and the guiding baseline S4 of the second check valve are transitioned using the Bezier curve, breaking through the geometric limitations of the circular arc line. It is required that the order number of the Bezier curve be ≥3, because at least a third-order Bezier curve (four control points) is needed to generate a curvature-continuous path. The guiding baseline S3 of the first check valve and the guiding baseline S4 of the second check valve adopt the Bezier curve. On the one hand, it makes the connection between the profile of the volute 200 and the check valve 100 smoother and more seamless, reducing the separation loss of the air flow in the volute 200 caused by the sudden change of curvature and lowering the aerodynamic noise caused by the vortex; on the other hand, the guiding baseline S3 of the first check valve is concave relative to the volute curve. The concave surface guided by the guiding baseline S3 of the first check valve can decelerate and pressurize the air flow at the outlet of the volute 200, inhibit the premature flow separation of the gas from the outlet wall surface of the volute 200, and reduce the aerodynamic noise; the guiding baseline S4 of the second check valve is convex relative to the volute curve. The convex surface guided by the guiding baseline S4 of the second check valve plays a role in converging the air flow. The combined action of the guiding baseline S3 of the first check valve and the guiding baseline S4 of the second check valve can make the air flow distribution at the outlet of the check valve 100 uniform, solving the problems of large-scale eddy current and flow dead zone existing in the outlet area of the volute 200, which has been obtained through simulation analysis. In addition, increasing the height of the check valve 100 can make the internal air flow uniform in advance, reducing the problems of turbulent flow and uneven flow velocity distribution at the outlet.

[0072] As Figures 1 to 11As shown in the figure, the volute provided in this embodiment includes a volute rear plate 230, a volute front plate 240, a volute shroud 210, and a volute tongue 220. The volute shroud 210 and the volute tongue 220 are sequentially connected between the volute rear plate 230 and the volute front plate 240. The inner wall of the volute shroud 210 is formed by a volute curve S2, and the volute curve S2 is determined by the equation wherein, R2 is the radius of the impeller 400; b2 is the blade outlet width of the impeller 400; B is the volute thickness; α is the airflow angle after the impeller passage outlet; is the angle between the line connecting the point on the volute curve S2 and the center O and the starting ray, and a0, a1, b1, ω are correction and adjustment constant terms, and -10 ≤ a0 ≤ 10, -10 ≤ a1 ≤ 10, a1 ≥ a0, 20 ≤ b1 ≤ 25, 0.2 ≤ ω ≤ 0.5.

[0073] It should be noted that the volute tongue 220 and the volute shroud 210 can be a split structure or an integral structure. In this embodiment, the volute tongue 220 is a concave curved surface structure. The volute tongue curve S1 forming the inner wall of the volute tongue 220 can be formed by a Bezier curve, or can be designed by the design method of the volute tongue in the prior art.

[0074] Compared with the existing structure, the volute 200 provided in this embodiment can locally control the shape of the spiral line of the volute curve S2, and can maintain the smooth transition of the curve. At the same time, the volute curve S2 is locally expanded compared with the original structure, the airflow passage becomes larger, the resistance of the gas in the flow passage is reduced, and thus the aerodynamic noise is reduced.

[0075] The air duct structure provided in this embodiment includes a check valve 100 and the above-mentioned volute 200. The check valve 100 is arranged at the outlet of the volute 200. The check valve 100 includes a first check valve side plate 110 and a second check valve side plate 120. The first check valve side plate 110 is connected to one end of the volute shroud 210 away from the volute tongue 220, and the second check valve side plate 120 is connected to one end of the volute tongue 220 away from the volute shroud 210. The inner wall of the first check valve side plate 110 is formed by a first check valve guiding baseline S3, the inner wall of the second check valve side plate 120 is formed by a second check valve guiding baseline S4, the inner wall of the volute tongue 220 is formed by a volute tongue curve S1. The first check valve guiding baseline S3 is a concave curve towards the second check valve guiding baseline S4 direction with respect to the volute curve S2, and the second check valve guiding baseline S4 is a convex curve away from the first check valve guiding baseline S3 direction with respect to the volute curve S2.

[0076] In actual use, on the one hand, it makes the connection between the volute 200 and the check valve 100 smoother, reducing the separation loss of the air flow in the volute 200 caused by sudden curvature changes and reducing the aerodynamic noise caused by vortices. On the other hand, the guiding baseline S3 of the first check valve is concave with respect to the volute curve S2. The concave surface guided by the guiding baseline S3 of the first check valve can decelerate and pressurize the air flow at the volute outlet, inhibit the premature flow separation of the gas from the volute outlet wall surface, and reduce the aerodynamic noise. The guiding baseline S4 of the second check valve is convex with respect to the volute curve S2, and the convex surface guided by the guiding baseline S4 of the second check valve serves to converge the air flow. The combined action of the guiding baseline S3 of the first check valve and the guiding baseline S4 of the second check valve can make the air flow distribution at the check valve outlet uniform, solving the problems of large-scale vortices and flow dead zones in the volute outlet area. In addition, increasing the height of the check valve can make the internal air flow uniform in advance, reducing the problems of turbulent flow and uneven flow velocity distribution at the outlet.

[0077] As Figures 1 to 11 shown, the air duct structure provided by the present invention includes a check valve 100 and a volute 200; the check valve 100 is arranged at the outlet of the volute 200; the volute 200 includes a volute rear plate 230, a volute front plate 240, a volute shroud 210 and a volute tongue 220, and the volute shroud 210 and the volute tongue 220 are sequentially connected between the volute rear plate 230 and the volute front plate 240; the check valve 100 includes a first check valve side plate 110 and a second check valve side plate 120, the first check valve side plate 110 is connected to one end of the volute shroud 210 away from the volute tongue 220, and the second check valve side plate 120 is connected to one end of the volute tongue 220 away from the volute shroud 210;

[0078] The inner side wall of the first check valve side plate 110 is formed by the guiding baseline S3 of the first check valve, the inner side wall of the second check valve side plate 120 is formed by the guiding baseline S4 of the second check valve, the inner side wall of the volute tongue 220 is formed by a volute tongue curve, and the inner side wall of the volute shroud 210 is formed by a volute curve, and the volute curve is determined by the equation wherein, R2 is the radius of the impeller 400; b2 is the blade outlet width of the impeller 400; B is the thickness of the volute 200; α is the air flow angle after the impeller channel outlet; is the angle between the line connecting a point on the volute curve and the center O and the starting ray, and a0, a1, b1, ω are correction and adjustment constant terms, and -10 ≤ a0 ≤ 10, -10 ≤ a1 ≤ 10, a1 ≥ a0, 20 ≤ b1 ≤ 25, 0.2 ≤ ω ≤ 0.5.

[0079] As Figures 3 to 6As shown in the figure, the present embodiment provides a schematic diagram of a duct structure applied to a side suction duct. Specifically, the duct structure includes a check valve 100 and a volute 200. The check valve 100 is connected to the outlet of the volute 200. Among them, the volute 200 includes a volute front plate 240, a volute rear plate 230, a volute shroud 210, and a volute tongue 220. The volute shroud 210 and the volute tongue 220 are connected and arranged between the volute front plate 240 and the volute rear plate 230, and their sides are connected to the volute front plate 240 and the volute rear plate 230. The inner contour of the volute shroud 210 is formed by a volute curve, and the inner contour of the volute tongue 220 is formed by a volute tongue curve. The check valve 100 includes a first check valve side plate 110 and a second check valve side plate 120 arranged oppositely. The first check valve side plate 110 is connected to the volute shroud 210, and its inner contour is formed by a first check valve guiding baseline S3. The second check valve side plate 120 is connected to the volute tongue 220, and its inner contour is formed by a second check valve guiding baseline S4.

[0080] Specifically, the first check valve guiding baseline S3, the volute curve S2, the volute tongue curve S1, and the second check valve guiding baseline S4 can be determined according to the above-mentioned construction method of the volute profile line, and the positions of the determined points P1, P2, P3, P4, P5, and P6 can be obtained. At the same time, in this duct structure, further, the range of the starting placement angle θ0 satisfies: 0 ≤ θ0 ≤ 45°. Preferably, in this embodiment, the starting placement angle θ0 is 40°.

[0081] The included angle between the line connecting P2 and the center O and the reference line is θ1, and θ0 < θ1 < 90°. The included angle between the line connecting point P5 and the center O and the reference line is defined as θ2, and θ2 satisfies θ1 < θ2 < 90°.

[0082] Preferably, in this embodiment, the included angle θ1 between the line connecting point P2 and the center O and the reference line is 78°; the included angle θ2 between the line connecting point P5 and the center O and the reference line is 82°.

[0083] Preferably, the volute tongue curve S1, the first check valve guiding baseline S3, and the second check valve guiding baseline S4 are all determined by the Bezier curve equation. The first check valve guiding baseline S3 is a concave curve relative to the volute curve in the direction of the second check valve guiding baseline S4, and the second check valve guiding baseline S4 is a convex curve relative to the volute curve S2 in the direction away from the first check valve guiding baseline S3.

[0084] As Figures 7 to 11 shown, the present embodiment provides a schematic diagram of a duct structure applied to a thin duct. The specific structure is similar to the duct structure applied to the side suction duct described above. Among them, Figure 7 is the profile line diagram of this duct structure. Among them, θ0 is 37°, θ1 is 72°, and θ2 is 75°.Figure 8 and Figure 9 is the air duct structure diagram, Figure 10 and Figure 11 is the structure diagram of the range hood applying this air duct structure.

[0085] The range hood provided by the present invention includes the above-mentioned air duct structure, and also includes a motor 300 and an impeller 400. Among them, the motor 300 is used to drive the impeller 400 to rotate, and the axis of the motor 300 coincides with the center O. Therefore, this range hood also has the advantages of the above-mentioned air duct structure.

[0086] In this embodiment, as Figures 13 to 16 shown, the simulation analysis comparison of the air duct structure applied in the side suction air duct and the air duct structure of the original structure is as follows:

[0087] 1) Flow field comparison analysis

[0088] As Figure 13 and Figure 14 shown, it can be known through simulation. Original structure: The wind speed at the outlet section is small and the speed distribution is uneven. There are flow dead zones and large low-speed areas. In the area near the lower end of the volute tongue 220, there are large-scale eddies, and there is energy dissipation in the air flow here, which not only affects the fan efficiency, but also causes the flow separation near the blades due to air flow stall to intensify, increasing the aerodynamic noise;

[0089] Improved structure: The wind speed at the outlet section is increased and the wind speed distribution is uniform, the flow dead zone is eliminated, and the eddy current at the lower end of the volute tongue 220 is eliminated, which is beneficial to reducing the aerodynamic noise.

[0090] 2) Broadband noise analysis

[0091] As Figure 15 and Figure 16 shown, it can be seen from the distribution cloud diagram of the position and intensity of the main noise sources on the air duct surface predicted by the Curle dipole noise source model that the Curle broadband noise source model can calculate the noise of the pressure fluctuation of the fluid acting on the solid boundary surface. The maximum surface sound intensity of the original structure is about 83 dB, and the maximum surface sound intensity of the improved structure is reduced to 80 dB, and the distribution range is further reduced. It can be speculated that the improved structure can reduce the aerodynamic noise of the air duct system.

[0092] 3) Experimental comparison analysis (side suction air duct)

[0093] The test results of the overall air performance and noise of the whole machine

[0094] Test parameters Original complete machine Improved complete machine Maximum static pressure (Ps2nmax), power of the electronic control board: 365W 1020Pa 1180Pa Maximum air volume (Qvmax) <![CDATA[18.2m 3 / min]]> <![CDATA[18.3 m 3 / min]]> Total pressure efficiency (η) at the standard-specified 7 air volumes 32.1％ 37.2％ Measured fan speed under strong gear 720rpm 620rpm Measured noise of sound power 63.3dB(A) 61.1dB(A)

[0095] Experimental data show that, for the improved air duct, when the power of the electric control board is 365W, the maximum static pressure is increased from 1020Pa to 1180Pa, an increase of 160Pa; the full-pressure efficiency is increased from 32.1% to 37.2% at the standard air volume, an increase of 5.1%, and the measured fan speed is reduced from 720rpm to 620rpm at the strong gear. The optimized air duct structure scheme with integrated modeling of the volute 200 and the check valve 100 can reduce the overall machine noise by about 2.2dB(A) in actual measurement.

[0096] In summary, compared with the prior art, the method for constructing the volute profile provided by the present invention locally controls the shape of the volute curve S2 through the equation provided in the method for constructing the volute profile provided by the present invention, so as to maintain the smooth transition of the curve. At the same time, the first quadrant curve of the volute curve is locally expanded compared with the original structure, the second quadrant curve is locally expanded compared with the original structure, and the fourth quadrant curve is expanded compared with the original structure, so that the airflow flow channel becomes larger, the flow channel resistance is reduced, and the aerodynamic noise is reduced.

[0097] Compared with the existing structure, the volute provided by the present invention can locally control the shape of the spiral line of the volute curve S2, and can maintain the smooth transition of the curve. At the same time, the volute curve is locally expanded compared with the original structure, the airflow flow channel becomes larger, and the resistance of the gas in the flow channel is reduced, thereby reducing the aerodynamic noise.

[0098] The air duct structure provided by the present invention, on the one hand, makes the connection between the volute and the check valve smoother, reduces the separation loss of the airflow in the volute due to the sudden change of curvature, and reduces the aerodynamic noise caused by the vortex; on the other hand, the first check valve guide baseline S3 is concave relative to the volute curve, and the concave surface guided by the first check valve guide baseline S3 can decelerate and pressurize the airflow at the volute outlet, inhibit the gas from flowing away from the volute outlet wall too early, and reduce the aerodynamic noise; the second check valve guide baseline S4 is convex relative to the volute curve, and the convex surface guided by the second check valve guide baseline S4 plays a role in gathering the airflow. The combined effect of the first check valve guide baseline S3 and the second check valve guide baseline S4 can make the airflow at the check valve outlet evenly distributed, solve the problem of large-scale vortex and flow dead zone in the volute outlet area, and in addition, the height of the check valve is increased, which can make the internal airflow even in advance, and reduce the problems of outlet turbulence and uneven flow velocity distribution.

[0099] The range hood provided by the present invention comprises the above-mentioned air duct structure, and therefore, the range hood also has the advantages of the above-mentioned air duct structure.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing a volute profile, characterized in that, Including: Taking the center O of the impeller (400) as the origin, with the starting ray as the starting point, through the equation Determine the spiral casing curve S2; Wherein, R2 is the radius of the impeller (400); b2 is the blade outlet width of the impeller (400); B is the volute thickness; α is the air flow angle after the impeller passage outlet; is the included angle between the line connecting the point on the volute curve S2 and the center O and the starting ray, and a0, a1, b1, ω are correction and adjustment constant terms, and -10 ≤ a0 ≤ 10, -10 ≤ a1 ≤ 10, a1 ≥ a0, 20 ≤ b1 ≤ 25, 0.2 ≤ ω ≤ 0.

5.

2. The method for constructing the volute profile according to claim 1, characterized in that, Determine the center O, determine the reference line and the starting installation angle θ0, and determine the starting ray according to the reference line and the starting installation angle θ0; The step of determining the reference line includes: drawing a line parallel to the straight line segment L1 of the circular outlet of the check valve through the center O for determination.

3. The method for constructing the volute profile according to claim 2, wherein Determine the positions of the first point P1, the second point P2, the third point P3, the fourth point P4, the fifth point P5 and the sixth point P6; The second point P2 is a point on the volute curve S2, and the included angle between the line connecting it and the center O and the reference line is θ1, and 0 < θ1 < 90°; The third point P3 is the intersection point of the starting ray and the volute curve S2; Determine the fourth point P4 and the sixth point P6 through the straight line segment L1 of the circular outlet of the check valve, and the midpoint of the straight line connecting the fourth point P4 and the sixth point P6 is the fifth point P5; the included angle between the line connecting the fifth point P5 and the center O and the reference line is θ2, θ1 < θ2 < 90°; Construct a volute tongue curve S1 between the first point P1 and the second point P2; construct a first check valve guiding baseline S3 between the third point P3 and the fourth point P4; determine a second check valve guiding baseline S4 between the sixth point P6 and the first point P1.

4. The construction method of the volute profile according to claim 3, characterized in that, The volute tongue curve S1, the first check valve guiding baseline S3 and the second check valve guiding baseline S4 are all determined by the Bezier curve equation.

5. The method for constructing a volute profile according to any one of claims 2-4, characterized in that, The range of the starting installation angle θ0 satisfies: 0 ≤ θ0 ≤ 45°.

6. The method for constructing the volute profile according to claim 5, wherein, The starting installation angle θ0 is 40°.

7. The method for constructing the volute profile according to claim 3, wherein The included angle θ1 between the line connecting the second point P2 and the center O and the reference line is 78°; The included angle θ2 between the line connecting the fifth point P5 and the center O and the reference line is 82°.

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