volute structure, centrifugal fan and air conditioner

Abstract

This utility model discloses a volute structure, a centrifugal fan, and an air conditioner. The volute structure includes: a volute, with air inlets on two opposite end faces; and two recesses on the volute tongue, symmetrically distributed about the volute's axis of rotation (YOZ). A vertical plane (XOY) passing through the volute's central axis when the volute is placed vertically is used as the projection plane, perpendicular to the volute's axis of rotation (YOZ). The projection of the recesses onto the vertical plane (XOY) is a smooth, continuous curve (A0B0C0). This utility model, through a symmetrical concave, inclined design of the volute tongue, weakens the strong impact of the spiral airflow at the volute outlet on the tongue, improves the uniformity of the airflow distribution, effectively increases air volume, and reduces wind noise.

Description

Technical Field

[0001] This utility model relates to the field of centrifugal fan technology, and in particular to volute structure, centrifugal fan and air conditioner. Background Technology

[0002] With the trend towards miniaturization, noise reduction, and high static pressure in air conditioners, symmetrical double-suction centrifugal fans have become core aerodynamic components in duct-type air conditioning systems due to their high air pressure characteristics. This fan consists of an impeller and a volute. Its unique air intake channel causes a non-uniform airflow velocity distribution inside the volute, with a high velocity in the middle and low velocity on both sides, exhibiting a spiral flow along the circumference. This non-uniform flow pattern causes the volute tongue area to be subjected to periodic airflow impacts, leading to two problems:

[0003] 1. Increased aerodynamic losses – The volute tongue structure does not fit the spiral airflow path, and the continuous collision with the volute tongue increases the dissipation of turbulent kinetic energy and reduces the efficiency of the fan.

[0004] 2. Noise and vibration deterioration - Excessive local airflow velocity causes strong impact with the volute tongue, resulting in sound pressure superposition in the axial direction, which leads to noise deterioration.

[0005] To mitigate the aforementioned problems, most existing technologies focus on optimizing the volute profile. For example, utility model patent CN112303023A proposes a wave-shaped volute structure, which reconstructs the volute profile by alternating multiple segments of circular arcs and straight lines, increasing the fit between the airflow path and the volute wall, and improving internal flow efficiency. However, such solutions have significant limitations. The splicing of multiple curve segments requires high-precision mold positioning, which greatly increases the complexity of processing. Moreover, fixed curvature combinations are difficult to match dynamic flow changes under different operating conditions, and local backflow still exists at non-design points.

[0006] Therefore, in order to address the pain point that it is difficult to coordinate structural complexity and aerodynamic performance in existing technologies, there is an urgent need for a low-cost, highly flow field adaptable improved volute design. Utility Model Content

[0007] To address the shortcomings of existing technologies, such as complex structures and poor aerodynamic performance, this invention proposes a volute structure, a centrifugal fan, and an air conditioner. By designing a symmetrical concave inclined volute tongue, the strong impact of the spiral airflow at the volute outlet on the volute tongue is weakened, improving the uniformity of the airflow distribution in the volute, effectively increasing air volume and reducing wind noise.

[0008] The technical solution adopted in this utility model is to design a volute structure, including: a volute, with air inlets on two opposite end faces of the volute, and two recesses on the volute tongue, the two recesses being symmetrically distributed about the YOZ axis of the volute's center plane.

[0009] Furthermore, the vertical plane XOY passing through the central axis of the volute when it is placed upright is used as the projection plane. The vertical plane XOY is perpendicular to the axis-perpendicular center plane YOZ of the volute. The projection of the recessed part on the vertical plane XOY is a smooth continuous curve A0B0C0.

[0010] Furthermore, one end of the continuous curve A0B0C0 is connected to the axis-perpendicular center plane YOZ, and the other end is connected to the side wall of the volute. The point where the continuous curve A0B0C0 connects to the axis-perpendicular center plane YOZ is point A0, the lowest point of the continuous curve A0B0C0 is point B0, and the point where the continuous curve A0B0C0 connects to the side wall of the volute is point C0. In the axial direction of the volute, the distance between point A0 and point B0 is L1, and the distance between point B0 and point C0 is L2. The range of L1:L2 is [0.33, 1].

[0011] Furthermore, the recessed portion includes: an inclined section, a pitted section, and a rounded corner section arranged sequentially along the air outlet direction; the inner arc surface of the volute is a guide surface; the outer edge of the air outlet is an outlet straight section; the inclined section is tangentially connected to the guide surface and the pitted section respectively; and the rounded corner section is tangentially connected to the pitted section and the outlet straight section respectively.

[0012] Furthermore, the recessed portion is formed by segmented scanning of the hybrid line abcd along the axial direction of the volute, divided into segments A0B0 and B0C0; the profiles of the inclined segment, the recessed segment, and the rounded corner are respectively the arc line ab, the line segment bc, and the arc line cd. The radius r of the arc line ab is a preset fixed value, and the angle θ between the line segment bc and the exit straight line segment is in the range of [10°, 30°]. The characteristic length l of the line segment bc is constrained by a segmented sine function along the axial direction of the volute.

[0013] Furthermore, the scanning equation for the mixed line abcd is:

[0014] Segment A0B0: l=1+s1×δ×sin(90×t)

[0015] Segment B0C0: l=1+s1×δ×sin(90+90×t)

[0016] The radius r of the arc ab is:

[0017] r = s² × δ

[0018] Where r is the characteristic radius of the arc ab, s1 takes values ​​in the range of [1.5, 2.5], s2 takes values ​​in the range of [2, 3], δ takes values ​​in the range of [6mm, 12mm], and t is the scanning position scaling parameter, t = 0 to 1, t = 0 is the scanning start point, and t = 1 is the scanning end point.

[0019] This utility model also proposes a centrifugal fan, including: a volute and an impeller installed in the inner cavity of the volute, wherein the volute adopts the above-described volute structure.

[0020] Furthermore, the air inlet of the volute is connected to a collector.

[0021] This utility model also proposes an air conditioner, including the centrifugal fan described above.

[0022] In some embodiments, the air conditioner is a ducted air conditioner.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The volute tongue of the volute has two recesses, which are symmetrically distributed about the YOZ axis of the volute. This can effectively integrate multiple spiral airflows into two relatively regular streams, reduce the impact of the spiral airflow at the volute outlet on the volute tongue, improve the airflow state between the volute tongue and the outlet, and effectively reduce wind noise.

[0025] 2. The recessed part includes an inclined section and a pit section, whose cross-sectional profiles are tangent circular arcs and straight lines, respectively. The inclined section offsets the superposition of sound pressure in the axial direction caused by the airflow impact, and the pit section works in conjunction with the inclined section to buffer the airflow impact and rectify the spiral airflow, thus optimizing the spiral airflow path.

[0026] 3. The line segment bc of the recessed part forms a certain angle with the straight line segment of the air outlet. The characteristic length of the line segment bc is constrained by a piecewise sine function along the volute axis. By controlling the variation law of this characteristic length, the distribution range of the recessed part and the position of the lowest point of the concave part are adjusted to match the optimal path of airflow impact. Attached Figure Description

[0027] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein:

[0028] Figure 1 This is a three-dimensional schematic diagram of the centrifugal fan of this utility model;

[0029] Figure 2 This is a three-dimensional schematic diagram of the volute structure of this utility model;

[0030] Figure 3 This is a schematic diagram of the air outlet surface of the volute structure of this utility model;

[0031] Figure 4 yes Figure 3 A cross-sectional view of section AA after the impeller is installed;

[0032] Figure 5 This is a schematic diagram of the recessed part of the volute structure of this utility model;

[0033] Figure 6 yes Figure 4 A partial schematic diagram at point B in the middle;

[0034] Figure 7a These are the velocity distribution cloud map and velocity vector map of the XOY section of a conventional volute.

[0035] Figure 7b This is a velocity distribution cloud map and velocity vector map of the XOY section of the volute structure of this utility model;

[0036] Figure 8a These are velocity distribution cloud maps and trace maps of the conventional volute exit surface;

[0037] Figure 8b This is a velocity distribution cloud map and trace map of the exit surface of the volute structure of this utility model;

[0038] Figure 9 This is a comparison chart of the measured noise levels of the novel volute structure and a conventional volute under different airflow conditions. Attached image description:

[0040] 1. Volute; 11. Sidewall; 12. Guide surface; 121. Straight section at outlet; 13. Collector; 14. Volute tongue; 141. Inclined section; 142. Dimpled section; 143. Rounded corner section; 2. Impeller. Detailed Implementation

[0041] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0042] like Figure 1 As shown, the volute structure proposed in this utility model is applicable to centrifugal fans, especially double-suction centrifugal fans. A double-suction centrifugal fan is a centrifugal fan with a special structure. Its core feature is that air inlets are symmetrically opened on both sides of the impeller 2, allowing airflow to be simultaneously drawn in from both ends along the axis of the impeller 2. After being accelerated by the rotation of the impeller 2, the airflow is guided out from the outlet by the volute 1.

[0043] Due to the unique airflow path of the double-suction centrifugal fan, the airflow velocity inside the volute 1 exhibits a non-uniform state along the axial direction, being high in the middle and low on both sides. The flow along the circumference of the volute 1 forms a certain spiral shape. This spiral airflow strongly impacts the volute tongue 14 of the volute 1, severely affecting the airflow and generating significant noise. Therefore, the volute structure of this invention improves the shape of the volute tongue to achieve high airflow and low noise.

[0044] like Figure 2 , 3As shown, specifically, the volute structure includes: a volute 1, with air inlets symmetrically arranged on two opposite end faces of the volute 1; and two recesses on the volute tongue 14 of the volute 1, the two recesses being perpendicular to the center plane YOZ about the axis of the volute 1 (see...). Figure 4 Symmetrical distribution. The vertical center plane refers to the reference plane that is perpendicular to the impeller axis and passes through the geometric symmetry center of the volute. Since the vertical center axis has multiple attributes such as structural symmetry axis and airflow interface, it is usually used as the spatial coordinate reference of the fan.

[0045] This design integrates multiple spiral airflows into two relatively regular streams through symmetrically arranged recesses, reducing the impact of the spiral airflow at the volute outlet on the volute tongue 14 and improving the airflow state between the volute tongue 14 and the outlet position. It is not only simple in structure and low in processing cost, but also effectively increases air volume and reduces wind noise.

[0046] like Figure 3 As shown, when the volute 1 is placed vertically, the vertical plane XOY passing through the central axis of the volute (see...) Figure 3 As the projection surface, the vertical plane XOY is perpendicular to the axis-perpendicular center plane YOZ of the volute 1. The projection of the recess on the vertical plane XOY is a smooth continuous curve A0B0C0. The smooth curve makes the pressure gradient change continuously when the airflow flows along the wall of the recess, avoiding flow separation and vortex generation. Moreover, the curvature of the smooth curve is relatively gentle, and there will be no discrete noise caused by abrupt curvature changes, which plays a role in noise suppression.

[0047] In some feasible embodiments of this utility model, one end of the continuous curve A0B0C0 is connected to the axis perpendicular center plane YOZ, and the other end is connected to the side wall 11 of the volute 1. The point where the continuous curve A0B0C0 connects to the axis perpendicular center plane YOZ is point A0, the lowest point of the continuous curve A0B0C0 is point B0, and the point where the continuous curve A0B0C0 connects to the side wall of the volute 1 is point C0. In the vertical direction ( Figure 3 Along the Y-axis (as shown), the height of point B0 is less than that of points A0 and C0. In the axial direction of the volute 1 (…),… Figure 3 On the X-axis (as shown), the distance between points A0 and B0 is L1, and the distance between points B0 and C0 is L2. The preferred range for the ratio of L1 to L2 is [0.33, 1]. By controlling this ratio, the relative position of point B0 (the lowest point) in the axial direction is controlled, thereby matching the optimal position of the airflow impact. When the ratio of L1 to L2 is less than the preferred range, the A0B0 segment is too short, which can easily cause abnormal sound quality. When the ratio of L1 to L2 is greater than the preferred range, the local vortices on both sides cannot be effectively controlled.

[0048] like Figure 5As shown, in a preferred embodiment of this utility model, the recessed portion includes: an inclined section 141, a recessed section 142, and a rounded section 143 arranged sequentially along the air outlet direction. The inner arc surface of the volute 1 is a guide surface 12, and one end of the guide surface 12 connected to the volute tongue 14 is the starting end. The outer edge of the air outlet is the outlet straight section 121. The inclined section 141 is tangentially connected to the starting end of the guide surface 12 and the recessed section 142, respectively. The rounded section 143 is tangentially connected to the recessed section 142 and the outlet straight section 121, respectively. This design uses the inclined section to stagger the axial sound pressure superposition caused by the airflow impact, and the recessed section 142, in conjunction with the inclined section 141, buffers the airflow impact and straightens the spiral airflow, optimizing the spiral airflow path.

[0049] like Figure 6 As shown, in some feasible embodiments of this utility model, the recessed portion is formed by segmented scanning of the mixing line abcd along the axial direction of the volute, divided into segments A0B0 and B0C0. The profiles of the inclined segment, the recessed segment, and the rounded corner are respectively the arc line ab, the line segment bc, and the arc line cd. The radius r of the arc line ab is a preset fixed value. The preferred range of the angle θ between the line segment bc and the outlet straight line segment is [10°, 30°], used to match the angle of airflow impact. When the value of the angle θ is greater than the preferred range, the internal circulation of the volute is aggravated; when the value of the angle θ is less than the preferred range, the optimal path of airflow impact cannot be matched. The characteristic length l of the line segment bc is constrained by a piecewise sine function along the axial direction of the volute. By controlling the variation law of this characteristic length, the distribution range of the recessed portion and the position of the lowest point of the concavity are adjusted to match the optimal path of airflow impact.

[0050] In a preferred embodiment of this invention, the scanning equation for the hybrid line abcd is:

[0051] Segment A0B0: l=1+s1×δ×sin(90×t)

[0052] Segment B0C0: l=1+s1×δ×sin(90+90×t)

[0053] The radius r of the arc ab is:

[0054] r = s² × δ

[0055] Where r is the characteristic radius of the arc ab;

[0056] The preferred value range for s1 is [1.5, 2.5], and the preferred value range for s2 is [2, 3]. The functions of s1 and s2 are to control the distribution range of the depression and the lowest point of the depression in the vertical direction. Figure 2When the values ​​of s1 and s2 are greater than the preferred range (as shown in the Y-axis direction), the distribution range is too large and the lowest point is too low, which cannot effectively suppress the backflow of air. When the values ​​of s1 and s2 are less than the preferred range, the distribution range is too small and the lowest point is too high, which cannot effectively weaken the impact of the airflow.

[0057] δ is the minimum clearance between the volute tongue and the impeller. The preferred range of δ is [6mm, 12mm]. δ is used to describe the positional relationship between the volute tongue and the impeller. When the value of δ is greater than the preferred range, the internal circulation of the volute is aggravated, and the air volume and static pressure are severely reduced. When the value of δ is less than the preferred range, the airflow impact is aggravated, the noise is worsened, and there is also an assembly risk.

[0058] t is the scanning position scaling parameter, t = 0 to 1. When t = 0, it is the scanning start point, and when t = 1, it is the scanning end point. Specifically, segment A0B0 is from A0 to B0, t increases from 0 to 1, and the value of l increases from 1 to 1+s1+δ; segment B0C0 is from B0 to C0, t increases from 0 to 1, and the value of l decreases from 1+s1+δ to 1.

[0059] To demonstrate the effectiveness of this invention in increasing the air volume of duct-type air conditioners, the air volume of different embodiments using the above-described volute structure was compared with that of a conventional volute of the same size under the same operating conditions, as shown in the table below:

[0060]

[0061]

[0062] Among them, since δ is the minimum clearance between the volute tongue and the impeller, a fixed value is generally taken based on the actual assembly deviation during the design process. In all the above embodiments, δ is taken as 8mm. The value of s2 has little impact on the air volume. A fixed value is generally taken based on experience. In all the above embodiments, s2 is taken as 2.5.

[0063] To further demonstrate the effect of this utility model on improving the uniformity of airflow at the volute outlet, the simulated velocity cloud map, velocity vector map, and trace map of the optimal embodiment for improving airflow with the above-mentioned volute structure (Example 5) are compared with those of a conventional volute of the same size. The results and analysis are as follows:

[0064] Figures 7a to 7b To compare the velocity distribution cloud diagrams and velocity vector diagrams of the novel volute structure and the conventional volute structure in the vertical XOY section under the same operating conditions, from... Figures 7a to 7b As can be seen, there is obvious axial flow in the airflow. In conventional volutes, there are obvious vortices on both sides of the volute tongue position, and the airflow impact velocity in the middle area is relatively high. However, the volute structure of this utility model has no obvious vortices on both sides of the corresponding position, and the airflow impact velocity in the middle area is weakened.

[0065] Figures 8a to 8b For the velocity distribution cloud map and trace map of the volute structure of this utility model and the conventional volute structure at the volute exit surface under the same operating conditions, from Figures 8a to 8b As can be seen, the airflow is irregularly spiral-shaped. Conventional volutes have a clear low-speed zone on the right side, and the spiral-shaped airflow at the outlet is turbulent. However, the volute of this utility model does not have a clear low-speed zone, and the spiral-shaped airflow at the outlet is more regular.

[0066] To further demonstrate the noise reduction effect of this patented volute casing in duct-type air supply mode, the noise levels of Examples 1, 5, and 9 were compared with those of a conventional volute casing under an external static pressure of 50 Pa and different air volumes. Specific data are shown in the table below, and the comparison curves are shown in the table below. Figure 9 .

[0067]

[0068]

[0069] Based on the experimental data summarized in the table above and Figure 9 The comparison curves show that, under the same airflow conditions, the noise of the volute structure of this utility model is lower than that of the conventional volute.

[0070] like Figure 1 As shown, this utility model also proposes a centrifugal fan, which is a double-suction centrifugal fan. Specifically, the centrifugal fan includes: a volute 1 and an impeller 2 installed in the inner cavity of the volute 1. The volute 1 adopts the aforementioned volute structure. By symmetrically designing the concave inclination of the volute tongue 14 of the volute 1, the strong impact of the spiral airflow at the volute outlet on the volute tongue is weakened, the uniformity of the airflow distribution in the volute is improved, the air volume of the centrifugal fan is increased, and the wind noise is effectively reduced.

[0071] In some feasible embodiments of this utility model, the air inlet of the volute 1 is provided with a collector 13. The contraction curve of the collector 13 can eliminate inlet turbulence and improve the uniformity of airflow velocity distribution. Specifically, the volute tongue 14 is provided at the air outlet of the volute 1. The volute tongue 14 is connected to the side wall 11 of the volute in the axial direction and to the guide surface 12 of the volute in the radial direction. The collector at the air inlet is connected to the side wall 11 of the volute. The side wall 11, the guide surface 12, the collector 13, and the volute tongue 14 together constitute the inner cavity of the volute. After the impeller 2 rotates and does work, the airflow flows from the air inlets on both sides of the volute through the collector into the inner cavity of the volute. After being concentrated and guided in the inner cavity of the volute, it is blown out from the air outlet of the volute.

[0072] This utility model also proposes an air conditioner using the above-mentioned centrifugal fan. The type of air conditioner can be designed according to specific needs, including but not limited to duct air conditioners.

[0073] It should be noted that the terminology used above is for describing specific embodiments only and is not intended to limit the exemplary embodiments according to this utility model. When the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The order of execution of actions, steps, etc., in the apparatus and methods shown in the specification and drawings can be implemented in any order unless a specific express order is specified, and as long as the output of the preceding process is not used in the subsequent process. Similar sequential terms used for ease of description do not imply that such an order must be followed.

[0074] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0075] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A volute structure, including: A volute, wherein air inlets are provided on two opposite end faces of the volute, and a volute tongue is provided at the air outlet of the volute, characterized in that the volute tongue of the volute has two recesses, the two recesses being symmetrically distributed about the YOZ axis of the volute.

2. The volute structure according to claim 1, characterized in that, The vertical plane XOY passing through the central axis of the volute when it is placed upright is used as the projection plane. The vertical plane XOY is perpendicular to the axis-perpendicular center plane YOZ of the volute. The projection of the recessed part on the vertical plane XOY is a smooth continuous curve A0B0C0.

3. The volute structure according to claim 2, characterized in that, One end of the continuous curve A0B0C0 is connected to the axis perpendicular center plane YOZ, and the other end is connected to the side wall of the volute. The point where the continuous curve A0B0C0 connects to the axis perpendicular center plane YOZ is point A0. The lowest point of the continuous curve A0B0C0 is point B0. The point where the continuous curve A0B0C0 connects to the side wall of the volute is point C0. In the axial direction of the volute, the distance between point A0 and point B0 is L1, and the distance between point B0 and point C0 is L2. The range of L1:L2 is [0.33, 1].

4. The volute structure according to claim 1, characterized in that, The recessed portion includes: an inclined section, a pitted section, and a rounded corner section arranged sequentially along the air outlet direction. The inner arc surface of the volute is a guide surface, and the outer edge of the air outlet is an outlet straight section. The inclined section is tangentially connected to the guide surface and the pitted section, respectively, and the rounded corner section is tangentially connected to the pitted section and the outlet straight section, respectively.

5. The volute structure according to claim 4, characterized in that, The recessed portion is formed by segmented scanning of the mixed line abcd along the axial direction of the volute, and is divided into segments A0B0 and B0C0. The profiles of the inclined segment, the recessed segment, and the rounded corner are respectively arc ab, line segment bc, and arc cd. The radius r of the arc ab is a preset fixed value. The angle θ between the line segment bc and the exit straight line segment is in the range of [10°, 30°]. The characteristic length l of the line segment bc is constrained by a piecewise sine function along the volute axis.

6. The volute structure according to claim 5, characterized in that, The scanning equation for the hybrid line abcd is: A0B0 segment: ; B0C0 segment: ; The radius r of the arc ab is: ； Where r is the feature radius of the arc ab, s1 takes values ​​in the range of [1.5, 2.5], s2 takes values ​​in the range of [2, 3], δ takes values ​​in the range of [6mm, 12mm], and t is the scanning position ratio parameter, t=0~1, t=0 is the scanning start point, and t=1 is the scanning end point.

7. Centrifugal fan, including: The volute and the impeller installed in the inner cavity of the volute, characterized in that the volute adopts the volute structure according to any one of claims 1 to 6.

8. The centrifugal fan according to claim 7, characterized in that, The air inlet of the volute is connected to a collector.

9. An air conditioner, characterized in that, The air conditioner includes the centrifugal fan as described in claim 7 or 8.

10. The air conditioner according to claim 9, characterized in that, The air conditioner is a duct-type air conditioner.

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