Volute structure, centrifugal fan and air conditioner

Abstract

The invention discloses a volute structure, a centrifugal fan and an air conditioner, the volute structure comprises a volute, two opposite end faces of the volute are provided with air inlets, a volute tongue of the volute is provided with two concave parts, and the two concave parts are symmetrically distributed about the axis vertical central plane YOZ of the volute; a vertical plane XOY penetrating through the central axis of the volute when the volute is vertically placed serves as a projection plane, the vertical plane XOY is perpendicular to the axis vertical central plane YOZ of the volute, and the projection of the concave part on the vertical plane XOY is a smooth continuous curve A0B0C0. According to the volute, the volute tongue of the volute is symmetrically and obliquely designed in a concave mode, strong impact of spiral airflow at an outlet of the volute on the volute tongue is weakened, the distribution uniformity of air supply airflow of the volute is improved, the air volume is effectively increased, and air noise is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of centrifugal fans, and in particular to a volute structure, a centrifugal fan and an air conditioner. Background Art

[0002] As air conditioners develop towards miniaturization, low noise, and high static pressure, symmetrical double-suction centrifugal fans, due to their high air pressure characteristics, have become a core aerodynamic component in ducted air conditioning systems. These fans consist of an impeller and a volute. Their specialized inlet flow path creates an uneven airflow distribution within the volute, with high velocity in the center and low velocity at the sides, resulting in a spiral flow pattern along the circumference. This uneven flow pattern causes the volute tongue area to experience periodic airflow impacts, leading to two problems:

[0003] 1. Increased aerodynamic loss - the volute tongue structure does not fit the spiral airflow path, and the continuous collision with the volute tongue increases the turbulent energy dissipation and reduces the fan efficiency;

[0004] 2. Noise and vibration deterioration - the local air flow velocity is too large, causing a strong impact on the volute tongue, and there is a superposition of sound pressure in the axial direction, which leads to noise deterioration.

[0005] To mitigate these issues, most existing technologies focus on optimizing the volute profile. For example, the invention patent with publication number CN112303023A proposes a wavy volute structure, which reconstructs the volute profile by alternating multiple arcs and straight lines, thereby increasing the fit between the airflow path and the volute wall and improving internal flow efficiency. However, this approach has significant limitations. The splicing of multiple curves requires high-precision mold positioning, which increases processing complexity. Furthermore, fixed curvature combinations are difficult to match the dynamic flow changes under different working conditions, and localized backflow still occurs at non-design points.

[0006] Therefore, in order to address the pain point of the existing technology where structural complexity and aerodynamic performance are difficult to coordinate, a low-cost, high-flow-field-adaptability volute improvement solution is urgently needed. Summary of the Invention

[0007] In order to solve the defects of the existing technology such as complex structure and poor aerodynamic performance, the present invention proposes a volute structure, a centrifugal fan and an air conditioner. By performing a symmetrical inward-concave inclined design on the volute tongue of the volute, the strong impact of the spiral airflow at the volute outlet on the volute tongue is weakened, the uniformity of the air flow distribution of the volute is improved, the air volume is effectively increased and the wind noise is reduced.

[0008] The technical solution adopted by the present invention is to design a volute structure, including: a volute, two opposite end faces of the volute are provided with air inlets, the volute tongue is provided with two recessed parts, and the two recessed parts are symmetrically distributed about the axial vertical center plane YOZ of the volute.

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

[0010] Furthermore, one end of the continuous curve A0B0C0 is connected to the vertical center plane YOZ, and the other end is connected to the side wall of the volute. The point where the continuous curve A0B0C0 is connected to the vertical 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 is connected to the side wall of the volute is point C0; wherein, in the axial direction of the volute, the distance between point A0 and point B0 is L1, the distance between point B0 and point C0 is L2, and the value range of L1:L2 is [0.33, 1].

[0011] Furthermore, the recessed portion includes: an inclined section, a pit section and a rounded section arranged in sequence along the air outlet direction, the inner arc surface of the volute is the guide surface, the outer edge of the air outlet is the outlet straight line segment, the inclined section is tangently connected to the guide surface and the pit section respectively, and the rounded section is tangently connected to the pit section and the outlet straight line segment respectively.

[0012] Furthermore, the recessed portion is formed by segmented scanning of the mixed line abcd along the axial direction of the volute, which is divided into the A0B0 segment and the B0C0 segment; the profile lines of the inclined segment, the pit segment and the fillet are the arc line ab, the line segment bc and the arc line cd respectively, the radius r of the arc line ab is a preset fixed value, the value range of the angle θ between the line segment bc and the outlet straight line segment is [10°, 30°], and 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 of the mixed line abcd is:

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

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

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

[0017] r=s2×δ

[0018] Among them, r is the characteristic radius of the arc ab, the value range of s1 is [1.5, 2.5], the value range of s2 is [2, 3], the value range of δ is [6 mm, 12 mm], 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.

[0019] The present invention also provides a centrifugal fan, comprising a volute and an impeller installed in an inner cavity of the volute, wherein the volute adopts the above-mentioned volute structure.

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

[0021] The present invention also provides an air conditioner, comprising the centrifugal fan.

[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 is equipped with two concave parts, which are symmetrically distributed about the axial center plane YOZ of the volute. They can effectively integrate multiple spiral airflows into two relatively regular ones, weaken 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 concave portion includes an inclined section and a pit section, whose cross-sectional profiles are tangent arc lines and straight line segments, respectively. The inclined section staggers the superposition of sound pressure in the axial direction caused by the airflow impact, while the pit section cooperates with the inclined section to buffer the airflow impact and rectify the spiral airflow, thereby optimizing the spiral airflow path.

[0026] 3. The line segment bc of the concave part forms a certain angle with the straight line segment of the outlet. The characteristic length of the line segment bc is constrained by a segmented sine function along the axial direction of the volute. By controlling the change law of this characteristic length, the distribution range of the concave part and the position of the lowest point of the concave part are adjusted to match the optimal path of the airflow impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention is described in detail below with reference to the embodiments and accompanying drawings, in which:

[0028] Figure 1 It is a three-dimensional schematic diagram of the centrifugal fan of the present invention;

[0029] Figure 2 It is a three-dimensional schematic diagram of the volute structure of the present invention;

[0030] Figure 3 Schematic diagram of the air outlet surface of the volute structure of the present invention;

[0031] Figure 4 yes Figure 3 Schematic diagram of the cross section at AA after the impeller is installed;

[0032] Figure 5 Schematic diagram of the concave portion of the volute structure of the present invention;

[0033] Figure 6 yes Figure 4 Partial schematic diagram of point B in the middle;

[0034] Figure 7a It is the velocity distribution cloud diagram and velocity vector diagram of the conventional volute XOY section;

[0035] Figure 7b The velocity distribution cloud diagram and velocity vector diagram of the XOY section of the volute structure of the present invention;

[0036] Figure 8a It is the velocity distribution cloud map and trace map of the conventional volute outlet surface;

[0037] Figure 8b It is the velocity distribution cloud map and trace map of the outlet surface of the volute structure of the present invention;

[0038] Figure 9 This is a comparison chart of the measured noise between the volute structure of the present invention and the conventional volute at different air volumes;

[0039] 1. Volute; 11. Side wall; 12. Guide surface; 121. Outlet straight section; 13. Collector; 14. Volute tongue; 141. Inclined section; 142. Concave section; 143. Rounded corner section; 2. Impeller. DETAILED DESCRIPTION

[0040] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is 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 the present invention and are not intended to limit the present invention.

[0041] like Figure 1 As shown, the volute structure proposed in the present invention is suitable for centrifugal fans, particularly double-suction centrifugal fans. Double-suction centrifugal fans are a special type of centrifugal fan. Their core feature is the symmetrical air inlets on both sides of the impeller 2, allowing air to be drawn in simultaneously from both ends of the impeller 2's axis. After being accelerated by the impeller 2's rotation, air is guided by the volute 1 and discharged through the air outlet.

[0042] Due to the unique airflow path of double-suction centrifugal fans, the airflow velocity within the volute 1 exhibits an uneven axial pattern, with high velocity in the center and low velocity on both sides. The flow along the circumference of the volute 1 exhibits a certain spiral pattern. This spiral airflow strongly impacts the volute tongue 14, severely reducing airflow volume and generating noticeable noise. To address this issue, the volute structure of the present invention achieves high airflow with low noise by improving the shape of the volute tongue.

[0043] like Figure 2 、 3As shown, specifically, the volute structure includes: a volute 1, two opposite end surfaces of the volute 1 are symmetrically provided with air inlets, and the volute tongue 14 of the volute 1 is provided with two recessed parts, the two recessed parts are about the vertical center plane YOZ of the volute 1 (see Figure 4 ) symmetrically distributed. The axial center plane is a reference plane perpendicular to the impeller axis and passing through the volute's geometric center of symmetry. Due to its multiple properties as a structural symmetry axis and airflow interface, it is often used as the fan's spatial coordinate reference.

[0044] This design integrates multiple spiral airflows into two relatively regular ones through symmetrically arranged recessed parts, weakening 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 not only has a simple structure and low processing cost, but also effectively increases the air volume and reduces wind noise.

[0045] like Figure 3 As shown, when the volute 1 is placed vertically, the vertical plane XOY (see Figure 3 ) is used as the projection surface, the vertical plane XOY is perpendicular to the axial center plane YOZ of the volute 1, and the projection of the recessed portion on the vertical plane XOY is a smooth continuous curve A0B0C0. The smooth curve allows the pressure gradient to change continuously when the airflow flows along the wall of the recessed portion, thereby avoiding flow separation and generating vortices. In addition, the curvature of the smooth curve is relatively gentle, and there will be no discrete noise caused by sudden changes in curvature, thereby playing a noise suppression role.

[0046] In some feasible embodiments of the present invention, one end of the continuous curve A0B0C0 is connected to the vertical 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 is connected to the vertical 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 is connected to the side wall of the volute is point C0. Figure 3 In the Y-axis direction shown in FIG, the height of point B0 is smaller than that of point A0 and point C0. In the axial direction of the volute 1 ( Figure 3 In the X-axis direction (shown in the figure), the distance between points A0 and B0 is L1, and the distance between points B0 and C0 is L2. The preferred range of L1:L2 is [0.33, 1]. By controlling this ratio, the relative position of point B0 (the lowest point) in the axial direction is controlled to match the optimal position of airflow impact. When the L1:L2 ratio is less than the preferred range, the A0B0 segment is too short, which can easily cause abnormal sound quality. When the L1:L2 ratio is greater than the preferred range, the local vortices on both sides cannot be effectively controlled.

[0047] like Figure 5As shown, in a preferred embodiment of the present invention, the recessed portion includes: an inclined section 141, a concave section 142, and a rounded section 143, which are arranged in sequence along the air outlet direction. The inner arc surface of the volute 1 is the guide surface 12, and the 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 concave section 142, respectively. The rounded section 143 is tangentially connected to the concave section 142 and the outlet straight section 121, respectively. This design staggers the sound pressure superposition of the airflow impact in the axial direction by the inclined section, and the concave section 142 cooperates with the inclined section 141 to buffer the airflow impact and rectify the spiral airflow, thereby optimizing the spiral airflow path.

[0048] like Figure 6 As shown, in some feasible embodiments of the present invention, the concave portion is formed by segmented scanning of the mixed line abcd along the axial direction of the volute, and is divided into the A0B0 segment and the B0C0 segment. The profile lines of the inclined segment, the pit segment and the fillet are the arc line ab, the line segment bc and the arc line cd respectively. The radius r of the arc line ab is a preset fixed value. The preferred value range of the angle θ between the line segment bc and the outlet straight line segment is [10°, 30°], which is used to match the angle of the airflow impact. When the value of the angle θ is greater than the preferred value range, the circulation in the volute is intensified. When the value of the angle θ is less than the preferred value range, the optimal path of the airflow impact cannot be matched. The characteristic length l of the line segment bc is constrained by a segmented sine function along the axial direction of the volute. By controlling the change law of the characteristic length, the distribution range of the concave portion and the position of the lowest point of the concave are adjusted to match the optimal path of the airflow impact.

[0049] In a preferred embodiment of the present invention, the scanning equation of the mixing line abcd is:

[0050] A0B0 segment: l = 1 + s1 × δ × sin (90 × t)

[0051] B0C0 segment: l = 1 + s1 × δ × sin (90 + 90 × t)

[0052] The radius r of the arc ab is:

[0053] r=s2×δ

[0054] Where r is the characteristic radius of the arc ab;

[0055] The preferred value range of s1 is [1.5, 2.5], and the preferred value range of s2 is [2, 3]. The functions of s1 and s2 are to control the distribution range of the concave part and the vertical direction of the lowest point of the concave part ( Figure 2When the values of s1 and s2 are greater than the preferred value range, the distribution range is too large and the lowest point is too low, which cannot effectively suppress the backflow of the airflow. When the values of s1 and s2 are less than the preferred value range, the distribution range is too small and the lowest point is too high, which cannot effectively weaken the impact of the airflow.

[0056] δ is the minimum gap between the volute tongue and the impeller. The optimal value 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 optimal value range, the circulation in the volute is intensified, and the air volume and static pressure are severely attenuated. When the value of δ is less than the optimal value range, the airflow impact is aggravated, the noise is worsened, and there is also an assembly risk.

[0057] 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; specifically, the A0B0 segment is along A0 to B0, t increases from 0 to 1, and the value of l increases from 1 to 1+s1+δ; the B0C0 segment is along B0 to C0, t increases from 0 to 1, and the value of l decreases from 1+s1+δ to 1.

[0058] In order to demonstrate the effect of the present invention in increasing the air volume of a ducted air conditioner, the air volume of different embodiments using the above-mentioned volute structure is compared with that of a conventional volute of the same size under the same operating conditions, as shown in the following table:

[0059]

[0060]

[0061] Among them, since δ is the minimum gap between the volute tongue and the impeller, a fixed value is generally taken according to the actual assembly deviation during the design process. In all the above embodiments, δ is taken as 8 mm. The value of s2 has little effect on the air volume. Generally, a fixed value is taken according to experience. In all the above embodiments, s2 is taken as 2.5.

[0062] To further demonstrate the effect of the present invention on improving the uniformity of air supply at the volute outlet, the simulated velocity cloud diagram, velocity vector diagram, and trajectory diagram of the best embodiment for increasing air volume with the above-mentioned volute structure (above-mentioned embodiment 5) are compared with those of a conventional volute of the same size. The results and analysis are as follows:

[0063] Figures 7a to 7b The velocity distribution cloud diagram and velocity vector diagram of the volute structure of the present invention and the conventional volute structure in the vertical plane XOY section under the same operating conditions are shown in the figure. Figures 7a to 7b It can be seen from the figure that there is obvious axial flow in the airflow. In the conventional volute at the volute tongue position, there are obvious vortices in the two side areas, and the airflow impact velocity in the middle area is relatively high. However, in the volute structure of the present invention, there is no obvious vortex in the two side areas at the corresponding position, and the airflow impact velocity in the middle area is weakened.

[0064] Figures 8a to 8b The velocity distribution cloud and trace diagram of the volute structure of the present invention and the conventional volute structure at the volute outlet surface under the same operating conditions are shown in the figure. Figures 8a to 8b It can be seen from the figure that the airflow is irregularly spiral. There is an obvious low-speed area on the right side of the conventional volute, and the spiral airflow at the outlet is turbulent. However, there is no obvious low-speed area in the volute of the present invention, and the spiral airflow at the outlet is relatively regular.

[0065] In order to further demonstrate the noise reduction effect of the volute of the present invention in the state of air supply of the duct type complete machine, the noise of Example 1, Example 5, Example 9 and the conventional volute under the conditions of 50pa external static pressure and different air volume are compared. The specific data are shown in the table below, and the comparison curve is shown in Figure 9 .

[0066]

[0067]

[0068] According to the experimental data in the above table and Figure 9 From the comparison curve, it can be found that under the same air volume working condition, the noise of the volute structure of the present invention is lower than that of the conventional volute.

[0069] like Figure 1 As shown, the present invention 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 above-mentioned volute structure. By designing the volute tongue 14 of the volute 1 symmetrically with an inwardly concave tilt, the strong impact of the spiral airflow at the volute outlet on the volute tongue is weakened, the uniformity of the airflow distribution of the volute is improved, the air volume of the centrifugal fan is increased, and the wind noise is effectively reduced.

[0070] In some feasible embodiments of the present invention, the air inlet of the volute 1 is provided with a collector 13. The contraction curve of the collector 13 can eliminate the inlet turbulence and improve the uniformity of the air velocity distribution of the inlet. 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 volute cavity. 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 volute cavity, and is concentrated and guided in the volute cavity before being blown out from the volute outlet.

[0071] The present invention also proposes an air conditioner using the centrifugal fan. The type of air conditioner can be designed according to specific needs, including but not limited to a duct-type air conditioner.

[0072] It should be noted that the terms used above are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. When the terms "comprise" and / or "include" 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 devices and methods shown in the specification and the drawings can be implemented in any order as long as there is no special explicit limitation on the order and as long as the output of the previous processing is not used in the subsequent processing. Similar sequential terms used for the convenience of description do not mean that they must be implemented in such an order.

[0073] Techniques, methods, and apparatus known to those of ordinary skill in the relevant 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 limiting. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Volute structure, including: The volute has two opposite end faces provided with air inlets, and is characterized in that the volute tongue is provided with two recessed portions, and the two recessed portions are symmetrically distributed about the axial vertical center plane YOZ of the volute.

2. The volute structure according to claim 1, characterized in that: A vertical plane XOY passing through the central axis of the volute when the volute is placed upright is used as a projection plane. The vertical plane XOY is perpendicular to the axial center plane YOZ of the volute, and the projection of the recessed portion 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 vertical 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 vertical 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, the distance between point B0 and point C0 is L2, and the value 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 pit section and a rounded section arranged in sequence 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 line segment; the inclined section is tangently connected to the guide surface and the pit section respectively; and the rounded section is tangently connected to the pit section and the outlet straight line segment respectively.

5. The volute structure according to claim 4, characterized in that: The concave portion is formed by segmented scanning of the mixing line abcd along the axial direction of the volute, and is divided into segments A0B0 and B0C0; The profiles of the inclined section, the concave section, and the rounded corners are arc line ab, line segment bc, and arc line cd, respectively. The radius r of the arc line ab is a preset fixed value. The angle θ between the line segment bc and the outlet straight line segment has a value 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.

6. The volute structure according to claim 5, characterized in that: The scanning equation of the mixed line abcd is: A0B0 segment: l = 1 + s1 × δ × sin (90 × t) B0C0 segment: l = 1 + s1 × δ × sin (90 + 90 × t); The radius r of the arc line ab is: r=s2×δ Among them, r is the characteristic radius of the arc ab, the value range of s1 is [1.5, 2.5], the value range of s2 is [2, 3], the value range of δ is [6 mm, 12 mm], 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: A volute and an impeller installed in an 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 with a flow collector.

9. An air conditioner, characterized in that The air conditioner includes the centrifugal fan according to 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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