Centrifugal movable impeller and centrifugal axial flow combined fan comprising same

Abstract

The utility model provides a centrifugal type movable impeller and a centrifugal axial flow combined fan comprising the same, the centrifugal type movable impeller is arranged between an impeller front cover plate and an impeller rear cover plate, the centrifugal type movable impeller comprises a plurality of blades, and each blade comprises a suction surface and a pressure surface. The suction surface is provided with a first trailing edge point, the pressure surface is provided with a second trailing edge point, the first trailing edge point and the second trailing edge point form an outlet of the blade through a connecting line, the connecting line of the first trailing edge point and the second trailing edge point is smaller than the thickness of the blade, the second trailing edge point serves as a vertex, and the second trailing edge point serves as the vertex. A first included angle is formed between the first tail edge point and the pressure face and between the second tail edge point and the pressure face, and the value range of the first included angle is smaller than or equal to 100 degrees. By limiting the size of the first included angle, the suction effect of the suction surface relative to the pressure surface is reduced, and then the separation vortex flowing out of the blade outlet is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to centrifugal impeller technical field, especially centrifugal impeller and centrifugal axial flow combined fan containing it. BACKGROUND

[0002] The centrifugal-axial flow combined fan is widely used in the current range hood industry. The centrifugal-axial flow fan, that is, the fan using the centrifugal impeller to increase pressure and the axial flow static blade grid to recover kinetic energy, for such a fan, in order to ensure that the riveted impeller has sufficient strength and does not deform or even disintegrate at high speed, the blade must have considerable thickness. In a typical case, the blade thickness is more than 1.5 mm. In addition, in order to make the impeller outflow more uniform, the number of blades is also designed to be larger in order to expect to weaken the abnormal sound (commonly known as "blade frequency abnormal sound" in the industry, that is, the abnormal noise with a frequency equal to the blade passing frequency) when the impeller tail sweeps the static blade grid. Therefore, the blade body blocks a considerable part of the flow path in the impeller. The adverse consequences include but are not limited to: the thick blade tail causes large wake, resulting in loss and thus reducing the efficiency of the fan; the thick dynamic blade tail separates the suction surface and the pressure surface of the blade, so that they need to flow through a longer path to mix with each other, thus increasing the flow non-uniformity at the outlet of the dynamic blade. This state of flow non-uniformity cannot be improved by increasing the number of blades. In fact, the more the number of blades, the greater the proportion of the blade thickness in the flow passage, and the higher the flow velocity in the main flow area at the outlet of the blade. Therefore, increasing the number of blades may actually lead to an increase in flow non-uniformity at the outlet of the dynamic blade, ultimately resulting in an increase in blade frequency abnormal sound. SUMMARY

[0003] The utility model wants to solve the technical problem that the blade tail is thick, the flow at the outlet of the dynamic blade is non-uniform, and the efficiency of the fan is poor in the prior art, and provides a centrifugal dynamic blade and a centrifugal axial flow combined fan containing the same.

[0004] The utility model solves the above technical problems by the following technical scheme:

[0005] A centrifugal dynamic blade is arranged between a front cover plate and a rear cover plate of an impeller, and comprises a plurality of blades, each blade comprising a suction surface and a pressure surface, the suction surface having a first tail edge point, the pressure surface having a second tail edge point, the first tail edge point and the second tail edge point forming an outlet of the blade by a connecting line, the connecting line between the first tail edge point and the second tail edge point being smaller than the thickness of the blade, the first tail edge point, the second tail edge point and the pressure surface forming a first included angle with the second tail edge point as a vertex, the first included angle being less than or equal to 100°.

[0006] In the present application, the blade outlet formed by connecting the first and second trailing edge points is set to be less than the thickness of the blade, so as to thin the trailing edge of the blade, increase the effective flow area of the impeller outlet, and improve the performance of the fan containing the centrifugal rotor. In addition, by reducing the size of the line connecting the first and second trailing edge points, the flow fields of the suction surface and the pressure surface are closer and mix earlier, thereby reducing the circumferential unevenness. By limiting the size of the first included angle, the suction effect of the suction surface on the pressure surface is reduced, and the separation vortex from the blade outlet is reduced.

[0007] Preferably, the ratio of the line connecting the first and second trailing edge points to the thickness of the blade is less than or equal to 0.7.

[0008] In the present application, by limiting the size of the line connecting the first and second trailing edge points in a proportional manner, the effective thinning of the blade outlet is ensured.

[0009] Preferably, the pressure surface further has a fourth trailing edge point, the suction surface further has a third trailing edge point, the distance between the fourth trailing edge point and the third trailing edge point is the thickness of the blade, and the distance between the fourth trailing edge point and the second trailing edge point is greater than or equal to the thickness of the blade.

[0010] In the present application, by limiting the distance between the fourth trailing edge point and the second trailing edge point, the size of the thinning area of the blade outlet is limited, and the excessive thinning of the area affecting the efficiency of the impeller is avoided.

[0011] Preferably, the first trailing edge point is connected to the third trailing edge point by a contour line, and the first trailing edge point is connected to the suction surface by the contour line.

[0012] In the present application, by connecting the first trailing edge point and the third trailing edge point by a contour line to form a thinning area of the blade outlet, the flow fields of the suction surface and the pressure surface are closer and mix earlier, thereby reducing the circumferential unevenness.

[0013] Preferably, the first trailing edge point is the vertex, the second trailing edge point, the first trailing edge point, and the third trailing edge point form a second included angle, and the value of the second included angle is less than or equal to 135°.

[0014] In the present application, by the above arrangement, the airflow is more uniform when passing through.

[0015] Preferably, the contour line is a straight line or an arc contour line.

[0016] In the present scheme, the first and third trailing edge points are obtained by cutting the blade outlet in a straight line direction, which can be completed by one machining process, and is more convenient. When cutting the blade outlet in an arc-shaped direction, polishing is needed to obtain the arc-shaped profile, which is beneficial to improve the working efficiency of the impeller, and the noise during the working of the impeller can be reduced compared with cutting in a straight line direction.

[0017] Preferably, a first polishing angle is arranged at the third trailing edge point, and the curvature radius of the first polishing angle is greater than or equal to the thickness of the blade.

[0018] In the present scheme, the above arrangement is used to make the airflow more smooth and uniform when flowing through the place.

[0019] Preferably, a second polishing angle is arranged at the first trailing edge point, and the curvature radius of the second polishing angle is greater than or equal to 0.2 times the thickness of the blade.

[0020] In the present scheme, the above arrangement is used to make the airflow more smooth and uniform when flowing through the place.

[0021] Preferably, when the second polishing angle is arranged at the first trailing edge point, the size of the line connecting the first trailing edge point and the second trailing edge point is less than or equal to 0.1 times the thickness of the blade.

[0022] In the present scheme, the above arrangement is used to limit the size of the blade outlet.

[0023] A centrifugal-axial combined fan, comprising the centrifugal moving impeller as described above, and further comprising an axial static blade row, wherein the centrifugal moving impeller is coaxially arranged with the axial static blade row.

[0024] In the present scheme, the centrifugal-axial combined fan comprises the above centrifugal moving impeller, so as to improve the effective flow area of the impeller outlet by improving the blade structure, and improve the performance of the fan comprising the centrifugal moving impeller. In addition, by reducing the size of the line connecting the first trailing edge point and the second trailing edge point, the flow fields of the suction surface and the pressure surface of the blade are closer and mixed earlier, so as to reduce the circumferential unevenness, and the cost is low and the working efficiency of the impeller is ensured, so that the centrifugal-axial combined fan can meet the user's demand.

[0025] The positive progress effect of the utility model lies in: the utility model forms the blade outlet by connecting the first tail edge point and the second tail edge point, and sets the blade outlet to be smaller than the thickness of the blade, so as to thin the blade tail edge, increase the effective flow area of the impeller outlet, and improve the performance of the fan containing the centrifugal moving blade wheel. In addition, by reducing the size of the line connecting the first tail edge point and the second tail edge point, the flow field of the suction surface and the pressure surface of the blade is closer and mixes earlier, thereby reducing the uneven degree in the circumferential direction. By limiting the size of the first included angle, the suction effect of the suction surface on the pressure surface is reduced, and then the separation vortex flowing out of the blade outlet is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a structure schematic view of the centrifugal axial-flow combined fan of a preferred embodiment of the utility model.

[0027] Figure 2 It is a schematic view of the blade outlet of a preferred embodiment of the utility model.

[0028] Figure 3 It is a structure schematic view of the blade of a preferred embodiment of the utility model.

[0029] Figure 4 It is a structure schematic view of the blade with straight line of a preferred embodiment of the utility model.

[0030] Figure 5 It is a structure schematic view of the blade with arc-shaped line of a preferred embodiment of the utility model.

[0031] Figure 6 It is a comparison view of the blade outlet flow angle of a preferred embodiment of the utility model.

[0032] Figure 7 It is a comparison view of the blade outlet performance of a preferred embodiment of the utility model.

[0033] BRIEF DESCRIPTION OF DRAWINGS:

[0034] Impeller front cover plate 10

[0035] Impeller rear cover plate 20

[0036] Blade 30

[0037] Suction surface 31

[0038] Pressure surface 32

[0039] First tail edge point 1

[0040] Second tail edge point 2

[0041] First included angle θ

[0042] Third tail edge point 3

[0043] Fourth trailing edge point 4

[0044] Second included angle a DETAILED DESCRIPTION

[0045] The utility model will be described in detail below with a preferred embodiment and in combination with the drawings.

[0046] The embodiment provides a centrifugal impeller, and the specific structure is shown in Figure 1 、 Figure 2 and Figure 3 The centrifugal impeller is arranged between a front cover plate 10 and a rear cover plate 20 of the impeller, and the centrifugal impeller comprises a plurality of blades 30, the blade 30 comprises a suction surface 31 and a pressure surface 32, the first trailing edge point 1 is arranged on the suction surface 31, the second trailing edge point 2 is arranged on the pressure surface 32, the first trailing edge point 1 and the second trailing edge point 2 form the outlet of the blade 30 through a connecting line, the connecting line between the first trailing edge point 1 and the second trailing edge point 2 is smaller than the thickness of the blade 30, the first trailing edge point 1, the second trailing edge point 2 and the pressure surface 32 form a first included angle a with the pressure surface 32 as a vertex, and the value range of the first included angle a is less than or equal to 100°.

[0047] Specifically, the suction surface 31 and the pressure surface 32 are arranged in parallel, and the distance between the suction surface 31 and the pressure surface 32 is the thickness of the blade 30. The outlet of the blade 30 is provided with the first trailing edge point 1 and the second trailing edge point 2, the first trailing edge point 1 is arranged on the suction surface 31, the second trailing edge point 2 is arranged on the pressure surface 32, the first trailing edge point 1 and the second trailing edge point 2 form the outlet of the blade 30 through a connecting line, and the size of the connecting line is smaller than the thickness of the blade 30, that is, the size of the outlet of the blade 30 is smaller than the thickness of the blade 30, so that the structure of the suction surface 31 and the pressure surface 32 is close to each other at the outlet, that is, the flow fields of the suction surface 31 and the pressure surface 32 are closer, compared with the thickness of the blade 30 to the outlet of the blade 30, the gas flow can be mixed earlier, thereby reducing the circumferential unevenness.

[0048] In addition, the outlet of the blade 30 formed by connecting the first trailing edge point 1 and the second trailing edge point 2 is arranged to be smaller than the thickness of the blade 30, so as to thin the trailing edge of the blade and increase the effective flow area of the outlet of the impeller, so that the performance of the fan comprising the centrifugal impeller is improved, as shown in Figure 7 The fan comprising the centrifugal impeller reduces the required rotating speed by 0.5% under the same pressure rise and flow rate, and the efficiency is improved.

[0049] As shown in Figure 6 The embodiment limits the size of the first included angle a, compared with greater than 100°, the size of the outlet of the blade 30 is reduced, the gas flow is branched and mixed, the suction of the suction surface 31 to the pressure surface 32 is reduced, and then the separation vortex flowing out of the outlet of the blade 30 is reduced.

[0050] Preferably, the first included angle θ is less than or equal to 90°. By further reducing the size of the first included angle θ, the mixing effect of the split flow is improved, and the effect of the separation vortex is reduced.

[0051] In the present embodiment, the ratio of the line connecting the first trailing edge point 1 and the second trailing edge point 2 to the thickness of the blade 30 is less than or equal to 0.7. By proportionally limiting the size of the line connecting the first trailing edge point 1 and the second trailing edge point 2, the effective thinning of the outlet of the blade 30 is ensured.

[0052] Preferably, the ratio of the line connecting the first trailing edge point 1 and the second trailing edge point 2 to the thickness of the blade 30 is less than or equal to 0.5, so that the size of the outlet of the blade 30 is further thinned, and the mixing effect of the blade 30 on the airflow is improved.

[0053] Further, in the present embodiment, the pressure surface 32 further has a fourth trailing edge point 4, and the suction surface 31 further has a third trailing edge point 3, the distance between the fourth trailing edge point 4 and the third trailing edge point 3 is the thickness of the blade 30, and the distance between the fourth trailing edge point 4 and the second trailing edge point 2 is greater than or equal to the thickness of the blade 30.

[0054] Specifically, the fourth trailing edge point 4 is arranged close to the second trailing edge point 2, the distance between the fourth trailing edge point 4 and the third trailing edge point 3 is the thickness of the blade 30, that is, the third trailing edge point 3 and the fourth trailing edge point 4 are oppositely arranged, and the line connecting the two is perpendicular to the suction surface 31 or the pressure surface 32, so as to achieve the distance between the fourth trailing edge point 4 and the third trailing edge point 3 being the thickness of the blade 30. On this basis, by limiting the distance between the fourth trailing edge point 4 and the second trailing edge point 2, the size of the thinned region of the outlet of the blade 30 is limited, so as to avoid the thinned region being too large and affecting the working efficiency of the impeller. It should be noted that, in the present embodiment, the second trailing edge point 2 and the fourth trailing edge point 4 are located on the same straight line, and the thinned region of the outlet of the blade 30 is located on the suction surface 31.

[0055] Preferably, the distance between the fourth trailing edge point 4 and the second trailing edge point 2 is greater than or equal to 1.5 times the thickness of the blade 30. By increasing the distance between the fourth trailing edge point 4 and the second trailing edge point 2, the thinned region of the blade 30 is correspondingly increased, and the mixing effect of the blade 30 on the airflow is improved.

[0056] In the present embodiment, the first trailing edge point 1 and the third trailing edge point 3 are connected by a contour line, and the first trailing edge point 1 is connected to the suction surface 31 by a contour line.

[0057] Specifically, the line connecting the first trailing edge point 1 and the second trailing edge point 2 forms the blade 30 outlet, and the third trailing edge point 3 connects the blade 30 outlet and the suction surface 31 through a curve line to form a closed structure. It can be understood that connecting the first trailing edge point 1 and the third trailing edge point 3 through a curve line to form a blade 30 outlet thinning area is thinner than the thickness of the blade 30 itself, so that the flow fields of the suction surface 31 and the pressure surface 32 are closer and mix earlier, thereby reducing the circumferential unevenness.

[0058] In the embodiment, the first trailing edge point 1 is the vertex, the second trailing edge point 2, the first trailing edge point 1 and the third trailing edge point 3 form a second included angle α, and the value of the second included angle α is less than or equal to 135°. By limiting the size of the second included angle α, compared with greater than 135°, the size of the blade 30 outlet is increased, which not only ensures the work efficiency of the blade 30 outlet, but also makes the airflow more uniform when passing through the blade 30 outlet.

[0059] Preferably, the value of the second included angle α is less than or equal to 120°. By reducing the value of the second included angle α, the size of the blade 30 outlet is further reduced, and the mixing effect of the blade 30 is improved.

[0060] As shown in Figure 4 In the embodiment, the curve line is a straight line.

[0061] Specifically, the blade 30 outlet is processed by chamfering or grinding to form a thinning area, which improves the performance of the blade 30. At the same time, the blade 30 outlet is cut along the straight line direction to obtain the first trailing edge point 1 and the third trailing edge point 3, which can be completed by one-time processing, which is more convenient.

[0062] Preferably, as shown in Figure 5 The curve line is an arc curve line. Compared with the straight line, the arc curve line is polished after cutting. Taking the first trailing edge point 1 as an example, a sharp included angle is formed between the first trailing edge point 1 and the curve line after cutting to obtain the arc curve line. Compared with the straight line, the arc curve line is smoother at the first trailing edge point 1 and the third trailing edge point 3, which is beneficial to improve the working efficiency of the impeller, and the noise during the working of the impeller can be correspondingly reduced compared with cutting along the straight line direction.

[0063] In the embodiment, a first polishing angle is arranged at the third trailing edge point 3, and the curvature radius of the first polishing angle is greater than or equal to the thickness of the blade 30.

[0064] Specifically, the first polishing angle between the profile line and the suction surface 31 is formed by polishing, and the first polishing angle is a circular arc. Compared with a sharp angle, the circular arc makes the airflow smoother and less likely to separate when passing through the circular arc. Therefore, the airflow mixed with the pressure surface 32 is more uniform. It can be understood that the curvature radius is the radius of the circular arc, which is a prior art and will not be described in detail here.

[0065] Preferably, the curvature radius of the first polishing angle is greater than or equal to 3 times the thickness of the blade 30. By further reducing the range of the curvature radius, the circular arc corresponding to the first polishing angle is more gentle than the curvature radius of the first polishing angle, which is greater than or equal to the thickness of the blade 30, i.e., 1 times the thickness of the blade 30, so that the airflow passing through the circular arc is smoother and more uniform.

[0066] In the present embodiment, the second polishing angle is provided at the first trailing edge point 1, and the curvature radius of the second polishing angle is greater than or equal to 0.2 times the thickness of the blade 30. By limiting the curvature radius of the second polishing angle, the airflow passing through the second polishing angle is smoother and more uniform. It can be understood that the first polishing angle and the second polishing angle cooperate with each other to make the airflow on the suction surface 31 flow to the outlet and mix with the airflow on the pressure surface 32 more quickly and smoothly, thereby improving the uniformity of the airflow mixed by the blade 30.

[0067] In the present embodiment, when the second polishing angle is provided at the first trailing edge point 1, the size of the line connecting the first trailing edge point 1 and the second trailing edge point 2 is less than or equal to 0.1 times the thickness of the blade 30. By limiting the size of the line connecting the first trailing edge point 1 and the second trailing edge point 2 after polishing, airflow separation at this point is avoided.

[0068] The present embodiment also provides a centrifugal-axial combined fan, which comprises the centrifugal moving impeller described above. The centrifugal-axial combined fan further comprises an axial static blade row, and the centrifugal moving impeller is coaxially arranged with the axial static blade row.

[0069] Specifically, the centrifugal-axial combined fan comprises the centrifugal moving impeller described above to improve the effective flow area of the impeller outlet by the blade 30, so that the performance of the fan comprising the centrifugal moving impeller is improved. In addition, by reducing the size of the line connecting the first trailing edge point 1 and the second trailing edge point 2, the flow fields of the suction surface 31 and the pressure surface 32 are closer to each other and mix with each other earlier, thereby reducing the degree of circumferential unevenness, reducing the cost and ensuring the working efficiency of the impeller, so that the centrifugal-axial combined fan can meet the user's demand.

[0070] Although the specific embodiments of the present application are described above, those skilled in the art should understand that this is only an example, the protection scope of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present application, but these changes and modifications all fall within the protection scope of the present application.

Claims

1. A centrifugal impeller disposed between an impeller front shroud and an impeller back shroud, the centrifugal impeller comprising a plurality of blades, the blades including a suction surface and a pressure surface, wherein, The suction surface has a first trailing edge point, the pressure surface has a second trailing edge point, the first trailing edge point and the second trailing edge point form an outlet of the blade through a connecting line, the connecting line of the first trailing edge point and the second trailing edge point is smaller than the thickness of the blade, the first trailing edge point, the second trailing edge point and the pressure surface form a first included angle with the second trailing edge point as a vertex, the first included angle is less than or equal to 100°.

2. The centrifugal impeller of claim 1, wherein The connecting line of the first trailing edge point and the second trailing edge point is less than or equal to 0.7 times the thickness of the blade.

3. The centrifugal impeller of claim 1 wherein, The pressure surface further has a fourth trailing edge point, the suction surface further has a third trailing edge point, the distance between the fourth trailing edge point and the third trailing edge point is the thickness of the blade, the distance between the fourth trailing edge point and the second trailing edge point is greater than or equal to the thickness of the blade.

4. The centrifugal impeller of claim 3 wherein, The first trailing edge point is connected to the suction surface through a contour line.

5. The centrifugal impeller of claim 4 wherein, The second trailing edge point, the first trailing edge point and the third trailing edge point form a second included angle with the first trailing edge point as a vertex, the second included angle is less than or equal to 135°.

6. The centrifugal impeller of claim 4 wherein, The contour line is a straight line or an arc-shaped contour line.

7. The centrifugal impeller of claim 6 wherein, The third trailing edge point is provided with a first polishing corner, and the curvature radius of the first polishing corner is greater than or equal to the thickness of the blade.

8. The centrifugal impeller of claim 7, wherein The first trailing edge point is provided with a second polishing corner, and the curvature radius of the second polishing corner is greater than or equal to 0.2 times the thickness of the blade.

9. The centrifugal impeller of claim 8 wherein, When the first trailing edge point is provided with a second polishing corner, the size of the connecting line of the first trailing edge point and the second trailing edge point is less than or equal to 0.1 times the thickness of the blade.

10. A centrifugal mixed flow fan characterized by The centrifugal-axial combined fan comprises the centrifugal impeller according to any one of claims 1-9, and further comprises an axial static blade row, and the centrifugal impeller and the axial static blade row are coaxially arranged.

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