US20200370563A1

US20200370563A1 - Centrifugal heat dissipation fan

Info

Publication number: US20200370563A1
Application number: US16/858,756
Authority: US
Inventors: Tsung-Ting Chen; Wen-Neng Liao; Cheng-Wen Hsieh; Kuang-Hua Lin; Wei-Chin Chen; Chun-Chieh Wang
Original assignee: Acer Inc
Current assignee: Acer Inc
Priority date: 2019-05-24
Filing date: 2020-04-27
Publication date: 2020-11-26
Also published as: CN111980966B; TWI710706B; TW202043628A; CN111980966A

Abstract

A centrifugal heat dissipation fan including a housing and an impeller is provided. The housing has at least one inlet and at least one outlet. The impeller is disposed in the housing and rotates about an axis. The inlet is located in an axial direction of the axis and corresponds to the impeller. The outlet is located in a radial direction relative to the axis. The inlet is divided into a compression section and a release section in the rotation direction of the impeller, and the compression section has a uniform first radial dimension relative to the axis. The release section has an extended second radial dimension relative to the axis, and the second radial dimension is greater than the first radial dimension.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 108118049, filed on May 24, 2019. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND

Technical Field

The disclosure relates to a fan. More particularly, the disclosure relates to a centrifugal heat dissipation fan.

Description of Related Art

In the current trend, electronic apparatuses (e.g., notebook computers or tablet computers) are gradually designed to be light and thin, and as such, heat dissipation fans installed in the internal space of the electronic apparatuses are required to be miniaturized as the internal space is limited. Since the space is limited, airflow of the heat dissipation fans may not smoothly enter or exit the heat dissipation fans, so that heat dissipation efficiency of the fans is thus affected.
Taking a centrifugal heat dissipation fan for example, the flowing path needs to be designed to be scroll-like in a gradually extending manner, so that sufficient pressure differences are generated when the working fluid flows in or out of the fan. In this way, the working fluid enters the fan in the axial direction and is discharged from the fan in the radial direction through changes of such pressure differences. Nevertheless, through such design, at the location where the flowing path gradually expands, since the working fluid turns (from the axial direction to the radial direction) at a high speed, noise is easily generated.
Therefore, how to change the related structure of the existing centrifugal heat dissipation fans so as to address the noise problem is an important issue in this field.

SUMMARY

The disclosure provides a centrifugal heat dissipation fan in which a compression section and a release section of different dimensions are formed at an inlet, so that a trajectory of a working fluid is accordingly improved, and less noise is thus generated.
A centrifugal heat dissipation fan provided by an embodiment of the disclosure includes a housing and an impeller. The housing has at least one inlet and at least one outlet. The impeller is disposed in the housing and rotates about an axis. The inlet is located in an axial direction of the axis and corresponds to the impeller. The outlet is located in a radial direction relative to the axis. The inlet is divided into a compression section and a release section in the rotation direction of the impeller, and the compression section has a uniform first radial dimension relative to the axis. The release section has an extended second radial dimension relative to the axis, and the second radial dimension is greater than the first radial dimension.
In view of the above, the compression section and the release section having different dimensions are formed at the inlet of the centrifugal heat dissipation fan. The compression section has the uniform first radial dimension with respect to the rotation axis of the impeller, the release section has the extended second radial dimension with respect to the rotation axis of the impeller, and the second radial dimension is greater than the first radial dimension. In this way, when entering the housing from the release section, the working fluid is directly pushed towards the outlet by the airflow in the housing without flowing through the blade area of the impeller. Therefore, turning of the trajectory of the working fluid is effectively reduced, and the noise generated is accordingly reduced.
To make the aforementioned more comprehensible, several embodiments accompanied with drawings are described in detail as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.

FIG. 1A is a three-dimensional view of a centrifugal heat dissipation fan according to an embodiment of the disclosure.

FIG. 1B is an exploded view of the centrifugal heat dissipation fan of FIG. 1A.

FIG. 1C is a top view of the centrifugal heat dissipation fan of FIG. 1A.

FIG. 2 is a schematic view of a flow field in a housing of the centrifugal heat dissipation fan.

FIG. 3 and FIG. 4 are top views of the centrifugal heat dissipation fan according to different embodiments of the disclosure.

FIG. 5A is a three-dimensional view of a centrifugal heat dissipation fan according to another embodiment of the disclosure.

FIG. 5B is an exploded view of the centrifugal heat dissipation fan of FIG. 5A.

FIG. 5C is a top view of the centrifugal heat dissipation fan of FIG. 5A.

FIG. 6A and FIG. 6B are comparison diagrams of measurement of sound quality of the centrifugal heat dissipation fan.

FIG. 7 and FIG. 8 are top views of the centrifugal heat dissipation fan according to different embodiments of the disclosure.

FIG. 9 is a schematic view of a flow field in the housing of the centrifugal heat dissipation fan.

FIG. 10 to FIG. 12 are top views of the centrifugal heat dissipation fan according to different embodiments of the disclosure.

DESCRIPTION OF THE EMBODIMENTS

FIG. 1A is a three-dimensional view of a centrifugal heat dissipation fan according to an embodiment of the disclosure. FIG. 1B is an exploded view of the centrifugal heat dissipation fan of FIG. 1A. FIG. 1C is a top view of the centrifugal heat dissipation fan of FIG. 1A. With reference to FIG. 1A to FIG. 1C together, in this embodiment, a centrifugal heat dissipation fan 100 includes a housing 110 and an impeller 120 disposed therein. The housing 110 is formed by a component 111 and a component 112. The component 111 has an inlet E1, the component 112 has inlets E3, and an outlet E2 is formed after the component 111 and the component 112 are combined. The impeller 120 rotates about an axis C1 in the housing 110 and includes a wheel hub 121 and blades 122 disposed around the wheel hub 121. The inlets E1 and E3 are located in an axial direction of the axis C1 and correspond to the impeller 120, and the outlet E2 is located in a radial direction relative to the axis C1. When the impeller 120 rotates, a working fluid (e.g., air) enters the housing 110 through the inlets E1 and E3 and is discharged from the housing 110 from the outlet E2.
With reference to FIG. 1C again, taking the inlet E1 of this embodiment for example, the inlet E1 is divided into a compression section E11 and a release section E12 in a rotation direction (a counter-clockwise direction in FIG. 1C) of the impeller 120. The compression section E11 has a uniform first radial dimension L1 relative to the axis C1, the release section E12 has an extended second radial dimension L2 relative to the axis C1, and the second radial dimension L2 is greater than the first radial dimension L1. Herein, the second radial dimension L2 gradually extends from the first radial dimension L1 to a maximum value and then gradually reduces to the first radial dimension L1. Each of the radial dimensions described above is a radius of the inlet E1 which is formed based (relative) on the axis C1. Certainly, in other embodiments that are not shown, each of the radial dimensions may also be a diameter of the inlet E1 instead relative to the axis C1.
Further, the blades 122 have a third radial dimension L3 with respect to the axis C1. As regards the inlet E1 and the working fluid entering the housing 110 through the inlet E1, a portion of the working fluid entering the housing 110 through the compression section E11 is compressed when the impeller 120 rotates. The compression section E11 starts from a starting point ST1 corresponding to a tongue portion 112 a of the housing 110. From the starting point ST1 to an end point EN1 of the compression section E11, the portion of the working fluid entering the housing 110 from this area is compressed by the impeller 120. In this embodiment, a central angle θ1 of the compression section E11 with respect to the axis C1 is 175 degrees to 215 degrees (from the starting point ST1 to the end point EN1). Moreover, in this embodiment, in the compression section E11, the third radial dimension L3 of the blades 122 is greater than the first radial dimension L1 of the compression section E11 (L3>L1), so that the portion of the working fluid is prevented from leaking out from the same position when entering the housing 110 through the compression section E11.
Next, the working fluid is continuously compressed by the impeller 120 in the housing 110. When the blades 122 of the impeller 120 of this embodiment pass through the release section E12, since the second radial dimension L2 of the release section E12 is variable and extended, the difference between the third radial dimension L3 and the second radial dimension L2 is gradually reduced, until portions of the release section E12 expose ends of the blades 122. That is, as shown in a region A1 of FIG. 1C, a portion of the working fluid entering the housing 110 through the region A1 is not in contact with the blades 122 of the impeller 120 and is driven by the portion of the working fluid which is compressed in the housing 110 instead and thus is discharged out of the housing 110 from the outlet E2. In this embodiment, a starting point ST2 of the release section E12 is the end point EN1 of the compression section E11, and a central angle θ2 provided between the starting point ST2 of the release section E12 and an end point EN2 of the release section E12 relative to the axis C1 is 40 degrees to 130 degrees.
In other words, if a plane P1 on which the outlet E2 is located is treated as the basis, the starting point ST2 of the release section E12 is a location at which rotation is performed by a central angle θ3 around the axis C1 based on a radial plane P2 with respect to the axis C1, where the central angle θ3 is 20 degrees. The radial plane P2 is parallel to the plane P1 on which the outlet E2 is located, and the direction of the 20-degree rotation is opposite to the rotation direction of the impeller 120 (the clockwise direction in FIG. 1C). In another embodiment that is not shown, the starting point ST2 of the release section E12 may also be obtained through rotation by the central angle θ3 (20 degrees) in the rotation direction of the impeller 120. That is, the location of the starting point ST2 is obtained through rotation by +/−20 degrees based on the radial plane P2 with respect to the axis C1. Moreover, as regards the inlet E1 of the present embodiment, the second radial dimension L2 is 1.2 to 1.5 times greater than the first radial dimension L1. The first radial dimension L1 is designed to be 70% to 85% of the third radial dimension L3 of the blades 122.
In addition, with reference to FIG. 1B, the inlets E3 of this embodiment also exhibit an extended structure (the release section E12) similar to the structure described above. In other words, the present embodiment is suitable for any arrangement of which the release section E12 having the second radial dimension L2 is disposed at the inlet or the inlets E3.
Based on the foregoing corresponding relations between member configuration and member dimensions, the centrifugal heat dissipation fan 100 may achieve the effect of reducing turning of a trajectory of the working fluid at the release section E12. In contrast, in a centrifugal heat dissipation fan of the related art, a trajectory of a working fluid is required to be driven by blades to turn so that the working fluid may be discharged in the radial direction after making an entry in the axial direction. Compared to such centrifugal heat dissipation fan of the related art, in this embodiment, the working fluid is less susceptible to be or is prevented from being in contact with the blades 122 at the release section E12. Instead, the portion of the working fluid entering the housing 110 from the release section E12 is more susceptible to be or is completely driven by the portion of the working fluid being compressed at the compression section E11 to be discharged from the housing 110. In this way, noise generated by the working fluid when passing through and being in contact with the blades 122 is effectively lowered.
FIG. 2 is a schematic view of a flow field in a housing of the centrifugal heat dissipation fan. With reference to FIG. 2 and FIG. 1C together, in the flow field depicted in FIG. 2, a flow velocity of the working fluid in the housing 110 is represented by the light to dark illustration manner, and a darker grey scale means a faster flow velocity. In other words, in the corresponding relations between member arrangement and member dimensions shown in FIG. 1A to FIG. 1C of this embodiment, that is, the corresponding relation between the arrangement of the compression section E11 and the release section E12 of the inlet E1 and the blades 122 is determined by the flow velocity of the working fluid in the flow field in the housing 110 shown in FIG. 2. In short, the release section E12 of this embodiment is the location at which the flow velocity of the working fluid reaches a maximum value in the housing 110. In contrast, a location at which the second radial dimension L2 of the release section E12 reaches its maximum value is the location at which the flow velocity of the working fluid reaches its maximum value. Further, according to the trend of variations of flow velocity in the flow field, the area of the release section E12 (the starting point ST2, the end point EN2, and the central angle θ2) may be accordingly defined. That is, the region Al is set to correspond to the darkest grey scale area shown in FIG. 2.
As the release section is defined by flow velocity changes in the flow field, different variation profiles may thus be formed therefrom. FIG. 3 and FIG. 4 are top views of the centrifugal heat dissipation fan according to different embodiments of the disclosure. With reference to FIG. 3 first, in this embodiment, the compression section E11 of the inlet E1 is identical to that described in the foregoing embodiment, but a different release section E13 is provided. The release section E13 of this embodiment has a toothed shape and has depressions 113 a and convex portions 113 b. From FIG. 3, it can be clearly seen that when the blades 122 pass through the release section E13, the blades 122 are obscured by the convex portions 113 b but are exposed by the depressions 113 a. Herein, the convex portions 113 b may be treated as the portions of the blades 122 being obscured by the inlet E1 at the release section E12 in the foregoing embodiment. The depressions 113 a may be treated as the portions of the blades 122 being exposed from the inlet E1 at the release section E12 in the foregoing embodiment, which is equivalent to the portion of the region Al.
Next, with reference to FIG. 4, different from the inlet E1 having a dimensional shape that gradually extends and gradually shrinks provided by the foregoing embodiment, a release section E14 of the inlet of this embodiment has a uniform radial dimension. That is, each of the blades 122 passing through the release section E1 4 is exposed from the inlet E1.
FIG. 5A is a three-dimensional view of a centrifugal heat dissipation fan according to another embodiment of the disclosure. FIG. 5B is an exploded view of the centrifugal heat dissipation fan of FIG. 5A. FIG. 5C is a top view of the centrifugal heat dissipation fan of FIG. 5A. With reference to FIG. 5A to FIG. 5C together, different from the centrifugal heat dissipation fan having only one outlet as described above, a centrifugal heat dissipation fan 200 of this embodiment has a housing 210 which is formed by components 211 and 212 and has a first outlet E5 and a second outlet E6 after the components 211 and 212 are combined. When the impeller 120 rotates, a working fluid enters the housing 210 through inlets E4 and E7 and flows out of the housing 210 through the outlets E5 and E6. The corresponding relation of the inlets E4 and E7 is similar to the corresponding relation of the inlets E1 and E3 as described above, and the inlet E4 is thus taken as an example for illustration in the following.
In this embodiment, since the first outlet E5 and the second outlet E6 are provided, a compression section E41 and a release section of the inlet E4 are required to be accordingly adjusted. Further, the release section of this embodiment is divided into a first sub section E42 and a second sub section E43. The first sub section E42 corresponds to the first outlet E5, the second sub section E43 corresponds to the second outlet E6, and the first sub section E42 is connected between the compression section E41 and the second sub section E43 in the rotation direction (the counter-clockwise rotation is adopted in FIG. 5C) of the impeller 120.
Specifically, the compression section E41 starts from a starting point ST3 corresponding to a tongue portion 212 a of the housing 210. That is, the tongue portion 212 a acts as a starting point (the starting point ST3 of the compression section E412) of compression performed by the impeller 120 to the working fluid flowing into the housing 210. An end point EN3 of the compression section E41 is a starting point ST4 of the release section (based on the first sub section E42), and a central angle θ4 of the compression section E41 with respect to an axis C2 is 85 degrees to 125 degrees. Next, the starting point ST4 of the release section is the end point EN3 of the compression section E41, and an end point EN4 of the release section is a point obtained through rotation by a central angle θ5 starting from the starting point ST4. Herein, the central angle θ5 is 40 degrees to 220 degrees.
From another perspective, similar to the foregoing embodiments, the first outlet E5 may also be treated as the basis for defining the starting point ST4 of the release section in this embodiment. For instance, based on a radial plane P4 generated by the axis C2, the starting point ST4 of the release section may be obtained through rotation of the radial plane P4 by a central angle θ6 in a direction opposite to the rotation direction of the impeller 120. Herein, the central angle θ6 is 20 degrees, and the radial plane P4 is parallel to a plane P3 on which the first outlet E5 is located. In addition, as regards the second outlet E6, the starting point ST4 of the release section may also be obtained through the similar manner (i.e., a plane P5 on which the second outlet E6 is located and a radial plane P6). Nevertheless, it is worth noting that an angle change is presented between the first outlet E5 and the second outlet E6, and as shown in FIG. 5C, a central angle difference of 90 degrees is provided therebetween. Therefore, when rotation is performed by a central angle θ7 in the direction opposite to the rotation direction of the impeller 120 based on the radial plane P6, the central angle difference of 90 degrees needs to be calculated. That is, when the central angle θ7 is 20 degrees, the starting point ST4 of the release section is obtained through rotation of the radial plane P6 by 110 degrees (20 degrees plus 90 degrees) in the direction opposite to the rotation direction of the impeller 120.
In this embodiment, a first radial dimension of the compression section E41 is similar to the first radial dimension L1 of the compression section E11 described above, a second radial dimension of the release section (the first sub section E42 and the second sub section E43) is also similar to the second radial dimension L2 of the release section E12 described above, and the blades 122 also have a third radial dimension identical to the third radial dimension L3 provided in the foregoing embodiments, the corresponding relations related to the radial dimensions are thus no longer described. Note that similar to the foregoing embodiments, the flow velocity of the flow field in the housing 210 of the centrifugal heat dissipation fan 200 is used to divide the release section. The second radial dimension of the release section gradually extends from the first radial dimension of the compression section E41 to reach the first sub section E42 and gradually shrinks to the first radial dimension of the compression section E41 from the second sub section E43. Moreover, the working fluid reaches the maximum value of flow velocity respectively at the first sub section E42 and the second sub section E43, respectively, so that a region A2 shown in FIG. 5C is formed, and this region is the area where the release section exposes the blades 122.
FIG. 6A and FIG. 6B are comparison diagrams of measurement of sound quality of the centrifugal heat dissipation fan. With reference to FIG. 6A and FIG. 6B together, the centrifugal heat dissipation fan 200 having double outlets is taken as an example herein. FIG. 6A is a diagram presenting measurement of a sound spectrum generated when no extended release section is provided, and FIG. 6B is a diagram presenting measurement of a sound spectrum generated when extended release section as shown in FIG. 5A to FIG. 5C is provided. As regards the blades 122 of the impeller 120, a number of the blades 122 is presented to be 59, and a rotational speed is exemplified as being 3,100 rpm. A frequency generated by the centrifugal heat dissipation fan 200 caused by the rotational speed is 51.67 rps. Next, 59*51.67=3048.63 (Hz) is performed. That is, sound pressures corresponding to 3048.63 (Hz) are identified in the measured sound frequency diagrams (FIG. 6A and FIG. 6B) to present that the sound pressures are generated by the centrifugal heat dissipation fan 200.
As described above, it can thus be known that the sound pressure corresponding to the frequency of 3048.63 (Hz) is 22.18 dB(A) in FIG. 6A and the sound pressure corresponding to the frequency of 3048.63 (Hz) is 19.12 dB(A) in FIG. 6B. In other words, when the total sound pressure difference is not great (AES1=45.8 dB(A) and AES2=44.1 dB(A) as shown in FIG. 6A and AES1=45.9 dB(A) and AES2=44.2 dB(A) as shown in FIG. 6B, and AES1 and AES2 herein respectively represent the sound pressures measured at the left and right ears or the left and right sound tracks), noise is effectively lowered (from 22.18 dB(A) to 19.12 dB(A)) through the extended release section shown in FIG. 5A to FIG. 5C.
FIG. 7 and FIG. 8 are top views of the centrifugal heat dissipation fan according to different embodiments of the disclosure. With reference to FIG. 7 first, a release section E44 of the embodiment has a plurality of smooth portions 213 a and a plurality of radial depressions 213 b, and the two are arranged in an alternating manner surrounding the axis C2. Similar to what is shown by the embodiment of FIG. 3, when the blades 122 pass through the release section E44, the smooth portions 213 a obscure the blades 122, and the radial depressions 213 b expose the blades 122.
Further, with reference to FIG. 8, a release section E45 of this embodiment has a uniform dimension. That is, similar to what is shown by the embodiment of FIG. 4, the blades 122 passing through the release section E45 are all exposed by the release section E45.
FIG. 9 is a schematic view of a flow field in the housing of the centrifugal heat dissipation fan. With reference to FIG. 9 in comparison to FIG. 5C, similar to what is shown in FIG. 2, FIG. 9 represents arrangement of the extended release section based on the centrifugal heat dissipation fan 200 having double outlets shown in FIG. 5A to FIG. 5C. That is, the location at which the flow velocity of the flow field reaches the maximum value may be clearly seen in FIG. 9. As such, the release section may be accordingly disposed corresponding to the inlet E4 by a designer, so that the flow velocity of the working fluid in the housing 210 may reach the maximum value respectively at the first sub section E42 and the second sub section E43. In this way, the working fluid flowing into the housing 210 from the inlet E4 is not in contact with the blades 122, and that the noise problem is effectively solved.
FIG. 10 to FIG. 12 are top views of the centrifugal heat dissipation fan according to different embodiments of the disclosure. With reference to FIG. 10, in this embodiment, different from the region A2 shown in FIG. 5C which is continuous, the region A2 of the inlet E4 of this embodiment is divided into two regions A3 and A4 separated from each other. That is, in an inlet E4 a, the region A3 having an extended radial diameter corresponds to the first outlet E5, and the other region A4 having an extended radial diameter corresponds to the second outlet E6. That is, the portion (the portion without an extended radial diameter) between the region A3 and the region A4 may still be configured to serve as a portion allowing a working fluid from an external environment to be supplemented.
According to the illustration of FIG. 10, it can be clearly seen that in the embodiments shown by FIG. 11 and FIG. 12, the region A3 in an inlet E4b of FIG. 11 is configured to mainly correspond to the first outlet E5, and the region A4 in an inlet E4c of FIG. 12 is configured to mainly correspond to the second outlet E6. The effect similar to what is provided in the foregoing embodiments may still be provided to the corresponding outlets because of the extended radial diameters. Further, note that changes and areas (corresponding central angles) of the radial diameters of the inlets shown in FIG. 10 to FIG. 12 are similar to that described in the foregoing embodiments, and repeated description is thus omitted. Note that although the fans shown in
FIG. 10 to FIG. 12 are exemplified as having double outlets, a fan having a single outlet may still be applied.
In view of the foregoing, in the embodiments of the disclosure, the compression section and the release section having different dimensions are formed at the inlet of the centrifugal heat dissipation fan. The compression section has the uniform first radial dimension with respect to the rotation axis of the impeller, the release section has the extended second radial dimension with respect to the rotation axis of the impeller, and the second radial dimension is greater than the first radial dimension. In this way, when entering the housing from the release section, the working fluid is directly pushed towards the outlet by the airflow in the housing without flowing through the blade area of the impeller. Therefore, turning of the trajectory of the working fluid is effectively reduced, and the noise generated by the working fluid in contact with the impeller is accordingly reduced.
Further, regardless of the single outlet structure or the double outlet structure to be provided in the centrifugal heat dissipation fan, the release sections of the two structures are arranged in the same manner, and such arrangement is required to be made based on the flow velocity of the flow field formed by the working fluid in the housing. In this way, the location in the flow field at which the flow velocity occurs corresponds to the location of the inlet at which the extended radial dimension reaches the maximum value, so that the portion of the working fluid flowing into the housing from such location may be pushed by the compressed portion of the working fluid.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents.

Claims

What is claimed is:

1. A centrifugal heat dissipation fan, comprising:

a housing, having at least one inlet and at least one outlet; and

an impeller, disposed in the housing, rotating about an axis, the at least one inlet located in an axial direction of the axis and corresponding to the impeller, the at least one outlet located in an radial direction relative to the axis, the at least one inlet divided into a compression section and a release section in a rotation direction of the impeller, wherein the compression section has a uniform first radial dimension relative to the axis, the release section has an extended second radial dimension relative to the axis, and the second radial dimension is greater than the first radial dimension.

2. The centrifugal heat dissipation fan as claimed in claim 1, wherein the impeller rotates and causes a working fluid to flow into the housing through the at least one inlet and flow out of the housing though the at least one outlet, and a flow velocity of the working fluid in the housing reaches a maximum value at the release section.

3. The centrifugal heat dissipation fan as claimed in claim 1, wherein the impeller rotates and causes a working fluid to flow into the housing through the at least one inlet and flow out of the housing though the at least one outlet, the second radial dimension gradually extends from the first radial dimension to a maximum value and then gradually reduces to the first radial dimension, and a location where the second radial dimension reaches the maximum value is a location where the flow velocity of the working fluid reaches a maximum value.

4. The centrifugal heat dissipation fan as claimed in claim 1, wherein the release section has a toothed shape.

5. The centrifugal heat dissipation fan as claimed in claim 1, wherein the second radial dimension is uniform.

6. The centrifugal heat dissipation fan as claimed in claim 1, wherein the second radial dimension is 1.2 to 1.5 times greater than the first radial dimension.

7. The centrifugal heat dissipation fan as claimed in claim 1, wherein blades of the impeller have a third radial dimension relative to the axis, and the first radial dimension is 70% to 85% of the third radial dimension.

8. The centrifugal heat dissipation fan as claimed in claim 1, wherein the impeller rotates and causes a working fluid to flow into the housing through the at least one inlet and flow out of the housing though the at least one outlet, and at least portions of the release section expose ends of the blades when the blades of the impeller pass through the release section, so that a portion of the working fluid flowing into the housing from the at least portions is not in contact with the blades of the impeller.

9. The centrifugal heat dissipation fan as claimed in claim 1, wherein the housing has a tongue portion, the tongue portion corresponds to a starting point of the compression section in the rotation direction of the impeller, and a central angle provided between the starting point of the compression section and an end point of the compression section relative to the axis is 175 degrees to 215 degrees.

10. The centrifugal heat dissipation fan as claimed in claim 1, wherein the housing has a tongue portion, the tongue portion corresponds to a starting point of the compression section in the rotation direction of the impeller, a starting point of the release section is an end point of the compression section, and a central angle provided between the starting point of the release section and an end point of the release section relative to the axis is 40 degrees to 130 degrees.

11. The centrifugal heat dissipation fan as claimed in claim 1, wherein a starting point of the release section is a position obtained through rotation by +/−20 degrees about the axis relative to a radial direction of the axis, and the radial direction is parallel to a plane where the at least one outlet is located.

12. The centrifugal heat dissipation fan as claimed in claim 1, wherein the housing has a first outlet and a second outlet, the release section is divided into a first sub section and a second sub section, the first sub section corresponds to the first outlet, the second sub section corresponds to the second outlet, and the first sub section is connected between the compression section and the second sub section in the rotation direction of the impeller.

13. The centrifugal heat dissipation fan as claimed in claim 12, wherein a flow velocity of the working fluid in the housing reaches a maximum value respectively at the first sub section and the second sub section.

14. The centrifugal heat dissipation fan as claimed in claim 12, wherein the impeller rotates and causes a working fluid to flow into the housing through the at least one inlet and flow out of the housing though the at least one outlet, the second radial dimension gradually extends from the first radial dimension to reach the first sub section and gradually reduces to the first radial dimension from the second sub section, and a flow velocity of the working fluid reaches a maximum value respectively at the first sub section and the second sub section.

15. The centrifugal heat dissipation fan as claimed in claim 12, wherein the release section has a plurality of radial depressions, and blades of the impeller are exposed when passing through each of the radial depressions.

16. The centrifugal heat dissipation fan as claimed in claim 12, wherein the housing has a tongue portion, the tongue portion corresponds to a starting point of the compression section in the rotation direction of the impeller, and a central angle provided between the starting point of the compression section and an end point of the compression section relative to the axis is 85 degrees to 125 degrees.

17. The centrifugal heat dissipation fan as claimed in claim 12, wherein the housing has a tongue portion, the tongue portion corresponds to a starting point of the compression section in the rotation direction of the impeller, a starting point of the release section is an end point of the compression section, and a central angle provided between the starting point of the release section and an end point of the release section relative to the axis is 40 degrees to 220 degrees.

18. The centrifugal heat dissipation fan as claimed in claim 12, wherein a starting point of the release section is a position obtained through rotation by +/−20 degrees about the axis relative to a radial direction of the axis, and the radial direction is parallel to a plane where the at least one outlet is located.