Axial flow fan with multiple segment blades

• US 20040062654A1
• Filed: 12/18/2002
• Published: 04/01/2004
• Est. Priority Date: 09/27/2002
• Status: Active Grant

• Current Assignee: Delta Electronics Incorporated
• Original Assignee: Delta Electronics Incorporated
• Inventors: Chang, Shun-Chen, Huang, Wen-Shi, Lin, Kuo-Cheng
• Granted Patent: US 7,025,569 B2
• Time in Patent Office: Days
• US Class Current: 416/223R
• CPC Class Codes: F04D 29/327 with non identical blades
• CPC Class Codes: F04D 29/38 Blades for axial flow compressors F04D29/324
• CPC Class Codes: F04D 29/384 characterised by form
• CPC Class Codes: F04D 29/681 especially adapted for elastic fluid pumps

Abstract

An axial flow fan with a plurality of segment blades is described. The axial flow fan has a base, a hub and a plurality of blade units. The hub is mounted on, or pivots on, the base and supports the blade units. Each of the blade units is connected to a periphery of the hub and extends radially outward from the base has a plurality of segment blades. A segment space between the segment blades reforms a boundary layer of fluid passing over the segment blades and reduces the thickness of the boundary layer on the blade surfaces. As a result, the separation between the blade surfaces and fluid is avoided to maintain a laminar flow of the fluid adjacent to the segment blades.

Claims

1. A blade structure with multiple segment blades, comprising:

a hub; and

a plurality of blade units connected to a periphery of the hub and extending radially outward from the periphery, wherein each of the blade units at least includes a first blade and a second blade, and a segment space is positioned between the first blade and the second blade to maintain a laminar flow of fluid passing over a surface region of the first blade and the second blade.

2. The blade structure with multiple segment blades of claim 1, wherein the segment space between the first blade and the second blade in a flow direction of the fluid comprises a state of separation.

3. The blade structure with multiple segment blades of claim 1, wherein the segment space between the first blade and the second blade in a flow direction of the fluid comprises a state of overlap.

4. The blade structure with multiple segment blades of claim 1, wherein a first length of the first blade in a flow direction of the fluid is greater than a second length of the second blade along the flow direction.

5. The blade structure with multiple segment blades of claim 1, the first blade having a first leading edge and a first rear edge to define a first chord line, and a first incident angle (A₁) being defined as an angle between an entry direction of the fluid into the first leading angle and the first chord line, wherein the first incident angle (A₁) comprises a range of about 0°

<

A₁≦

30°

to keep a laminar flow of the fluid adjacent to the first rear edge.

6. The blade structure with multiple segment blades of claim 1, the second blade having a second leading edge and a second rear edge to define a second chord line, and a second incident angle (A₂) being defined as an angle between an entry direction of the fluid into the second leading angle and the second chord line, wherein the second incident angle (A₂) comprises a range of about 0°

<

A₂≦

30°

to keep a laminar flow of the fluid adjacent to the second rear edge.

7. A blade structure with multiple segment blades, comprising:

a hub; and

a plurality of blade units connected to a periphery of the hub and extending radially outward from the periphery, wherein each of the blade units at least includes a first blade and a second blade, a first length of the first blade in a flow direction of the fluid is greater than a second length of the second blade in the flow direction, and a segment space between the first blade and the second blade maintains a laminar flow of fluid passing over a surface region of the first blade and the second blade.

8. The blade structure with multiple segment blades of claim 7, wherein the segment space between the first blade and the second blade in a flow direction of the fluid comprises a state of separation.

9. The blade structure with multiple segment blades of claim 7, wherein the segment space between the first blade and the second blade in a flow direction of the fluid comprises state of overlap.

10. The blade structure with multiple segment blades of claim 7, the first blade having a first leading edge and a first rear edge to define a first chord line, and a first incident angle (A₁) being defined as an angle between an entry direction of the fluid into the first leading angle and the first chord line, wherein the first incident angle (A₁) comprises a range of about 0°

<

A₁≦

30°

to keep a laminar flow of the fluid adjacent to the first rear edge.

11. The blade structure with multiple segment blades of claim 7, the second blade having a second leading edge and a second rear edge to define a second chord line, and a second incident angle (A₂) being defined as an angle between an entry direction of the fluid into the second leading angle and the second chord line, wherein the second incident angle (A₂) comprises a range of about 0°

<

A₂≦

30°

to keep a laminar flow of the fluid adjacent to the second rear edge.

12. An axial flow fan with multiple segment blades, the axial flow fan comprising:

a frame base;

a hub pivotally connected to the frame base to support the multiple segment blades; and

a plurality of blade units connected to a periphery of the hub and extending radially outward from the periphery, wherein each of the blade units at least includes a first blade and a second blade and a segment space between the first blade and the second blade keeps a laminar flow of fluid passing over a surface region of the first blade and the second blade.

13. The axial flow fan with multiple segment blades of claim 12, wherein the segment space between the first blade and the second blade in a flow direction of the fluid comprises a state of separation.

14. The axial flow fan with multiple segment blades of claim 12, wherein the segment space between the first blade and the second blade in a flow direction of the fluid comprises a state of overlap.

15. The axial flow fan with multiple segment blades of claim 12, wherein a first length of the first blade in a flow direction of the fluid is greater than a second length of the second blade along the flow direction.

16. The axial flow fan with multiple segment blades of claim 12, the first blade having a first leading edge and a first rear edge to define a first chord line, and a first incident angle (A₁) being defined as an angle between an entry direction of the fluid into the first leading angle and the first chord line, wherein the first incident angle (A₁) comprises a range of about 0°

<

A₁≦

30°

to keep a laminar flow of the fluid adjacent to the first rear edge.

17. The axial flow fan with multiple segment blades of claim 12, the second blade having a second leading edge and a second rear edge to define a second chord line, and a second incident angle (A₂) being defined as an angle between an entry direction of the fluid into the second leading angle and the second chord line, wherein the second incident angle (A₂) comprises a range of about 0°

<

A₂≦

30°

to maintain a laminar flow of the fluid adjacent to the first rear edge.

18. An axial flow fan with multiple segment blades, the axial flow fan comprising:

a frame base;

a hub pivotally connected to the frame base to support a plurality of rotating blade units; and

a plurality of still blade units mounted to the frame base and extended radially outward from the periphery to introduce fluid into the rotating blade units, wherein each of the still blade units at least includes a first blade and a second blade, and a segment space between the first blade and the second blade maintains a laminar flow of the fluid passing over a surface region of the first blade and the second blade.

19. The axial flow fan with multiple segment blades of claim 18, wherein the segment space between the first blade and the second blade in a flow direction of the fluid comprises a state of separation.

20. The axial flow fan with multiple segment blades of claim 18, wherein the segment space between the first blade and the second blade in a flow direction of the fluid comprises a state of overlap.

21. The axial flow fan with multiple segment blades of claim 18, wherein a first length of the first blade in a flow direction of the fluid is greater than a second length of the second blade along the flow direction.

22. The axial flow fan with multiple segment blades of claim 18, the first blade having a first leading edge and a first rear edge to define a first chord line, and a first incident angle (A₁) being defined as an angle between an entry direction of the fluid into the first leading angle and the first chord line, wherein the first incident angle (A₁) comprises a range of about 0°

<

A₁≦

30°

.

23. The axial flow fan with multiple segment blades of claim 18, the second blade having a second leading edge and a second rear edge to define a second chord line, and a second incident angle (A₂) being defined as an angle between an entry direction of the fluid into the second leading angle and the second chord line, wherein the second incident angle (A₂) comprises a range of about 0°

<

A₂≦

30°

.