Claims
- 1. A fan and housing combination comprising a fan having a hub that rotates on an axis and blades extending outwardly from the hub to a circular band that connects the blade tips, the combination also comprising a housing surrounding the fan to control airflow the combination being characterized in that:
- a) a portion of the housing is positioned outward of the fan band and there are running clearances between the band and the housing such that recirculating airflow moves in a pathway between the fan and the housing; and
- b) stationary flow control vanes are connected to the housing in a position to encounter and redirect recirculating airflow.
- 2. The fan and housing combination of claim 1 in which the fan is positioned downstream of a heat exchanger, whereby the fan draws air through the heat exchanger.
- 3. The fan and housing combination of claim 1 in which the housing is positioned upstream from a heat exchanger, whereby the fan pushes air through the heat exchanger.
- 4. The fan and housing combination of claim 1 in which the housing is a duct.
- 5. The fan and housing combination of claim 1 in which the housing and the vanes are a single injection molded plastic unit.
- 6. The fan and housing combination of claim 1 characterized by a radial fan-to-housing clearance of at least 0.25% of the fan diameter.
- 7. The fan and housing combination of claim 1 characterized in that an airflow recirculation pathway is formed between the fan band and the housing, and at least a portion of the vanes is positioned in the pathway.
- 8. The fan and housing combination of claim 1 or claim 7 in which the housing is characterized by a reduction in radius at a location rearward of the trailing edge of the fan band.
- 9. The fan and housing combination of claim 8 in which the pathway has an inlet formed between the fan band and the housing, and at least a portion of the vanes is positioned radially outward of the pathway inlet.
- 10. The fan and housing combination of claim 9 in which the radially innermost face of the vanes is rounded.
- 11. The fan and housing combination of claim 8 in which the housing radius reduction reduces the housing inner radius to R.sub.r, such that R.sub.r <C+R.sub.b, where R.sub.b is the outer radius of the trailing edge of the fan band, and C is the radial fan-to-housing clearance.
- 12. The fan and housing combination of claim 8 in which the housing radius reduction reduces the housing inner radius to a radius that is approximately equal to or less than the outer radius of the trailing edge of the fan band.
- 13. The fan and housing combination of claim 12 in which the housing radius reduction reduces the housing radius to a radius that is less than the outer radius of the trailing edge of the fan band.
- 14. The fan and housing combination of claim 8 in which the housing comprises a rearward housing segment extending from the radius reduction rearwardly to rearward housing terminus.
- 15. The fan and housing combination of claim 14 in which the housing comprises elongated motor supports which extend from the rearward housing segment to a centrally positioned motor mount.
- 16. The fan and housing combination of claim 14 in which, as the housing extends rearwardly from the location of the radius reduction, the inside diameter of the housing increases.
- 17. The fan and housing assembly of claim 16 in which, as the housing extends rearwardly from the location of the radius reduction, the thickness of the housing decreases.
- 18. The fan and housing combination of claim 8 in which an inlet to the pathway is formed between the housing and the trailing edge of the band, and the shroud comprises a portion which extends first rearwardly and then inwardly and forwardly, forming a pocket axially rearward of the inlet.
- 19. The fan and housing combination of clam 18 in which at least a portion of the vanes extends into the pocket.
- 20. The fan and housing combination of claim 8 in which at least a portion of the vanes is axially rearward of the trailing edge of the band, and the vanes are characterized by a reduction in radius at a position axially rearward of the trailing edge of the fan band.
- 21. The fan and housing combination of claim 1 or claim 7 in which the recirculating airflow pathway includes an outlet formed between the housing and an outwardly flaring segment of the leading edge of the fan band.
- 22. The fan and housing combination of claim 1 in which the vanes are straight taken in a section in a plane normal to the fan axis.
- 23. The fan and housing combination of claim 22 in which the vanes are non-radial taken in a section in a plane normal to the fan axis.
- 24. The fan and housing combination of claim 22 in which the vanes are radial taken in a section in a plane normal to the fan axis.
- 25. The fan and housing combination of claim 1 in which the vanes are curved taken in a section in a plane normal to the fan axis.
- 26. The fan and housing combination of claim 1 characterized in that the vanes are positioned at least in part upstream of the fan band.
- 27. The fan and housing combination of claim 1 in which said vanes are all part a single injection molded plastic assembly.
- 28. The fan and housing combination of claim 1 in which said airflow recirculation pathway comprises a restriction upstream (from the perspective of recirculating airflow) of the vanes.
- 29. The fan and housing combination of claim 28 wherein the cross-sectional area of said pathway at said restriction is less than 1/2 the cross-sectional area of the outlet to said pathway.
- 30. The fan and housing combination of claim 28 wherein said band comprises a lip extending from the band to establish the restriction between the lip and the housing.
- 31. The fan and housing of claim 26 in which the vanes are positioned entirely upstream of the fan band.
- 32. The fan and housing combination of claim 1 or claim 26 wherein said vanes have a beveled end face.
- 33. The fan and housing combination of claim 32 wherein the end faces of said vanes are beveled by at least 20.degree..
- 34. The fan and housing combination of claim 26 wherein said vanes are arranged in an array whose inward tips are connected by an inner ring.
- 35. The fan and housing combination of claim 32 in which the high pressure side of the vanes has a concave portion adjacent to the end face of the vanes.
- 36. The fan and housing combination of claim 35 in which the radius of said concave portion is between 0.1 S and 1.0 S, where S is the spacing between adjacent vanes.
- 37. The fan and housing combination of claim 35 in which the high pressure side of said vanes is curved in a plane normal to the fan axis.
- 38. The fan and housing combination of claim 37 in which the high pressure side of said vanes is substantially cylindrical in a plane normal to the fan axis, having a radius of curvature between 0.15 D and 0.3 D, where D is the fan diameter.
- 39. The fan and housing combination of claim 34 in which:
- a) the end faces of said vanes are beveled by at least 20.degree.;
- b) the high pressure side of the vanes has a concave portion adjacent to the end face of the vanes, having a radius of curvature of between 0.1 S and 1.0 S, where S is the spacing between adjacent vanes; and
- c) the high pressure side of the vanes is substantially cylindrical in section in a plane normal to the fan axis, having a radius of curvature of between 0.15 D and 0.3 D, where D is the fan diameter.
- 40. The fan and housing combination of claim 18 in which elongated motor supports extend radially inwardly from said shroud portion to a centrally positioned motor mount.
- 41. The fan and housing combination of claim 9 in which the radially innermost face of the vanes is beveled.
- 42. A combination axial flow automotive fan and housing, said fan having a hub that rotates on an axis and blades extending outwardly from the hub to a circular band that connects the blade tips, the combination also comprising a housing surrounding the fan to control airflow, the combination being characterized in that:
- a) a portion of the housing is positioned outward of the fan band and there are running clearances between the band and the housing such that recirculating airflow moves in a pathway between the fan and the housing; and
- b) stationary flow control vanes are connected to the housing in a position to encounter and redirect recirculating airflow.
CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation of application Ser. No. 08/113,952, filed Aug. 30, 1993, now abandoned, which is a continuation-in-part of application Ser. No. 08/052,811, filed Apr. 28, 1993, now U.S. Pat. No. 5,297,931, which is a continuation of application Ser. No. 07/753,418, filed Aug. 30, 1991, now abandoned.
US Referenced Citations (27)
Foreign Referenced Citations (10)
Number |
Date |
Country |
0118769 |
Sep 1984 |
EPX |
0122892 |
Oct 1984 |
EPX |
0168594 |
May 1985 |
EPX |
1905269 |
Aug 1970 |
DEX |
2462465 |
Apr 1977 |
DEX |
62-282198 |
Aug 1987 |
JPX |
0282198 |
Dec 1987 |
JPX |
2124303 |
Feb 1984 |
GBX |
918559 |
Apr 1982 |
SUX |
WO8601263 |
Feb 1986 |
WOX |
Non-Patent Literature Citations (2)
Entry |
A. R. Azimian et al., "Application of Recess Vanced Casing Treatment to Axial Flow Fans," Journal of Turbomachinery, Jan., 1990, vol. 112, pp. 145-150. |
M. Ziabasharhagh et al., "Recess Vane Passive Stall Control," Presented at the International Gas Turbine and Aeroengine Congress and Exposition, Cologne, Germany, Jun. 1-4, 1992, pp. 1-10. |
Continuations (2)
|
Number |
Date |
Country |
Parent |
113952 |
Aug 1993 |
|
Parent |
753418 |
Aug 1991 |
|
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
52811 |
Apr 1993 |
|