SINGLE THICKNESS BLADE WITH LEADING EDGE SERRATIONS ON AN AXIAL FAN
A fan with a hub, one or more single thickness fan blades coupled to the hub, each single thickness fan blade having a length L 1 and a width W, a single relative thickness, a plurality of serrations over a length L 2 of a leading edge.
1 . A fan, comprising:
a hub;
one or more single thickness fan blades coupled to the hub, each single thickness fan blade having a length L 1 and a width W, and further comprising:
a single relative thickness; and
a plurality of serrations over a length L 2 of a leading edge.
2 . The fan of claim 1 wherein the ratio of the width W to length L 2 is approximately unity.
3 . The fan of claim 1 wherein the width W is approximately uniform along the length L 1 of each of the single thickness fan blades.
4 . The fan of claim 1 wherein the plurality of serrations for each of the single thickness fan blades have a spacing S.
5 . The fan of claim 1 wherein the plurality of serrations for each of the single thickness fan blades are formed by a saw-tooth pattern with no spacing between each individual serration.
6 . The fan of claim 1 wherein the plurality of serrations for each of the single thickness fan blades are formed along a straight section of the leading edge.
7 . The fan of claim 1 where the plurality of serrations for each of the single thickness fan blades are formed along a section of each of the fan blades that has the width W.
8 . The fan of claim 1 wherein each of the single thickness fan blades further comprises a plurality of holes for securing the blade to the hub.
9 . The fan of claim 1 wherein each of the single thickness fan blades is secured to the hub by one of bolts, rivets or spot welds.
10 . The fan of claim 1 wherein the plurality of serrations reduce a sound power for sound frequencies between 125 Hz and 5000 Hz relative to a fan with fan blades having no serrations.
11 . A fan, comprising:
a hub having two or more spokes;
two or more fan blades, each coupled to one of the spokes of the hub, each fan blade having a length L 1 and a width W, and further comprising:
a single relative thickness; and
a plurality of serrations over a length L 2 of a leading edge.
12 . The fan of claim 11 wherein the ratio of the width W to length L 2 is approximately unity.
13 . The fan of claim 11 wherein the width W is approximately uniform along the length L 1 of each of the fan blades.
14 . The fan of claim 11 wherein the plurality of serrations for each of the fan blades have a spacing S.
15 . The fan of claim 11 wherein the plurality of serrations for each of the fan blades are formed by a saw-tooth pattern with no spacing between each individual serration.
16 . The fan of claim 11 wherein the plurality of serrations for each of the fan blades are formed along a straight section of the leading edge.
17 . The fan of claim 11 wherein the plurality of serrations for each of the fan blades are formed along a section of each of the fan blades that has the width W.
18 . The fan of claim 11 wherein each of the fan blades further comprises a plurality of holes for securing the blade to the hub.
19 . The fan of claim 11 wherein each of the fan blades is secured to the hub by one of bolts, rivets or spot welds.
20 . A fan, comprising:
a hub having a plurality of spokes;
one or more single thickness fan blades, each coupled to one of the spokes of the hub, each single thickness fan blade having a length L 1 and a width W, and further comprising:
a single relative thickness; and
a plurality of serrations over a length L 2 of a leading edge;
wherein the ratio of the width W to length L 2 is approximately unity, the width W is approximately uniform along the length L 1 of each of the single thickness fan blades, the plurality of serrations for each of the single thickness fan blades have a spacing S, the plurality of serrations for each of the single thickness fan blades are formed by a saw-tooth pattern with no spacing between each individual serration, the plurality of serrations for each of the single thickness fan blades are formed along a straight section of the leading edge, the plurality of serrations for each of the single thickness fan blades are formed along a section of each of the single thickness fan blades that has the width W, each of the blades further comprises a plurality of holes for securing the single thickness fan blade to the hub, and each of the single thickness fan blades is secured to the hub by one of bolts, rivets or spot welds.