# Patent

## Title
Axial flow fan

## Abstract

A fan or rotor design where the surface profile may be configured to desired dimensions particular to a given operating environment is disclosed.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims the priority benefit of U.S. provisional patent application No. 60/827,677 filed Sep. 29, 2006 and entitled “Axial Flow Fan” and U.S. provisional patent application No. 60/950,610 filed Jul. 19, 2007 and entitled “Surface Profile for a Quiet Rotor or Stator.” The disclosure of these commonly owned applications are incorporated herein by reference.
This application is related to U.S. Pat. No. 5,934,877 for a “Rotor with Logarithmic Scaled Shape” and U.S. Pat. No. 6,702,552 for an “Impeller Having Blade(s) Conforming to the Golden Section of a Logarithmic Curve.” The disclosures of these commonly owned patents are incorporated herein by reference.


BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally concerns axial flow fans and rotors. More specifically, the present invention concerns a surface profile for axial flow fans and rotors used in environments requiring high output in conjunction with constrained fan size including but not limited to electronics cooling.
2. Description of the Related Art
Fan and rotor design has undergone little change over the past century. As a result, fans and rotors remain relatively inefficient. A part of this inefficiency is the result of fans and rotors generating a considerable amount of noise and turbulence. Similarly, fans and rotors used in liquid environments typically result in cavitation. Noise, turbulence, and cavitation reduce the operational efficiency of the fan and rotor.
A chart illustrating inefficiencies with respect to flow and sound in a series of 92×38 mm computer fans as found in the prior art are shown in FIG. 1A. A similar chart illustrating inefficiencies with respect to flow and torque in prior art fan design is shown in FIG. 1B. FIG. 1B illustrates, specifically, a 22′′ best-in-class A/C fan with a standard bell shroud operating at 850 rpm.
Much of the noise, turbulence, and unwanted torque in prior art fan design may be attributable to the surface design of the fan or rotor. In many instances, fans and rotors are implemented in a particular operating environment based on a pre-existing design. These pre-existing designs are not necessarily designed or intended for that particular operating environment. Nevertheless, these pre-existing designs may achieve results that are adequate or ‘good enough’ for that particular environment.
Determining which pre-existing design is adequate or ‘good enough’ for a particular environment is a never-ending exercise. Trial and error will continually redefine the best adequate or ‘good enough’ design implementation. Notwithstanding these adequate results, some degree of the aforementioned noise, turbulence, and/or unwanted torque will inevitably remain.
There is, therefore, a need in the art for fan and rotor design where the surface profile may be configured to desired dimensions particular to a given operating environment.
SUMMARY OF THE INVENTION
Embodiments of the present invention provide for an axial flow fan that is quieter for the same or better output throughout a range of operating points compared to prior art fan designs. References to an axial flow fan or any fan are meant to be inclusive with respect to rotors and other blade designs.
In one exemplary embodiment, a method for constructing an axial fan is disclosed. In this exemplary method, a spline is drafted to connect a plurality of points along a radius cut sketch to form a blade surface. The blade surface is then offset by a constant amount and filled to form a single blade. The single blade is oriented with respect to a hub and patterned along with a total number of blades to be affixed to the hub. The single blade and remaining blades are then attached to the hub.
In another embodiment, a fan apparatus is disclosed. The fan apparatus includes a hub a blade coupled to the hub, the blade including a blade surface. The blade surface is created by drafting a spline to connect a plurality of points along a radius cut sketch. The blade is created by offsetting the blade surface by a constant amount and filling the blade surface to form a single blade.
Another exemplary method provides for constructing an axial fan. The exemplary method includes drafting a spline to connect a plurality of points along a radius cut sketch to form a blade surface. A complimentary airfoil shape is then created. The airfoil is then lofted into a solid.
A computer-readable storage medium is also disclosed. The medium has embodied thereon a program being executable by a processor to perform a method for constructing an axial fan.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a chart exhibiting flow and sound inefficiencies in prior art fan design.
FIG. 1B is a chart exhibiting flow and torque inefficiencies in prior art fan design.
FIG. 2A is a chart exhibiting flow and sound efficiency of a fan as may be designed in accordance with an exemplary embodiment of the present invention as compared to the inefficiencies of prior art fans like those shown in FIG. 1A.
FIG. 2B is a chart exhibiting flow and torque efficiency of a fan as may be designed in accordance with an exemplary embodiment of the present invention as compared to the inefficiencies of a prior art fan like that shown in FIG. 1B.
FIG. 3 illustrates an exemplary fan and surface profile according to an embodiment of the present invention.
FIG. 4 illustrates an exemplary surface profile of a fan blade according to an alternative embodiment of the present invention.
FIG. 5 illustrates an exemplary method for constructing a blade surface according to an embodiment of the present invention.
FIG. 6 illustrates a method for forming a blade according to an embodiment of the present invention.
FIG. 7 illustrates an alternative method for forming a blade according to an embodiment of the present invention.
FIG. 8 illustrates an exemplary method for constructing a fan according to an embodiment of the present invention.
FIGS. 9A-9E illustrate exemplary fans constructed utilizing the surface profile disclosed with respect to FIG. 3.
FIGS. 10A-10E illustrate exemplary fans constructed utilizing the surface profile disclosed with respect to FIG. 4.



DETAILED DESCRIPTION
Embodiments of the present invention provide for a fan that is quieter for the same or better output throughout a range of operating points compared to prior art fan designs. FIG. 2A is a chart exhibiting flow and sound efficiency of an exemplary fan as may be designed in accordance with the present invention compared to the inefficiencies of a prior art fan like that found in FIG. 1A. FIG. 2B, in turn, is a chart exhibiting flow and torque efficiency of an exemplary surface profile as may be designed for a fan in accordance with the present invention compared to the inefficiencies of a prior art fan like that found in FIG. 1B.
FIG. 3 illustrates a portion of an exemplary fan 300 and surface profile 330 according to an embodiment of the present invention. Fan 300 may be motor driven or subject to the natural flow of a fluid (e.g., liquid or gas). Fan 300 includes a hub 310, which may be approximately cylindrical or conical in shape. Hub 310 may be hollowed like that of FIG. 9A or solid as is shown in FIG. 10E. Hub 310 may also include a cap like that shown in FIG. 9B. Hub 310 may be altered with radii, chamfers, and/or blends with symmetry about the Y-axis as illustrated throughout FIGS. 9 and 10. Hub 310 may be configured to an appropriate height and diameter in order to incorporate a desired motor and hub-tip ratio as illustrated throughout FIGS. 9 and 10.
Blades 320 are circularly patterned around hub 310. Blades 320 may be permanently or temporarily coupled or affixed to the hub 310 through various techniques as known in the art. The surface profile 330 of blades 320 may be configured in accordance with the various profiles described in U.S. Pat. Nos. 5,934,877 and 6,702,552, the disclosure of which has been previously incorporated herein by reference. For example, a portion of the surface profile 330 of fan blade 320 may conform to a logarithmic spiral. The radius of that particular logarithmic spiral may unfold at a constant order of growth when measured at equiangular radii, which may sometimes be referred to as the Golden Section.
Surface profile 330 configurations may also correspond to external or internal shell configurations as found in nature. For example, the surface profile 330 of blade 320 may conform to the shell of the phylum Mollusca, class Cephalopoda, genus Nautilus. An alternative surface profile-to-shell configuration may be inclusive of the shell shaping of the phylum Mollusca, class Gastropoda, genus Conus, Conidae, Turbinidea, or Volutidae. Shell configurations from other members of phylum Mollusca, class Gastropoda or Cephalopoda may also be implemented with respect to the surface profile 330 of blade 320.
Various other surface configurations may be implemented in accordance with embodiments of the present invention. For example, surface profile 330 of blade 320 may be defined by the following tables. In Tables I-IX, Cartesian points are taken at even intervals along the span of the blade, which corresponds to an 87 mm diameter fan. In the context of FIG. 3, axis Y represents the hub axis and serves as the zero reference for all radial measurements. All dimensions in Tables I-IX are in millimeters. The blade surface may be constructed through a method like that disclosed in the context of FIG. 5.







TABLE I







22.5 mm Radius












Pt #
X
Y
Z
















1
−5.389
−2.463
21.845



2
−2.804
−0.447
22.325



3
−1.548
0.621
22.447



4
−0.338
1.725
22.497



5
4.187
6.381
22.107



6
6.236
8.883
21.619



7
8.171
11.467
20.964



8
9.981
14.098
20.165



9
11.645
16.791
19.252



10
12.675
18.611
18.590

















TABLE II







25 mm Radius












Pt#
X
Y
Z
















1
−6.755
−3.085
24.070



2
−5.230
−1.984
24.447



3
−3.708
−0.850
24.723



4
−2.209
0.344
24.902



5
−0.743
1.590
24.989



6
0.680
2.866
24.991



7
2.072
4.159
24.914



8
4.740
6.826
24.547



9
7.203
9.653
23.940



10
9.536
12.571
23.110



11
11.695
15.578
22.096



12
13.656
18.668
20.941

















TABLE III







27.5 mm Radius












Pt #
X
Y
Z
















1
−8.339
−3.663
26.205



2
−6.681
−2.508
26.676



3
−5.014
−1.334
27.039



4
−3.379
−0.118
27.292



5
−1.774
1.140
27.443



6
−0.200
2.438
27.499



7
1.360
3.757
27.466



8
2.898
5.107
27.347



9
4.395
6.508
27.147



10
5.841
7.963
26.873



11
7.233
9.452
26.532



12
9.896
12.488
25.658



13
12.351
15.634
24.571



14
14.594
18.869
23.308

















TABLE IV







30 mm Radius












Pt #
X
Y
Z
















1
−10.052
−4.175
28.266



2
−8.259
−2.972
28.841



3
−6.454
−1.744
29.298



4
−2.895
0.799
29.860



5
−1.145
2.119
29.978



6
0.589
3.464
29.994



7
2.300
4.847
29.912



8
3.968
6.289
29.736



9
5.597
7.786
29.473



10
7.177
9.315
29.129



11
10.171
12.444
28.223



12
11.578
14.055
27.676



13
12.919
15.705
27.076



14
15.426
19.108
25.730

















TABLE V







32.5 mm Radius












Pt #
X
Y
Z
















1
−11.904
−4.628
30.241



2
−8.077
−2.121
31.480



3
−6.134
−0.832
31.916



4
−4.200
0.476
32.227



5
−0.387
3.180
32.498



6
3.326
6.035
32.329



7
5.121
7.551
32.094



8
6.879
9.111
31.764



9
10.229
12.302
30.848



10
13.307
15.645
29.651



11
16.096
19.177
28.234

















TABLE VI







35 mm Radius












Pt #
X
Y
Z
















1
−13.944
−5.042
32.102



2
−11.950
−3.756
32.897



3
−9.913
−2.465
33.567



4
−7.835
−1.168
34.112



5
−5.747
0.160
34.525



6
−1.625
2.908
34.962



7
2.419
5.778
34.916



8
4.393
7.286
34.723



9
6.319
8.865
34.425



10
10.022
12.110
33.535



11
11.778
13.779
32.959



12
13.453
15.502
32.311



13
15.045
17.284
31.602



14
16.552
19.129
30.839

















TABLE VII







37.5 mm Radius












Pt #
X
Y
Z
















1
−16.217
−5.442
33.812



2
−14.137
−4.107
34.733



3
−12.003
−2.783
35.527



4
−9.813
−1.473
36.193



5
−7.592
−0.132
36.724



6
−3.163
2.655
37.366



7
1.205
5.545
37.481



8
3.361
7.039
37.349



9
5.468
8.607
37.099



10
7.519
10.247
36.738



11
9.510
11.916
36.274



12
11.447
13.606
35.710



13
13.311
15.339
35.058



14
15.077
17.149
34.335



15
16.736
19.050
33.558

















TABLE VIII







40 mm Radius












Pt #
X
Y
Z
















1
−18.694
−5.801
35.363



2
−16.540
−4.436
36.420



3
−14.332
−3.083
37.344



4
−12.065
−1.755
38.137



5
−9.759
−0.412
38.791



6
−7.428
0.970
39.304



7
−5.073
2.390
39.677



8
−0.382
5.301
39.998



9
4.225
8.324
39.776



10
6.454
9.943
39.476



11
8.614
11.644
39.062



12
10.707
13.380
38.540



13
12.752
15.132
37.913



14
14.711
16.945
37.197



15
16.538
18.880
36.421

















TABLE IX







42.5 mm Radius












Pt #
X
Y
Z
















1
−21.317
−6.090
36.767



2
−19.109
−4.701
37.962



3
−16.842
−3.324
39.020



4
−12.129
−0.612
40.732



5
−9.709
0.774
41.376



6
−7.262
2.199
41.875



7
−2.365
5.103
42.434



8
0.080
6.575
42.500



9
2.514
8.074
42.426



10
4.912
9.640
42.215



11
7.231
11.300
41.880



12
9.460
13.033
41.434



13
11.633
14.797
40.877



14
13.759
16.584
40.211



15
15.754
18.503
39.472










FIG. 4 illustrates an exemplary surface profile 410 of a fan blade 400 according to an alternative embodiment of the present invention. Surface profile 410 may correspond to a blade coupled or affixed to a hub like the fan 300 shown in FIG. 3. The surface profile 410 of fan blade 400 in FIG. 4 has been defined by the Cartesian points as referenced in Tables X-XXVI (below) and taken at even intervals along the axis of the fan blade 400. The X, Y, and Z axis are orthogonal to one another and oriented as shown in FIG. 4. Like tables I-IX, all dimensions are in millimeters.







TABLE X







z = 0 mm










X
Y














−15.143
−23.188



−14.326
−22.832



−13.543
−22.424



−12.092
−21.431



−10.769
−20.241



−9.567
−18.931



−8.467
−17.536



−7.442
−16.078



−5.577
−13.054



−3.900
−9.921



−2.423
−6.683



−1.140
−3.369



0.000
0.000



1.470
5.110



2.078
7.697



2.576
10.311



3.158
15.563



3.063
20.820



2.698
23.451



2.425
24.763



2.094
26.055



0.214
31.012



−0.392
32.199



−1.055
33.364



−2.543
35.567



−4.264
37.579



−6.176
39.433

















TABLE XI







z = 5 mm










X
Y














−11.448
−21.282



−10.262
−20.347



−9.220
−19.270



−8.278
−18.093



−7.405
−16.861



−5.804
−14.307



−4.345
−11.667



−3.026
−8.955



−1.861
−6.181



−0.828
−3.356



0.111
−0.493



1.605
4.777



2.219
7.445



2.718
10.142



3.285
15.559



3.152
20.975



2.756
23.684



2.464
25.033



2.110
26.361



0.100
31.441



−0.550
32.655



−1.259
33.838



−2.848
36.059



−4.681
38.070



−6.717
39.906

















TABLE XII







z = 10 mm










X
Y














−9.055
−19.049



−8.218
−18.097



−7.448
−17.100



−6.051
−15.004



−4.790
−12.815



−3.650
−10.566



−1.700
−5.933



−0.091
−1.161



1.427
4.243



2.559
9.716



3.150
15.287



3.183
18.115



3.003
20.923



1.906
26.433



1.465
27.782



0.961
29.098



−0.226
31.637



−1.658
34.046



−2.476
35.197



−3.368
36.305



−5.342
38.334



−7.510
40.159

















TABLE XIII







z = 15 mm










X
Y














−7.636
−16.833



−6.407
−15.142



−5.294
−13.382



−3.400
−9.666



−1.841
−5.788



−0.520
−1.823



1.028
3.721



2.187
9.359



2.794
15.067



2.623
20.801



2.171
23.646



1.454
26.416



0.460
29.106



−0.142
30.420



−0.810
31.697



−4.123
36.335



−5.129
37.364



−6.209
38.335



−8.496
40.128

















TABLE XIV







z = 20 mm










X
Y














−6.748
−14.747



−5.797
−13.336



−4.930
−11.879



−3.443
−8.825



−1.117
−2.431



0.442
3.175



1.607
8.854



2.225
14.633



2.247
17.565



2.033
20.472



1.556
23.345



1.212
24.767



0.793
26.176



−1.576
31.479



−3.193
33.910



−4.118
35.055



−5.109
36.129



−7.282
38.061



−9.650
39.775

















TABLE XV







z = 25 mm










X
Y














−6.097
−12.664



−5.414
−11.525



−4.785
−10.362



−3.674
−7.973



−1.861
−3.015



−0.288
2.627



0.863
8.346



1.461
14.168



1.463
17.118



1.220
20.041



0.706
22.931



−0.102
25.770



−1.196
28.484



−2.586
31.057



−3.400
32.287



−4.294
33.466



−6.282
35.609



−8.535
37.464



−10.991
39.098

















TABLE XVI







z = 30 mm










X
Y














−5.585
−10.399



−4.067
−7.100



−2.804
−3.695



−1.189
1.944



−0.064
7.667



0.486
13.491



0.463
16.449



0.189
19.383



−0.363
22.272



−0.751
23.699



−1.217
25.108



−3.828
30.353



−4.679
31.560



−5.615
32.715



−7.690
34.793



−10.027
36.564



−12.561
38.097

















TABLE XVII







z = 35 mm










X
Y














−5.162
−7.551



−4.098
−4.761



−2.368
0.873



−1.217
6.608



−0.708
12.454



−0.704
13.936



−0.758
15.427



−1.060
18.379



−1.647
21.280



−2.058
22.709



−2.552
24.119



−3.772
26.814



−5.307
29.331



−6.199
30.519



−7.177
31.651



−9.340
33.665



−11.769
35.341



−14.399
36.754

















TABLE XVIII







z = 40 mm










X
Y














−4.536
−2.789



−3.114
2.520



−2.292
7.928



−2.135
10.675



−2.170
13.441



−2.907
18.884



−3.250
20.222



−3.664
21.546



−4.704
24.098



−6.028
26.505



−6.800
27.653



−7.645
28.755



−9.517
30.760



−11.648
32.479



−14.038
33.894



−16.570
35.051

















TABLE XIX







z = 45 mm










X
Y














−3.952
5.610



−3.744
9.858



−4.047
14.086



−4.411
16.191



−4.929
18.258



−6.455
22.212



−6.949
23.159



−7.488
24.086



−8.690
25.845



−10.056
27.471



−11.599
28.952



−13.298
30.240



−15.124
31.311



−17.062
32.195



−19.063
32.962

















TABLE XX







z = −5 mm










X
Y














−19.764
−24.408



−18.389
−24.124



−17.077
−23.624



−14.607
−22.303



−12.354
−20.650



−11.318
−19.698



−10.354
−18.686



−7.038
−14.217



−5.603
−11.812



−4.294
−9.345



−2.231
−4.690



−0.511
0.098



0.964
5.079



2.097
10.148



2.738
15.274



2.712
20.412



2.387
22.987



2.136
24.271



1.829
25.537



0.074
30.408



−0.494
31.579



−1.117
32.730



−2.524
34.917



−4.159
36.924



−5.979
38.785

















TABLE XXI







z = −10 mm










X
Y














−21.148
−24.550



−19.540
−23.946



−17.984
−23.240



−15.006
−21.576



−13.608
−20.570



−12.302
−19.447



−9.977
−16.914



−8.556
−14.998



−7.262
−13.011



−4.973
−8.872



−3.030
−4.542



−1.367
−0.074



0.131
4.783



1.301
9.730



2.016
14.737



2.087
19.764



1.814
22.288



1.591
23.550



1.314
24.796



−0.307
29.601



−1.426
31.897



−2.762
34.067



−4.328
36.060



−6.086
37.906

















TABLE XXII







z = −15 mm










X
Y














−21.794
−24.790



−20.175
−23.944



−18.591
−23.032



−17.082
−22.071



−15.621
−21.055



−12.915
−18.773



−10.552
−16.093



−8.510
−13.142



−5.128
−6.869



−3.707
−3.589



−2.436
−0.232



−0.930
4.469



0.255
9.261



1.019
14.115



1.181
18.994



0.970
21.446



0.540
23.894



−0.937
28.601



−1.982
30.851



−3.246
32.984



−4.740
34.943



−6.430
36.756

















TABLE XXIII







z = −20 mm










X
Y














−22.214
−26.282



−20.683
−24.942



−19.172
−23.578



−17.670
−22.205



−16.180
−20.819



−14.728
−19.392



−13.353
−17.905



−10.889
−14.728



−8.742
−11.328



−6.831
−7.765



−3.661
−0.323



−2.183
4.174



−1.014
8.742



−0.234
13.401



−0.037
15.773



−0.005
18.144



−0.510
22.827



−1.071
25.139



−1.836
27.393



−3.977
31.617



−4.658
32.603



−5.400
33.542



−7.006
35.315

















TABLE XXIV







z = −25 mm










X
Y














−22.961
−27.642



−22.018
−26.664



−21.095
−25.669



−19.289
−23.642



−15.812
−19.472



−12.680
−15.049



−9.911
−10.389



−8.345
−7.520



−6.615
−4.030



−5.102
−0.441



−3.634
3.837



−3.014
6.011



−2.481
8.210



−1.722
12.644



−1.476
17.128



−1.592
19.393



−1.890
21.635



−3.064
25.986



−3.957
28.073



−5.049
30.035



−6.358
31.855



−7.844
33.558

















TABLE XXV







z = −30 mm










X
Y














−4.440
6.519



−3.341
13.018



−3.243
16.316



−3.330
17.977



−3.515
19.623



−4.193
22.849



−4.700
24.428



−5.326
25.969



−6.933
28.834



−8.986
31.417

















TABLE XXVI







z = −35 mm










X
Y














−5.258
14.085



−5.583
18.053



−5.972
20.003



−6.524
21.926



−8.139
25.532



−9.219
27.183



−10.437
28.755










Both prototype and manufactured surfaces resulting from the application of Tables I-IX and Tables X-XXVI may conform to these points within reasonable process tolerances.
FIG. 5 illustrates an exemplary method 500 for constructing a blade surface according to an embodiment of the present invention. In step 510, a radius cut is sketched. Points are identified along that radius cut in step 520 and a spline is drafted to connect the aforementioned points in step 530. In step 540, each radius cut sketch is lofted in increasing radius order to form a surface. The surface may be extended or trimmed at the edges to reach the exact desired dimensions in step 550.
FIG. 6 illustrates a method 600 for forming a blade according to an embodiment of the present invention. In step 610, the surface (as may be created through the method described with respect to FIG. 5) is offset by a constant amount. In step 620, the offset is filled to form a single blade. In optional step 630, the bluntness of the leading and/or trailing edges may be altered for desired operating conditions.
FIG. 7 illustrates an alternative method 700 for forming a blade according to an embodiment of the present invention. In step 710, a complimentary airfoil shape is created. In step 720, a semi- or fully-airfoil blade cross-section is created on one or both sides of the blade. This cross-section may then be lofted into a solid in step 730. Alterations may also be made with respect to the bluntness of the leading and/or trailing edges for the purpose of desired operating conditions in step 740.
FIG. 8 illustrates an exemplary method 800 for constructing a fan according to an embodiment of the present invention. In step 810, blades are oriented with respect to the hub, which may include rotating the in-tact blade surface about an axis to change the pitch, dihedral, or sweep angle as they pertain to desired fan performance. The blade is then patterned around the hub or other fixturing device in step 820 for the appropriate number of blades. Blades can be fully or partially attached to the hub in step 830 and radiused as desired. Alterations may also be made to the leading and/or trailing edge bluntness in order to achieve desired operation conditions.
While Tables I-IX, for example, dictate an 87 mm diameter fan, the blade surface, full blade, and/or final fan may be scaled to change the size and output of the fan as may the measurements set forth in Tables X-XXVI. The resulting fan blade may be mirrored or run in either rotation. Additional attributes may be added to the fan including radii, mid-blade or blade-tip winglets (vertical extrusions out of the blade), full or partial-depth rings, extended or indented turbulators (bumps or cavities along the blade to change boundary layer behavior or noise), embossings, fastening devices, coatings and so forth. Additional surface features and/or strategic roughness may be employed. Furthermore, this blade surface may also be used in a similar fashion to make a non-rotating fan, or stator.
The methods disclosed with respect to FIGS. 5-8 may be embodied in computer software. A computer-readable storage medium may have embodied thereon a program. The program may be executable by a processor to perform the methods or combinations thereof as disclosed herein. These methods may be applicable in the field of computer-aided drafting or design, which may include three-dimensional design tools. The results of such computer-aided drafting and design may be rendered on a display device (e.g., a computer monitor) or printed to a tangible medium such as a computer printout. These results may be annotated with measurement information.
FIGS. 9A-9E illustrate exemplary fans constructed utilizing the surface profile disclosed with respect to FIG. 3. These fan configurations are exemplary and various elements thereof (e.g., hub, blade number, blade configuration, stators) may be interchangeably combined with one another and in conjunction with a particular surface profile to construct a fan in accordance with an embodiment of the present invention.
FIG. 9A illustrates an exemplary fan including five blades arranged about a cylindrical and hollowed hub.
FIG. 9B illustrates another exemplary fan including seven blades arranged about a cylindrical and capped hub.
FIG. 9C illustrates an exemplary fan including five blades with serrated edges and arranged about a conical hub.
FIG. 9D illustrates an exemplary fan including twelve blades with a notched edge and arranged about a cylindrical and capped hub.
FIG. 9E illustrates an exemplary fan including two blades and arranged about a cylindrical hub, the fan being enclosed within a stator.
FIGS. 10A-10E illustrate exemplary fans constructed utilizing the surface profile disclosed with respect to FIG. 4. These fan configurations are exemplary and various elements thereof (e.g., hub, blade number, blade configuration, stators) may be interchangeably combined with one another and in conjunction with a particular surface profile to construct a fan in accordance with an embodiment of the present invention.
FIG. 10A illustrates an exemplary fan including three blades extending outward in three-dimensions from an otherwise flat, two-dimensional hub.
FIG. 10B illustrates an exemplary fan including six blades and arranged about a cylindrical and solid hub, the fan being enclosed within a stator.
FIG. 10C illustrates an exemplary fan including three blades extending outward in three-dimensions from a conical hub.
FIG. 10D illustrates an exemplary fan including fourteen blades and arranged about a cylindrical hub, each of the blades being coupled to one another by intermediate ‘webbing.’
FIG. 10E illustrates an exemplary fan including four blades and arranged about a cylindrical and solid hub.
While the present invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements or steps thereof without departing from the true spirit and scope of the present invention. For example, methods of design may be applied to methods of manufacture.

## Claims

1. A method for axial fan design, the method comprising:
executing instructions embodied in a computer-readable storage medium to draft a spline to connect a plurality of points along a radius cut sketch to form a blade surface displayed on a display device, the instructions executed by a processor communicatively coupled to the display device;
offsetting the blade surface by a constant amount;
filling the blade surface to form a single blade, the single blade displayed on the display device, wherein a portion of the blade surface conforms to a logarithmic spiral, the radius of the logarithmic spiral unfolding at a constant order of growth when measured at equiangular radii;
orienting the single blade with respect to a hub on the display device;
patterning the single blade with a total number of blades to be affixed to the hub around the hub; and
executing instructions embodied in a computer-readable storage medium to attach the single blade and the remaining blades from the total number of blades to the hub, the instructions executed by a processor, the hub and attached blades displayed on the display device.

2. The method of claim 1, wherein the plurality of points are connected in increasing radius order.

3. The method of claim 1, further comprising executing instructions embodied in a computer-readable storage medium to extend the blade surface at an edge to achieve a desired dimension.

4. The method of claim 1, further comprising executing instructions embodied in a computer-readable storage medium to trim the blade surface at an edge to achieve a desired dimension.

5. The method of claim 1, wherein orienting the single blade includes executing instructions embodied in a computer-readable storage medium to rotate the blade surface about an axis to change a pitch angle, the instructions executed by a processor.

6. The method of claim 1, wherein orienting the single blade includes executing instructions embodied in a computer-readable storage medium to rotate the blade surface about an axis to change a dihedral angle, the instructions executed by a processor.

7. The method of claim 1, wherein orienting the single blade includes executing instructions embodied in a computer-readable storage medium to rotate the blade surface about an axis to change a sweep angle, the instructions executed by a processor.

8. The method of claim 1, wherein the attachment is temporary.

9. The method of claim 1, wherein the attachment is permanent.

10. The method of claim 1, wherein a portion of the blade surface conforms to an internal or external shell configuration from the phylum Mollusca and classes Gastropoda or Cephalopoda.

11. A fan apparatus, comprising:
a hub; and
a blade coupled to the hub, the blade including a blade surface, wherein the blade surface is designed by drafting a spline to connect a plurality of points along a radius cut sketch and the blade is designed by offsetting the blade surface by a constant amount and filling the blade surface to form a single blade, wherein a portion of the blade surface conforms to a logarithmic spiral, the radius of the logarithmic spiral unfolding at a constant order of growth when measured at equiangular radii.

12. The fan apparatus of claim 11, wherein the plurality of points are connected in increasing radius order.

13. The fan apparatus of claim 11, wherein the blade surface has been extended at an edge to achieve a desired dimension.

14. The fan apparatus of claim 11, wherein the blade surface has been rotated about an axis with respect to the orientation of the blade surface to the hub.

15. The fan apparatus of claim 14, wherein the rotation about the axis changes a pitch angle, dihedral angle, or sweep angle.

16. A method for axial fan design, the method comprising:
executing instructions embodied in a computer-readable storage medium to draft a spline to connect a plurality of points along a radius cut sketch to form a blade surface displayed on a display device, wherein a portion of the blade surface conforms to a logarithmic spiral, the radius of the logarithmic spiral unfolding at a constant order of growth when measured at equiangular radii, the instructions executed by a processor communicatively coupled to the display device;
creating a complimentary airfoil shape;
lofting the airfoil shape into a solid;
orienting the solidified blade with respect to a hub, the solidified blade oriented through the execution of computer-readable instructions executed by a processor, the oriented blade displayed on a display device;
patterning the solidified blade with a total number of blades to be affixed to the hub around the hub; and
executing instructions embodied in a computer-readable storage medium to attach the solidified blade and the remaining blades from the total number of blades to the hub, the instructions executed by a processor, the hub and attached blades displayed on the display device.

17. The method of 16, further comprising executing computer readable instructions to alter a leading edge or trailing edge bluntness of the blade surface.

18. The method of claim 16, wherein the airfoil shape is created on a first side of the blade surface.

19. The method of claim 16, wherein the airfoil shape is created on the second side of the blade surface.

20. The method of claim 16, wherein the airfoil blade is partially based on the surface.

21. The method of claim 16, wherein the airfoil blade is fully based on the surface.

22. A non-transitory computer-readable storage medium having embodied thereon a program, the program being executable by a processor to perform a method for axial fan design, the method comprising:
drafting a spline to connect a plurality of points along a radius cut sketch to form a blade surface, wherein a portion of the blade surface conforms to a logarithmic spiral, the radius of the logarithmic spiral unfolding at a constant order of growth when measured at equiangular radii;
offsetting the blade surface by a constant amount;
filling the blade surface to form a single blade;
orienting the single blade with respect to a hub;
patterning the single blade with a total number of blades to be affixed to the hub around the hub; and
displaying the single blade and the remaining blades from the total number of blades as being attached to the hub.

23. A non-transitory computer-readable storage medium having embodied thereon a program, the program being executable by a processor to perform a method for axial fan design, the method comprising:
drafting a spline to connect a plurality of points along a radius cut sketch to form a blade surface, wherein a portion of the blade surface conforms to a logarithmic spiral, the radius of the logarithmic spiral unfolding at a constant order of growth when measured at equiangular radii;
creating a complimentary airfoil shape;
lofting the airfoil shape into a solid blade;
orienting the solidified blade with respect to a hub;
patterning the solidified blade with a total number of blades to be affixed to the hub around the hub; and
displaying the solidified blade and the remaining blades from the total number of blades as being attached to the hub.