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2.3.3 Propeller Geometry Development Through CAD
After the blade design is detennined to be satisfactory, the program will create a text file
(OpenPVL_CADblade.txt) to export the propeller blade geometry. The file provides a
series of points that deseribe each foil section ofthe blade. This file was then used as an
input for the CAD software RHINO, which generates the points for the foil sections. The
propeller geometry is generated by creating closed splines for each sections and
connecting the sections to generate a blade. The hub design is the following step, and then
based on the designed number ofblades to add all blades onto the hub [20]. After the
propeller geometry is generated, a file can be created by RHINO to fabricate a prototype
for testing by a rapid prototyping (RP) machine (.STL fonnat). The RP part can then be
tcstc..'d. If the testing results arc not satisfied, designers can go back to modify the
propeller geometry in RHINO or regenerate a new design in OpenPVL, and then
prototype and test again. These fabrication-tesling·modification procedures arc repeated
until a satisfactory propeller is created.
In 2007, D'Epagnier designed an AUV propeller using OpenPVL code, and the AUV
Propeller has the following characteristics [20]:
The propeller has three blades.
The propeller is operated on the vehicle at 120 RPM in order 10 reach a speed of
1.0m/s.
The diameter of the propeller is 0.6096 m.
The required forward thrust ofthe propeller is 75 N.
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