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modifications
Modifications
→Manufacturing
The main function of the nacelle is to maintain the generator in position and to maintain all the assembly stable on the top of the tower. The tail fin is also fixed on the nacelle. It will orientate the hub en front of the wind. We decided to use the 3D printing to create an original shape. Indeed, 3D printing allows the design of pieces that would be extremely expensive to create with classic manufacturing means. The shape we designed uses the Venturi effect to create an air flux on the surface or the generator. It permits to cool it more efficiently and so to increase the general efficiency. The ABS is a thermoplastic and doesn't resist at high temperatures. In our project, the uses of this type of cooling turned out to be necessary. The assembly of the nacelle is shown on the hereby picture.
==Manufacturing& Assembly== The different pieces we designed during the project are available in CAD format and stl format. The first format allows anybody who would like to do it to improve the pieces or to try new designs. The second one is the format used by most 3D printers. It allows the direct printing of the prototype. The main parameters that we used for the manufacturing of the pieces are the printing precision and the filling. Regarding precision, we used the best precision available on the Up Mini, layers of 0.2mm. The precision is important for the profiles of the blades because it influences the aerodynamics. The Up Mini has 4 different filling parameters: negligible, slight, medium and full. We used te medium filling for most of the pieces. It allowed to obtain pieces sufficiently resistant for reasonable masses and costs. Moreover, it was important not to weigh down the blades to limit centrifugal stresses. The only pieces fully filled are:* the hub part that transmits the torque because it is the piece more inclined to delamination* the parts of the nacelle that constrain the generator because they also suffer important stresses The assembly of the different parts is simple:* blades are assembled with threaded rods and M3 nuts. L'assemblages des différentes parties se fait simplement:* les pales s'assemblent avec des tiges filetées et des écrous de M3. Les clavettes utilisées pour guider l'assemblage sont de forme parallélépipédique de 4mm de côté. (voir dessins techniques pour la longueur des tiges filetées et la longueur des clavettes (dépend du set de pale choisi))* Tous les autres boulons utilisés sont de type M5 (les différentes longueur sont disponibles dans les dessins techniques)
==Tests==