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Wing/Turbine Blade

Mi_Pot

New member
Good evening,


I am in the process of designing a three bladed wind turbine and I have a few queries pertaining to the modelling in Pro/E.


The blades will be integrated into the nose cone for manufacture on an RP machine and I was therefore planning to create the nose cone as a revolved feature and from there set up a datum plane perpendicular to the radial direction at some point within the feature. The blades would then be modelled as a protrusion outwards from this datum plane with a series of airfoil sections. My main question relates to how exactly I should create the tip. Our preliminary design sketches give us aradius where the last airfoil is to be situated allowing us a specific dimension in which to design the tip. I have heard people suggesting datum curves but I have no experience of this. What would you guys suggest?


Finally, once the part has been modelled there is an issue in that there is a maximum size of part which can be manufactured in the RP. Therefore we intended to make an arbitrary cut at some point along the blade and then have the nose cone and part blade manufactured seperately from the other part blade and tip section. How would I go about doing this in Pro/E if I saw wanted to have a dovetail joint through the two parts?


Many thanks,


Michael
 
Mi_Pot,

I vote for VSS to make the shape.

Do you intend to have functional use of the RP after re-assembly? The dovetail is a simple cut if you choose to do that. You can then make copies for each part you want to prototype and remove what is not needed in each part.

cheers,

M
 
So you suggest I create the complete part, then remove material through an extrusion to get rid of the bits I don't want and then create an assembly?
 
Can't use VSS if blade is defined by a "series" of airfoil sections...


May want to create an ibl file and from there you can create either curves, surface or solid - use curves for trial geometry 'cause if there're probs then surfaces or solids will probably bomb on you and curve will notand will allow you to examine the geometry.


As to the tip, are you planning a "full" radius ?
 
So I guess a protrusion is the way forward for the main blade profile.


For the tip we have several designs we are considering which we are hoping to run through CCM+ in a few weeks. Our main area of interest concerns a Hoener tip.
 
What format is your airfoil data in? Usually you want a rotor blade to be balanced structurally by aligning all of the aerodynamic centers (Usually the 1/4 chord) along a line and applying twist to each airfoil. The best thing to do is have a set of points that imports with the xy center being the aerodynamic center. Now you just create coordinate systems in the places you want the airfoils to start and naturally apply the twist to the coordinate systems. You can put a datum curve through each set of points and shoot a surface from boundries through every airfoil. The best thing about this approach is the fact that it is very easy to import new datum points or change the twist to achieve the right air flow!


Email: carpedm8936@yahoo.com for more detailed information, but this is a pretty standard approach in aerospace.
 
Thanks for that ctolman. It's nice to know how the industry does it.


Our aero data has been defined in such a way that twist angles are given about the leading edge and we we're going to align all the sections by this point. I haven't covered a large amount of thin airfoil theory so perhaps your reccommendation of the 1/4 chord line as the aero centre would be a better avenue to persue?


Our airfoil data sheets are defined with the leading edge at x=0.0 and the trailing edge at x=1.0. I would rather not go through the route of editing coordinate files so I guess we would have to keep it like this. Can the csys be translated once the airfoil geometry has been imported?
 
Hi guys.


I have managed to create the model Ihad in mind. For the tip design I had a play with using boundary blends and this really was the easiest way to do it wefound with two curves to specify the planform andthe airfoil sections at the wing tip to specify the profile. This has meant that there aretwo surfaces forming thetip - one from thelow pressure surface and one from the high p. surface. Is thereanyway tosolidify between these two surfaces? Another issue we had was that since one of the boundary curves originates from the leading edge of the airfoil pro/e has createdmore of a point there rather than taking the leading edge profile of the airfoil... how can I get pro/e to better simulate the airfoil profile?


Cheers
 
I assume you want a specific Trailing edge thickness??? If so, you set your curve to start at the top of the TE and end at the bottom of the TE. (Basically the curve should wrap around the entire airfoil leaving a gap to connect the TE. Shoot a surface between two curves like this and you will see the wing shape with a gap at the TE. Shoot a surface right between that gap and merge the surfaces. Create some end surfaces by sketching and filling the sketches and merge them into the original surfaces. You should than be able to solidify the merged quilt!
 

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