Creating Impeller blade 2

[cgelang]

Greetings everyone.

Does anybody tried making an impeller blade. Just want to know what's the best approach or command in UG on the swerling shape of the blade. I only have angle input on the 2d for the blade, I still figuring out how these angle be applied in UG to get the shape. I would be very grateful to somebody who can share their experty.

Thanks in advance guys.

lang, cge

 

[hudson888]

Lang,

I'm sure we've modelled a few but it is often the case that they don't contain a twist as it usually makes them exceedingly difficult to manufacture. Anyway a sweep with an angular law and linear function allows you to induce a twist about the guide curve as an axis by a set angle.

If you post your version of NX and some of the material or CAD files then we'd probably get closer to figuring an appropriate response.

Cheers

Hudson

 

[cgelang]

Excellent Hudson, I get the shape that I want. Sweep by angular law really is the solution, I've just know these UG function right now. Thanks to your input it's really a big help to me that is still learning.

Once again, thank you so much.

Regards,
lang, cge

 

[SiW979]

I'm not sure how an impellar looks, but have a look at the attached file, it is a prop I modelled a while ago using some quite basic commands. It's nice though as is is fuly parametric, go into the expressions, find the one named OUTER PITCH and change it from 45 to 15 for example. See what you think.

Best regards

Simon (NX4.0.4.2 MP4 - TCEng 9.1.3.6.c)

http://www.jcb.com

Life shouldn't be measured by the number of breaths you take, but rather how many times it's taken away...

 

[potrero]

JCBCad
thanks for sharing; that's a cool part.

 

[gieter]

Lang,

Just out of curiosity: I think the 2D blade chape normally is a volute, but how do you determine the angle of the blade (from a geometric point of view, not a UG modeling point of view)?

regs,

Gieter,

 

[adrag]

Dont mean to hijack the thread, but how do you give it the chrome look with the desert reflection?

Al

 

[potrero]

the "chrome look" is a result of viewing the part in "Studio" rendering style...

 

[hudson888]

Actually it was just done with face analysis>reflection tools in that case. I think that just about everyone gets that licence.

Cheers

Hudson

 

[cowski]

@adrag
Or, by analyzing the faces using the reflection option (you can pic from a variety of pictures to use as the reflection).

 

[SiW979]

The actual path to get to the reflection mapping is Analysis -> Shape -> Face -> Reflection. then pick the middle icon at the top which is scene images, drag a window around your CAD model, select an image and click apply. From then on all you need to do is select a different image and click apply, you will not need to select faces again unless you modify the model. You can also very easily toggle between normal model shading, wire frame and the reflection mapping by using the rick click radial popup menus and picking the bottom right one which is anlaysis.

For your information, the reflection mapping is more of an industrial design tool for people who model class A surfaces such as car body panels. It anables the designer to identify irregularities in the surfaces, such as non-tangency or inflections as these will distort the light and show them up very easily.

For us non felt-tip fairy type design engineers, the reflection mapping is a nice way to get some decent looking images for presentations etc.

Best regards

Simon (NX4.0.4.2 MP4 - TCEng 9.1.3.6.c)

http://www.jcb.com

Life shouldn't be measured by the number of breaths you take, but rather how many times it's taken away...

 

[adrag]

Thanks guys. I've never had the time to learn that functionality. Seems like whenever I started to mess with it, I'd get another hot project in and it kept being put on the back burner. But sometimes I have to send a jpeg of the model to a customer and it would be nice to make it look pretty.

Al

 

[cbrn]

Careful with the design of engineeristically-correct propeller / turbine blades !!!
They obey to very strict fluid-dynamics laws and generally end up with double-curvature shapes. The design parameters, however, are leading-edge angles and trailing-edge angles, plus various other such as angular span etc...

There is no simple way to model such a blade with a CAD, in the case you want to keep the design parameters "as they are". Most of the time appropriate routines generate points-clouds, very seldom the parametric model uses the exact same parameters used in the calculation / design of the blade profile.
With Pro/Engineer, something like 10 years ago, I found a way to do this.
With UG, this seems far more difficult though various workarounds DO exist (where I work, a particular method is used but it is obviously top secret !).
For my own pleasure, I made a model of a Francis turbine using the parametric definitions of Hermite curves. Thanks to this, the "piloting" parameters are exactly the ones an hydraulic engineer uses when he defines the blade. But the math underlying is a bit complicated... I described it in an old thread dated 2005 or so... I even can't remember the exact title.
Sorry for not being more precise,

Regards

 

[wmalan]

Check out

http://www.stroemtec.com/en/products.html

as an example of what's possible.

GE and others have created in-house functions as well to do these things. We machine turbine products and I can tell you every customer has there own way of doing things. Most come to us as ugly patches. Very few actually model the variable fillets at the hub area properly.

--
Bill

 

[cgelang]

Thanks for all the reply. Specially JCBCAD. I learn new ideas from your post. To cbrn, very interesting points and advise, I get back the engineer if it meets all the parameter requirements as per design.

Once again thanks.

Lang, cge