Rotor Geometry Generation

ddutt · January 19, 2011, 06:18

Hi.

I need to model a rotor from an axial compressor with the specifications as given in the attachment.

These are from
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720002376_1972002376.pdf
Page 35 (not of the document. it is the number you have to key in to reach that page)

From what I understand, these are standard rotor specifications.
But they are not in any suitable coordinate system (basically, I know what these values are but do not know how to practically model it)

I would like to know how I could generate a point cloud using the given data so as to be able to import it into a standard modeling software.

Thanks

RossFS · January 20, 2011, 00:17

Solution: generate b-spline surfaces from the points. This will give you nice smooth curves from not too many points. Software for doing this:

SolidWorks Premium and Student edition allow you to import point cloud data and generate a model in CAD.
You do this via the add in "ScanTo3D"
You may have to smooth out the surface though, but SolidWorks ought to be able to do this.

The academic and full versions of ICEM CFD (from ANSYS) will let you import point cloud data also:
File -> import geometry -> "Formatted point data"
You can use the points to generate B-spline curves or surfaces with this software and then mesh it too.

EdgeCAM will take in point cloud data also and export to a variety of formats, but it was giving me troubles when trying to generate b-spline surfaces from the points.

Maybe check out the free software:
Point clout to NURBS
I think this outputs in .igs format which you should be able to open in quite a few software packages

ddutt · January 20, 2011, 01:27

Hey.

Yes, I know about generating the b splines. But for that I need the points first. When I look at the data I have, I do not see any point data at all. I do not know which coordinate system to use or what to input, so as to get the point cloud data.

I have previous experience using a coordinate measuring machine and making b splines using the point cloud data generated by that. But in this case, I do not have the physical object with me, hence I cannot do that.

Can you interpret the data I have. It can also be found here

http://ntrs.nasa.gov/archive/nasa/ca...1972002376.pdf
on page 33.

I need to be able to create a point cloud from the given data

ddutt · January 20, 2011, 01:29

I shall be using ANSYS ICEM.

RossFS · January 20, 2011, 16:14

What I can get out of your .bmp file:
They give you 13 points running from tip to hub and it looks like they provide quite a bit of data that you can use to turn into points at certain locations (span, thickness, chord, axial dimension, blade angles etc) as far as I can tell.

Use Appendix C (pg 30 in the pdf/ pg 27) to work out what each item in the tables are then look up these definitions and you should be able to construct the rotor

ddutt · January 21, 2011, 01:07

Hi

I think I need an airfoil design expert!

Yeah. I think that is what it will come to eventually. I shall have to google each term and manually generate all the points.

That'll take two weeks. Darn.

NASA should make it easier to interpret their data, if they have already made it public.

Anyway, thanks for trying.

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January 20, 2011, 00:17		#2
RossFS Member Join Date: Feb 2010 Location: Australia Posts: 65 Rep Power: 16	Solution: generate b-spline surfaces from the points. This will give you nice smooth curves from not too many points. Software for doing this: SolidWorks Premium and Student edition allow you to import point cloud data and generate a model in CAD. You do this via the add in "ScanTo3D" You may have to smooth out the surface though, but SolidWorks ought to be able to do this. The academic and full versions of ICEM CFD (from ANSYS) will let you import point cloud data also: File -> import geometry -> "Formatted point data" You can use the points to generate B-spline curves or surfaces with this software and then mesh it too. EdgeCAM will take in point cloud data also and export to a variety of formats, but it was giving me troubles when trying to generate b-spline surfaces from the points. Maybe check out the free software: Point clout to NURBS I think this outputs in .igs format which you should be able to open in quite a few software packages

January 20, 2011, 01:27		#3
ddutt New Member Devraj Dutt Join Date: Jan 2011 Posts: 7 Rep Power: 15	Hey. Yes, I know about generating the b splines. But for that I need the points first. When I look at the data I have, I do not see any point data at all. I do not know which coordinate system to use or what to input, so as to get the point cloud data. I have previous experience using a coordinate measuring machine and making b splines using the point cloud data generated by that. But in this case, I do not have the physical object with me, hence I cannot do that. Can you interpret the data I have. It can also be found here http://ntrs.nasa.gov/archive/nasa/ca...1972002376.pdf on page 33. I need to be able to create a point cloud from the given data

January 20, 2011, 01:29		#4
ddutt New Member Devraj Dutt Join Date: Jan 2011 Posts: 7 Rep Power: 15	I shall be using ANSYS ICEM.

January 20, 2011, 16:14		#5
RossFS Member Join Date: Feb 2010 Location: Australia Posts: 65 Rep Power: 16	What I can get out of your .bmp file: They give you 13 points running from tip to hub and it looks like they provide quite a bit of data that you can use to turn into points at certain locations (span, thickness, chord, axial dimension, blade angles etc) as far as I can tell. Use Appendix C (pg 30 in the pdf/ pg 27) to work out what each item in the tables are then look up these definitions and you should be able to construct the rotor

January 21, 2011, 01:07		#6
ddutt New Member Devraj Dutt Join Date: Jan 2011 Posts: 7 Rep Power: 15	Hi I think I need an airfoil design expert! Yeah. I think that is what it will come to eventually. I shall have to google each term and manually generate all the points. That'll take two weeks. Darn. NASA should make it easier to interpret their data, if they have already made it public. Anyway, thanks for trying.