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Mr. Ben Mitchell

KA-Series Propeller

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Hi,

 

I'm entirely new to CAESES, flow modeling, CFD and pretty much everything else you guys are all here for, and I'm hoping someone can help a bit.

 

I'm working on a project where I want to start from a KA-series prop (probably a KA-4-70) and then adjust the pitch and other values to optimize for my application.

 

After going through the tutorials, I'm realizing there's a very tall learning curve associated with modeling / simulating in CAESES.  I want to learn this package, but I also have a project I'm trying to finish.

 

Does anyone have a KA-series propeller model they'd be willing to share to jumpstart this process for me?   Failing that, any guidance on how I go from something like the attached to a useful model would be EXTREMELY appreciated.

 

 

 

 

 

 

Thanks!

-Ben

 

 

post-777-0-80510900-1478754005_thumb.png

post-777-0-93621800-1478754010_thumb.png

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Hi Ben,

 

I do not have a KA-series propeller I can give you. But we are working on a wageningen B-series prop at the moment and looking at the data of the KA-series, the design process should be similar.

 

So I would recommend you follow these steps:

 

1) create the points for all the profiles (from 0.2 r/R to 1.0 r/R) from the data. Out of these points create an interpolation curve for each section

 

2) Use a skinning (lofted surface), with all the sections created in step one, to create the main part of the blade

 

  --> These two steps are best done in a feature, for more information have a look at the tutorials within CAESES regarding features or look at this blog post. It contains a great guide regarding feature programming.

 

3) Create the tip of the blade by using a separate feature

 

4) Create the fillet between the hub and the blade. Best done by using Breps ( Edge Fillet --> See tutorial "Introduction to BReps")

 

I hope this gives you an idea on how to do it. If you have further questions feel free to ask.

 

Regards,

Simon

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If I could ask some follow-on questions:

 

I'm looking at translating the tabular data into an understanding of the actual geometry so I can do the modeling appropriately, and I'm running into confusion that the googles haven't helped to resolve.

 

There are two tables, one of which includes values for Distance of max thickness from leading edge in % of length of section and another that contains values for the distance of the ordinates from the maximum thickness to the leading and trailing edges on the face and back of the prop.  I'm struggling to interpret this stuff:

 

1. For sections at positions greater than 0.6R, the "Distance of max thickness" table has no values.  Why?

 

2. I must not be understanding "distance of the ordinates" correctly.  Shouldn't "distance of maximum thickness from the leading edge" match the distance of the max thickness ordinate from the leading edge?  I'm really unclear what that Ordiantes of the Ka-screw series table is telling me.

 

Thanks!

-Ben

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I may be starting to understand this better, actually.

 

It seems really convoluted, but if I'm correct:

 

In the ordinates table, the percentages values (column headers) allow me to calculate an "X" coordinate value for a point in X-Y space.  To do this I would first calculate the blade width at the r/R section as a function of Diameter, Blade Count and Ae/Ao.  Then I'd determine an X-coordinate for the max thickness point based on it's percentage distance from the leading edge.  And finally I'd add or subtract from that value by the percentages in table 3B to determine for any r/R section where the ordinates are located along the X-axis.

 

For the Y-values I similarly work out toward the extremes from the point of max thickness using the appropriate percentages of total thickness for that section from Table 3B.

 

For a hypothetical 4-bladed 10-inch diameter propeller with an Ae/Ao of 0.70, that would give me the following coordinates:

 

post-777-0-39520600-1478806929_thumb.png

 

Assuming that's right, I'm still a bit confused on how to proceed:

The lines described by these curves appear to be in their own coordinate systems, no? The Back curve starts and ends at Y=0, where the Face curve starts at Y=0.08084 and ends at Y=0.13332.

 

And resolving this isn't a simple transformation since the fact that the Face curve starts and ends at different Y-values means that the length between its start and end coordinates is different from that for the Back curve, which has the same extent along the X-axis but starts and finishes at the same Y-position.  If you rotated one curve so all the end points were colinear, the ends wouldn't connect...

 

I think I'm getting closer here, but I'm still confused.

 

Oh, and I'm assuming that the face ordinate table ends at 0.5 because it's a straight line from 0.6 on out?

But what about determining the starting X coordinate for the point of max thickness for the Back curves when the distance of max thickness to leading edge values are null in the first table for r/R 0.7 and above?

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Hi Ben,

 

sorry, I am not an expert on the Ka-Series myself.

 

It might be possible, that the ordinates of the points need to be added, if I do that a good looking profile is the result, but I do not know if that is the correct way and I could not find any detailed in information in the literature.

 

I am pretty sure the face from 0.5 on is a straight line, because it is similar for other series propellers. I would also assume for the profiles of 0.7 and higher the maximum thickness is at half of the chord length, as it is shown in the images of the sections.

 

If you have further questions on how to set it up in Caeses just let me know.

 

Cheers,

Simon

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I may be starting to understand this better, actually.

 

It seems really convoluted, but if I'm correct:

 

In the ordinates table, the percentages values (column headers) allow me to calculate an "X" coordinate value for a point in X-Y space.  To do this I would first calculate the blade width at the r/R section as a function of Diameter, Blade Count and Ae/Ao.  Then I'd determine an X-coordinate for the max thickness point based on it's percentage distance from the leading edge.  And finally I'd add or subtract from that value by the percentages in table 3B to determine for any r/R section where the ordinates are located along the X-axis.

 

For the Y-values I similarly work out toward the extremes from the point of max thickness using the appropriate percentages of total thickness for that section from Table 3B.

 

For a hypothetical 4-bladed 10-inch diameter propeller with an Ae/Ao of 0.70, that would give me the following coordinates:

 

attachicon.gifScreen Shot 2016-11-10 at 11.41.37 AM.png

 

Assuming that's right, I'm still a bit confused on how to proceed:

The lines described by these curves appear to be in their own coordinate systems, no? The Back curve starts and ends at Y=0, where the Face curve starts at Y=0.08084 and ends at Y=0.13332.

 

And resolving this isn't a simple transformation since the fact that the Face curve starts and ends at different Y-values means that the length between its start and end coordinates is different from that for the Back curve, which has the same extent along the X-axis but starts and finishes at the same Y-position.  If you rotated one curve so all the end points were colinear, the ends wouldn't connect...

 

I think I'm getting closer here, but I'm still confused.

 

Oh, and I'm assuming that the face ordinate table ends at 0.5 because it's a straight line from 0.6 on out?

But what about determining the starting X coordinate for the point of max thickness for the Back curves when the distance of max thickness to leading edge values are null in the first table for r/R 0.7 and above?

sir i m also doing work on this propeller .. I m also not able to interpret the data given in table .. if u got the idea how to model ka 4 70 propeller .. can u help me out . CAN u tell me how interpret the data and how to incorporate this darta in CAD software for modelling it

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I may be starting to understand this better, actually.

 

It seems really convoluted, but if I'm correct:

 

In the ordinates table, the percentages values (column headers) allow me to calculate an "X" coordinate value for a point in X-Y space.  To do this I would first calculate the blade width at the r/R section as a function of Diameter, Blade Count and Ae/Ao.  Then I'd determine an X-coordinate for the max thickness point based on it's percentage distance from the leading edge.  And finally I'd add or subtract from that value by the percentages in table 3B to determine for any r/R section where the ordinates are located along the X-axis.

 

For the Y-values I similarly work out toward the extremes from the point of max thickness using the appropriate percentages of total thickness for that section from Table 3B.

 

For a hypothetical 4-bladed 10-inch diameter propeller with an Ae/Ao of 0.70, that would give me the following coordinates:

 

attachicon.gifScreen Shot 2016-11-10 at 11.41.37 AM.png

 

Assuming that's right, I'm still a bit confused on how to proceed:

The lines described by these curves appear to be in their own coordinate systems, no? The Back curve starts and ends at Y=0, where the Face curve starts at Y=0.08084 and ends at Y=0.13332.

 

And resolving this isn't a simple transformation since the fact that the Face curve starts and ends at different Y-values means that the length between its start and end coordinates is different from that for the Back curve, which has the same extent along the X-axis but starts and finishes at the same Y-position.  If you rotated one curve so all the end points were colinear, the ends wouldn't connect...

 

I think I'm getting closer here, but I'm still confused.

 

Oh, and I'm assuming that the face ordinate table ends at 0.5 because it's a straight line from 0.6 on out?

But what about determining the starting X coordinate for the point of max thickness for the Back curves when the distance of max thickness to leading edge values are null in the first table for r/R 0.7 and above?

Could you explain your table?  For what section is it? Did you get the geometry?  I'm now checking geometry of sections and have some questions also. 
1) Strange coordinates for face LE 100% - 33 / back LE 95% - 27,40 at section 0,2R 
2) How to calculate LE nose radius correctly? 

post-1091-0-56998000-1549812537_thumb.png

post-1091-0-75768300-1549812549_thumb.png

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