B-Wageningen propeller diagrams

Discussion in 'Props' started by zzerachiel, Jun 1, 2010.

  1. zzerachiel
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    zzerachiel Junior Member

    Hy,

    I searched all over the internet for the B-Wageningen propeller diagrams and couldn't find any good diagram.

    I need the Kt-J, Kq-J with n0, kd and kn coeficients displayed.

    Can someone tell me where i can find them ?

    The only diagrams i've found have't got the n0, kd and kn coeficients and i really need them.

    BTW, n0 is eta0 :)

    I need those diagrams for a didactical project.

    Thank you.
     
  2. daiquiri
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    daiquiri Engineering and Design

  3. zzerachiel
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    zzerachiel Junior Member

    I already have those, but i cannot find the above mentioned coeficients.

    I was wondering if i can find the diagrams separated ( Kt-J and Kq-J ), since at college we work with that kind of diagrams.
     
  4. daiquiri
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    daiquiri Engineering and Design

    Can you please define n0, kd ,and kn coefficients?
     
  5. zzerachiel
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    zzerachiel Junior Member

    Ok, here is how the diagram i work with is organized.

    We have 2 diagrams KT-J and KQ-J, separated.

    On each diagram we have :

    P/D or H/D ( propeller pitch ) - family of horizontal curves ( ex. from 0.5 to 1.3 )
    etaP = familily of vertical curves ( ex. from 0.1 to 0.75 )
    etaOPT - another horizontal curve ( only one ), intersecting the etaP and P/D curves
    DiameterOPT ( dOPT ) - a horizontal curve, just like etaOPT but beneath it

    kd and kn are a series of curves intersecting all the above mentioned curves. Their profile is like a loose C.

    The resulting diagram is similar to a rectangular triangle.

    Those coeficients don't have a name, or at least i don't know it, they are part of the analitical formulas for the Kt and Kq
     
  6. daiquiri
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    daiquiri Engineering and Design

    You have confused me with therms "horizontal curves" and "vertical curves". I've had to rotate the J-K diagram by 90° to grasp the meaning of your words. :D

    I think you are looking for Bp-delta charts. You can get yourself a copy of Dave Gerr's "The Propeller Handbook". It costs around $10 + shipping fee at Amazon.com, but it is worth much more than that, you won't regret spending that money.
     
  7. zzerachiel
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    zzerachiel Junior Member

    As soon as i put my hands on the diagrams i will scan one of them and show it here :)

    Thank you for your time.
     
  8. jehardiman
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    jehardiman Senior Member

    Is it really eta"P"? or is it eta"B" or eta"D" or eta"R"

    eta"B" is the behind hull efficiency = measured thrust*Va/(2*pi*n*measured torque)

    eta"D" is the propulsive efficiency = effective power/delivered power = eta"H"*eta"R"*eta"O"

    eta"R" is the relative rotative efficiency = eta"B"/eta"O" = open water torque/ behind hull torque

    eta"O" is the open water efficiency = open water thrust*Va/(2*pi*n*open water torque)

    eta"H" is the hull efficiency = thrust deduction/wake fraction = (1-t)/(1-w) in Taylor notation

    If the purpose of the graphic was to find the optimum D, n, and P/D given an value of eta"B", then it all make sense. Therefore, from the description kd and kn would be curves of constant diameter and constant rps.

    Anyway, a picture of the graphic would help make more sense of what you are trying to find...kd and kn are not coefficients that I recall from van Manen. UofM bookstore through university Mircofilms used to have the original NSMB text and Bp-delta curves from the series. My copies are buried in a box right now.
     
    Last edited: Jun 1, 2010
  9. zzerachiel
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    zzerachiel Junior Member

    It is etaP as far as i can tell, the diagram i have is handwritten ( the letters/numbers not the lines :) ).

    So, here is the path i must follow to make a preliminary design for the propeller :

    Please excuse my bad english, but i'm romanian.

    calculate AE/AD = (1.3+0.3z)T/(p0-pv)D^2+k
    calculate Kn = 0.565Va/sqrt(n)*sqrt(sqrt(rho*Va/Pd);
    find out Jopt from the KQ-J
    calculate Dopt
    etc

    In the end i must have P/D, J, eta0 ( propeller randament ), KT.

    I don't know if i named eta0 correctly :)
     
  10. b1ck0
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    b1ck0 Senior Member

    Kn - Optimal Diameter curve ( design parameter for D(opt) )
    Kd - Optimal revolutions curve ( design parameter for n(opt) )

    That's what he's looking for ... I have the diagrams of Bulgarian Ship Hydrodynamic Centre from 1983 and these curves are drown there but I don't have scaner now ....

    The only thing I can do, is to interpolate the curves and give you the Equations ...
     
  11. zzerachiel
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    zzerachiel Junior Member

    Thank you b1ck0, that's what i'm looking for.

    Sorry, but i'm rather new in the fied and i don't have much tehnical information.

    I think that tomorow i will copy the diagrams tomorow and i hope this week i can scan them and upload them somewhere.
     
  12. b1ck0
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    b1ck0 Senior Member

    You will copy them, from where ?
     
  13. zzerachiel
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    zzerachiel Junior Member

    Well, i must give the project/homework until Thursday, and all i have to do from now is insert the coeficients.

    The project/homework is pretty straight-forward but i can't do much without the diagrams.

    No need to interpolate, but it would be nice to upload those diagrams somewhere :)
     
  14. zzerachiel
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    zzerachiel Junior Member

    Wel, from a friend, but i can get them tomorow.

    They are from a book "Propeller Calculation" written by Horia DUmitrescu.

    Again, sorry for the translation.
     

  15. b1ck0
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    b1ck0 Senior Member

    I will scan them ... but after 1-2 days ... if you want ... give me your propeller coefficients and I will tell you Kn and Kd :)
     
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