B-series

hi

can anyone please explain what does a B-Series propeller means?? is this some sort of standard design for propellers?

 

It refers to the Wageningen B-series of props. It is a propeller series that has a large amount of test work to produce a whole set of data that is reduced to "simple" empirical equations to calculate prop performance.

You can read all about the data here:
http://deepblue.lib.umich.edu/bitstream/2027.42/3557/5/bab2786.0001.001.pdf
It is a big file so will take a while to load.

Although commonly used it constrains the shape of props. There are better analysis techniques using primarily analytical methods based on the fundamental physics. These are much more flexible in application. The freeware JavaProp will work just as well for water props as air props providing the fluid parameters are set accordingly.

Rick W

 

The full name is "Wageningen B-series propellers". It is a series of propellers tested in the Netherlands Ship Model Basin and succesively expressed in the polinomial form by the people from Michigan University. Thanks to this availability of test data it has become a popular prop series and a reference for many prop-analysis and design software.
You can find a paper with the polinomials for this series at:

http://deepblue.lib.umich.edu/bitstream/2027.42/3557/5/bab2786.0001.001.pdf

P.S.
Ooooops, sorry Rick. I have doubled your post.
I didn't refresh my screen before pressing "reply".

 

Reynolds > 2*10^6

How do you calculate the Reynolds number in Wageningen B-Series:

1) Re=n*D^2/v

2) Re =n*D*C/v

3) Re=Va*C/v

4) Re=Va*D/v

5) Re=C*V(0.7)/v

v=kinematic viscosity[m^2/s]
n=revolutions/sec
D=Diameter [m]
C=cord propeller at sections 0.7[m]
Va=Axial velocity[m/s]
V(0.7)=velocity resulting = (Va^2+(2*Pi*0.7*R*n)^2)^(1/2)[m/s]

thanks to all

 

Actually, Rn changes along the span of the blade so if you evaluate it at 0.75 r then the Rn would be:

R|0.75 = C|0.75*sqrt(Va^2+(0.75*pi*n*D)^2)/mu

Which is effectively the same a 5).

FWIW, the Wageningen curve fit coefficients are not developed from Reynolds methods but from Taylor Bp-sigma coefficients. So knowing the Rn along the blade will only be of use in blade element modeling which was used to fair the experimental Bp-sigma curves for a constant Rn. For the Bp-sigma coefficients commonly used, Rn = 2x10^6 | 0.75R.