Wageningen B series , Performance

Hi ,

I lately studied on wageningen b series propeller design. I designed 5,4,3 bladed propellers and when i put them into CFD analysis ,i had discrepancy between the design thrust and the CFD thrust around 15-25 % .

I wonder if any of you encountered a problem like this.

And dou you have any idea about the P/D ( pitch ratio) limitation ?. All the KT- KQ-J charts show that maksimum P/D is 1.4 but is there any optimum pitch

 

It is not a problem, the CFD is wrong. As for P/D, it is important to remember that the B series is a standard series, it is not wake adapted. If you are looking for an optimum wheel and not just buying one "off the shelf", then you will have to design it, and the wake adapted pitch line, by other methods..such a Lerb's lifting line or Kerwin's lifting surface.

 

You should b able to get a much better result, especially on thrust. Is the torque also off?

There are too many potential areas where you could have gone off the rails to make any really useful guesses, but you should be ale to match the data from the open curves very closely (1-2%).

 

Johneck, in my best analysis, thrust error is 10% and torque error is 15%. I've plotted the open curves by using Mathcad and using the KT KQ coefficients. So, i dont think there is an error even if over than 1%. I dont know what to do...

I come up with these problems while design of single propeller and i am planning to design Counter rotating Propellers : )

 

What CFD software are you using?

How much experience do you have with CFD? Have you modeled the flow around a simple shape with the software? If so how good were results?

 

Autodesk CFD simulation. around 10 experiences i have and still, results are imprecise.

i have modeled the flow just like how MIT and Hyndai did: )

 

Guys, Thank you all.

There is another and last question about Counter Rotating Propellers....

Do you have any idea or is there any basic relation between the Pitch ratios of the aft and for propellers.? It seems the aft prop should have higher pitch than the frw prop. But at which ratio??

 

Get Morgan's 1960 paper "The Design of Counterrotating Propellers Using Lerb's Theory" from SNAME Transactions.