preliminary propeller design

hi guys, i'd like to make a thesis related to the preliminary propeller design, so finding the optimum circulation.. I found in internet a thesis wich use a matlab tool related to the induction factors.. could I use it for my thesis??
Any ideas of how continue the thesis??

thanks

 

If you don't show us what you've found, it will be difficult to answer...

 

these are the 2 projects..

http://dspace.mit.edu/bitstream/handle/1721.1/49872/463483489.pdf?sequence=1


www.dem.ist.utl.pt/~m_pta/pdf/30projecto.pdf


I'd like to compare the optimization method of the second project with the exact solution of the first project..
What do you think??

 

anyone can help me??

 

Well, both works you have linked describe in a pretty detailed manner the mathematical formulation used. The first work is purely teoretical, no comparisons with experimental data are shown - while the second one shows some validation results.

I am not familiar with the OpenProp, don't know if it uses a lifting-line or a vortex-panel formulation. Don't have time now to investigate into the software documentation.
But, generally speaking, all lifting-line prop design software share some common accuracy issues, which become more pronounced with increased blade loading - like under-predicting Kt and Kq at low J. This is due to increased inluence of transverse flow components (which are neglected in the lifting-line formulation), but also due to methods used for the evaluation of induced velocity components, which are not very reliable at high disc loadings. A blade wake made of constant-diameter helical vortices is a mathematical hack valid for a lightly loaded propeller disc, but giving an increasing error as the loading becomes higher and the wake contracts.

Furthermore, there is a problem of the spanwise velocity of separated flows in the root (hub) region, which is induced by the centrifugal force. It is not accounted for in the 2D airfoil lift-drag curves on which lifting-line mathematical formulation relies, and significantly modifies the post-stall characteristics of the affected area of the blade. It is a well-known phenomena to aeronautical engineers which have to deal with high-rpm props and rotors, though I don't know how important it is for ship props which are revving at lower speeds (and hence centrifugal forces acting on separated boundary layers are much lower).

Vortex-panel methods have the capability of anlysis of more complex 3D-shaped propellers, like highly skewed or raked props. They can give a more detailed info about points of possible onset of cavitation. But they also tend to underpredict the coefficients at low J's, mainly due to inability to model the leading-edge flow separation at high blade loadings.

That said, if your design point is in a low or moderate-low disc loading zone, you can use the above tools for a preliminary prop design and optimization. Because of the aforementioned hydrodynamical issues, don't be too confident in the results at J < 0.4 (or even 0.5) without further validation. And also don't rely the results if the pressure distribution indicate the possibility of cavitating areas of the blade.

Cheers!