Category: Marine Propulsion

We’ve recently designed a customized propeller for naval architects L2O naval

Their project is a hybrid sail + electric boat that carries passengers on regular lines in Brittany.

Since the boat is battery-powered, a propeller optimization has been carried to outperform the best available traditional B-series propeller.

The gains are following :

• 6% of gain in consumption
• 2x increase of strength
• significative cavitation inception

Cavitation maps comparison :

After our loop of optimization with OpenFOAM, the propeller has been re-checked in CFD by L2O with FINE Marine. A very good agreement has been found in the results.

Few ressources are publicly available to validate propeller numerical tools.

Among the exceptions is the VP1304 case : a variable pitch propeller design by SVA with published open-water results.

In an attempt to validate our VLM code for propulsion case, we have used the geometry tables of this propeller and made a reverse analysis with Vortex Lattice Method.
Below is displayed the comparison which show a good agreement between experimental data and VLM computation.

We can see we have margin of progress for small J values where our model seems to stall before the real one. However it is worth noting the good prediction around the nominal J for this propeller.

We have designed the propulsion system ( propeller + duct-like casing ) for a small electrical motor distributed by a well-known French brand of sporting goods