The bent propeller tips function similarly to “winglets” on airliners to reduce drag and increase efficiency

Propeller designers at the Carderock Division of the Naval Surface Warfare Center (NSWCCD) are increasingly relying on simulations to predict the performance of propellers, and to evaluate novel design features for efficiency and military utility. Such simulations are included in the NavyFOAM computational fluid dynamics (CFD) solver, which is being developed under HPCMP CREATETM.  The Reynolds-Averaged Navier-Stokes (RANS) capability, turbulence modeling, and wall models allowed NSWCCD to develop and evaluate a novel tip shape to increase the efficiency and cavitation performance of a propeller. Furthermore, the NavyFOAM analytical results for thrust, torque, and efficiency compared very well with results from experiments performed on model scale hardware, giving greater confidence in the accuracy of the CFD simulations.

HPCMP resources enabled:

• Optimizations in NavyFOAM enabled faster full-scale results, allowing for more conditions to be examined.
• Excellent correlation with model scale experimental data increased confidence in simulation accuracy.
• Quicker turnaround on CFD simulations allowed for more design variations to be examined in detail.
• 3D-RANS performance evaluation of propeller designs at full-scale Reynolds number, including full scale geometric details (e.g., trailing-edge bevel), too small to be included in a model scale propeller.

The RANS-based CFD solvers in NavyFOAM developed under HPCMP CREATETM enabled NSWCCD propeller designers to evaluate model and full-scale performance for fixed-pitch propellers, yielding a potential 2%-4% increase in efficiency based on a novel design methodology and tip feature.