FIRST ESTIMATE BLADE ELEMENT PROPELLER MOMENTUM THEORY

Author: Lauren Jordan Contact: l.jordan@student.tudelft.nl

HOW TO USE THIS PROGRAMME

1. Open 'Input_information.toml' and replace the inputs with your aircraft's information. If you want to print graphs that show the induction factors, correction factor and twist across the blade, set 'graph' to true. If not, set to false.
2. Open 'Propeller_BEM.py' and run the file.

ABOUT THE PROGRAMME This programme should be used to get an initial rough estimate of the power required and thrust generated by the propellers at a specific speed.

Looking at the power available of your engines, you can deduce what your maximum speed. This calculation is done by calculating the power needed to turn the props (torque) and the drag caused by the blades with a specific propeller geometry and RPM.

This programme assumes that the blade has an ideal twist distirbution, thus experiencing only 3 degrees angle of attack. The ideal twist distribution is an output and can be used for further analysis. Be sure to check that the blade tips stay under Mach 1!

All assumptions:

1. Constant AoA of 3 degrees.
2. Blade hub effects are neglegible.
3. Constant chord.

RECOMMENDATIONS

The next steps to be taken are to add the blade hub effects, incorporate the actual distributed chord and to choose a twist distribution. From there a more accurate maximum speed and power required can be determined.

USEFUL SOURCES

1. I used the paper: Propeller Blade Element Momentum Theory with Vortex Wake Deflection [Rwigema, M.K., 2010] to create this programme.
2. Where I got the lift and drag coefficient of my airfoil at 3 degrees AoA: http://airfoiltools.com/