RCAIDE.Library.Methods.Powertrain.Converters.Rotor.design_propeller

design_propeller#

design_propeller(prop, number_of_stations=20)[source]#

Optimizes propeller chord and twist distribution given input parameters.

Parameters:

prop (RCAIDE.Library.Components.Powertrain.Converters.Rotor) –
Propeller component with the following attributes:
- fidelitystr
  Analysis fidelity level
- number_of_bladesint
  Number of blades on the propeller
- tip_radiusfloat
  Tip radius of the propeller [m]
- hub_radiusfloat
  Hub radius of the propeller [m]
- cruiseData
  
  Cruise conditions
  
  design_angular_velocityfloat
  Rotation rate [rad/s]
  
  design_freestream_velocityfloat
  Freestream velocity [m/s]
  
  design_Clfloat
  Design lift coefficient
  
  design_altitudefloat
  Design altitude [m]
  
  design_thrustfloat, optional
  Design thrust [N] (specify either thrust or power)
  
  design_powerfloat, optional
  Design power [W] (specify either thrust or power)
- airfoilsdict
  Dictionary of airfoil objects
- airfoil_polar_stationslist
  Indices of airfoil polars for each radial station
number_of_stations (int, optional) – Number of radial stations for blade discretization, default 20

Returns:

prop –

Propeller with optimized parameters:

cruise.design_powerfloat
Design power [W]
cruise.design_thrustfloat
Design thrust [N]
cruise.design_torquefloat
Design torque [N·m]
max_thickness_distributionarray_like
Maximum thickness distribution [m]
twist_distributionarray_like
Blade twist distribution [rad]
chord_distributionarray_like
Blade chord distribution [m]
radius_distributionarray_like
Radial station positions [m]
cruise.design_power_coefficientfloat
Design power coefficient
cruise.design_thrust_coefficientfloat
Design thrust coefficient
mid_chord_alignmentarray_like
Mid-chord alignment [m]
thickness_to_chordarray_like
Thickness-to-chord ratio
blade_solidityfloat
Blade solidity

Return type:

RCAIDE.Library.Components.Powertrain.Converters.Rotor

Notes

This function implements the design methodology from “Design of Optimum Propellers” by Adkins and Liebeck to optimize propeller chord and twist distributions. It iteratively solves for the optimal circulation distribution that minimizes induced losses.

The design process follows these steps:

Calculate atmospheric properties at the design altitude
Compute non-dimensional thrust or power coefficient
Initialize the wake skew angle (zeta)
Iteratively solve for the optimal circulation distribution:
1. Compute the Prandtl momentum loss factor
2. Determine the product of relative velocity and chord (Wc)
3. Calculate Reynolds number and Mach number at each station
4. Compute optimal angle of attack and drag coefficient
5. Calculate the efficiency parameter (epsilon = Cd/Cl)
6. Determine axial and tangential induction factors
7. Compute chord and blade twist angle
8. Calculate derivatives for thrust and power integrals
9. Update the wake skew angle (zeta)
Calculate final performance parameters (thrust, power, efficiency)
Compute thickness distribution and blade solidity

Major Assumptions

Either design thrust or design power must be specified (not both)
The design is optimized for a single operating condition
Airfoil performance is based on 2D characteristics
The wake is modeled with a constant skew angle

Theory The method is based on the classical blade element momentum theory with modifications to account for wake rotation. The key parameter in the optimization is the wake skew angle (zeta), which relates to the induced velocities.

The optimal circulation distribution minimizes induced losses while satisfying the thrust or power constraint. The method iteratively solves for this distribution by updating the wake skew angle until convergence.

References

[1] Adkins, C.N. and Liebeck, R.H., “Design of Optimum Propellers”, Journal of Propulsion and Power, Vol. 10, No. 5, 1994, pp. 676-682

design_propeller#

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