RCAIDE.Library.Methods.Powertrain.Converters.Rotor.Performance.Actuator_Disc_Theory.Actuator_Disk_performance

Actuator_Disk_performance#

Actuator_Disk_performance(rotor, conditions)[source]#

Analyzes a general rotor given geometry and operating conditions using Actuator Disc Theory.

Parameters:
  • rotor (Data) –

    Rotor component with the following attributes:
    • number_of_bladesint

      Number of blades on the rotor

    • tip_radiusfloat

      Tip radius of the rotor [m]

    • hub_radiusfloat

      Hub radius of the rotor [m]

    • cruiseData
      Cruise conditions
      • design_efficiencyfloat

        Design efficiency at cruise

      • design_torque_coefficientfloat

        Design torque coefficient at cruise

    • body_to_prop_velfunction

      Function to transform velocity from body to propeller frame

    • orientation_euler_angleslist

      Orientation of the rotor [rad, rad, rad]

  • conditions (Data) –

    Flight conditions with:
    • freestreamData
      Freestream properties
      • densitynumpy.ndarray

        Air density [kg/m³]

      • speed_of_soundnumpy.ndarray

        Speed of sound [m/s]

    • framesData

      Reference frames - body : Data

      Body frame
      • transform_to_inertialnumpy.ndarray

        Rotation matrix from body to inertial frame

      • inertialData
        Inertial frame
        • velocity_vectornumpy.ndarray

          Velocity vector in inertial frame [m/s]

    • energyData
      Energy conditions
      • convertersdict

        Converter energy conditions indexed by tag - commanded_thrust_vector_angle : numpy.ndarray

        Commanded thrust vector angle [rad]

        • blade_pitch_commandnumpy.ndarray

          Blade pitch command [rad]

        • omeganumpy.ndarray

          Angular velocity [rad/s]

Returns:

Results are stored in conditions.energy.converters[rotor.tag]:
  • thrustnumpy.ndarray

    Thrust vector [N]

  • powernumpy.ndarray

    Power [W]

  • rpmnumpy.ndarray

    Rotational speed [RPM]

  • omeganumpy.ndarray

    Angular velocity [rad/s]

  • power_coefficientnumpy.ndarray

    Power coefficient

  • thrust_coefficientnumpy.ndarray

    Thrust coefficient

  • torque_coefficientnumpy.ndarray

    Torque coefficient

  • speed_of_soundnumpy.ndarray

    Speed of sound [m/s]

  • densitynumpy.ndarray

    Air density [kg/m³]

  • tip_machnumpy.ndarray

    Tip Mach number

  • efficiencynumpy.ndarray

    Efficiency

  • torquenumpy.ndarray

    Torque [N·m]

  • orientationnumpy.ndarray

    Orientation matrix

  • advance_rationumpy.ndarray

    Advance ratio

  • velocitynumpy.ndarray

    Velocity vector [m/s]

  • disc_loadingnumpy.ndarray

    Disc loading [N/m²]

  • power_loadingnumpy.ndarray

    Power loading [N/W]

  • thrust_per_bladenumpy.ndarray

    Thrust per blade [N]

  • torque_per_bladenumpy.ndarray

    Torque per blade [N·m]

  • blade_pitch_commandnumpy.ndarray

    Blade pitch command [rad]

  • commanded_thrust_vector_anglenumpy.ndarray

    Commanded thrust vector angle [rad]

  • figure_of_meritnumpy.ndarray

    Figure of merit

Return type:

None

Notes

This function implements the Actuator Disc Theory to analyze rotor performance. It calculates thrust, torque, power, and efficiency based on the rotor geometry and operating conditions.

The computation follows these steps:
  1. Extract rotor parameters and operating conditions

  2. Transform velocity from inertial to rotor frame

  3. Calculate rotational speed and diameter

  4. Compute torque using the design torque coefficient

  5. Calculate power and thrust

  6. Compute performance metrics (thrust coefficient, power coefficient, etc.)

  7. Store results in the conditions data structure

Major Assumptions
  • Actuator disc theory assumes a uniform pressure jump across the rotor disc

  • The rotor is modeled as an infinitely thin disc

  • The flow is steady, incompressible, and inviscid

  • The rotor efficiency is constant and equal to the design value

Theory Actuator Disc Theory models the rotor as an infinitely thin disc that creates a pressure jump in the flow. The theory relates thrust, power, and induced velocity through momentum and energy conservation principles.

Key relationships include:
  • Thrust: \(T = \eta\cdot P/V\)

  • Torque coefficient: \(Cq = Q/(ρ·n²·D⁵)\)

  • Thrust coefficient: \(Ct = T/(ρ·n²·D⁴)\)

  • Power coefficient: \(Cp = P/(ρ·n³·D⁵)\)

  • Figure of Merit: \(FM = T·√(T/(2·ρ·A))/P\)

where:
  • T is thrust

  • P is power

  • V is velocity

  • η is efficiency

  • Q is torque

  • ρ is density

  • n is rotational speed

  • D is diameter

  • A is disc area