RCAIDE.Library.Methods.Powertrain.Converters.Fan.compute_fan_performance

compute_fan_performance#

compute_fan_performance(fan, conditions)[source]#

Computes the thermodynamic performance of a fan in a gas turbine engine.

Parameters:

  • fan (RCAIDE.Library.Components.Converters.Fan) –

    Fan component with the following attributes:
    • tagstr

      Identifier for the fan

    • working_fluidData

      Working fluid properties object

    • pressure_ratiofloat

      Pressure ratio across the fan

    • polytropic_efficiencyfloat

      Polytropic efficiency of the compression process

  • conditions (RCAIDE.Framework.Mission.Common.Conditions) –

    Flight conditions with:
    • energyData
      Energy conditions
      • convertersdict

        Converter energy conditions indexed by tag - inputs : Data

        Input conditions - stagnation_temperature : numpy.ndarray

        Stagnation temperature at fan inlet [K]

        • stagnation_pressurenumpy.ndarray

          Stagnation pressure at fan inlet [Pa]

        • static_pressurenumpy.ndarray

          Static pressure at fan inlet [Pa]

        • static_temperaturenumpy.ndarray

          Static temperature at fan inlet [K]

        • mach_numbernumpy.ndarray

          Mach number at fan inlet

Returns:

Results are stored in conditions.energy.converters[fan.tag].outputs:
  • stagnation_temperaturenumpy.ndarray

    Stagnation temperature at fan exit [K]

  • stagnation_pressurenumpy.ndarray

    Stagnation pressure at fan exit [Pa]

  • static_temperaturenumpy.ndarray

    Static temperature at fan exit [K]

  • static_pressurenumpy.ndarray

    Static pressure at fan exit [Pa]

  • stagnation_enthalpynumpy.ndarray

    Stagnation enthalpy at fan exit [J/kg]

  • work_donenumpy.ndarray

    Work done by the fan [J/kg]

  • mach_numbernumpy.ndarray

    Mach number at fan exit

Return type:

None

Notes

This function computes the thermodynamic properties at the fan exit based on the inlet conditions and fan characteristics. It calculates the temperature rise, pressure rise, and work done by the fan during the compression process.

The computation follows these steps:

  1. Extract inlet conditions (temperature, pressure, Mach number)

  2. Compute working fluid properties (gamma, Cp)

  3. Calculate stagnation pressure at exit using pressure ratio

  4. Compute stagnation temperature at exit using polytropic efficiency

  5. Calculate static temperature and pressure at exit based on exit Mach number

  6. Compute stagnation enthalpy at inlet and exit

  7. Calculate work done by the fan (exit - inlet stagnation enthalpy)

  8. Store all results in the conditions data structure

Major Assumptions

  • Constant polytropic efficiency and pressure ratio

  • Mach number is preserved from inlet to exit

Theory The stagnation temperature ratio across the fan is related to the pressure ratio by:

\[\frac{T_{t,out}}{T_{t,in}} = \left(\frac{P_{t,out}}{P_{t,in}}\right)^{\frac{\gamma-1}{\gamma \eta_{p}}}\]
where:

  • \(T_{t,out}\) is the exit stagnation temperature

  • \(T_{t,in}\) is the inlet stagnation temperature

  • \(P_{t,out}\) is the exit stagnation pressure

  • \(P_{t,in}\) is the inlet stagnation pressure

  • \(\gamma\) is the ratio of specific heats

  • \(\eta_{p}\) is the polytropic efficiency

References

[1] Cantwell, B., “AA283 Course Notes”, Stanford University https://web.stanford.edu/~cantwell/AA283_Course_Material/AA283_Course_Notes/

See also

RCAIDE.Library.Methods.Powertrain.Converters.Compressor.compute_compressor_performance

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