RCAIDE.Library.Methods.Powertrain.Converters.Turboshaft.size_core

size_core

size_core(turboshaft, conditions)

Sizes the core flow for a turboshaft engine at the design condition.

Parameters:

• turboshaft (RCAIDE.Library.Components.Converters.Turboshaft) –

  Turboshaft engine component with the following attributes:

  • tagstr

    Identifier for the turboshaft

  • reference_temperaturefloat

    Reference temperature [K]

  • reference_pressurefloat

    Reference pressure [Pa]

  • design_powerfloat

    Design power output [W]

  • compressorData

    Compressor component

    • mass_flow_ratefloat

      Mass flow rate through the compressor [kg/s]

  • mass_flow_ratefloat

    Mass flow rate through the turboshaft [kg/s]

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

  Flight conditions with:

  • energyData

    Energy conditions

    • convertersdict

      Converter energy conditions indexed by tag

      • total_temperature_referencefloat

        Reference total temperature [K]

      • total_pressure_referencefloat

        Reference total pressure [Pa]

      • non_dimensional_powerfloat

        Non-dimensional power

Returns:

Results are stored in the turboshaft object:

• mass_flow_ratefloat

  Mass flow rate through the turboshaft [kg/s]

• compressor.mass_flow_ratefloat

  Mass flow rate through the compressor [kg/s]

Return type:

None

Notes

This function sizes the core flow of a turboshaft engine based on the design power requirement and the non-dimensional power computed from the engine cycle analysis. It calculates the dimensional mass flow rate needed to produce the specified design power and corrects it to the reference conditions.

The computation follows these steps:

1. Extract reference conditions and engine parameters

2. Compute non-dimensional power using the compute_power function

3. Calculate the dimensional mass flow rate required to produce the design power

4. Correct the mass flow rate to the reference conditions

5. Store the results in the turboshaft object

Major Assumptions

• Perfect gas behavior

• Turboshaft engine with free power turbine

Theory The dimensional mass flow rate is calculated as:

\[\dot{m}_{air} = \frac{P_{design}}{P_{sp}}\]

The corrected mass flow rate for the compressor is:

\[\dot{m}_{compressor} = \frac{\dot{m}_{air}}{\sqrt{\frac{T_{ref}}{T_{t,ref}}}\frac{P_{t,ref}}{P_{ref}}}\]

where:

• \(P_{design}\) is the design power

• \(P_{sp}\) is the non-dimensional power

• \(T_{ref}\) is the reference temperature

• \(T_{t,ref}\) is the reference total temperature

• \(P_{ref}\) is the reference pressure

• \(P_{t,ref}\) is the reference total pressure

References

[1] Mattingly, J.D., “Elements of Gas Turbine Propulsion”, AIAA Education Series, 2005, pp. 332-336 [2] Stuyvenberg, L., “Helicopter Turboshafts”, University of Colorado, 2015 https://www.colorado.edu/faculty/kantha/sites/default/files/attached-files/70652-116619_-_luke_stuyvenberg_-_dec_17_2015_1258_pm_-_stuyvenberg_helicopterturboshafts.pdf

See also

RCAIDE.Library.Methods.Powertrain.Converters.Turboshaft.compute_power