RCAIDE.Library.Methods.Powertrain.Propulsors.Turbofan.compute_thurst

compute_thurst

Functions

compute_thrust(turbofan, conditions)

Computes thrust and other performance metrics for a turbofan engine.

compute_thrust(turbofan, conditions)

Computes thrust and other performance metrics for a turbofan engine.

Parameters:

• turbofan (RCAIDE.Library.Components.Propulsors.Turbofan) –

  Turbofan engine component with the following attributes:

  • tagstr

    Identifier for the turbofan

  • reference_temperaturefloat

    Reference temperature for mass flow scaling [K]

  • reference_pressurefloat

    Reference pressure for mass flow scaling [Pa]

  • compressor_nondimensional_massflowfloat

    Non-dimensional mass flow parameter [kg·√K/(s·Pa)]

  • SFC_adjustmentfloat

    Adjustment factor for specific fuel consumption

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

  Flight conditions with:

  • freestreamData

    Freestream properties

    • isentropic_expansion_factornumpy.ndarray

      Ratio of specific heats (gamma)

    • velocitynumpy.ndarray

      Freestream velocity [m/s]

    • speed_of_soundnumpy.ndarray

      Speed of sound [m/s]

    • mach_numbernumpy.ndarray

      Freestream Mach number

    • pressurenumpy.ndarray

      Freestream pressure [Pa]

    • gravitynumpy.ndarray

      Gravitational acceleration [m/s²]

    • specific_heat_at_constant_pressurenumpy.ndarray

      Specific heat at constant pressure [J/(kg·K)]

  • energy.propulsors[turbofan.tag]Data

    Turbofan-specific conditions

    • fuel_to_air_rationumpy.ndarray

      Fuel-to-air ratio

    • total_temperature_referencenumpy.ndarray

      Reference total temperature [K]

    • total_pressure_referencenumpy.ndarray

      Reference total pressure [Pa]

    • fan_nozzle_exit_velocitynumpy.ndarray

      Fan nozzle exit velocity [m/s]

    • fan_nozzle_static_pressurenumpy.ndarray

      Fan nozzle static pressure [Pa]

    • fan_nozzle_area_rationumpy.ndarray

      Fan nozzle area ratio

    • core_nozzle_exit_velocitynumpy.ndarray

      Core nozzle exit velocity [m/s]

    • core_nozzle_static_pressurenumpy.ndarray

      Core nozzle static pressure [Pa]

    • core_nozzle_area_rationumpy.ndarray

      Core nozzle area ratio

    • flow_through_corenumpy.ndarray

      Fraction of flow through core

    • flow_through_fannumpy.ndarray

      Fraction of flow through fan

    • bypass_rationumpy.ndarray

      Bypass ratio

    • throttlenumpy.ndarray

      Throttle setting [0-1]

Returns:

Results are stored in conditions.energy.propulsors[turbofan.tag]:

• thrustnumpy.ndarray

  Total thrust force [N]

• fan_thrustnumpy.ndarray

  Thrust from fan stream [N]

• core_thrustnumpy.ndarray

  Thrust from core stream [N]

• thrust_specific_fuel_consumptionnumpy.ndarray

  Thrust specific fuel consumption [kg/(N·hr)]

• non_dimensional_thrustnumpy.ndarray

  Non-dimensional thrust

• core_mass_flow_ratenumpy.ndarray

  Core mass flow rate [kg/s]

• fuel_flow_ratenumpy.ndarray

  Fuel flow rate [kg/s]

• powernumpy.ndarray

  Power output [W]

• specific_impulsenumpy.ndarray

  Specific impulse [s]

Return type:

None

Notes

This function implements a thermodynamic model for a turbofan engine to calculate thrust, fuel consumption, and other performance metrics. It computes thrust from both the core and fan streams, accounting for momentum and pressure forces.

Major Assumptions

• Perfect gas behavior

• Thrust is calculated from momentum and pressure forces at the nozzle exits

Theory The non-dimensional thrust components are calculated as:

\[ \begin{align}\begin{aligned}F_{nd,fan} = \phi_{fan} \cdot (\gamma \cdot M_0^2 \cdot (V_{fan}/V_0 - 1) + A_{fan} \cdot (P_{fan}/P_0 - 1))\\F_{nd,core} = \phi_{core} \cdot (\gamma \cdot M_0^2 \cdot (V_{core}/V_0 - 1) + A_{core} \cdot (P_{core}/P_0 - 1))\end{aligned}\end{align} \]

where:

• \(\phi_{fan}\) is the flow through fan fraction

• \(\phi_{core}\) is the flow through core fraction

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

• \(M_0\) is the freestream Mach number

• \(V_{fan}\) is the fan nozzle exit velocity

• \(V_{core}\) is the core nozzle exit velocity

• \(V_0\) is the freestream velocity

• \(A_{fan}\) is the fan nozzle area ratio

• \(A_{core}\) is the core nozzle area ratio

• \(P_{fan}\) is the fan nozzle static pressure

• \(P_{core}\) is the core nozzle static pressure

• \(P_0\) is the freestream pressure

The specific thrust is then:

\[F_{sp} = \frac{F_{nd,fan} + F_{nd,core}}{\gamma \cdot M_0}\]

References

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

See also

RCAIDE.Library.Methods.Powertrain.Propulsors.Turbofan.compute_turbofan_performance, RCAIDE.Library.Methods.Powertrain.Propulsors.Turbofan.size_core