RCAIDE.Library.Methods.Powertrain.Propulsors.Turbojet.compute_thurst

compute_thurst

Functions

compute_thrust(turbojet, conditions)

Computes thrust and other performance metrics for a turbojet engine.

compute_thrust(turbojet, conditions)

Computes thrust and other performance metrics for a turbojet engine.

Parameters:

• turbojet (RCAIDE.Library.Components.Propulsors.Turbojet) –

  Turbojet engine component with the following attributes:

  • tagstr

    Identifier for the turbojet

  • 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]

  • energy.propulsors[turbojet.tag]Data

    Turbojet-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]

    • 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

    • throttlenumpy.ndarray

      Throttle setting [0-1]

Returns:

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

• thrustnumpy.ndarray

  Thrust force [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 turbojet engine to calculate thrust, fuel consumption, and other performance metrics. It uses the outputs from the core nozzle to determine the overall engine performance.

Major Assumptions

• Perfect gas behavior

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

Theory The non-dimensional thrust is calculated as:

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

where:

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

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

• \(M_0\) is the freestream Mach number

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

• \(V_0\) is the freestream velocity

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

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

• \(P_0\) is the freestream pressure

The specific thrust is then:

\[F_{sp} = \frac{F_{nd}}{\gamma \cdot M_0}\]

References

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

See also

RCAIDE.Library.Methods.Powertrain.Propulsors.Turbojet.compute_turbojet_performance, RCAIDE.Library.Methods.Powertrain.Propulsors.Turbojet.size_core