RCAIDE.Library.Methods.Powertrain.Converters.Ram.compute_ram_performance
compute_ram_performance#
- compute_ram_performance(ram, conditions)[source]#
Computes the thermodynamic properties of air at the inlet of a propulsion system.
- Parameters:
ram (RCAIDE.Library.Components.Converters.Ram) –
- Ram air converter component with the following attributes:
- tagstr
Identifier for the ram air converter
- working_fluidData
Working fluid properties object
conditions (RCAIDE.Framework.Mission.Common.Conditions) –
- Flight conditions with:
- freestreamData
- Freestream properties
- pressurenumpy.ndarray
Freestream static pressure [Pa]
- temperaturenumpy.ndarray
Freestream static temperature [K]
- mach_numbernumpy.ndarray
Freestream Mach number
- Returns:
- Results are stored in:
- conditions.freestream:
- stagnation_temperaturenumpy.ndarray
Freestream stagnation temperature [K]
- stagnation_pressurenumpy.ndarray
Freestream stagnation pressure [Pa]
- isentropic_expansion_factornumpy.ndarray
Ratio of specific heats (gamma) [unitless]
- specific_heat_at_constant_pressurenumpy.ndarray
Specific heat at constant pressure [J/(kg·K)]
- gas_specific_constantnumpy.ndarray
Gas specific constant [J/(kg·K)]
- speed_of_soundnumpy.ndarray
Speed of sound [m/s]
- conditions.energy.converters[ram.tag].outputs:
- stagnation_temperaturenumpy.ndarray
Stagnation temperature [K]
- stagnation_pressurenumpy.ndarray
Stagnation pressure [Pa]
- isentropic_expansion_factornumpy.ndarray
Ratio of specific heats (gamma) [unitless]
- specific_heat_at_constant_pressurenumpy.ndarray
Specific heat at constant pressure [J/(kg·K)]
- gas_specific_constantnumpy.ndarray
Gas specific constant [J/(kg·K)]
- static_temperaturenumpy.ndarray
Static temperature [K]
- static_pressurenumpy.ndarray
Static pressure [Pa]
- mach_numbernumpy.ndarray
Mach number
- velocitynumpy.ndarray
Velocity [m/s]
- speed_of_soundnumpy.ndarray
Speed of sound [m/s]
- Return type:
None
Notes
This function computes the stagnation (total) properties of the air at the inlet of a propulsion system based on the freestream conditions. It calculates the stagnation temperature and pressure using isentropic flow relations, and also computes various thermodynamic properties of the working fluid.
- The computation follows these steps:
Extract freestream conditions (pressure, temperature, Mach number)
Compute working fluid properties (gamma, Cp, R, speed of sound)
Calculate freestream velocity from Mach number and speed of sound
Compute stagnation temperature and pressure using isentropic flow relations
Store results in both freestream and ram output conditions
- Major Assumptions
Isentropic flow from freestream to inlet
No losses in the inlet
Working fluid properties are computed at freestream conditions
Theory The stagnation temperature and pressure are calculated using the following isentropic relations:
\[T_0 = T \left(1 + \frac{\gamma - 1}{2} M^2 \right)\]\[P_0 = P \left(1 + \frac{\gamma - 1}{2} M^2 \right)^{\gamma/(\gamma-1)}\]- where:
\(T_0\) is the stagnation temperature
\(T\) is the static temperature
\(P_0\) is the stagnation pressure
\(P\) is the static pressure
\(\gamma\) is the ratio of specific heats
\(M\) is the Mach number
References
[1] Cantwell, B., “AA283 Course Notes”, Stanford University https://web.stanford.edu/~cantwell/AA283_Course_Material/AA283_Course_Notes/