# RCAIDE/Library/Components/Powertrain/Sources/Fuel_Tanks/Cryogenic_Tank.py
#
# Created: Jun 2026, M. Clarke
# (consolidated from Liquid_Hydrogen_Tank.py and Liquid_Natural_Gas_Tank.py)
# ----------------------------------------------------------------------------------------------------------------------
# IMPORT
# ----------------------------------------------------------------------------------------------------------------------
from .Non_Integral_Tank import Non_Integral_Tank
import RCAIDE
from RCAIDE.Framework.Core import Units, Data
from RCAIDE.Library.Components import Component
from RCAIDE.Library.Methods.Powertrain.Sources.Fuel_Tanks.Integral_Tank.compute_wing_transverse_integral_tank_volume import compute_wing_transverse_integral_tank_volume
from RCAIDE.Library.Methods.Powertrain.Sources.Fuel_Tanks.Integral_Tank.compute_wing_integral_tank_volume import compute_wing_integral_tank_volume
from RCAIDE.Library.Methods.Powertrain.Sources.Fuel_Tanks.Non_Integral_Tank.compute_wing_non_integral_tank_volume import compute_wing_non_integral_tank_volume
from RCAIDE.Library.Methods.Powertrain.Sources.Fuel_Tanks.Non_Integral_Tank.compute_prismatic_tank_volume import compute_prismatic_tank_volume
from RCAIDE.Library.Methods.Powertrain.Sources.Fuel_Tanks.Non_Integral_Tank.compute_rounded_end_cylindrical_tank_volume import compute_rounded_end_cylindrical_tank_volume
from RCAIDE.Library.Methods.Powertrain.Sources.Fuel_Tanks.Non_Integral_Tank.compute_wing_transverse_non_integral_tank_volume import compute_wing_transverse_non_integral_tank_volume
from RCAIDE.Library.Methods.Powertrain.Sources.Fuel_Tanks.Cryogenic_Tank.compute_cryogenic_cylindrical_tank_volume import compute_cryogenic_cylindrical_tank_volume
from RCAIDE.Library.Methods.Powertrain.Sources.Fuel_Tanks.Cryogenic_Tank.compute_cryogenic_conformal_tank_volume import compute_cryogenic_conformal_tank_volume
from RCAIDE.Library.Methods.Mass_Properties.Center_of_Gravity import compute_cylinder_center_of_gravity
from RCAIDE.Library.Methods.Mass_Properties.Moment_of_Inertia import compute_rounded_end_cylinder_moment_of_inertia, compute_cuboid_moment_of_inertia
# ----------------------------------------------------------------------------------------------------------------------
# Cryogenic Tank
# ----------------------------------------------------------------------------------------------------------------------
[docs]
class Cryogenic_Tank(Non_Integral_Tank):
"""
A non-integral cryogenic fuel tank for liquid hydrogen, liquid natural gas,
or other cryogenic propellants.
The user must set ``fuel`` and ``design_inlet_temperature`` for the specific
cryogenic propellant being stored.
Attributes
----------
geometry_type : str
Tank shape: 'cylindrical', 'conformal', or 'prismatic' (default: 'cylindrical').
design_inlet_temperature : float or None
Nominal inlet temperature of the cryogen [K] (default: None).
design_altitude : float
Design altitude for thermal/structural sizing [m].
design_heat_flux : float
Maximum allowable heat leak per unit area [W/m²] (default: 20).
design_total_heat_transfer : float
Maximum allowable total heat leak [W] (default: 2000).
ullage_volume_fraction : float
Fraction of internal volume reserved for ullage (default: 0.07).
safety_factor : float
Structural factor of safety (default: 1.6).
pressure_factor : float
Internal pressure multiplier for sizing (default: 5).
"""
def __defaults__(self):
self.tag = 'cryogenic_tank'
self.geometry_type = 'cylindrical'
self.design_inlet_temperature = None
self.design_altitude = None
self.design_isa_deviation = 0
self.design_heat_flux = None
self.design_total_heat_transfer = None
self.ullage_volume_fraction = None
self.inner_structure.material = RCAIDE.Library.Attributes.Materials.Aluminum_2219()
self.insulation.material = RCAIDE.Library.Attributes.Materials.Vacuum_Cellular_Multilayer_Insulation()
self.design_external_pressure = 0
self.tank_accesories_weight_factor = 1.5
self.safety_factor = 1.6
self.pressure_factor = 5
[docs]
def compute_volume(self, wings, fuselages, fuel_tanks):
"""Computes the net fuel volume and cryogenic structure/insulation sizing.
The method operates in two stages. First, the outer envelope is determined
from the wing geometry (or from user-supplied dimensions for standalone
tanks). Second, cryogenic-specific sizing works inward from that envelope
to compute insulation thickness, structural wall thickness, and the
resulting net fuel volume.
Cylindrical
-----------
- Wing spanwise: outer envelope from ``compute_wing_non_integral_tank_volume``
- Wing transverse: outer envelope from ``compute_wing_transverse_non_integral_tank_volume``
- Standalone: outer envelope from ``compute_rounded_end_cylindrical_tank_volume``
using user-set ``lengths.external`` and ``diameters.external``
- Then: ``compute_cryogenic_cylindrical_tank_volume`` sizes
insulation and structure inward
Conformal
---------
- Wing spanwise: outer envelope from ``compute_wing_integral_tank_volume``
- Wing transverse: outer envelope from ``compute_wing_transverse_integral_tank_volume``
- Then: ``compute_cryogenic_conformal_tank_volume`` sizes
insulation and structure inward
Prismatic
---------
- Uses user-set ``lengths.external``, ``widths.external``, ``heights.external``
- Then: ``compute_cryogenic_conformal_tank_volume`` sizes
insulation and structure inward
"""
if self.geometry_type == 'cylindrical':
if self.wing_tag is not None and self.transverse_tank is False:
compute_wing_non_integral_tank_volume(self, wings[self.wing_tag], fuel_tanks)
elif self.wing_tag is not None and self.transverse_tank is True:
compute_wing_transverse_non_integral_tank_volume(self, wings[self.wing_tag], fuel_tanks)
else:
compute_rounded_end_cylindrical_tank_volume(self)
if hasattr(fuel_tanks, self.tag):
compute_cryogenic_cylindrical_tank_volume(self, fuel_tanks)
elif self.geometry_type == 'conformal':
if self.wing_tag is not None and self.transverse_tank is False:
compute_wing_integral_tank_volume(self, wings[self.wing_tag])
elif self.wing_tag is not None and self.transverse_tank is True:
compute_wing_transverse_integral_tank_volume(self, wings[self.wing_tag], fuel_tanks)
if hasattr(fuel_tanks, self.tag):
compute_cryogenic_conformal_tank_volume(self, fuel_tanks)
elif self.geometry_type == 'prismatic':
compute_cryogenic_conformal_tank_volume(self, fuel_tanks)
else:
raise NotImplementedError
return
[docs]
def compute_moments_of_inertia(self, vehicle, center_of_gravity=[[0, 0, 0]]):
outer_length = self.lengths.external
outer_radius = self.diameters.external / 2
inner_length = self.inner_structure.lengths.internal
if self.geometry_type == 'cylindrical':
inner_radius = self.inner_structure.diameters.internal / 2
_, _ = compute_rounded_end_cylinder_moment_of_inertia(
self, outer_length, outer_radius,
inner_length=inner_length, inner_radius=inner_radius,
center_of_gravity=center_of_gravity, fuel_tank=True)
elif self.geometry_type == 'conformal' and self.transverse_tank:
pass
elif self.geometry_type == 'conformal' and self.transverse_tank is False:
thickness = self.inner_structure.thickness + self.insulation_thickness
_, _ = compute_cuboid_moment_of_inertia(
self,
outer_length=self.lengths.external,
outer_width=self.widths.external,
outer_height=self.heights.external,
inner_length=self.lengths.external - 2 * thickness,
inner_width=self.widths.external - 2 * thickness,
inner_height=self.heights.external - 2 * thickness,
center_of_gravity=center_of_gravity, fuel_tank=True)
return
[docs]
def compute_center_of_gravity(self, vehicle):
if self.geometry_type == 'cylindrical':
length = self.lengths.external + self.diameters.external
_ = compute_cylinder_center_of_gravity(self, length)
return
