"""
Estimation of power systems weight
"""
# This file is part of FAST-OAD : A framework for rapid Overall Aircraft Design
# Copyright (C) 2021 ONERA & ISAE-SUPAERO
# FAST is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
import numpy as np
from openmdao.core.explicitcomponent import ExplicitComponent
[docs]class PowerSystemsWeight(ExplicitComponent):
"""
Weight estimation for power systems (generation and distribution)
This includes:
- Auxiliary Power Unit (APU)
- electric systems
- hydraulic systems
Based on formulas in :cite:`supaero:2014`, mass contribution C1
"""
[docs] def setup(self):
self.add_input("data:geometry:cabin:NPAX1", val=np.nan)
self.add_input("data:weight:airframe:flight_controls:mass", val=np.nan, units="kg")
self.add_input("data:weight:aircraft:MTOW", val=np.nan, units="kg")
self.add_input("tuning:weight:systems:power:auxiliary_power_unit:mass:k", val=1.0)
self.add_input(
"tuning:weight:systems:power:auxiliary_power_unit:mass:offset", val=0.0, units="kg"
)
self.add_input("tuning:weight:systems:power:electric_systems:mass:k", val=1.0)
self.add_input(
"tuning:weight:systems:power:electric_systems:mass:offset", val=0.0, units="kg"
)
self.add_input("tuning:weight:systems:power:hydraulic_systems:mass:k", val=1.0)
self.add_input(
"tuning:weight:systems:power:hydraulic_systems:mass:offset", val=0.0, units="kg"
)
self.add_input("settings:weight:systems:power:mass:k_elec", val=1.0)
self.add_output("data:weight:systems:power:auxiliary_power_unit:mass", units="kg")
self.add_output("data:weight:systems:power:electric_systems:mass", units="kg")
self.add_output("data:weight:systems:power:hydraulic_systems:mass", units="kg")
[docs] def setup_partials(self):
self.declare_partials("*", "*", method="fd")
# pylint: disable=too-many-locals
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
npax1 = inputs["data:geometry:cabin:NPAX1"]
flight_controls_weight = inputs["data:weight:airframe:flight_controls:mass"]
mtow = inputs["data:weight:aircraft:MTOW"]
k_c11 = inputs["tuning:weight:systems:power:auxiliary_power_unit:mass:k"]
offset_c11 = inputs["tuning:weight:systems:power:auxiliary_power_unit:mass:offset"]
k_c12 = inputs["tuning:weight:systems:power:electric_systems:mass:k"]
offset_c12 = inputs["tuning:weight:systems:power:electric_systems:mass:offset"]
k_c13 = inputs["tuning:weight:systems:power:hydraulic_systems:mass:k"]
offset_c13 = inputs["tuning:weight:systems:power:hydraulic_systems:mass:offset"]
k_elec = inputs["settings:weight:systems:power:mass:k_elec"]
# Mass of auxiliary power unit
temp_c11 = 11.3 * npax1 ** 0.64
outputs["data:weight:systems:power:auxiliary_power_unit:mass"] = (
k_c11 * temp_c11 + offset_c11
)
# Mass of electric system
temp_c12 = k_elec * (0.444 * mtow ** 0.66 + 2.54 * npax1 + 0.254 * flight_controls_weight)
outputs["data:weight:systems:power:electric_systems:mass"] = k_c12 * temp_c12 + offset_c12
# Mass of the hydraulic system
temp_c13 = k_elec * (0.256 * mtow ** 0.66 + 1.46 * npax1 + 0.146 * flight_controls_weight)
outputs["data:weight:systems:power:hydraulic_systems:mass"] = k_c13 * temp_c13 + offset_c13