def air_path(aircraft, nei, altp, disa, speed_mode, speed, mass, rating):
"""
Retrieves air path in various conditions
"""
g = earth.gravity()
[pamb, tamb, tstd, dtodz] = earth.atmosphere(altp, disa)
mach = get_mach(pamb, speed_mode, speed)
fn, data = propu.thrust(aircraft, pamb, tamb, mach, rating, nei)
cz = lift_from_speed(aircraft, pamb, mach, mass)
[cx, lod] = aero.drag(aircraft, pamb, tamb, mach, cz)
if (nei > 0):
dcx = propu.oei_drag(aircraft, pamb, mach)
cx = cx + dcx * nei
lod = cz / cx
acc_factor = earth.climb_mode(speed_mode, dtodz, tstd, disa, mach)
slope = (fn / (mass * g) - 1 / lod) / acc_factor
vsnd = earth.sound_speed(tamb)
v_z = mach * vsnd * slope
return slope, v_z
def acceleration(aircraft, nei, altp, disa, speed_mode, speed, mass, rating):
"""
Aircraft acceleration on level flight
"""
wing = aircraft.wing
gam = earth.heat_ratio()
[pamb, tamb, tstd, dtodz] = earth.atmosphere(altp, disa)
mach = get_mach(pamb, speed_mode, speed)
fn, Data = propu.thrust(aircraft, pamb, tamb, mach, rating, nei)
cz = lift_from_speed(aircraft, pamb, mach, mass)
cx, lod = aero.drag(aircraft, pamb, tamb, mach, cz)
if (nei > 0):
dcx = propu.oei_drag(aircraft, pamb, mach)
cx = cx + dcx * nei
acc = (fn - 0.5 * gam * pamb * mach**2 * wing.area * cx) / mass
return acc
def forward_cg_stall(aircraft, altp, disa, nei, hld_conf, speed_mode, mass):
"""
Computes max forward trimmable CG position at stall speed
"""
wing = aircraft.wing
htp = aircraft.horizontal_tail
gam = earth.heat_ratio()
[pamb, tamb, tstd, dtodz] = earth.atmosphere(altp, disa)
[cz_max_wing, cz0] = airplane_aero.high_lift(
wing, hld_conf) # Wing maximum lift coefficient without margin
[cza_htp, xlc_htp, aoa_max_htp,
ki_htp] = frame_aero.htp_aero_data(aircraft)
cz_max_htp = cza_htp * aoa_max_htp
c_z = cz_max_wing - cz_max_htp # Max forward Cg assumed, HTP has down lift
mach = flight.speed_from_lift(aircraft, pamb, c_z, mass)
[cza_wo_htp, xlc_wo_htp,
ki_wing] = frame_aero.wing_aero_data(aircraft, mach, hld_conf)
if (nei > 0):
dcx_oei = nei * propu.oei_drag(pamb, mach)
else:
dcx_oei = 0
dw_angle = frame_aero.wing_downwash(
aircraft, cz_max_wing) # Downwash angle due to the wing
cx_basic, lod_trash = airplane_aero.drag(
aircraft, pamb, tamb, mach,
cz_max_wing) # By definition of the drag_ function
cxi_htp = (ki_htp * cz_max_htp**2) * (htp.area / wing.area
) # Induced drag generated by HTP
cx_inter = cz_max_htp * dw_angle # Interaction drag (due to downwash)
cx_trimmed = cx_basic + cxi_htp + cx_inter + dcx_oei
fn = 0.5 * gam * pamb * mach**2 * wing.area * cx_trimmed
cm_prop = propu.thrust_pitch_moment(aircraft, fn, pamb, mach, dcx_oei)
cg_max_fwd_stall = (cm_prop + xlc_wo_htp * cz_max_wing -
xlc_htp * cz_max_htp) / (cz_max_wing - cz_max_htp)
aoa_wing = (cz_max_wing - cz0) / cza_wo_htp # Wing angle of attack
aoa = aoa_wing - wing.setting # Reference angle of attack (fuselage axis versus air speed)
ih = -aoa + dw_angle - aoa_max_htp # HTP trim setting
speed = flight.get_speed(pamb, speed_mode, mach)
return cg_max_fwd_stall, speed, fn, aoa, ih, c_z, cx_trimmed
def fct_max_path(cz, aircraft, nei, altp, disa, speed_mode, mass, rating,
isformax):
pamb, tamb, tstd, dtodz = earth.atmosphere(altp, disa)
mach = speed_from_lift(aircraft, pamb, cz, mass)
speed = get_speed(pamb, speed_mode, mach)
[slope, vz] = air_path(aircraft, nei, altp, disa, speed_mode, speed,
mass, rating)
if (isformax == True):
return slope
elif (isformax == False):
return slope, vz, speed
def ceilings(aircraft, toc, oei_ceil):
design_driver = aircraft.design_driver
propulsion = aircraft.propulsion
weights = aircraft.weights
(MTO, MCN, MCL, MCR, FID) = propulsion.rating_code
disa = 15
# propulsion ceilings
#-----------------------------------------------------------------------------------------------------------
nei = 0
altp = toc
speed_mode = 2 # WARNING : iso Mach climb mode
speed = design_driver.cruise_mach
mass = 0.97 * weights.mtow
rating = MCL # Max Climb
slope, vz_clb = flight.air_path(aircraft, nei, altp, disa, speed_mode,
speed, mass, rating)
rating = MCR # Max Cruise
slope, vz_crz = flight.air_path(aircraft, nei, altp, disa, speed_mode,
speed, mass, rating)
# One engine inoperative ceiling
#-----------------------------------------------------------------------------------------------------------
nei = 1
altp = oei_ceil
speed_mode = 2 # WARNING : iso Mach climb mode
pamb, tamb, tstd, dtodz = earth.atmosphere(altp, disa)
speed = earth.vcas_from_mach(pamb, design_driver.cruise_mach)
mass = 0.95 * weights.mtow
rating = MCN
oei_slope, vz, oei_mach, cz = flight.max_path(aircraft, nei, altp, disa,
speed_mode, mass, rating)
#-----------------------------------------------------------------------------------------------------------
return vz_clb, vz_crz, oei_slope, oei_mach
def approach_speed(aircraft, altp, disa, mass, hld_conf):
"""
Minimum approach speed (VLS)
"""
wing = aircraft.wing
g = earth.gravity()
czmax, trash = airplane_aero.high_lift(wing, hld_conf)
stall_margin = regul.kvs1g_min_landing()
[pamb, tamb, tstd, dtodz] = earth.atmosphere(altp, disa)
[rho, sig] = earth.air_density(pamb, tamb)
vapp = numpy.sqrt(
(mass * g) / (0.5 * rho * wing.area * (czmax / stall_margin**2)))
return vapp
def take_off(aircraft, kvs1g, altp, disa, mass, hld_conf):
"""
Take off field length and climb path at 35 ft depending on stall margin (kVs1g)
"""
wing = aircraft.wing
propulsion = aircraft.propulsion
(MTO, MCN, MCL, MCR, FID) = propulsion.rating_code
czmax, cz_0 = airplane_aero.high_lift(wing, hld_conf)
rating = MTO
[pamb, tamb, tstd, dtodz] = earth.atmosphere(altp, disa)
[rho, sig] = earth.air_density(pamb, tamb)
cz_to = czmax / kvs1g**2
mach = flight.speed_from_lift(aircraft, pamb, cz_to, mass)
nei = 0 # For Magic Line factor computation
fn, trash = propu.thrust(aircraft, pamb, tamb, mach, rating, nei)
ml_factor = mass**2 / (cz_to * fn * wing.area * sig**0.8
) # Magic Line factor
tofl = 15.5 * ml_factor + 100.
nei = 1 # For 2nd segment computation
speed_mode = 1
speed = flight.get_speed(pamb, speed_mode, mach)
seg2path, vz = flight.air_path(aircraft, nei, altp, disa, speed_mode,
speed, mass, rating)
return seg2path, tofl
def specific_air_range(aircraft, altp, mass, mach, disa):
propulsion = aircraft.propulsion
(MTO, MCN, MCL, MCR, FID) = propulsion.rating_code
g = earth.gravity()
pamb, tamb, tstd, dtodz = earth.atmosphere(altp, disa)
vsnd = earth.sound_speed(tamb)
Cz = flight.lift_from_speed(aircraft, pamb, mach, mass)
[Cx, LoD] = airplane_aero.drag(aircraft, pamb, tamb, mach, Cz)
nei = 0.
sfc = propu.sfc(aircraft, pamb, tamb, mach, MCR, nei)
sar = (vsnd * mach * LoD) / (mass * g * sfc)
return sar
def vertical_tail_sizing(aircraft):
"""
Computes necessary VTP area variation to meet engine failure case constraint
Influence of CG position is ignored
"""
design_driver = aircraft.design_driver
propulsion = aircraft.propulsion
wing = aircraft.wing
vtp = aircraft.vertical_tail
aerodynamics = aircraft.aerodynamics
payload = aircraft.payload
c_of_g = aircraft.center_of_gravity
(MTO, MCN, MCL, MCR, FID) = propulsion.rating_code
cyb_vtp, xlc_vtp, aoa_max_vtp, ki_vtp = frame_aero.vtp_aero_data(aircraft)
payload = 0.5 * payload.nominal # Light payload
range = design_driver.design_range / 15 # Short mission
altp = design_driver.ref_cruise_altp
mach = design_driver.cruise_mach
disa = 30 # Hot condition
tow, block_fuel, block_time, total_fuel = sub_proc.mission_tow(
aircraft, payload, range, altp, mach, disa)
altp = 0
disa = 15
pamb, tamb, tstd, dtodz = earth.atmosphere(altp, disa)
stall_margin = regul.kvs1g_min_take_off()
czmax_to = aerodynamics.cz_max_to
mach_s1g = flight.speed_from_lift(aircraft, pamb, czmax_to, tow)
mach_35ft = stall_margin * mach_s1g # V2 speed
mach_mca = mach_35ft / 1.1 #Approximation of required VMCA
altp = 0
disa = 15
nei = 1
pamb, tamb, tstd, dtodz = earth.atmosphere(altp, disa)
fn, data = propu.thrust(aircraft, pamb, tamb, mach_mca, MTO, nei)
dcx_oei = propu.oei_drag(aircraft, pamb, tamb)
cn_prop = propu.thrust_yaw_moment(aircraft, fn, pamb, mach_mca, dcx_oei)
max_bwd_req_cg = xlc_vtp - (cn_prop * wing.mac) / (cyb_vtp * aoa_max_vtp)
c_of_g.max_bwd_oei_req_cg = c_of_g.max_bwd_req_cg
c_of_g.max_bwd_oei_cg = max_bwd_req_cg
c_of_g.max_bwd_oei_mass = tow
return
eff_chain = aircraft.power_elec_chain.overall_efficiency
kBLIe = aircraft.propulsion.bli_e_thrust_factor # Thrust increase due to BLI at iso shaft power for the e-fan
eff_h = kC + (1 - kC) * (kW * kBLIe * (eff_e_prop / eff_prop) * eff_chain +
(1 - kW))
sfc_factor = 1. / eff_h # factor on cruise SFC due to rear fuselage electric nacelle with bli
#------------------------------------------------------------------------------------------------------
shaft_power = aircraft.electric_engine.mcr_e_shaft_power
disa = 0.
altp = aircraft.design_driver.ref_cruise_altp
mach = aircraft.design_driver.cruise_mach
(pamb, tamb, tstd, dt_o_dz) = earth.atmosphere(altp, disa)
(e_fan_thrust, q_air,
dv_bli) = jet.fan_thrust_with_bli(aircraft.electric_nacelle, pamb, tamb,
mach, shaft_power)
vair = mach * earth.sound_speed(tamb)
kVbli = dv_bli / vair
# Print some results
#------------------------------------------------------------------------------------------------------
print("-------------------------------------------")
print("Global mass of electric chain = ", "%.0f" % global_e_mass, " kg")
print("Electric fan length = ", "%.2f" % aircraft.electric_nacelle.length,
" m")
def eval_propulsion_design(aircraft):
"""
Propulsion architecture design
"""
propulsion = aircraft.propulsion
propulsion.rating_code = (0,1,2,3,4)
if (propulsion.architecture==1):
engine = aircraft.turbofan_engine
eval_turbofan_engine_design(aircraft)
eval_turbofan_nacelle_design(aircraft)
elif (propulsion.architecture==2):
engine = aircraft.turbofan_engine
eval_turbofan_engine_design(aircraft)
eval_hybrid_engine_design(aircraft)
eval_hybrid_nacelle_design(aircraft)
else:
raise Exception("propulsion.architecture index is out of range")
(MTO,MCN,MCL,MCR,FID) = propulsion.rating_code
disa = 15.
altp = 0.
mach = 0.25
nei = 0.
(pamb,tamb,tstd,dtodz) = earth.atmosphere(altp,disa)
(Fn,Data) = propu.thrust(aircraft,pamb,tamb,mach,MTO,nei)
propulsion.reference_thrust_effective = (Fn/engine.n_engine)/0.80
propulsion.mto_thrust_ref = Fn/engine.n_engine
disa = aircraft.low_speed.disa_oei
altp = aircraft.low_speed.req_oei_altp
mach = 0.5*aircraft.design_driver.cruise_mach
nei = 1.
(pamb,tamb,tstd,dtodz) = earth.atmosphere(altp,disa)
(Fn,Data) = propu.thrust(aircraft,pamb,tamb,mach,MCN,nei)
propulsion.mcn_thrust_ref = Fn/(engine.n_engine-nei)
disa = 0.
altp = aircraft.design_driver.ref_cruise_altp
mach = aircraft.design_driver.cruise_mach
nei = 0.
(pamb,tamb,tstd,dtodz) = earth.atmosphere(altp,disa)
propulsion.sfc_cruise_ref = propu.sfc(aircraft,pamb,tamb,mach,MCR,nei)
if (propulsion.architecture==1):
sec = 0.
elif (propulsion.architecture==2):
fn,sec,data = propu.hybrid_thrust(aircraft,pamb,tamb,mach,MCR,nei)
else:
raise Exception("propulsion.architecture index is out of range")
propulsion.sec_cruise_ref = sec
(Fn,Data) = propu.thrust(aircraft,pamb,tamb,mach,FID,nei)
propulsion.fid_thrust_ref = Fn/engine.n_engine
disa = 0.
altp = aircraft.design_driver.top_of_climb_altp
mach = aircraft.design_driver.cruise_mach
nei = 0.
(pamb,tamb,tstd,dtodz) = earth.atmosphere(altp,disa)
(Fn,Data) = propu.thrust(aircraft,pamb,tamb,mach,MCL,nei)
propulsion.mcl_thrust_ref = Fn/engine.n_engine
(Fn,Data) = propu.thrust(aircraft,pamb,tamb,mach,MCR,nei)
propulsion.mcr_thrust_ref = Fn/engine.n_engine
return
def eval_wing_design(aircraft):
"""
Wing predesign
"""
design_driver = aircraft.design_driver
fuselage = aircraft.fuselage
vtp = aircraft.vertical_tail
nacelle = aircraft.turbofan_nacelle
weights = aircraft.weights
c_g = aircraft.center_of_gravity
wing = aircraft.wing
wing.t_o_c_t = 0.10
wing.t_o_c_k = wing.t_o_c_t + 0.01
wing.t_o_c_r = wing.t_o_c_k + 0.03
wing.sweep = 1.6 * max(0,
(design_driver.cruise_mach - 0.5)) # Empirical law
wing.dihedral = unit.rad_deg(5)
if (wing.morphing == 1): # Aspect ratio is driving parameter
wing.span = numpy.sqrt(wing.aspect_ratio * wing.area)
elif (wing.morphing == 2): # Span is driving parameter
wing.aspect_ratio = wing.span**2 / wing.area
else:
print("geometry_predesign_, wing_morphing index is unkown")
# Correlation between span loading and tapper ratio
wing.taper_ratio = 0.3 - 0.025 * (1e-3 * weights.mtow / wing.span)
# Factor 1.64 accounts for the part of HTP ref area hidden in the fuselage
wing.net_wetted_area = 1.64 * wing.area
wing.y_kink = 0.7 * fuselage.width + 1.4 * nacelle.width # statistical regression
wing.y_root = 0.5 * fuselage.width
wing.y_tip = 0.5 * wing.span
if (15 < unit.deg_rad(wing.sweep)): # With kink
Phi100intTE = max(0, 2 * (wing.sweep - unit.rad_deg(32)))
tan_phi100 = numpy.tan(Phi100intTE)
A = ((1 - 0.25 * wing.taper_ratio) * wing.y_kink +
0.25 * wing.taper_ratio * wing.y_root - wing.y_tip) / (
0.75 * wing.y_kink + 0.25 * wing.y_root - wing.y_tip)
B = (numpy.tan(wing.sweep) - tan_phi100) * (
(wing.y_tip - wing.y_kink) *
(wing.y_kink - wing.y_root)) / (0.25 * wing.y_root +
0.75 * wing.y_kink - wing.y_tip)
wing.c_root = (wing.area - B * (wing.y_tip - wing.y_root)) / (
wing.y_root + wing.y_kink + A *
(wing.y_tip - wing.y_root) + wing.taper_ratio *
(wing.y_tip - wing.y_kink))
wing.c_kink = A * wing.c_root + B
wing.c_tip = wing.taper_ratio * wing.c_root
else: # Without kink
wing.c_root = 2 * wing.area / (
2 * wing.y_root * (1 - wing.taper_ratio) +
(1 + wing.taper_ratio) * numpy.sqrt(wing.aspect_ratio * wing.area))
wing.c_tip = wing.taper_ratio * wing.c_root
wing.c_kink = ((wing.y_tip - wing.y_kink) * wing.c_root +
(wing.y_kink - wing.y_root) * wing.c_tip) / (
wing.y_tip - wing.y_root)
tan_phi0 = 0.25 * (wing.c_kink - wing.c_tip) / (
wing.y_tip - wing.y_kink) + numpy.tan(wing.sweep)
wing.mac = 2.*(3*wing.y_root*wing.c_root**2 \
+(wing.y_kink-wing.y_root)*(wing.c_root**2+wing.c_kink**2+wing.c_root*wing.c_kink) \
+(wing.y_tip-wing.y_kink)*(wing.c_kink**2+wing.c_tip**2+wing.c_kink*wing.c_tip) \
)/(3*wing.area)
wing.y_mac = ( 3*wing.c_root*wing.y_root**2 \
+(wing.y_kink-wing.y_root)*(wing.c_kink*(wing.y_root+wing.y_kink*2.)+wing.c_root*(wing.y_kink+wing.y_root*2.)) \
+(wing.y_tip-wing.y_kink)*(wing.c_tip*(wing.y_kink+wing.y_tip*2.)+wing.c_kink*(wing.y_tip+wing.y_kink*2.)) \
)/(3*wing.area)
x_mac_local = ( (wing.y_kink-wing.y_root)*tan_phi0*((wing.y_kink-wing.y_root)*(wing.c_kink*2.+wing.c_root) \
+(wing.y_tip-wing.y_kink)*(wing.c_kink*2.+wing.c_tip))+(wing.y_tip-wing.y_root)*tan_phi0*(wing.y_tip-wing.y_kink)*(wing.c_tip*2.+wing.c_kink) \
)/(3*wing.area)
wing.x_root = vtp.x_mac + 0.25 * vtp.mac - vtp.lever_arm - 0.25 * wing.mac - x_mac_local
wing.x_kink = wing.x_root + (wing.y_kink - wing.y_root) * tan_phi0
wing.x_tip = wing.x_root + (wing.y_tip - wing.y_root) * tan_phi0
wing.x_mac = wing.x_root+( (wing.x_kink-wing.x_root)*((wing.y_kink-wing.y_root)*(wing.c_kink*2.+wing.c_root) \
+(wing.y_tip-wing.y_kink)*(wing.c_kink*2.+wing.c_tip))+(wing.x_tip-wing.x_root)*(wing.y_tip-wing.y_kink)*(wing.c_tip*2.+wing.c_kink) \
)/(wing.area*3.)
if (wing.attachment == 1):
wing.z_root = 0
else:
wing.z_root = fuselage.height - 0.5 * wing.t_o_c_r * wing.c_root
wing.z_kink = wing.z_root + (wing.y_kink - wing.y_root) * numpy.tan(
wing.dihedral)
wing.z_tip = wing.z_root + (wing.y_tip - wing.y_root) * numpy.tan(
wing.dihedral)
# Wing setting
#-----------------------------------------------------------------------------------------------------------
g = earth.gravity()
gam = earth.heat_ratio()
disa = 0
rca = design_driver.ref_cruise_altp
mach = design_driver.cruise_mach
mass = 0.95 * weights.mtow
pamb, tamb, tstd, dtodz = earth.atmosphere(rca, disa)
cza_wo_htp = frame_aero.cza_wo_htp(mach, fuselage.width, wing.aspect_ratio,
wing.span, wing.sweep)
# AoA = 2.5° at cruise start
wing.setting = (0.97 * mass * g) / (0.5 * gam * pamb * mach**2 * wing.area
* cza_wo_htp) - unit.rad_deg(2.5)
return
def mission(aircraft, dist_range, tow, altp, mach, disa):
"""
Mission computation using breguet equation, fixed L/D and fixed sfc
"""
engine = aircraft.turbofan_engine
propulsion = aircraft.propulsion
battery = aircraft.battery
(MTO, MCN, MCL, MCR, FID) = propulsion.rating_code
g = earth.gravity()
pamb, tamb, tstd, dtodz = earth.atmosphere(altp, disa)
vsnd = earth.sound_speed(tamb)
tas = vsnd * mach
lod_max, cz_lod_max = airplane_aero.lod_max(aircraft, pamb, tamb, mach)
lod_cruise = 0.95 * lod_max
nei = 0.
sfc = propu.sfc(aircraft, pamb, tamb, mach, MCR, nei)
if (propulsion.architecture == 2):
fn, sec, data = propu.hybrid_thrust(aircraft, pamb, tamb, mach, MCR,
nei)
if (propulsion.architecture == 3):
fn, sec, data = propu.hybrid_thrust(aircraft, pamb, tamb, mach, MCR,
nei)
# Departure ground phases
#-----------------------------------------------------------------------------------------------------------
fuel_taxi_out = (34 + 2.3e-4 * engine.reference_thrust) * engine.n_engine
time_taxi_out = 540
fuel_take_off = 1e-4 * (2.8 + 2.3 / engine.bpr) * tow
time_take_off = 220 * tow / (engine.reference_thrust * engine.n_engine)
# Mission leg
#-----------------------------------------------------------------------------------------------------------
if (propulsion.architecture == 1):
fuel_mission = tow * (1 - numpy.exp(-(sfc * g * dist_range) /
(tas * lod_cruise)))
elif (propulsion.architecture == 2):
fuel_mission = tow*(1-numpy.exp(-(sfc*g*dist_range)/(tas*lod_cruise))) \
- (sfc/sec)*battery.energy_cruise
elif (propulsion.architecture == 3):
fuel_mission = tow*(1-numpy.exp(-(sfc*g*dist_range)/(tas*lod_cruise))) \
- (sfc/sec)*battery.energy_cruise
elif (propulsion.architecture == 4):
fuel_mission = tow * (1 - numpy.exp(-(sfc * g * dist_range) /
(tas * lod_cruise)))
else:
raise Exception("propulsion.architecture index is out of range")
time_mission = 1.09 * (dist_range / tas)
l_w = tow - fuel_mission
# Arrival ground phases
#-----------------------------------------------------------------------------------------------------------
fuel_landing = 1e-4 * (0.5 + 2.3 / engine.bpr) * l_w
time_landing = 180
fuel_taxi_in = (26 + 1.8e-4 * engine.reference_thrust) * engine.n_engine
time_taxi_in = 420
# Block fuel and time
#-----------------------------------------------------------------------------------------------------------
block_fuel = fuel_taxi_out + fuel_take_off + fuel_mission + fuel_landing + fuel_taxi_in
time_block = time_taxi_out + time_take_off + time_mission + time_landing + time_taxi_in
# Diversion and holding reserve fuel
#-----------------------------------------------------------------------------------------------------------
fuel_diversion = l_w * (1 -
numpy.exp(-(sfc * g * regul.diversion_range()) /
(tas * lod_cruise)))
fuel_holding = sfc * (l_w * g / lod_max) * regul.holding_time()
# Total
#-----------------------------------------------------------------------------------------------------------
design_range = aircraft.design_driver.design_range
fuel_total = fuel_mission * (1 + regul.reserve_fuel_ratio(design_range)
) + fuel_diversion + fuel_holding
#-----------------------------------------------------------------------------------------------------------
return block_fuel, time_block, fuel_total
def eval_hybrid_engine_design(aircraft):
"""
Thermal propulsive architecture design
"""
design_driver = aircraft.design_driver
fuselage = aircraft.fuselage
propulsion = aircraft.propulsion
engine = aircraft.turbofan_engine
nacelle = aircraft.turbofan_nacelle
battery = aircraft.battery
power_elec = aircraft.power_elec_chain
e_engine = aircraft.electric_engine
e_nacelle = aircraft.electric_nacelle
low_speed = aircraft.low_speed
(MTO,MCN,MCL,MCR,FID) = propulsion.rating_code
# Propulsion architecture design, definition of e-fan power in each fligh t phase
#-----------------------------------------------------------------------------------------------------------
# Initialisation
crm = design_driver.cruise_mach
toc = design_driver.top_of_climb_altp
rca = design_driver.ref_cruise_altp
roa = low_speed.req_oei_altp
# MTO MCN MCL MCR FIR
fd_disa = numpy.array([15. , 0. , 0. , 0. , 0. ])
fd_altp = numpy.array([0. , roa , toc, rca, rca])
fd_mach = numpy.array([0.25, crm/2, crm, crm, crm])
fd_nei = numpy.array([0. , 1. , 0. , 0. , 0. ])
e_engine.flight_data = {"disa":fd_disa, "altp":fd_altp, "mach":fd_mach, "nei":fd_nei}
e_fan_power = numpy.array([power_elec.mto,
power_elec.mcn,
power_elec.mcl,
power_elec.mcr,
power_elec.fid])
# Battery power feed is used in temporary phases only (take off and climb)
battery_power_feed = numpy.array([1,0,1,0,0])*battery.power_feed \
*e_nacelle.controller_efficiency \
*e_nacelle.motor_efficiency
e_power_ratio = numpy.zeros(5)
e_shaft_power = numpy.zeros(5)
for rating in propulsion.rating_code:
(Pamb,Tamb,Tstd,dTodZ) = earth.atmosphere(fd_altp[rating],fd_disa[rating])
(fn,data) = turbofan_thrust(aircraft,Pamb,Tamb,fd_mach[rating],rating,fd_nei[rating])
(fn_core,fn_fan0,fn0,shaft_power0) = data
if e_fan_power[rating]>1: # required eFan shaft power is given, turbofan shaft power ratio is deduced
# Fraction of the turbofan shaft power dedicated to electric generation
e_power_ratio[rating] = ( (e_fan_power[rating] - battery_power_feed[rating] \
)/ power_elec.overall_efficiency \
)/((shaft_power0)*(engine.n_engine-fd_nei[rating]))
# e-fan shaft power
e_shaft_power[rating] = e_fan_power[rating]
else: # required turbofan shaft power ration is given, absolute shaft power is deduced
# Shaft power dedicated to electric generator
shaft_power2 = e_power_ratio[rating]*shaft_power0*(engine.n_engine-fd_nei[rating])
# Fraction of the shaft power dedicated to the electric generation
e_power_ratio[rating] = e_fan_power[rating]
e_shaft_power[rating] = shaft_power2*power_elec.overall_efficiency \
+ battery_power_feed[rating]
# Storing results
e_engine.mto_e_power_ratio = e_power_ratio[MTO]
e_engine.mcn_e_power_ratio = e_power_ratio[MCN]
e_engine.mcl_e_power_ratio = e_power_ratio[MCL]
e_engine.mcr_e_power_ratio = e_power_ratio[MCR]
e_engine.fid_e_power_ratio = e_power_ratio[FID]
e_engine.mto_e_shaft_power = e_shaft_power[MTO]
e_engine.mcn_e_shaft_power = e_shaft_power[MCN]
e_engine.mcl_e_shaft_power = e_shaft_power[MCL]
e_engine.mcr_e_shaft_power = e_shaft_power[MCR]
e_engine.fid_e_shaft_power = e_shaft_power[FID]
# Engine performance update
#-----------------------------------------------------------------------------------------------------------
(Pamb,Tamb,Tstd,dTodZ) = earth.atmosphere(fd_altp[MTO],fd_disa[MTO])
(fn,data) = turbofan_thrust(aircraft,Pamb,Tamb,fd_mach[MTO],MTO,fd_nei[MTO])
(fn_core,fn_fan0,fn0,shaft_power0) = data
shaft_power1 = (1-e_power_ratio[MTO])*shaft_power0 # Shaft power dedicated to the fan at take off
Vsnd = earth.sound_speed(Tamb)
Vair = Vsnd*fd_mach[MTO]
fn_fan1 = nacelle.efficiency_prop*shaft_power1/Vair # Effective fan thrust
engine.kfn_off_take = (fn_core + fn_fan1)/fn0 # Thrust reduction due to power off take for the e-fan
return
def eval_hybrid_nacelle_design(aircraft):
"""
Hybrid propulsive architecture design
"""
design_driver = aircraft.design_driver
fuselage = aircraft.fuselage
wing = aircraft.wing
propulsion = aircraft.propulsion
engine = aircraft.turbofan_engine
nacelle = aircraft.turbofan_nacelle
e_engine = aircraft.electric_engine
e_nacelle = aircraft.electric_nacelle
(MTO,MCN,MCL,MCR,FID) = propulsion.rating_code
# Turbofan nacelles geometry adjustment
#-----------------------------------------------------------------------------------------------------------
nacWidth0 = 0.49*engine.bpr**0.67 + 4.8e-6*engine.reference_thrust # Reference dimensions of the nacelle without power off take
nacLength0 = 0.86*nacWidth0 + engine.bpr**0.37
kSize = numpy.sqrt(engine.kfn_off_take) # Diameter decrease due to max thrust decrease
kSize_eff = (kSize + engine.core_width_ratio * (1-kSize)) # Diameter decrease considering core is unchanged
nacelle.width = nacWidth0*kSize_eff # Real nacelle diameter assuming core section remains unchanged
nacelle.length = nacLength0*kSize_eff # Nacelle length is reduced according to the same factor
knac = numpy.pi*nacelle.width*nacelle.length
nacelle.net_wetted_area = knac*(1.48 - 0.0076*knac)*engine.n_engine
tan_phi0 = 0.25*(wing.c_kink-wing.c_tip)/(wing.y_tip-wing.y_kink) + numpy.tan(wing.sweep)
if (nacelle.attachment == 1) : # Nacelles are attached under the wing
nacelle.y_ext = 0.7 * fuselage.width + 1.4 * nacelle.width # statistical regression
nacelle.x_ext = wing.x_root + (nacelle.y_ext-wing.y_root)*tan_phi0 - 0.7*nacelle.length
nacelle.z_ext = - 0.5 * fuselage.height \
+ (nacelle.y_ext - 0.5 * fuselage.width) * numpy.tan(wing.dihedral) \
- 0.5*nacelle.width
elif (nacelle.attachment == 2) : # Nacelles are attached on rear fuselage
nacelle.y_ext = 0.5 * fuselage.width + 0.6 * nacelle.width # statistical regression
nacelle.x_ext = wing.x_root + (nacelle.y_ext-wing.y_root)*tan_phi0 - 0.7*nacelle.length
nacelle.z_ext = 0.5 * fuselage.height
# Electric nacelle is design by cruise conditions
#-----------------------------------------------------------------------------------------------------------
dISA = 0.
Altp = design_driver.ref_cruise_altp
Mach = design_driver.cruise_mach
(Pamb,Tamb,Tstd,dTodZ) = earth.atmosphere(Altp,dISA)
shaft_power = e_engine.mcr_e_shaft_power
hub_width = 0.5 # Diameter of the e fan hub
body_length = fuselage.length
body_width = fuselage.width
eval_bli_nacelle_design(e_nacelle,Pamb,Tamb,Mach,shaft_power,hub_width,body_length,body_width)
e_nacelle.x_axe = fuselage.length + 0.2*e_nacelle.width
e_nacelle.y_axe = 0
e_nacelle.z_axe = 0.91*fuselage.height - 0.55*fuselage.height
# Engine performance update
#-----------------------------------------------------------------------------------------------------------
fd = e_engine.flight_data
e_fan_thrust = numpy.zeros(5)
for rating in propulsion.rating_code:
altp = fd.get("altp")[rating]
disa = fd.get("disa")[rating]
mach = fd.get("mach")[rating]
nei = fd.get("nei")[rating]
(Pamb,Tamb,Tstd,dTodZ) = earth.atmosphere(altp,disa)
(fn,sec,data) = hybrid_thrust(aircraft,Pamb,Tamb,mach,rating,nei)
(fn_core,fn_fan1,fn_fan2,dVbli_o_V,shaft_power2,fn0,shaft_power0) = data
e_fan_thrust[rating] = fn_fan2
e_engine.mto_e_fan_thrust = e_fan_thrust[MTO]
e_engine.mcn_e_fan_thrust = e_fan_thrust[MCN]
e_engine.mcl_e_fan_thrust = e_fan_thrust[MCL]
e_engine.mcr_e_fan_thrust = e_fan_thrust[MCR]
e_engine.fid_e_fan_thrust = e_fan_thrust[FID]
Vair = Mach*earth.sound_speed(Tamb)
(eFanFnBli,q1,dVbli) = jet.fan_thrust_with_bli(e_nacelle,Pamb,Tamb,Mach,shaft_power)
(eFanFn,q0) = jet.fan_thrust(e_nacelle,Pamb,Tamb,Mach,shaft_power)
propulsion.bli_e_thrust_factor = eFanFnBli / eFanFn # Thrust increase due to BLI at iso shaft power for the e-fan
propulsion.bli_thrust_factor = 1. # Thrust increase due to BLI at iso shaft power for the turbofans (provision)
return