def h_fuel(self, wf, eta_b, w0, h0, comp):
if self.burn_model == 'CEA':
fuel_comp = cl.Composition(comp_def='Jet-A1')
my_fluid = cl.CeaFluid()
enthalpy_fuel = my_fluid.tp2h(self.tf, StandartPressure, fuel_comp)
# fuel to air mass ratio
fmr = wf * eta_b / (w0 * AirToFuelFlow)
# enthalpy combustion products
return (h0 + enthalpy_fuel * fmr) / (1 + fmr)
elif self.burn_model == 'RRD':
comp_air = cl.Composition('Air')
comp_stoi = cl.Composition('Air')
comp_stoi.FAR = FARStoi
my_fluid = cl.RRDFluid()
h_air = my_fluid.tp2h(self.t_ref, StandartPressure, comp_air)
h_stoi = my_fluid.tp2h(self.t_ref, StandartPressure, comp_stoi)
heating_corr = h_stoi + (h_stoi - h_air) / comp_stoi.FAR
# fuel to air mass ratio
fmr = wf * eta_b / (w0 * AirToFuelFlow)
# corrected fuel heating value
enthalpy_fuel = self.hv + heating_corr # +CP*(self.tf-self.t_ref)
# enthalpy combustion products
return (h0 + enthalpy_fuel * fmr) / (1 + fmr)
def heat_balance_calcs(self):
self.fgrc = self.wf / (self.in_station.w * AirToFuelFlow)
# set composition of combustion products
self.out_station.comp = self.current_fluid.burn_comp(
self.in_station.comp, cl.Composition(), self.fgrc)
# calc enthalpy of air at entry
self.in_station.h = self.current_fluid.tp2h(self.in_station.t,
self.in_station.p,
self.in_station.comp)
# calc enthalpy of combustion products
self.out_station.h = self.current_fuel.h_fuel(self.wf, self.eta_b,
self.in_station.w,
self.in_station.h,
self.out_station.comp)
# calculate outlet temperature
self.out_station.t = self.current_fluid.hp2t(self.out_station.h,
self.in_station.p,
self.out_station.comp)
# calculate outlet mass flow
self.out_station.w = self.in_station.w + self.wf / AirToFuelFlow * self.eta_b
def test_create_jeta1(self):
'''test if Jet-A1 is set up correctly'''
my_comp = cl.Composition(comp_def='Jet-A1')
self.assertEqual(my_comp.name, 'Jet-A1')
self.assertEqual(len(my_comp.structure), 1)
self.assertEqual(round(my_comp.r_spec, SignificantDigits),
round(48.878894767783656, SignificantDigits))
self.assertEqual(my_comp.mol_wgt, 0.1701)
self.assertEqual(my_comp.FAR, 1)
self.assertEqual(my_comp.WGR, 0)
def test_create_dry_air(self):
'''test if dry air is set up correctly'''
my_comp = cl.Composition(comp_def='Air')
self.assertEqual(my_comp.name, 'Air')
self.assertEqual(len(my_comp.structure), 4)
self.assertEqual(round(my_comp.r_spec, SignificantDigits),
round(287.0689197920102, SignificantDigits))
self.assertEqual(round(my_comp.mol_wgt, SignificantDigits),
round(0.02896273134, SignificantDigits))
self.assertEqual(my_comp.FAR, 0)
self.assertEqual(my_comp.WGR, 0)
def __init__(self,t=None,p=None,w=None,comp=None):
if t!=None and p!=None and w!=None and comp!=None:
self.set_sation(t, p, w, comp)
else:
self.t=0
self.p=0
self.cp=0
self.h=0
self.s=0
self.fluid = cl.CeaFluid()
self.comp = cl.Composition()
self.w=0
def plot_work_press_ratio(pressure_ratio, t_in):
comp = cl.Composition()
fluid_cea = cl.CeaFluid(eos_model='SOA')
fluid_cea.eos.set_coeffs(comp)
fluid_rrd = cl.RRDFluid()
delta_h_const = []
delta_h_mean_ideal = []
delta_h_mean_real = []
for pr in pressure_ratio:
kappa = fluid_cea.tp2kappa(t_in, StandartPressure, comp)
t_out_const = t_in * (pr)**((kappa - 1) / kappa)
t_out_mean_ideal = fluid_cea.isentropic_compression(
t_in, StandartPressure, pr * StandartPressure, comp)
t_out_mean_real = fluid_cea.isentropic_compression(t_in,
StandartPressure,
pr *
StandartPressure,
comp,
mode='real')
delta_h_const.append(
fluid_cea.tp2h(t_out_const, StandartPressure, comp) -
fluid_cea.tp2h(t_in, pr * StandartPressure, comp))
delta_h_mean_ideal.append(
fluid_cea.tp2h(t_out_mean_ideal, StandartPressure, comp) -
fluid_cea.tp2h(t_in, pr * StandartPressure, comp))
delta_h_mean_real.append(
fluid_cea.tp2h(
t_out_mean_real, StandartPressure, comp, mode='real') -
fluid_cea.tp2h(t_in, pr * StandartPressure, comp, mode='real'))
fig = plt.figure()
ax1 = fig.add_subplot(1, 1, 1)
#ax1.plot(pressure_ratio,eta_const,pressure_ratio,eta_mean_ideal,pressure_ratio,eta_mean_real)
ax1.plot(pressure_ratio, delta_h_const, pressure_ratio, delta_h_mean_ideal,
pressure_ratio, delta_h_mean_real)
ax1.set_xlabel('Pressure ratio [1]')
ax1.set_ylabel('spec. compressor work [J/kg]')
ax1.grid(True)
ax1.legend([
'$\delta h$ mit $\kappa=const$',
'$\delta h_{id}$ mit $\kappa=(T_{in}+T_{out})/2$',
'$\delta h_{re}$ mit $\kappa=(T_{in}+T_{out})/2$'
])
plt.show()
def test_create_wet_air_with_RH(self):
'''test if wet air is set up correctly using relative humidity'''
my_fluid = cl.CeaFluid()
my_comp = cl.Composition(comp_def='Air')
my_fluid.set_humidity(StandartTemperature + 20,
StandartPressure,
my_comp,
RH=1)
self.assertEqual(my_comp.name, 'Air')
self.assertEqual(len(my_comp.structure), 5)
self.assertEqual(round(my_comp.r_spec, SignificantDigits),
round(293.269688447603, SignificantDigits))
self.assertEqual(round(my_comp.mol_wgt, SignificantDigits),
round(0.028350355756201765, SignificantDigits))
self.assertEqual(my_comp.FAR, 0)
self.assertEqual(round(my_comp.WGR, SignificantDigits),
round(0.036854216859696774, SignificantDigits))
self.assertEqual(round(my_comp.get_fraction('H2O'), SignificantDigits),
round(0.05593629993099881, SignificantDigits))
def plot_pr_kappa(t_in, pressure_ratio):
comp = cl.Composition()
fluid_cea = cl.CeaFluid(eos_model='SOA')
fluid_cea.eos.set_coeffs(comp)
eta_is = 0.9
kappa_mean = []
kappa_ideal = fluid_cea.tp2kappa(t_in, StandartPressure, comp)
f1 = []
f2 = []
for pr in pressure_ratio:
t_out = fluid_cea.isentropic_compression(t_in,
StandartPressure,
pr * StandartPressure,
comp,
eta_isentropic=eta_is)
kappa_mean.append(
(kappa_ideal +
fluid_cea.tp2kappa(t_out, pr * StandartPressure, comp)) / 2)
f1.append(pr**((kappa_ideal - 1) / kappa_ideal))
f2.append(pr**((kappa_mean[-1] - 1) / kappa_mean[-1]))
fig = plt.figure()
ax1 = fig.add_subplot(1, 1, 1)
ax1.plot(pressure_ratio, f1, pressure_ratio, f2)
ax1.set_xlabel('Pressure ratio [1]')
ax1.set_ylabel('f(pressure ratio)')
#ax1.set_xticks([1,20,30,40,50,60,70,80,90,100])
#ax1.set_yticks([StandartTemperature,400,600,800,1000,1200,1400])
ax1.grid(True)
ax1.legend([
'$\kappa_{ideal}=const$',
'$\kappa_{ideal}=(\kappa_{in}+\kappa_{out})/2$'
])
plt.show()
def plot_cp(t_range=np.linspace(300, 2000, 100), p=1e5, RH=0):
fl_cea = cl.CeaFluid()
fl_rrd = cl.RRDFluid()
std_air = cl.Composition('Air')
fl_cea.set_humidity(StandartTemperature + 20,
StandartPressure,
std_air,
RH=RH)
cea_cp = []
rrd_cp = []
for t in t_range:
cea_cp.append(fl_cea.tp2cp(t, p, std_air))
rrd_cp.append(fl_rrd.tp2cp(t, p, std_air))
janaf_cp = get_ref_cp(t_range, p, std_air)
cea_cp = np.array(cea_cp)
rrd_cp = np.array(rrd_cp)
diff_cp_cea = (cea_cp - janaf_cp) / janaf_cp
diff_cp_rrd = (rrd_cp - janaf_cp) / janaf_cp
fig_cp = plt.figure()
ax = fig_cp.add_subplot(1, 2, 1)
ax.plot(t_range, janaf_cp)
ax.plot(t_range, cea_cp)
ax.plot(t_range, rrd_cp)
plt.legend(['JANAF', 'CEA', 'RRD'])
ax = fig_cp.add_subplot(1, 2, 2)
ax.plot(t_range, diff_cp_cea)
ax.plot(t_range, diff_cp_rrd)
plt.legend(['CEA', 'RRD'])
plt.show()
import numpy as np # numerical python for vector calcs
from constants import * # import all constants
# import matplotlib environment for plotting
import matplotlib as mpl
import matplotlib.pyplot as plt
####### INPUTS #######
t_in = 846 # temperature [K]
p_in = 512 # pressure [psi]
w_in = 56 # air flow [lb/s]
dtamb = 20
rh = 1
# init dummy fluid class and standart air as composition
dummy_fluid = cl.CeaFluid()
comp = cl.Composition('Air')
# set relative humidity of air to 1
dummy_fluid.set_humidity(StandartTemperature + dtamb,
StandartPressure,
comp,
RH=rh)
####### CALCULATIONS #######
# baseline for the plot will be online CEA results for rh=1
# initiate empty numpy arrays
eqr_range = np.array([])
t_range = np.array([])
# declare file handle
file1 = 'data/CEA_tool/cea_full_rh=1.dat'
# open file handle
'''
This is the main plot file. It imports all necessary libs and calls various plotting functions
'''
import sys
sys.path.insert(0, 'lib')
import plot_functions as plotfcn
import classes as cl
import numpy as np
from constants import PressureConversion, FLowConversion, StandartPressure, StandartTemperature
# init dummy fluid class and standart air as composition
dummy_fluid = cl.CeaFluid()
std_air = cl.Composition('Air')
# set relative humidity of air to 1
dummy_fluid.set_humidity(StandartTemperature + 20,
StandartPressure,
std_air,
RH=1)
#plotfcn.plot_combustion_temperature(846,512*PressureConversion,57*FLowConversion,std_air,baseline='Online CEA')
#plotfcn.plot_cp()
pressure_ratio = np.linspace(1, 100, 400)
#plotfcn.plot_work_press_ratio(pressure_ratio,StandartTemperature)
#plotfcn.plot_eff_press_ratio(pressure_ratio,StandartTemperature)
plotfcn.plot_burn_temp_comparison(512, 846, 56, t_fuel=382.5948)
def add_fluid(self, fluid_dict):
self.fluids.add(
cl.Composition('Mixture_' + str(len(self.fluids.data)), comp_def))
def plot_burn_temp_comparison(p_in, t_in, w_in, t_fuel=382.5948):
# load large and reduced chemestry set data from CEA website
FileNames = [
'data/online_cea_combustion/reducedChemSet_EQR_below1.dat',
'data/online_cea_combustion/reducedChemSet_EQR_above1.dat',
'data/online_cea_combustion/largeChemSet_EQR_below1.dat',
'data/online_cea_combustion/largeChemSet_EQR_above1.dat'
]
# read data from loaded files
T = np.array([])
CP = np.array([])
EQR = np.array([])
for i, inFile in enumerate(FileNames):
if i == 2:
Tred = T
CPred = CP
EQRred = EQR
T = np.array([])
CP = np.array([])
EQR = np.array([])
inputFile = open(inFile, 'r')
for line in inputFile:
if 'T, K' in line:
line = line.split()
T = np.append(T, float(line[2]))
if 'Cp, KJ/(KG)(K)' in line:
line = line.split()
CP = np.append(CP, float(line[2]))
if 'EQ.RATIO' in line:
line = line.split(',')
EQR = np.append(EQR, float(line[-1].split('=')[1]))
inputFile.close()
# reduced set of species using my cea calculation
dummy_fluid = cl.CeaFluid()
std_air = cl.Composition('Air')
dummy_fluid.set_humidity(StandartTemperature + 20,
StandartPressure,
std_air,
RH=1)
# set up combustor
comb = cmb.Combustor()
comb.current_fluid = cl.CeaFluid()
comb.in_station = stat.Station(t_in, p_in * PressureConversion,
w_in * FLowConversion, std_air)
comb.out_station = stat.Station(t_in, p_in * PressureConversion,
w_in * FLowConversion, std_air)
comb.current_fuel.tf = t_fuel
eqr_vec = np.linspace(0.25, 2, 20)
far_vec = eqr_vec * FARStoi
wf_vec = far_vec * comb.in_station.w * AirToFuelFlow
t_cea = np.array([])
for fuel_flow in np.nditer(wf_vec):
comb.wf = fuel_flow
comb.heat_balance_calcs()
t_cea = np.append(t_cea, comb.out_station.t)
comb.current_fluid = cl.RRDFluid()
comb.current_fuel.burn_model = 'RRD'
t_rrd = np.array([])
for fuel_flow in np.nditer(wf_vec):
comb.wf = fuel_flow
comb.heat_balance_calcs()
t_rrd = np.append(t_rrd, comb.out_station.t)
diff_CP = (CPred - CP) / CP
diff_T = (Tred - T) / T
diff_T_cea = (np.interp(EQR, eqr_vec, t_cea) - T) / T
diff_T_rrd = (np.interp(EQR, eqr_vec, t_rrd) - T) / T
######## CANTERA calculation ############
# Get all of the Species objects defined in the GRI 3.0 mechanism
species = {S.name: S for S in ct.Species.listFromFile('nasa.cti')}
# Create an IdealGas object including incomplete combustion species
complete_species = [
species[S] for S in ('Jet-A(g)', 'O2', 'N2', 'CO2', 'H2O', 'Ar')
]
gas2 = ct.Solution(thermo='IdealGas',
species=complete_species) #species.values())
T_incomplete = np.zeros(EQR.shape)
for i in range(len(EQR)):
gas2.TP = t_in, p_in * PressureConversion
gas2.set_equivalence_ratio(
EQR[i], 'Jet-A(g)',
'O2:0.19775868763, N2:0.7371626995, AR:0.008841156551, CO2:0.0003011563203 , H2O: 0.05593629993'
)
gas2.equilibrate('HP')
T_incomplete[i] = gas2.T
##### PLOT
fig = plt.figure()
ax = fig.add_subplot(1, 2, 1)
ax.plot(EQRred, Tred)
ax.plot(EQR, T)
ax.plot(eqr_vec, t_cea)
ax.plot(eqr_vec, t_rrd)
ax.plot(EQR, T_incomplete)
plt.xlim(0.25, 1.5)
plt.xlabel('Equivalence ratio, $\phi$')
plt.ylabel('Temperature [K]')
plt.grid(True)
plt.legend(
['Onl. CEA RCS', 'Onl. CEA full CS', 'My CEA', 'RRD', 'Cantera'])
ax = fig.add_subplot(1, 2, 2)
ax.plot(EQRred, diff_T)
ax.plot(EQR, diff_T_cea)
ax.plot(EQR, diff_T_rrd)
plt.grid(True)
plt.xlabel('Equivalence ratio, $\phi$')
plt.ylabel('delta T')
plt.xlim(0.25, 1.5)
plt.legend(['Onl. CEA RCS', 'My CEA', 'RRD'])
plt.show()
def plot_eff_press_ratio(pressure_ratio, t_in):
comp = cl.Composition()
fluid_cea = cl.CeaFluid(eos_model='SOA')
fluid_cea.eos.set_coeffs(comp)
eta_is = 0.9
eta_const = []
eta_real = []
t_out_test = []
t_out_ref = []
t_out_real = []
eta_base1 = []
eta_base2 = []
for pr in pressure_ratio:
#if pr == 1:
# eta_const.append(eta_is)
# eta_real.append(eta_is)
#else:
h_in = fluid_cea.tp2h(t_in, StandartPressure, comp)
kappa = fluid_cea.tp2kappa(t_in, StandartPressure, comp)
t_out_test.append(t_in *
(((pr**((kappa - 1) / kappa) - 1) / eta_is) + 1))
t_out_ref.append(
fluid_cea.isentropic_compression(t_in,
StandartPressure,
pr * StandartPressure,
comp,
eta_isentropic=eta_is))
t_out_real.append(
fluid_cea.isentropic_compression(t_in,
StandartPressure,
pr * StandartPressure,
comp,
mode='real',
eta_isentropic=eta_is))
kappa_mean = (kappa + fluid_cea.tp2kappa(
t_out_ref[-1], pr * StandartPressure, comp)) / 2
eta_base1.append(
(pr**((kappa - 1) / kappa) - 1) / ((t_out_test[-1] / t_in) - 1))
eta_base2.append((pr**((kappa_mean - 1) / kappa_mean) - 1) /
((t_out_ref[-1] / t_in) - 1))
s_is = fluid_cea.tp2s(t_in, StandartPressure, comp)
t_out_ref_is = fluid_cea.sp2t(s_is, pr * StandartPressure, comp)
h_out_ref_is = fluid_cea.tp2h(t_out_ref_is, pr * StandartPressure,
comp)
#h_out_const = fluid_cea.tp2h(t_out_ref[-1],pr*StandartPressure,comp)
#h_out_real = fluid_cea.tp2h(t_out_ref[-1],pr*StandartPressure,comp,mode='real')
h_out_const = fluid_cea.tp2h(t_out_real[-1], pr * StandartPressure,
comp)
h_out_real = fluid_cea.tp2h(t_out_real[-1],
pr * StandartPressure,
comp,
mode='real')
eta_const.append((h_out_ref_is - h_in) / (h_out_const - h_in))
eta_real.append((h_out_ref_is - h_in) / (h_out_real - h_in))
#eta_const.append((t_out_ref_is-t_in)/(t_out_real[-1]-t_in))
eta_const = np.array(eta_const)
eta_real = np.array(eta_real)
t_out_test = np.array(t_out_test)
t_out_ref = np.array(t_out_ref)
eta_base1 = np.array(eta_base1)
eta_base2 = np.array(eta_base2)
fig = plt.figure()
ax1 = fig.add_subplot(1, 1, 1)
#ax1.plot(pressure_ratio,eta_const,pressure_ratio,eta_mean_ideal,pressure_ratio,eta_mean_real)
ax1.plot(pressure_ratio, eta_const, pressure_ratio, eta_real,
[pressure_ratio[0], pressure_ratio[len(pressure_ratio) - 1]],
[0.9, 0.9])
ax1.set_xlabel('Pressure ratio [1]')
ax1.set_ylabel('isentropic efficiency [1]')
ax1.grid(True)
ax1.legend(['ideal $\eta_{is}$', 'real $\eta_{is}$'])
'''
ax2 = fig.add_subplot(2,2,2)
ax2.plot(pressure_ratio,(eta_real-eta_const))
ax2.set_xlabel('Pressure ratio [1]')
ax2.set_ylabel('delta isentropic efficiency [1]')
ax2.grid(True)
ax2.legend(['dev. real $\eta_{is}$'])
ax3 = fig.add_subplot(2,2,3)
ax3.plot(pressure_ratio,t_out_test/t_in,pressure_ratio,t_out_ref/t_in)
ax3.set_xlabel('Pressure ratio [1]')
ax3.set_ylabel('Outlet Temperature [K]')
ax3.grid(True)
ax3.legend(['$\kappa=const$','$\kappa=(\kappa_{in}+\kappa_{out})/2$'])
ax4 = fig.add_subplot(2,2,4)
ax4.plot(pressure_ratio,eta_base1,pressure_ratio,eta_base2)
ax4.set_xlabel('Pressure ratio [1]')
ax4.set_ylabel('isentropic efficiency [1]')
ax4.set_ylim([0.85,0.95])
ax4.grid(True)
ax4.legend(['$\kappa=const$','$\kappa=(\kappa_{in}+\kappa_{out})/2$'])
'''
plt.show()
#plot_t_out(t_in,t_out_test,t_out_ref,t_out_real)
plot_pr_kappa(t_in, pressure_ratio)
