# ideal-shock-test.py
#
# $ prep-gas ideal-air.inp ideal-air-gas-model.lua
# $ python3 ideal-shock-test.py
#
# PJ, 2019-11-28
#
import math
from eilmer.gas import GasModel, GasState, GasFlow
gmodel = GasModel('ideal-air-gas-model.lua')
state1 = GasState(gmodel)
state1.p = 125.0e3 # Pa
state1.T = 300.0 # K
state1.update_thermo_from_pT()
state1.update_sound_speed()
print("state1: %s" % state1)
print("normal shock (in ideal gas), given shock speed")
vs = 2414.0
state2 = GasState(gmodel)
flow = GasFlow(gmodel)
v2, vg = flow.ideal_shock(state1, vs, state2)
print("v2=%g vg=%g" % (v2, vg))
print("state2: %s" % state2)
# $ python3 conical-shock-test.py
#
# PJ, 2019-12-01
#
import math
def approxEqual(a, b):
result = math.isclose(a, b, rel_tol=1.0e-2, abs_tol=1.0e-5)
# print("a=",a, "b=",b, "rel=",(a-b)/b, "abs=",a-b, "result=",result)
return result
from eilmer.gas import GasModel, GasState, GasFlow
m1 = 1.5
print("Conical-shock demo for m1=%g" % m1)
gmodel = GasModel('cea-air13species-gas-model.lua')
state1 = GasState(gmodel)
state1.p = 100.0e3 # Pa
state1.T = 300.0 # K ideal air, not high T
state1.update_thermo_from_pT()
state1.update_sound_speed()
print("state1: %s" % state1)
v1 = m1*state1.a
print("v1=%g" % v1)
beta = 45.0 * math.pi/180.0
print(" given beta(degrees)=%g" % (beta*180/math.pi))
state_c = GasState(gmodel)
flow = GasFlow(gmodel)
theta_c, v_c = flow.theta_cone(state1, v1, beta, state_c)
print(" theta_c=%g degrees" % (theta_c*180/math.pi))
print(" v_c=%g" % (v_c))
# A script to compute the viscosity and thermal conductivity
# of air (as a mixture of N2 and O2) from 200 -- 20000 K.
#
# Author: Peter J. and Rowan J. Gollan
# Date: 2019-11-21
#
# To run this script:
# $ prep-gas thermally-perfect-N2-O2.inp thermally-perfect-N2-O2.lua
# $ python3 transport-properties-for-air.py
#
from eilmer.gas import GasModel, GasState
gasModelFile = 'thermally-perfect-N2-O2.lua'
gmodel = GasModel(gasModelFile)
gs = GasState(gmodel)
gs.p = 1.0e5 # Pa
gs.massf = {"N2":0.78, "O2":0.22} # approximation for the composition of air
outputFile = 'trans-props-air.dat'
print("Opening file for writing: %s" % outputFile)
f = open(outputFile, "w")
f.write("# 1:T[K] 2:mu[Pa.s] 3:k[W/(m.K)]\n")
lowT = 200.0
dT = 100.0
for i in range(199):
gs.T = dT*i + lowT
gs.update_thermo_from_pT()
gs.update_trans_coeffs()
# Typical use:
# $ python3 poshax.py
#
#------------------------------------------------------------------
from eilmer.gas import GasModel, GasState, GasFlow, ThermochemicalReactor
debug = False
print("Initialise a gas model.")
print("air 7 species Gupta-et-al reactions")
gmodel = GasModel("air-7sp-gas-model.lua")
nsp = gmodel.n_species
nmodes = gmodel.n_modes
if debug: print("nsp=", nsp, " nmodes=", nmodes, " gmodel=", gmodel)
reactor = ThermochemicalReactor(gmodel, "air-7sp-chemistry.lua")
# The example here matches the case discussed on page 63 of the thesis.
state1 = GasState(gmodel)
state1.p = 133.3 # Pa
state1.T = 300.0 # degree K
state1.massf = {"N2": 0.78, "O2": 0.22}
print("Free stream conditions, before the shock.")
state1.update_thermo_from_pT()
state1.update_sound_speed()
print(" state1: %s" % state1)
mach1 = 12.28
v1 = mach1 * state1.a
print("mach1:", mach1, "v1:", v1)
print("Stationary normal shock with chemically-frozen gas.")
flow = GasFlow(gmodel)
state2 = GasState(gmodel)
v2, vg = flow.normal_shock(state1, v1, state2)
def eos_derivatives(gas0, gmodel, tol=0.0001):
# Finite difference evaluation, assuming that gas0 is valid state already.
gas1 = GasState(gmodel)
gas1.copy_values(gas0)
p0 = gas0.p
rho0 = gas0.rho
u0 = gas0.u
#
drho = rho0 * tol
gas1.rho = rho0 + drho
gas1.update_thermo_from_rhou()
dpdrho = (gas1.p - p0) / drho
#
gas1.rho = rho0
du = u0 * tol
gas1.u = u0 + du
gas1.update_thermo_from_rhou()
dpdu = (gas1.p - p0) / du
#
return dpdrho, dpdu
# Step through a steady isentropic expansion,
# from stagnation condition to sonic condition.
#
# $ prep-gas ideal-air.inp ideal-air-gas-model.lua
# $ python3 isentropic-air-expansion.py
#
# Python port, PJ, 2019-11-21
#
import math
from eilmer.gas import GasModel, GasState
gmodel = GasModel('ideal-air-gas-model.lua')
gs = GasState(gmodel)
gs.p = 500e3 # Pa
gs.T = 300.0 # K
gs.update_thermo_from_pT()
# Compute enthalpy and entropy at stagnation conditions
h0 = gs.enthalpy
s0 = gs.entropy
# Set up for stepping process
dp = 1.0 # Pa, use 1 Pa as pressure step size
gs.p = gs.p - dp
mach_tgt = 1.0
# Begin stepping until Mach = mach_tgt
while True:
gs.update_thermo_from_ps(s0)
h1 = gs.enthalpy
v1 = math.sqrt(2*(h0 - h1))
m1 = v1/gs.a
if m1 >= mach_tgt:
print("Stopping at Mach=%g" % m1)
# $ python3 co2_scheme_validation.py
#
#------------------------------------------------------------------
from eilmer.gas import GasModel, GasState, GasFlow, ThermochemicalReactor
debug = False
print("Initialise a gas model.")
print("Park et al mars atmosphere reaction scheme.")
gmodel = GasModel("mars-atm-with-ions.lua")
nsp = gmodel.n_species
nmodes = gmodel.n_modes
if debug: print("nsp=", nsp, " nmodes=", nmodes, " gmodel=", gmodel)
reactor = ThermochemicalReactor(gmodel, "mars-atm-with-ions-chemistry.lua")
# The example here matches the case on p.17 of Park's publication
v1 = 8000
state1 = GasState(gmodel)
state1.rho = 0.15 * 101300 / v1**2 # freestream density according to Park to keep p after the shock at 0.15atm
print("Free stream desnity:", state1.rho)
state1.T = 210.0 # K, Mars surface temp
state1.massf = {
"CO2": 0.9664,
"N2": 0.0174,
"Ar": 0.0147,
"O2": 0.001,
"CO": 0.0005
}
print("Free stream conditions, before the shock.")
state1.update_thermo_from_rhoT()
state1.update_sound_speed()
print(" state1: %s" % state1)
mach1 = v1 / state1.a
# You will need to "make install" the loadable library
# and then invoke this script from a location where
# the gas-model Lua file is visible, as given by the path below.
#
# PJ 2019-07-24 direct use of FFI
# 2019-07-25 using Pythonic wrapper
#
from eilmer.gas import GasModel, GasState
gmodel = GasModel("ideal-air-gas-model.lua")
print("gmodel=", gmodel)
print("n_species=", gmodel.n_species, ", n_modes=", gmodel.n_modes)
print("species_names=", gmodel.species_names)
print("mol_masses=", gmodel.mol_masses)
gs = GasState(gmodel)
print("freshly minted gs=", gs)
gs.rho=1.1; gs.p=1.0e5; gs.T=300.0; gs.u=1.44e6; gs.massf=[1.0]
print("after setting some values")
print(" gs.rho=%g p=%g T=%g u=%g massf=%s a=%g k=%g mu=%g" %
(gs.rho, gs.p, gs.T, gs.u, gs.massf, gs.a, gs.k, gs.mu))
gmodel.update_thermo_from_pT(gs) # the way that we do the update in D
gmodel.update_sound_speed(gs) # not necessary from Python but is available
gmodel.update_trans_coeffs(gs)
print("after update thermo from pT")
print(" gs.rho=%g p=%g T=%g u=%g massf=%s a=%g k=%g mu=%g" %
(gs.rho, gs.p, gs.T, gs.u, gs.massf, gs.a, gs.k, gs.mu))
gs.p=3000.0; gs.T=99.0; gs.massf={'air':1.0}
gs.update_thermo_from_rhou() # update another way
gs.update_trans_coeffs()
print("after update thermo from rhou")
#------------------------------------------------------------------
# Start the main script...
debug = False
print("# Reacting pipe flow -- Bittker-Scullin test case 3.")
print(sample_header)
# Gas model setup
gmodel = GasModel("h2-o2-n2-9sp.lua")
nsp = gmodel.n_species
nmodes = gmodel.n_modes
if debug: print("nsp=", nsp, " nmodes=", nmodes, " gmodel=", gmodel)
print("# Gas properties at the start of the pipe.")
gas0 = GasState(gmodel)
gas0.p = 96.87e3 # Pa
x = 0.0 # m (inlet of pipe)
v = 4551.73 # m/s
gas0.T = 1559.0 # degree K
gas0.molef = {"O2": 0.1480, "N2": 0.5562, "H2": 0.2958}
gas0.update_thermo_from_pT()
dt_suggest = 1.0e-8 # suggested starting time-step for chemistry updater
print(sample_data(x, v, gas0, dt_suggest))
print("# Start reactions...")
reactor = ThermochemicalReactor(gmodel, "h2-o2-n2-9sp-18r.lua")
t = 0 # time is in seconds
t_final = 22.0e-6
t_inc = 0.05e-6
nsteps = int(t_final / t_inc)
# A script to output Cp and h for O2 over temperature range 200--20000 K.
#
# Author: Peter J. and Rowan J. Gollan
# Date: 2019-11-21
#
# To run this script:
# $ prep-gas O2.inp O2-gas-model.lua
# $ python3 thermo-curves-for-O2.py
#
from eilmer.gas import GasModel, GasState
gasModelFile = 'O2-gas-model.lua'
gmodel = GasModel(gasModelFile)
gs = GasState(gmodel)
gs.p = 1.0e5 # Pa
gs.massf = {"O2": 1.0}
outputFile = 'O2-thermo.dat'
print("Opening file for writing: %s" % outputFile)
f = open(outputFile, "w")
f.write("# 1:T[K] 2:Cp[J/kg/K] 3:h[J/kg]\n")
lowT = 200.0
dT = 100.0
for i in range(199):
gs.T = dT * i + lowT
gs.update_thermo_from_pT()
f.write(" %12.6e %12.6e %12.6e\n" % (gs.T, gs.Cp, gs.enthalpy))
return dpdrho, dpdu
#------------------------------------------------------------------
# Start the main script...
debug = False
print("# Reacting nozzle flow.")
print(sample_header)
# Gas model setup
gmodel = GasModel("h2-o2-n2-5sp.lua")
nsp = gmodel.n_species
nmodes = gmodel.n_modes
if debug: print("nsp=", nsp, " nmodes=", nmodes, " gmodel=", gmodel)
print("# Gas properties at the start of the pipe.")
gas0 = GasState(gmodel)
gas0.p = 81.0e3 # Pa
x = 0.0 # m (inlet of duct)
area = duct_area(x)
v = 1230.0 # m/s
gas0.T = 1900.0 # degree K
gas0.molef = {"O2":0.1865, "N2":0.7016, "H2":0.1119}
gas0.update_thermo_from_pT()
dt_suggest = 1.0e-12 # suggested starting time-step for chemistry
print(sample_data(x, area, v, gas0, dt_suggest))
if debug:
print("# species=", gmodel.species_names)
print("# massf=", gas0.massf)
print("# Start reactions...")
default="302.0",
help="Temperature (degree K) at which to evaluate the internal energy offset.")
(options, args) = parser.parse_args()
if options.tableName == None or options.gasModelFile == None:
parser.print_help()
print("")
print("Example 1: build-uniform-lut --gas-model=cea-air5species-gas-model.lua"+
" --table-name=air5species")
print("Example 2: build-uniform-lut --gas-model=cea-air13species-gas-model.lua"+
" --table-name=air13species --bounds=\"500,20000,-6.0,2.0\"")
print("Example 3: build-uniform-lut --gas-model=cea-co2-gas-model.lua"+
" --table-name=co2 --T-for-offset=650.0 --bounds=\"1000.0,20000,-6.0,2.0\"")
print("Example 4: build-uniform-lut --gas-model=cea-co2-ions-gas-model.lua"+
" --table-name=co2-ions --T-for-offset=1000.0 --bounds=\"1000.0,20000,-6.0,2.0\"")
print("")
print("Sometimes CEA2 has problems and the table will fail to build.")
print("The best approach to fixing the problem seems to be to raise")
print("the lower temperatures, as shown in examples 2, 3 and 4 (above).")
sys.exit()
T_min, T_max, log_rho_min, log_rho_max = [float(item) for item in options.bounds.split(',')]
T_for_offset = float(options.T_for_offset)
print("Density, Temperature ranges:")
print(" log_rho_min=", log_rho_min, "log_rho_max=", log_rho_max)
print(" T_min=", T_min, "T_max=", T_max)
print("Building table for gas model:", options.gasModelFile)
gmodel = GasModel(options.gasModelFile)
assert gmodel.n_modes == 0, "Use only a single-temperature gas model."
gs = GasState(gmodel)
build_table(gs, options.tableName, T_min, T_max, log_rho_min, log_rho_max, T_for_offset)
print("Done.")
# gasModelFile = "ideal-air-gas-model.lua" # Alternative
gmodel = GasModel(gasModelFile)
if gmodel.n_species == 1:
print("Ideal air gas model.")
air_massf = {"air": 1.0}
else:
print("Thermally-perfect air model.")
air_massf = {"N2": 0.78, "O2": 0.22}
print("Compute cycle states:")
gs = [] # We will build up a list of gas states
h = [] # and enthalpies.
# Note that we want to use indices consistent with the Lua script,
# so we set up 5 elements but ignore the one with 0 index.
for i in range(5):
gs.append(GasState(gmodel))
h.append(0.0)
for i in range(1, 5):
gs[i].massf = air_massf
print(" Start with ambient air")
gs[1].p = 100.0e3
gs[1].T = 300.0
gs[1].update_thermo_from_pT()
s12 = gs[1].entropy
h[1] = gs[1].enthalpy
print(" Isentropic compression with a pressure ratio of 8")
gs[2].p = 8 * gs[1].p
gs[2].update_thermo_from_ps(s12)
h[2] = gs[2].enthalpy
# A simple fixed-volume reactor.
# PJ & RJG 2019-11-25
#
# To prepare:
# $ prep-gas nitrogen-2sp.inp nitrogen-2sp.lua
# $ prep-chem nitrogen-2sp.lua nitrogen-2sp-2r.lua chem.lua
#
# To run:
# $ python3 fvreactor.py
from eilmer.gas import GasModel, GasState, ThermochemicalReactor
gm = GasModel("nitrogen-2sp.lua")
reactor = ThermochemicalReactor(gm, "chem.lua")
gs = GasState(gm)
gs.p = 1.0e5 # Pa
gs.T = 4000.0 # degree K
gs.molef = {'N2': 2 / 3, 'N': 1 / 3}
gs.update_thermo_from_pT()
tFinal = 200.0e-6 # s
t = 0.0
dt = 1.0e-6
dtSuggest = 1.0e-11
print("# Start integration")
f = open("fvreactor.data", 'w')
f.write(
'# 1:t(s) 2:T(K) 3:p(Pa) 4:massf_N2 5:massf_N 6:conc_N2 7:conc_N\n')
f.write("%10.3e %10.3f %10.3e %20.12e %20.12e %20.12e %20.12e\n" %
(t, gs.T, gs.p, gs.massf[0], gs.massf[1], gs.conc[0], gs.conc[1]))