How can I reverse the program adiabetic.py in CANTERA Python module such that it inputs the adiabetic temperature and gives output inlet temperature?

Question

I am doing a project on numerical analysis of laminar premixed flames at different level of complexities. I am in severe need of help as I am new to Python and Cantera. I have the following queries:

1. Can I modify the adiabetic.py module which primarily gives adiabatic temperature of a mixture from inlet temperature to something that can give me inlet temperature from adiabatic temperature as input?

Following is the program:

"""
Adiabatic flame temperature and equilibrium composition for a fuel/air mixture
as a function of equivalence ratio, including formation of solid carbon.
"""

import cantera as ct
import numpy as np
import sys
import csv

##############################################################################
# Edit these parameters to change the initial temperature, the pressure, and
# the phases in the mixture.

T = 300.0
P = 101325.0

# phases
gas = ct.Solution('gri30.xml')
carbon = ct.Solution('graphite.xml')

# the phases that will be included in the calculation, and their initial moles
mix_phases = [(gas, 1.0), (carbon, 0.0)]

# gaseous fuel species
fuel_species = 'CH4'

# equivalence ratio range
npoints = 50
phi = np.linspace(0.3, 3.5, npoints)

##############################################################################

mix = ct.Mixture(mix_phases)

# create some arrays to hold the data
tad = np.zeros(npoints)
xeq = np.zeros((mix.n_species,npoints))

for i in range(npoints):
    # set the gas state
    gas.set_equivalence_ratio(phi[i], fuel_species, 'O2:1.0, N2:3.76')

    # create a mixture of 1 mole of gas, and 0 moles of solid carbon.
    mix = ct.Mixture(mix_phases)
    mix.T = T
    mix.P = P

    # equilibrate the mixture adiabatically at constant P
    mix.equilibrate('HP', solver='gibbs', max_steps=1000)

    tad[i] = mix.T
    print('At phi = {0:12.4g}, Tad = {1:12.4g}'.format(phi[i], tad[i]))
    xeq[:,i] = mix.species_moles

# write output CSV file for importing into Excel
csv_file = 'adiabatic.csv'
with open(csv_file, 'w') as outfile:
    writer = csv.writer(outfile)
    writer.writerow(['phi','T (K)'] + mix.species_names)
    for i in range(npoints):
        writer.writerow([phi[i], tad[i]] + list(xeq[:,i]))
print('Output written to {0}'.format(csv_file))

if '--plot' in sys.argv:
    import matplotlib.pyplot as plt
    plt.plot(phi, tad)
    plt.xlabel('Equivalence ratio')
    plt.ylabel('Adiabatic flame temperature [K]')
    plt.show()

taken from: http://www.cantera.org/docs/sphinx/html/cython/examples/multiphase_adiabatic.html

Please ask me specific questions, as even I dont know specifically what to ask. But I know what I want to do.

Answer 1

This is an interesting question.

It should in principle not be too difficult. Assuming that you have given an inlet fuel composition, equivalence ratio, and adiabatic flame temp, the steps would be:

1. Set the temperature to the adiabatic flame temp and Equilibrate the fuel-air mixture for a set T and P.
2. Calculate (and save) the mixture-averaged enthalpy.
3. Set composition back to that of the inlet, and fit the Temperature until the mixture-averaged enthalpy matches that from step 2.