Mixing using Quantity objects

In this example, air and methane are mixed in stoichiometric proportions. This is a simpler, steady-state version of the example mix1.py.

Since the goal is to simulate a continuous flow system, the mixing takes place at constant enthalpy and pressure.

Requires: cantera >= 2.5.0

Tags: Python thermodynamics mixture

Set up streams

import cantera as ct

gas = ct.Solution('gri30.yaml')

# Stream A (air)
A = ct.Quantity(gas, constant='HP')
A.TPX = 300.0, ct.one_atm, 'O2:0.21, N2:0.78, AR:0.01'

# Stream B (methane)
B = ct.Quantity(gas, constant='HP')
B.TPX = 300.0, ct.one_atm, 'CH4:1'

# Set the molar flow rates corresponding to stoichiometric reaction,
# CH4 + 2 O2 -> CO2 + 2 H2O
A.moles = 1
nO2 = A.X[A.species_index('O2')]
B.moles = nO2 * 0.5

Compute the mixed state

M = A + B
print(M.report())

 gri30:

      temperature   300 K
         pressure   1.0133e+05 Pa
          density   1.1269 kg/m^3
 mean mol. weight   27.742 kg/kmol
  phase of matter   gas

                         1 kg             1 kmol
                    ---------------   ---------------
         enthalpy       -2.5351e+05       -7.0327e+06  J
  internal energy       -3.4342e+05       -9.5271e+06  J
          entropy            7221.9        2.0035e+05  J/K
   Gibbs function       -2.4201e+06       -6.7137e+07  J
heat capacity c_p            1070.4             29695  J/K
heat capacity c_v            770.71             21381  J/K

                     mass frac. Y      mole frac. X     chem. pot. / RT
                    ---------------   ---------------   ---------------
               O2            0.2192           0.19005           -26.334
              CH4          0.054952          0.095023           -54.676
               N2           0.71281           0.70588           -23.381
               AR          0.013032         0.0090498           -23.315
    [  +49 minor]                 0                 0

Show that this state corresponds to stoichiometric combustion

M.equilibrate('TP')
print(M.report())

 gri30:

      temperature   300 K
         pressure   1.0133e+05 Pa
          density   1.1269 kg/m^3
 mean mol. weight   27.742 kg/kmol
  phase of matter   gas

                         1 kg             1 kmol
                    ---------------   ---------------
         enthalpy       -3.0024e+06       -8.3292e+07  J
  internal energy       -3.0923e+06       -8.5786e+07  J
          entropy            7204.2        1.9986e+05  J/K
   Gibbs function       -5.1637e+06       -1.4325e+08  J
heat capacity c_p            1104.2             30633  J/K
heat capacity c_v            804.53             22319  J/K

                     mass frac. Y      mole frac. X     chem. pot. / RT
                    ---------------   ---------------   ---------------
              H2O           0.12341           0.19005           -121.32
              CO2           0.15074          0.095023           -185.83
               N2           0.71281           0.70588           -23.381
               AR          0.013032         0.0090498           -23.315
    [  +49 minor]        2.0428e-19        1.7711e-19