.. comb_species Species Mole Fractions ====================== Use RocketCEA versions 1.1.9 and greater to access to the combustion species mass fractions and mole fractions. .. warning:: Only use >= version 1.1.9 for Species Fractions. (Versions 1.1.6 through 1.1.8 have a bug.) Notice at the bottom of the sample run at :ref:`Standard Examples LOX/LH2 Performance ` that the combustion species mole fractions are displayed. CEA prints those values as:: MOLE FRACTIONS *H 0.03417 0.02810 0.00001 HO2 0.00003 0.00002 0.00000 *H2 0.24832 0.24538 0.24401 H2O 0.66590 0.68751 0.75598 H2O2 0.00001 0.00001 0.00000 *O 0.00334 0.00217 0.00000 *OH 0.04478 0.03446 0.00000 *O2 0.00345 0.00236 0.00000 RocketCEA provides the function `get_SpeciesMoleFractions` that returns two dictionaries. One with with species molecular weights and one with the combustion species mole fractions. The user can specify equilibrium or frozen values. .. note:: RocketCEA returns 4 columns of species concentrations. Columns are: (1) Injector Face, (2) Combustion Chamber, (3) Throat and (4) Exit For a :ref:`Finite Area Combustor ` , the Injector Face and Combustion Chamber will differ, otherwise the two are identical. A Display of the contents of those two dictionaries is shown below:: ROCKETCEA MOLE FRACTIONS (frozen=0, frozenAtThroat=0) *H 0.03417 0.03417 0.02810 0.00001 MW=1.00794 HO2 0.00003 0.00003 0.00002 0.00000 MW=33.0067 *H2 0.24832 0.24832 0.24538 0.24401 MW=2.01588 H2O 0.66590 0.66590 0.68751 0.75598 MW=18.0153 H2O2 0.00001 0.00001 0.00001 0.00000 MW=34.0147 *O 0.00334 0.00334 0.00217 0.00000 MW=15.9994 *OH 0.04478 0.04478 0.03446 0.00000 MW=17.0073 *O2 0.00345 0.00345 0.00236 0.00000 MW=31.9988 ======================================================= ROCKETCEA MOLE FRACTIONS (frozen=1, frozenAtThroat=0) *H 0.03417 0.03417 0.03417 0.03417 MW=1.00794 HO2 0.00003 0.00003 0.00003 0.00003 MW=33.0067 *H2 0.24832 0.24832 0.24832 0.24832 MW=2.01588 H2O 0.66590 0.66590 0.66590 0.66590 MW=18.0153 H2O2 0.00001 0.00001 0.00001 0.00001 MW=34.0147 *O 0.00334 0.00334 0.00334 0.00334 MW=15.9994 *OH 0.04478 0.04478 0.04478 0.04478 MW=17.0073 *O2 0.00345 0.00345 0.00345 0.00345 MW=31.9988 ======================================================= ROCKETCEA MOLE FRACTIONS (frozen=1, frozenAtThroat=1) *H 0.03417 0.03417 0.02810 0.02810 MW=1.00794 HO2 0.00003 0.00003 0.00002 0.00002 MW=33.0067 *H2 0.24832 0.24832 0.24538 0.24538 MW=2.01588 H2O 0.66590 0.66590 0.68751 0.68751 MW=18.0153 H2O2 0.00001 0.00001 0.00001 0.00001 MW=34.0147 *O 0.00334 0.00334 0.00217 0.00217 MW=15.9994 *OH 0.04478 0.04478 0.03446 0.03446 MW=17.0073 *O2 0.00345 0.00345 0.00236 0.00236 MW=31.9988 ======================================================= The script that produces the above output is: .. literalinclude:: ./_static/example_scripts/chk_froz_mole_frac.py Species Mass Fractions ---------------------- If mass fractions are preferred, that can be obtained by calling the method `get_SpeciesMassFractions`. Modifying the above mole fraction script to return mass fractions is shown below. .. literalinclude:: ./_static/example_scripts/chk_froz_mass_frac.py This script produces the following:: ROCKETCEA MASS FRACTIONS (frozen=0, frozenAtThroat=0) *H 0.00256 0.00256 0.00208 0.00000 MW=1.00794 HO2 0.00008 0.00008 0.00004 0.00000 MW=33.0067 *H2 0.03720 0.03720 0.03636 0.03486 MW=2.01588 H2O 0.89139 0.89139 0.91033 0.96514 MW=18.0153 H2O2 0.00003 0.00003 0.00001 0.00000 MW=34.0147 *O 0.00397 0.00397 0.00255 0.00000 MW=15.9994 *OH 0.05658 0.05658 0.04308 0.00000 MW=17.0073 *O2 0.00820 0.00820 0.00555 0.00000 MW=31.9988 ======================================================= ROCKETCEA MASS FRACTIONS (frozen=1, frozenAtThroat=0) *H 0.00256 0.00256 0.00256 0.00256 MW=1.00794 HO2 0.00008 0.00008 0.00008 0.00008 MW=33.0067 *H2 0.03720 0.03720 0.03720 0.03720 MW=2.01588 H2O 0.89139 0.89139 0.89139 0.89139 MW=18.0153 H2O2 0.00003 0.00003 0.00003 0.00003 MW=34.0147 *O 0.00397 0.00397 0.00397 0.00397 MW=15.9994 *OH 0.05658 0.05658 0.05658 0.05658 MW=17.0073 *O2 0.00820 0.00820 0.00820 0.00820 MW=31.9988 ======================================================= ROCKETCEA MASS FRACTIONS (frozen=1, frozenAtThroat=1) *H 0.00256 0.00256 0.00208 0.00208 MW=1.00794 HO2 0.00008 0.00008 0.00004 0.00004 MW=33.0067 *H2 0.03720 0.03720 0.03636 0.03636 MW=2.01588 H2O 0.89139 0.89139 0.91033 0.91033 MW=18.0153 H2O2 0.00003 0.00003 0.00001 0.00001 MW=34.0147 *O 0.00397 0.00397 0.00255 0.00255 MW=15.9994 *OH 0.05658 0.05658 0.04308 0.04308 MW=17.0073 *O2 0.00820 0.00820 0.00555 0.00555 MW=31.9988 =======================================================