43bd96b5ba
The CounterFlowDiffusionFlame (CFDF) code is able to perform more general cases of npflame_init for multiple species fuel and oxidizer streams. The stoichiometric mixture fraction in the CFDF code uses the Bilger definition of mixture fraction, using the conservation of elements C, H, and O. This method is used in the python module, but not the MATLAB npflame_init function. Also, the CFDF code uses the fuel stream density to calculate the fuel stream velocity and the oxidizer stream density to calculate the oxidizer stream velocity, where as the npflame_init code uses the fuel density for both velocity calculations. The elementMassFraction code is a MATLAB version of the python function: elemental_mass_fraction, which is needed to run the CFDF code. Update the diffflame.m example to use the more general CFDF function since the input parameters are different than the npflame_init function. This example is the same as the diffusion_flame.py sample in the Python module.
51 lines
1.8 KiB
Matlab
51 lines
1.8 KiB
Matlab
function elMassFrac = elementalMassFraction(tp, element)
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% ELEMENTALMASSFRACTION Determine the elemental mass fraction in gas object.
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% elMassFrac = elementalMassFraction(tp, element)
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% :param tp:
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% Object representing the gas, instance of class :mat:func:`Solution`,
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% and an ideal gas. The state of this object should be set to an
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% estimate of the gas state before calling elementalMassFraction.
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% :param element:
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% String representing the element name.
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% :return:
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% Elemental mass fraction within a gas object.
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%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% Check input parameters
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%
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if nargin ~= 2
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error('elementalMassFraction expects two input arguments.');
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end
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if ~isIdealGas(tp)
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error('Gas object must represent an ideal gas mixture.');
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end
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if ~ischar(element)
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error('Element name must be of format character.');
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end
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% Calculate the elemental mass fraction in a gas object. Equation used is
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% elMassFrac = sum of nAtoms(k,m)*Mel(m)*Y(k)/mw(k) where nAtoms(k,m) is
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% the number of atoms of element, m, in species, k; Mel(m) is the atomic
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% weight of the element, m; Y(k) is the mass fraction of species,k, in the
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% gas object; and mw(k) is the molecular weight of species, k.
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%
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n = nSpecies(tp);
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massFrac = massFractions(tp);
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spec = speciesNames(tp);
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eli = elementIndex(tp, element);
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M = atomicMasses(tp);
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Mel = M(eli);
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MW = molecularWeights(tp);
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% Initialize the element mass fraction as zero.
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elMassFrac = 0.0;
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% Use loop to perform summation of elemental mass fraction over all species.
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for i = 1:n
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natoms(i) = nAtoms(tp,spec{i},element);
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mw(i) = MW(i);
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Y(i) = massFraction(tp,spec{i});
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elMassFrac = elMassFrac + (natoms(i)*Mel*Y(i))/mw(i);
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end
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end
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