The simple chemical reacting system (SCRS) is one of the combustion models for computational fluid dynamics.
The simple chemical reacting system (SCRS) refers the global nature of the combustion process considering only the final species concentrations.
The detailed kinetics of the process is generally neglected and it postulates that combustion does proceed via a global one-step without intermediates.
[1] Infinitely fast chemical reaction is assumed with oxidants reacting in stoichiometric proportions to form products.
Now the transport equation reduces to Now defining the mixture fraction ‘f’, a non-dimensional variable in terms of ‘Φ’ we get Where the suffix ‘1’ denotes the fuel stream and ‘0’ denotes oxygen stream.
Now substituting the value of ‘Φ’ in the above mixture fraction equation we get In a fuel stream [mfu]1 = 1, [mox]1 = 0 and in an oxygen stream [mfu]0 = 0, [mox]0 = 1 Simplifying the above equation we get Now defining a new variable ‘fst’, a stoichiometric mixture where there is no oxygen and fuel present in the products is given by At fast chemical reactions 1.
If there is excess of oxygen present in the reactants, there will be no fuel left in the products.
Now the transport equation can be written as From the initial known masses of the oxygen and fuel, we can find out the masses of these values after combustion given by There are many inert gases included with the oxygen that do not take part in the reaction.