Consumption ratio, definition

C = consumption rate (tonne year ) r - fractional growth rate (% year ) t = time. Chapter 3 Definition of Stress, Strain, Poisson s Ratio, Elastic Moduli... 

Fractional conversion of a reactant, /A for reactant A, say, is the ratio of the amount of A reacted at some point (time or position) to the amount introduced into the system, and is a measure of consumption of the reactant. It is defined in equation 2.2-3 for a batch system, and in equation 2.3-5 for a flow system. The definition is the same whether the system is simple or complex. 

The emission index in general is defined as the mass of pollutant emitted per unit mass of fuel consumed. In quasi-steady diffusion flames, this is the ratio of the mass flux of pollutant out of the flame to the mass rate of consumption of fuel per unit flame area. Depending on the application, it may be more desirable to consider only the flux of pollutant to the air or the sum of the pollutant flux to both air and fuel. The latter definition is selected here, and a pollutant balance for the flame then enables the emission index to be expressed as the ratio of the mass rate of production of pollutant per unit area to the mass rate of consumption of fuel per unit area. In terms of the mass rate of production of species i per unit volume cDj, the mixture fraction, and the magnitude of its gradient VZ, the mass rate of production of species i per unit area is... 

Fractional conversion of a reactant is defined as the ratio of the amount consumed to that charged. In this book, the following definitions of yield, yield ratio, and selectivity are used The yield of a product is the ratio of the amount of reactant (or reactants) converted to the product to the total amount of reactant (or reactants) charged. The cumulative yield ratio of two products is the ratios of their yields. The instantaneous yield ratio is the ratio of the momentary rates of conversion to these products. The cumulative selectivity to a product is the ratio of the amount of reactant (or reactants) converted to that product to the amount consumed. The instantaneous selectivity is the ratio of the momentary rate of reactant conversion to the product to that of reactant consumption. Not used in this book is the extent of reaction, defined as the number of moles consumed or formed, divided by the stoichiometric coefficient of the respective participant. 

Some define differential selectivity as the ratio of a rate of production to a rate of reaction, in which case the denominator is a negative quantity and the corresponding selectivities are negative numbers. Our definition in terms of the rate of consumption of reactant is purely for the convenience of working with positive quantities. 

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