Oxygen Consumption as Air

Considering air with oxygen mole fraction as the number of moles of oxygen per kilogram of air is 

Usually, an excess amount of oxygen is supplied for sustaining complete reaction at the entire cathode active reaction area. Defining the excess air supply in terms of the stoichiometric factor, the air supply rate at inlet is given as 

The exit airflow rate is determined as the difference between inlet air flow rate and the oxygen consumption  

Substituting Equations 4.74 and 4.78b, the exit air flow rate is given as 

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