Question

Ethanol burns in a premixed flame at an air–fuel ratio (mass) of 7:1. Determine whether we have fuel lean or fuel rich mixture by calculating either ɸ or λ.

Answer 1

To determine whether the air-fuel ratio of 7:1 is fuel lean or fuel rich, you can calculate the equivalence ratio (ɸ) or the fuel-air ratio (λ). The equivalence ratio is the ratio of the actual fuel-air ratio to the stoichiometric fuel-air ratio. The fuel-air ratio is the ratio of the mass of fuel to the mass of air.

For the ethanol-air mixture described, the equivalence ratio can be calculated as ɸ = (7:1)/(14.5:1) = 0.48, which indicates that the mixture is fuel lean. The fuel-air ratio can be calculated as λ = 7/14.5 = 0.48, which again indicates that the mixture is fuel lean.