In combustion physics, fuel mass fraction is the ratio of fuel mass flow to the total mass flow of a fuel mixture. If an air flow is fuel free, the fuel mass fraction is zero; in pure fuel without trapped gases, the ratio is unity. As fuel is burned in a combustion process, the fuel mass fraction is reduced. The definition reads as
- is the mass of the fuel in the mixture
- is the total mass of the mixture
- ^ Kanury, a. (1975). Introduction to Combustion Phenomena. New York: Gordon and Breach. p. 150. ISBN 0-677-02690-0.