In disregard of the classical Fick's law

frequency was used to describe the speed of mass transfer between fuel and air. A frequency mass transfer mathematic model of fuel flush inerting was proposed

which employed frequency to describe the mass transfer speed with incomparable advantages than other inerting engineering models. Frequency mass transfer model calculated results were compared with certain experimental data of Federal Aviation Administration (FAA)

and the effectiveness was verified;the calculated results of frequency model and other models were also compared with A320 flight volume fraction of oxygen

showing that the frequency mass transfer model presents highest precision.Further simulation results show that increased fuel load could delay the inerting process

and frequency mass transfer model calculated result is obviously different from the calculated results of non-mass transfer and instant balancing situations when the fuel tank is nearly full.