Mathematical model for precursor gas residence time in isothermal CVD process of C/C composites

In the chemical vapor deposition (CVD) process of C/C composites, the dynamics and mechanism of precursor gas flowing behavior were analyzed mathematically, in which the precursor gas was infiltrated by the pressure difference of the gas flowing through felt. Differential equations were educed which characterized the relations among the pressure inside the felt, the pressure outside the felt of the precursor gas and the porosity of the felt as a function of CVD duration. The gas residence time during the infiltration process through the felt was obtained from the differential equations. The numerical verification is in good agreement with the practical process, indicating the good reliability of the current mathematical model.