A system and method for enhancing a diffusion limited CVI/CVD process is provided. The system may densify a porous structure by flowing a reactant gas around the porous structure. A mass flow controller may be configured to pulse the flow rate of the reactant gas around the porous structure. The mass flow controller may pulse the flow rate from a nominal flow rate to a first flow rate. The mass flow controller may pulse the first flow rate back to the nominal flow rate or to a second flow rate. The mass flow controller may pulse the flow rate between the nominal flow rate, the first flow rate, and the second flow rate, as desired.