Transport modeling and mapping of pulsed reactor dynamics near and beyond the onset of viscid flow

The objective of this work is to develop a high-fidelity transport model for pulsed reactor scenarios involving Knudsen and beyond-Knudsen (viscid flow) conditions. This is done to eventually support accurate analyses of flow regimes and micro-kinetic processes under dynamic conditions. The resulting model renders mass transport under mixed modes of diffusion, advection and eddy (turbulent) diffusion, allowing for variance of input conditions (pulse magnitudes, temperature, etc.), gaseous mixtures and various reactor designs. The model assumes a five-zone reactor, covering inlet, pre-catalyst, catalyst, post-catalyst and outlet zones. A chief attribute of the modeling approach herein is the detailed analysis it provides for quantification of multiple transport metrics over reactor space and time, a transport “map”. Key among these are the Knudsen number and the relative contribution of advection versus diffusion as the pulse intensity is increased. The ability to map the reactor transport is useful for determining an optimal loading configuration to observe desired kinetic quantities associated with different chemical reaction mechanisms.