Slugging flow reactor modeling

Plug flow reactor models must be constructed with a frame of reference in mind. An observer riding along on the tracer slug would see no change in concentration over the modeled time and could infer nothing about the reactor. 

In advance, comparative fixed-bed measurements were undertaken. It was ensured that the performance of a plug-flow operation with both flows having the same direction is superior to trickle-bed operation, using counter-flow instead. The plug flow was assumed to model the slug-flow behavior in the micro reactor. 

Kashid, M.N., Renken, A., and Kiwi-Minsker, L. (2010) CFD modelling of liquid-liquid multiphase microstructured reactor slug flow generation. 

Many reaction-transport models treat parcels of fiuid as if they are slugs flowing in a plug flow reactor. In real systems, hydrodynamic mixing and diffusion (Aris, 1956 Taylor, 1953) cause dispersion of species among the slugs. Gelhar et ah (1992) review the factors that affect dispersion in aquifer systems. 

In this model we further assume that the hydrodynamics of the system is adequately represented by the relations for slug flow and that the neutron physics may be described by means of the one-velocity model. Finally, we assume also that the fuel in the core is homogeneous and that the neutron macroscopic cross sections are time independent. On the basis of these assumptions we can write the following pair of differential equations to describe the circulating-fuel reactor ... 

Figure 8 Conversion as a function of reactor diameter. Bubbling bed models Solid lines two-phase bubbling bed model (19) with a =0 short dashes same model with =0.005 long-short broken lines Orcutt model with mixed dense phase. Slug flow model Hovmand-Davidson (A5,46). For conditions see Table 3.

Figure 10 Comparison between experimental data (49) in a 0.10 m reactor under slug flow conditions with reactor models KL - bubbling bed model (20) HD and HD - (46) without and with allowance for non-slugging entry region RP and RP - (48) without and with allowance for entry zone. U =0.02 m/s.

---