Extraparticle Concentration Gradients

Whether the criteria for intra- or extraparticle heat transport limitations are more severe than the corresponding ones for mass transport depends on the absolute value of the products ys x ft, and yb x Pe, respectively. In some cases the former product exceeds unity, but more often not [8], so internal temperature gradients do not occur frequently. The latter product is a factor Bim/Bih larger, generally >10 (gases), which means that in this case the extraparticle temperature gradient occurs earlier than an extraparticle concentration gradient. 

Figure 14. Diagnostic test for extraparticle concentration gradients keeping W/F° constant...

---