Channels diffusion

Deniz, S., Greitzer, E. and Cumpsty, N., 1998, Effects of Inlet Flow Field Conditions on the Performance of Centrifugal Compressor Diffusers Part 2 Straight-Channel Diffuser, ASME Paper No. 98-GT-474. 

Rodgers, C., 1982, The Perfoimance of Centrifugal Compressor Channel Diffusers, ASME Paper No. 82-GT-lO. 

The benefits refer to the ability to achieve defined thin, highly porous coatings in micro reactors. In combination with the small length scales of the channels, diffusion to the active sites is facilitated. The residence time can be controlled, accurately minimizing consecutive reactions which may reduce selectivity. 

Eatough, D. J., A. Wadsworth, D. A. Eatough, J. W. Crawford, L. D. Hansen, and E. A. Lewis, A Multiple-System, Multi-Channel Diffusion Denuder Sampler for the Determination of Fine-Par-ticulate Organic Material in the Atmosphere, Atmos. Environ., 27A, 1213-1219 (1993). 

Before applying this example of channel diffusion to practical evaluations, which will be the purpose of the following sections, we will briefly discuss the formal description of other important geometries of catalytic systems. 

The carrier saccharide adsorbs strongly at the cell surface by hydrophilic (ionic) bonding, and thereby presents a high surface concentration of the active steroid (either to surface receptors directly or for facilitated channel diffusion). 

The boundary conditions are specified temperatures or zero slope at the walls and zero slope at any planes of symmetry. Compare Equations 8.20 and 8.24. The major difference is that is now a function of x and y rather than just r. Compare also Equations 8.50 and 8.51. Elows in the cross-channel directions that correspond to Vr have been ignored because cross-channel diffusion in microscale devices will largely eliminate the concentration and temperature gradients that drive these flows. 

Figure 2-6 Simpie pipe diffuser made from Schedule 80 PVC 19 Figure 2-7 Open channel diffuser 19 Figure 2-8 Muitiple blade mechanical mixer 20 Figure 2-9 in-iine mechanical mixer 21...

Rh/Ce02 catalyst. Radial diffusion could be neglected in the model because of the high values of the Bodenstein number (>200) due to fast radial diffusion. Therefore, DR[ d c/dx ) + (l/r)(dc/dr)] = 0 in Equation 12.7. The model also involved the assumption that mass transfer limitations are obvious neither in the channel (diffusion to the catalyst layer) nor in the catalyst layer (pore diffusion). Moreover, an excellent isothermal behavior of the microchannel was confirmed by a good fit of the calculated values with the experimental results at a wide range of ethanol and water partial pressures, steam to carbon ratios, and temperatures. 

Stationary parts of a multistage centrifugal compressor include inlet guide vane, diaphragms, and casing. They form the various gas passages in a compressor inlet channel, diffusers, return bends, return channels, and discharge volute. 

Brachet A, Leterrier C, IrondeUe M et al (2010) Ankyrin G restricts ion channel diffusion at the axonal initial segment before the establishment of the diffusion barrier. J Cell Biol 191 383-395... 

---