Tubing configurations

Fig. 4. (a) Type-S pitot tube and thermocouple (b) side view of the correct pitot tube configuration when used ia conjunction with a sampling nozzle, where A is the static pressure opening plane and B is the impact pressure opening plane and (c) bottom view. 

Figure 41. Tube configuration used for bed expansion studies. Note all dimensions in cm scaled to equivalent sizes in the combustor. (From Glicksman etal., 1991b.)...

Fig. 11.26 SOFC configuration (a) Westinghouse single tube configuration (b) Argonne multichannel monolithic configuration (c) planar configuration.

The viscosity relates to the longest relaxation time in a system. If we consider Rouse diffusion along the tube with a Rouse diffusion coefficient DJ l/ NQ) then an initial tube configuration is completely forgotten when the mean-square displacement along the tube fulfils (r (t))tube=(contour length ly. Thus, for the longest relaxation time, we obtain ... 

Ultrafiltration hollow-fiber modules are usually made with a shell and tube configuration. The fibers are potted at both ends of the module with the fiber lumen open for recirculation of the process stream (Figure 21). Naturally, strainers or prefilters must be utilized to eliminate plugging of the fibers. At Nude-pore, it has been shown that larger diameter hollow fibers, 1.5 to 3mm in i.d., are much less prone to fouling. Fortunately, all UF hollow fiber systems can be back-washed and are amenable to a number of cleaning techniques. 

Experimental work has been published on a ring—disc electrode which is intermediate in geometry between the wall-jet and wall-tube configurations. Consequently, and as expected, intermediate collection efficiency values were measured [51]. 

The transient gas-particle dynamics of the earlier prototypes were found to deliver microparticles with a range of velocities and a nonuniform spatial distribution. For targeted delivery, however, especially in the area of gene and peptide delivery, the system should deliver particles with a narrow and controllable velocity range and a uniform spatial distribution. This was achieved with a certain embodiment called the contoured shock tube configured to achieve uniform particle impact conditions by entraining particles within a quasi-steady gas flow (Kendall et al. 2002). 

Gs is the mass flow per shell flow area. Since the shell fluid must flow perpendicular to the tube configuration, Eq. (5.6) is supplied to calculate Gs [7]. 

Other variables of importance in designing these tubular pyrolysis reactors include the mass velocity (or flow velocity) of the gaseous reaction mixture in the tubes, pressure, steam-to-hydrocarbon-feedstock ratio, heat flux through the tube wall, and tube configuration and spacing. Pressure drop in the reactor is of major importance, especially because of the extremely high flow velocities normally employed. 

Gabrielli and Perrot [23] carried out in situ mass measurements in well-defined flowing electrolyte with an electrochemical quartz crystal microbaiance (EQCM) adapted to a submerged impinging jet cell (wall tube configuration). The authors employed this new device for the study of nickel electrodeposition and evaluation of the cathodic efficiency. Under the conditions of their experiment (nozzle diameter d = 7 mm disc electrode diameter de = 5 mm and nozzle-to-electrode distance H = 2d), the current that flows at the electrode increases with the square root of flow rate (0-10 cm3 s"1). It should be noted that this approach is much simpler to implement than the rotating EQCM, while keeping control of the convective-diffusion conditions. 

These reactors are of shell-and-tube configuration and mostly have the catalyst in the tubes, although some ammonia converters have the... 

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