Vortex: flow

The product stream contains gases and soflds. The soflds are removed by using either cyclones, filters, or both in combination. Cyclones are devices used to separate soflds from fluids using vortex flow. The product gas stream must be cooled before being sent to the collection and refining system. The ALMA process uses cyclones as a primary separation technique with filters employed as a final separation step after the off-gas has been cooled and before it is sent to the collection and refining system (148). As in the fixed-bed process, the reactor off-gas must be incinerated to destroy unreacted butane and by-products before being vented to the atmosphere. 

The vessel design features a Chinese hat-like conical core stopper above the underflow sump, which is there to prevent the vortex from reaching the latter and reentraining the settled soHds. The core stopper is also beheved to stabilize and locate the vortex flow in the vessel. Overflow from the vessel is through a wide cylindrical insert through the Hd, similar to a vortex finder in a hydrocyclone (16), and an optional provision can be made for collecting any floatables in a float trap. 

Numerous studies for the discharge coefficient have been pubHshed to account for the effect of Hquid properties (12), operating conditions (13), atomizer geometry (14), vortex flow pattern (15), and conservation of axial momentum (16). From one analysis (17), the foUowiag empirical equation appears to correlate weU with the actual data obtained for swid atomizers over a wide range of parameters, where the discharge coefficient is defined as — QKA (2g/ P/) typical values of range between 0.3 and 0.5. 

Dometti, S. M. S. and Ranade, V. V., Simulation of vortex flow meters. National Workshop on Modelling in Hydraulie Engineering, CWPRS, June 1995. 

Endrcss and Hauser pic Technical Information TI03ID/06/e 11997). Vortex flow measuring system, pttwirl 70. 

Relation between flame speed Vj and maximum tangential velocity in an axially decaying vortex flow in a tube for various mixtures (tube diameter 31mm, the mean axial velocity 3m/s). (From Ishizuka, S., Combust. Flame, 82,176,1990.)... 

Before discussing about the flame speed along a vortex core, it is first necessary to be familiar with the flames in various vortex flows. To date, four types of vortex flows have been used to study the flame behaviors. They are (1) a swirl flow in a tube [1,10], (2) vortex ring [2,3,12,13,16], (3) a forced vortex flow in a rotating tube [11], and (4) line vortex [22]. 

When a tube is rotated, a very simple, forced vortex flow can be obtained, where the rotational velocity is constant along the axis of rotation. However, the flame behavior becomes very complicated because the space is confined by the wall. 

Appearance of the flame propagating in an axially decreasing vortex flow in a tube (fuel propane, fuel concentration 7.7%, tube 31 nun in inner diameter and 1000mm long, injector 4 slits of 2mm x 20mm, mean axial velocity 3m/s). 

TFF module types include plate-and-frame (or cassettes), hollow fibers, tubes, monoliths, spirals, and vortex flow. Figures 20-52 and 20-53 show several common module types and the flow paths within each. Hollow fiber or tubular modules are made by potting the cast membrane fibers or tubes into end caps and enclosing the assembly in a shell. Similar to fibers or tubes, monoliths have their retentive layer coated on the inside of tubular flow channels or lumens with a high-permeability porous structure on the shell side. 

Transport in Capillary and Vortex Flow Bioreactors 5.1.2.2.1 Mass Transfer Coefficients... 

Reactors which generate vortex flows (VFs) are common in both planktonic cellular and biofilm reactor applications due to the mixing provided by the VF. The generation of Taylor vortices in Couette cells has been studied by MRM to characterize the dynamics of hydrodynamic instabilities [56], The presence of the coherent flow structures renders the mass transfer coefficient approaches of limited utility, as in the biofilm capillary reactor, due to the inability to incorporate microscale details of the advection field into the mass transfer coefficient model. 

The vortex flow reactor was a glass Couette cell driven by a Bruker RheoNMR system. The cell consisted of a stationary outer glass tube with an id of 9 mm and a rotating inner glass tube with an od of 5 mm, giving a gap of 2 mm. The Couette was filled with cylindrical bacterial cells, F. nucleatum ( 2 x 20 pm), suspended in water at a concentration of =10" cells mL-1. 

For Gr, < 920, mass transfer could be represented by the forced-convection correlation and for Gr, > 920, by the free-convection correlation ofFenech and Tobias (F3). Tobias and Hickman (T2) also inferred the existence of cellular vortex flow near the electrode from deposition patterns, the induction length for this behavior agreeing with Eq. (44). 

For a uniform angular velocity ( > = constant, i.e., a solid body rotation ), n = — 1, whereas for a uniform tangential velocity ( plug flow ) n = 0, and for inviscid free vortex flow co = c/r2, i.e., n = 1. Empirically, the exponent n has been found to be typically between 0.5 and 0.9. The maximum value of Ve occurs in the vicinity of the outlet or exit duct (vortex finder) at r = De/2. 

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