Transverse-flow design

Porous center tube (b) Transverse-flow design... 

A coordinate of a point, containing liquid moving with velocity vav is designated Zav- As the front line is assumed to be straight, the fountain effect is described by the assumption that transverse flow occurs along this line from the part of the cross-section where the velocity is high... 

Problem 3-14. Design of a Cross-Flow Filter. In cross-flow filtration, a pressure drop G forces fluid containing neutrally buoyant particles to flow between two porous plates. There is also a transverse flow that forces the particles to collect on one of the plates. A key design question is how one determines the length of the filter. 

The power of the tensor formalism and the concept of effective slippage have then been demonstrated by exact solutions for two other potential applications optimization of transverse flow and anal3Aical results for hydrodynamic resistance to the approach of two surfaces. These examples demonstrate that properly designed superhydrophobic surfaces could generate a very strong transverse flow and significantly reduce the so-called "viscous adhesion." Finally, we have discussed how superhydrophobic surfaces could amplify electro kinetic pumping in microfluidic devices. 

Pulsed lasers capable of operation at repetition rates of 1 kHz and beyond have been constructed which make use of large transverse flows of reagents " see Figure 3.10. Design details of this type of laser have been given in refs. 123 and 125. These lasers have energies per pulse that are similar to those for the small flow-rate devices. The substantial improvement in... 

Figure 3.10. A high-repetition-rate transverse flow pulsed HF chemical laser used by Lucht/ based on the design of Jacobson et The flow cross section is 13 mm x...

Radial density gradients in FCC and other large-diameter pneumatic transfer risers reflect gas—soHd maldistributions and reduce product yields. Cold-flow units are used to measure the transverse catalyst profiles as functions of gas velocity, catalyst flux, and inlet design. Impacts of measured flow distributions have been evaluated using a simple four lump kinetic model and assuming dispersed catalyst clusters where all the reactions are assumed to occur coupled with a continuous gas phase. A 3 wt % conversion advantage is determined for injection feed around the riser circumference as compared with an axial injection design (28). 

The minimum number of the tube rows recommended to establish a proper air flow pattern is 4, although 3 rows can be used. The typical unit has 4-6 rows of tubes, but more can be used. Although more heat can be transferred by increasing the number of tubes, the required fan horsepower will be increased however, this balance must be optimized for an effective economical design. Tubes are laid out on transverse or longitudinal patterns however, the transverse is usually used due to the improved performance related to pressure drop and heat transfer. The tube pitch is quite important for best air-side performance. A typical representative tube arrangement for design optimization is for hare-tube O.D., tinned-tube O.D., and tube pitch ... 

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