Hydrodynamics influence

Probe/Insirumentalion Developments The principles of good practice in the design, construction and location of corrosion probes have been reviewed. Specific probe designs which acknowledge hydrodynamic influences and the combined effects of mass and heat transfer have been developed. 

It is still challenging to isolate hydrodynamic influences on drug dissolution in vivo from other factors that can play a role in absorption. 

Furthermore, one would not expect to observe conditions where a —l due to hydrodynamic influences, where water must be squeezed out of the way as two particles or aggregates approach one another. As shown by Han and Lawler [3], under Brownian motion equal sized spheres should have a maximum collision efficiency somewhat less than one (interpolating from their Fig. 4, 100 nm spheres would have a maximum a = 0.7, 5 pirn. spheres would have a maximum a = 0.45). If all retarding influences are considered, then, as is the case when measurements are conducted in the laboratory, it is unlikely under the majority of common conditions for collision efficiencies to approach unity. 

A number of points have become apparent as a result of our efforts to simulate the fluidized-bed reactor-preheater system studied by Kizer. Two of the most important are it is imperative to have good kinetic data for the reaction(s) that occur. It has been demonstrated that the interpretation of the results is profoundly affected by relatively small changes in the kinetics. The second important point is the recognition that there are regions of operation where both the reaction kinetics and the bed hydrodynamics influence the overall performance of the reactor. 

Hydrodynamic influences are also of order 0(a). To emphasize some of the main features we shall restrict the discussion to the situation where a v". ... 

Hydrodynamic influence on holding capacity of conventional hydrostatic traps... 

The hydrodynamic holding capacity of conventional hydrostatic traps is not only determined by the direct hydrodynamic influence on the sealing characteristics of the barrier rocks, or barrier rocks and faults, but also combined influence of the geometry of the trap and the hydrodynamic condition in the carrier-reservoir rock. This can be illustrated by looking at the hydrodynamic influence on the position of a hydrocarbon accumulation in a conventional hydrostatic trap. 

Identification of the hydrodynamic influence on the hydrocarbon migration system... 

Hydrodynamic influence Hydrodynamic condition Characteristics migration pattern... 

Since the Stokes equations are linear and homogeneous, the velocities produced by different forces and boundaries at different points in the liquid are additive. Nevertheless, the solution to a multiparticle arrangement is still somewhat formidable. The important physical feature is that in a low Reynolds number flow the hydrodynamic influence of an applied force or boundary falls off relatively slowly with increasing distance. In particular, the velocity u produced at a point r by a force F acting at the origin, corresponding to a point particle, can be shown to be... 

Of special interest is hydrodynamic influence of other particles on the considered solid particle, moving in a viscous liquid. If the volumetric content of soUd particles is small, then particles are rather far apart and are scarcely affecting each other. Hence, as a first approximation one can assume that particles move independently and the given expressions for velocities and resistances of particles are true. However, at particles approach down to distances comparable to then-sizes, hydrodynamic interactions between them become essential and cannot be neglected. 

The novel and perspective field of tubular turbulent apparatus application is the carrying out of fast chemical processes with formation of solid phase. This provides wide possibilities for modification of metal-complex Ziegler-Natta catalytic systems at the expense of hydrodynamic influence on disperse structure of micro-heterogeneous catalysts particles, receipt of high-effective anti-agglomerates for synthetic rubbers, etc.. 

The Reynold number has to be large in order to avoid hydrodynamic influence on the oligomer distribution, and there must be the possibility for a pre-run in order to avoid any impurity traces... 

Pmvost J, Comet JF, Legrand J Hydrodynamics influence on light conversion in photobioreactors an energetically consistent analysis, Chem Eng Sd 63(14) 3679—3694, 2008. 

Pruvost J, Cornet JP, LegrandJ Hydrodynamics influence on fight conversion in photobioreactors an energeticahy consistent analysis, Chem Eng Sci 63 3679—3694, 2008. 

The hydrodynamic influence on the suspension stored at different time intervals in different reactors, results in a similar decrease of the particle size. This can be observed in the parallel shift of the graphs showing the dependence of the particle diameter of calcium stearate upon storage time under different synthesis conditions (Figure... 

The parameters and consequently the efficiency of PV strongly depends on the properties of the membrane material. Common membrane materials are various dense polymers and microporous inorganic membranes (zeolithes, silica,. ..) either with hydrophilic or organophilic character. Furthermore composite membranes offer the possibility to combine different materials for the dense active layer and the porous support layer. Besides membrane material fluid hydrodynamics influences the efficiency of separation. The pressure drop especially on the permeate side reduces the driving force of the most permeating components. 

Optimal reactor design is critical for the effectiveness and economic viability of AOPs. The WAO process poses significant challenges to chemical reactor engineering and design, due to the (i) multiphase nature of WAO reactions (ii) temperatures and pressures of the reaction and (iii) radical reaction mechanism. In multiphase reactors, complex relationships are present between parameters such as chemical kinetics, thermodynamics, interphase/intraphase intraparticle mass transport, flow patterns, and hydrodynamics influencing reactant mass transfer. Complex models of WAO are necessary to take into account the influence of catalyst wetting, the interface mass-transfer coefficients, the intraparticle effective diffusion coefficient, and the axial dispersion coefficient. " ... 

It is evident that the critical load beyond which lubrication breaks down is a function of speed. When the speed is very high, e.g. U=1S m/s, it is difficult to observe the EHL failure because the hydrodynamic action is strong. However, the film would eventually break if the load continued to go infinitely heavy. When the speed is low, on the other hand, the critical load becomes light as a result of weak hydrodynamic influence, and the lubricant film can easily drop down to zero. The higher the speed, therefore, Ae heavier the critical load would be. Note that a very small value of hJKx =0.00000015 has been used as the practically zero in Figure 4. 

By the term EHL film breakdown , the author meant to explore the mechanical parameters that may reduce the hydrodynamic influence and, as a result, reduce the EHL filmthickness to practically zero, at which other films may become dominant in supporting the load and protecting the surfaces. The current topic is different from film collapse , which is a more complicated phenomenon in general. Typically, the EHL film is at least one or two orders of magnitude thicker than the boundary film. Therefore, the term practically zero for the EHL film can rnean a sufficiently small value at which the hydrodynamic action becomes negligible and the boundary film (or other films or even dry contact) becomes dominant. In most cases it may not necessarily mean an absolute zero gap between the two surfaces. The revised paper better reflects this definition. 

Figure 14. Effect of temperature on coal dissolution rate coefficient, indicating hydrodynamic influence...

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