Fluid-flow conditions

O = Oxidizing potential R = Reducing potential T = Temperature S = Salts in solution F = Fluid flow conditions A = Agitation... 

Figure 2 was constructed by contouring of values calculated from the flow net of figure 1. Much more complex diagrams are possible provided sufficient information concerning the aquifer and fluid-flow conditions can be obtained. For simple boundary conditions and homogeneous aquifers, a direct analytical solution for isochronal surfaces is available [2]. 

The mass and heat transfer analogies make possible an evaluation of the mass-transfer coefficient (k) and provide insight into how membrane geometry and fluid-flow conditions can be specified to optimize flux (4). For laminar flow ... 

H. Synthesis under Variable Fluid-Flow Conditions 39... 

The above analysis has considered the laminar heat transfer from an isothermal surface. In many practical problems the surface heat flux is essentially constant, and the objective is to find the distribution of the plate-surface temperature for given fluid-flow conditions. For the constant-heat-flux case it can be shown that the local Nusselt number is given by... 

Van Gauwhergen, D. and J. Baeyens (1997). Macroscopic fluid flow conditions in spiral-wound membrane elements. Desalination. 110, 3, 287-299. 

The physics of the substrate rotation after the solution is dispensed leads to a fluid flow condition where the rotational accelerations are exactly balanced by the viscous drag felt within the solution at each stratum level. This flow condition was first described by Emslie, Bonner, and Peck (hereafter referred to as EBP) and their article has been the foundation for many more recent studies. For most solutions, another important balance is established between viscous outward radial flow of the solution on the surface of the substrate and the evaporation of... 

The receiver vessel can be of several formats but will frequently be packed with internal packing to eliminate entrainment of the extracted components forming in the rapidly expanding critical fluid. Flow conditions under ambient conditions are measured with the aid of a flow meter, FM, and fluid totalizing module, GT. This described SFE unit can be changed to accommodate fractionation and reaction experiments as has been shown and documented in our laboratories at a modest cost (34). Such equipment today exists commercially but may be more limited with respect to pressure range, fluid flow rate, and size of the extraction chamber (34). 

The limiting current density for a given elecnode reaction, cell geometry, and fluid flow condition is most easily determined experimentally, from a polarization curve such as that shown in Figures... 

External mass and heat transfer resistances between the bulk gas phase and the surface of the catalyst pellets which are functions of the fluid flow conditions around the pellets. 

The diffusion of A through B will depend not only on the physical properties of A and B but also the prevailing fluid flow conditions. 

Han, G. 2003. Rock Stability under Different Fluid Flow Conditions. PhD thesis. University of Waterloo, Waterloo, ON, Canada. 

Piping or plumbing systems made of copper alloys are susceptible to erosion-corrosion in unfavorable fluid flow conditions. Erosion-corrosion can occur when erosive action of the flowing stream removes the protective copper oxide film from the metal surface, and thus exposing the bare metal surface to a corrosive environment (44). 

The thickness of the diffusion layer is strongly related to the fluid flow conditions and only in rather simple cases 6 can be calculated as function of characteristic hydrodynamic parameters. An order of magnitude is about one tenth of the hydrodynamic laminar boundary layer thickness. Because the diffusion layer is very small, one can totalize the phenomena occurring in it and suppose that the diffusion layer belongs to the electrode. This will lead to the concept of concentration overpotential (see section 1.ii.3). 

Research in macromolecular transport using Brownian dynamics is fundamental in that either a parameterized class of fluid flow conditions is considered or a particular experiment is modeled with well-known geometric and fluid conditions. 

The external mass transfer resistance depends heavily on fluid flow conditions, such as temperature, pressure, and superficial velocity, in the reactor and the particle size of the catalyst. Varying these parameters can help to reduce the external diffusion restriction, for example, by increasing the velocity of the fluid phase over the particles. 

If the pipelines are located in deep water or inaccessible places, maintenance and/or replacement of pipes and clean-up of oil spills is difficult and expensive. The use of expensive stainless steel or other alloys is not a viable solution due to the required capital costs, which are not economically feasible in many cases. Hence the strategy to combat corrosion problems is to use carbon steel pipes, but reduce and, if possible, prevent the rate of material losses. An important method of corrosion reduction practiced in the oil and gas industry is the use of corrosion inhibitors. The inhibitors act by bonding to the metal surface and forming a protective film. The performance of the inhibitor depends on the metal surface, the inhibitor composition, and fluid flow conditions. Some of the inhibitors are not effective because of the multiphase flow conditions in the pipelines. When selecting an inhibitor, it is essential to know its effectiveness in the specific service environment. Detailed knowledge of the metal surface conditions, the operating temperature and pressure, the fluid properties, the solution pH, and the multiphase flow conditions is essential. 

The large decrease in corrosion rates in carbonic acid between 7 and 70 days is attributed to the eventual formation of protective surface films that may be fragile imder certain fluid flow conditions. 

The film theory therefore predicts that F and the A -type mass-transfer coefficients for different solutes being transferred under the same fluid-flow conditions are directly proportional to the D s for the solutes. On the other hand, we observe for turbulent flow a much smaller dependency, proportional to Jviiere./Ljna.yJb.e anythingirom.nearly xerQ to,0,8, OI..Q.9, depending upon the... 

The uniform and well-defined fluid flow conditions of microreactors also provide opportunities to better control the dynamics of nanomaterial synthesis. Kroon et cd. [102] studied the eSects of mixing on the coagulation processes of CdS NPs vrithout a stabilizer using simple predpitation reaction of CdN03 and Na2S. Their results indicate that the use of a static micromixer and laminar flow reactor could produce a dispersed CdS NP solution that is stable for hours. In contrast, the batch reactor... 

Heat transfer by convection is more difficult to analyze than heat transfer by conduction because no single property of the heat transfer medium, such as thermal conductivity, can be defined to describe the mechanism. Heat transfer by convection varies from situation to situation (upon the fluid flow conditions), and it is frequently coupled with the mode of fluid flow. 

Various materials of construction for refinery and petrochemical plant service may exhibit accelerated metal loss under unusual fluid-flow conditions. Attack is caused by a combination of flow velocity (mechanical factors) and corrosion (electrochemical factors) known as erosion-corrosion. 

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