Turbulent flow in pipelines

A distinctive feature of fluidized beds is a high rate of heat transfer between the fluid and immersed surfaces. Some numerical values are shown on Figure 17.37. For comparison, air in turbulent flow in pipelines has a coefficient of about 25 Btu/(hr)(sqft)(°F). (a) is of calculations from several correlations of data for the conditions identified in Table 17.19 (b) shows the effect of diameters of quartz particles and (c) pertains to 0.38 mm particles of several substances. 

As in the case of Newtonian fluids, one of the most important practical problems involving non-Newtonian fluids is the calculation of the pressure drop for flow in pipelines. The flow is much more likely to be streamline, or laminar, because non-Newtonian fluids usually have very much higher apparent viscosities than most simple Newtonian fluids. Furthermore, the difference in behaviour is much greater for laminar flow where viscosity plays such an important role than for turbulent flow. Attention will initially be focused on laminar-flow, with particular reference to the flow of power-law and Bingham-plastic fluids. 

A proper geometric design of the system in order to get a laminar flow with minimum turbulence, as in pipelines of large diameters and avoid abrupt changes or streamline bends. 

A distribution of drops is formed in the intensely turbulent flow in a pipeline, where the average drop radius, is given by ... 

The smallest size pipeline loop usually considered for measurements intended for industrial scale-up is lin. (2.54 cm) inside diameter [178]. The results are used to determine laminar versus turbulent flow regimes and as input in flow models [178]. Nasr-El-Din [182,183] reviews the methods used to predict pressure drops across emulsions flowing in pipelines, as well as those used to sample and measure oil and solid concentrations in pipelines. An example of an equation for the prediction of water-in-crude oil (North Sea crude oil) emulsion viscosity is given in Equation (6.48). 

On the other hand, Sf under turbulent flow in the pipeline [6] is ... 

When it is necessary to estimate the pressure drop in a pipeline where turbulent flow conditions exist, the following formula will give an approximation ... 

Because concentrated flocculated suspensions generally have high apparent viscosities at the shear rates existing in pipelines, they are frequently transported under laminar flow conditions. Pressure drops are then readily calculated from their rheology, as described in Chapter 3. When the flow is turbulent, the pressure drop is difficult to predict accurately and will generally be somewhat less than that calculated assuming Newtonian behaviour. As the Reynolds number becomes greater, the effects of non-Newtonian behaviour become... 

In the absence of extreme turbulence, the average particle diameters formed by two or three phase flow in a pipeline are much larger than for other causes of entrainment. This usually allows good efficiency for... 

Schmerwitz H, Reher EO (1986) Effect of elastic properties on turbulent flow of petroleum and petroleum products in pipelines Wiss Z Tech Hochsch Carl Schorlemmer Leuna-Merseburg 28 235... 

Another interesting application of the data in Fig. 2.20 for dispersion coefficients in turbulent flow is in calculating the mixing that occurs in long pipelines. Many refined petroleum products are distributed by pipelines which may extend over hundreds of kilometres. The same pipeline is used to convey several different products, each... 

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