Pipes fluid flow in

Basic Ideas to Evaluate Newtonian and Non-Newtonian Flow 

We have spent a lot of time in this book so far discussing the movement and processing of fluids through different types of equipment, but how is the process fluid conveyed from one piece of equipment to another  

In general the answer is, It is carried by pipes, and in most cases the pipes are circular cross-section and made from carbon steel. 

1 Field Engineer s Method for Estimating Pipe Flow 

One day I asked Norman how he would calculate the pressure loss for flow through circular cross-section pipes—the sort of pipes that are used throughout most process plants that we work in. I felt sure he would have some simple method. Here is the method with an example of its use for a pressure drop survey, more or less as he gave them to me. 

The pressure drop (AP) for fluids flowing through pipe lines of any diameter may be approximated by the following formula. I ve checked this correlation in the field. Caution This formula only applies if viscosity is low and flow is turbulent. By low viscosity, I mean something less than 2 or 3 cP, or perhaps 10 SSU (seconds saybolt universal). Water, warm diesel oil, and hot gas oil all fall within this category. 

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Experimental techniques to visualize flows have been extensively used to define fluid flow in pipes and air flow over lift and control surface of airplanes. More recently this technology has been appHed to the coating process and it is now possible to visualize the flow patterns (16,17). The dimensions of the flow field are small, and the flow patterns both along the flow and inside the flow are important. Specialized techniques such as utilizing small hydrogen bubbles, dye injection, and optional sectioning, are required to visualize these flows. 

Figure 8-32. Correlation for the dispersion of fluids flowing in pipes. (Source Levenspiel, 0., Ind. Eng. Chem., 50, 343, 1958.)...

The friction losses for fluid flow in pipe valves and fittings are determined as presented in Chapter 2. Entrance and exit losses must be considered in these determinations, but are not to be determined for the pump entrance or discharge connections into the casing. 

Particles of fluid flowing in pipes act in the same manner. The flow is streamlined if the fluid flows slowly enough, and remains streamlined at greater velocities if the diameter of the pipe is small. If the velocity of flow or size of pipe is increased sufficiently, the flow becomes turbulent. 

Under normal circumstances, the laminar-turbulent transition occurs at a Reynolds number of about 2100 for Newtonian fluids flowing in pipes. 

Figure 13.15 Correlation for the dispersion of fluids flowing in pipes, adapted from Levenspiel (1958b).

A useful discussion of incompressible fluid flow in pipes and the influence of surface roughness and friction factors on pumping is found in Perry s Chemical Engineer s Handbook (49). 

The same is true for fluid flow in piping. Experimental data must first be established to solve the piping fluid flow problems, specifically the / factor, also called the hL factor in the Fig. 6.1 analogy. Please note also that / is dimensionless. The / factor is used later in this chapter. The hL factor is in units of feet it is a force, requiring a workload, which is the force of friction resisting fluid flow. This friction of resistance is on the internal wall surface of the pipe. 

The kinetic-energy terms of the various energy balances developed h include the velocity u, which is the bulk-mean velocity as defined by the equati u = m/pA Fluids flowing in pipes exhibit a velocity profile, as shown in Fi 7.1, which rises from zero at the wall (the no-slip condition) to a maximum the center of the pipe. The kinetic energy of a fluid in a pipe depends on actual velocity profile. For the case of laminar flow, the velocity profile parabolic, and integration across the pipe shows that the kinetic-ertergy should properly be u2. In fully developed turbulent flow, the more common in practice, the velocity across the major portion of the pipe is not far fro... 

Plot for estimating film coefficients for fluids flowing in pipes and tubes. [Based on Eqs. (25) and (26).]... 

Figure 14-6 Correlation for dispersion of fluids flowing in pipes. (From O.Levenspiel, Chemical Reaction Engineering, 2nd. ed. Copyright 1972 John Wiley Sons, Inc. Reprinted by permission of John Wiley Sons, Inc. All rights reserved.) [Note D =...

The velocity u in the kinetic-energy terms of energy balances is tire bulk-mean velocity as defined by the equation, u = Fluids flowing in pipes exlribit a velocity profile, as... 

To understand the mechanism of the turbulent mixing process occurring in pipe reactors, we have to consider first some of the properties of fluid flow in pipes. Resistance to fluid flow in a pipe has two components, the viscous friction of the fluid itself within the pipe, which increases as the fluid viscosity increases, and the pressure differential caused by a liquid level difference or a pressure difference between the two vessels. 

FIGURE 1.3 Fluid flow characteristics and profiles of fluid flow in pipes (a) At low Reynolds numbers, where streamline flow is obtained throughout the cross section, (b) At high Reynolds numbers, where turbulent flow is obtained for most of pipe volume. Streamline flow is only obtained in a thin boundary layer adjacent to the pipe wall where the influence of the wall and viscous forces control turbulence. 

Pioneering work by Osborne Reynolds in the late 19th century added considerably to the understanding of fluid flow in relation to surfaces, and established concepts on which subsequent theoretical, empirical, and practical work could be based. The principal finding was in connection with fluid flow in pipes, visually demonstrating the difference between laminar and turbulent flow. Reynolds discovered that the dimensionless number that now bears his name, the Reynolds number Re), defined the flow condition in a tube. 

S OLID-LIQUID FLOWS are encountered in a variety of applications ranging from food to mining industries (I). Unlike single fluid flow in pipes, slurry flow in pipelines is complex. The complexity of these flows has necessitated the use of empirical equations in the design of slurry handling equipment, often leading to expensive systems. This complexity depends on the physical properties of the solid particles, for example, particle density, shape, and mean diameter. It also depends on the viscosity and density of the carrier fluid and, finally, on the operating con-... 

Measurement of fluid flow in pipes, udng oti e, nozzle, and Venturi... 

Fluid flow in pipes/ conduits relatively constant for Re > 2000. 

As an example for fluid flow in pipes, we propose a system similar to the one we solved in Excel in Chapter 3. We would like to feed two tanks with a total flow of 100,000 kg/h. The information related to the system is given in Table 8.8. The initial pressure is atmospheric and the final pressure at the tanks should also be atmospheric. The question is to determine the flow rate that reaches each tank, the pump outlet pressure, and its cost. In other words, compute the pump energy and the split fraction. 

In the previous section we derived three II groups to describe fluid flow in pipes ... 

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