Friction factor Colebrook equation

Where ij. is defined as the kinematic viscosity (centistokes), and is a constant with a value of 2,213.8 in USCS units and 353.68 in SI units. An empirical relation for the Fanning friction factor is the Colebrook-White equation ... [Pg.517]

The Colebrook equation [6, 58] is considered a reliable approach to determining the friction factor, f (Moody factor)... [Pg.68]

If the Reynolds number is greater than 4,000, the flow will generally be turbulent and the friction factor can be calculated from the Colebrook equation ... [Pg.173]

The model for turbulent drag reduction developed by Darby and Chang (1984) and later modified by Darby and Pivsa-Art (1991) shows that for smooth tubes the friction factor versus Reynolds number relationship for Newtonian fluids (e.g., the Colebrook or Churchill equation) may also be used for drag-reducing flows, provided (1) the Reynolds number is defined with respect to the properties (e.g., viscosity) of the Newtonian solvent and (3) the Fanning friction factor is modified as follows ... [Pg.180]

Churchill also provided a single equation that may be used for Reynolds numbers in laminar, transitional, and turbulent flow, closely fitting/= 16/Re in the laminar regime, and the Colebrook formula, Eq. (6-38), in the turbulent regime. It also gives unique, reasonable values in the transition regime, where the friction factor is uncertain. [Pg.11]

The reader will note that both the Karman-Nikuradse and the Colebrook equations are implicit in the friction factor and require a trial and error solution. For hand calculations, it is often simpler to use the friction factor chart. [Pg.204]

Fouling factors, heat transfer, 180 data, 183, 184, 186 Fourier equation, 169 Fractionation. See Distillation Fractionator conntrol lower ends, 49,50 upper ends, 51,52 Freeze drying, 639 cvcle lengths. 639 products 646 Friction, 93 Friction factor, 92 Colebrook equation, 94 granular beds, 117 non-Newtonian fluids, 109 Rounds equation, 94... [Pg.750]

Chemical engineers are familiar with the Fanning (or Darcy) friction factor,/, the Moody chart of/vs. Reynolds number, Rg, and how all of this fits together to calculate pressure drop for a given fluid flow in a given sized pipe. The friction factor is calculated from the Colebrook equation ... [Pg.15]

For smooth pipes, the agreement between the Petukhov and Colebrook equations is very good. The friction factor is minimum for a smooth pipe (but still not zero because of the no-slip condition), and increase,s with roughness (Fig. 8-25). [Pg.493]

The Colebrook equation is implicit inf, and thus the determination of the friction factor requires some iteration unless an equation solver such as EES is used. All approximate explicit relation for/was given by S. E. Haaland in 1983 as... [Pg.494]

In turbulent flow, wall roughness increases the heat transfer coefficient h by a factor of 2 or more [Dipprey and Saber.sky (1963)]. The convection heat transfer coefficient for rough tubes can be calculated approximately from the Nusselt number relations such as Eq. 8-71 by using the friction factor determined from the Moody chart or the Colebrook equation. However, this approach is not very accurate since there is no further increase in h with/for /> 4/sn,ooih [Norris (1970)1 and correlations developed specifically for rough tubes should be used when more accuracy is desired. [Pg.494]

The friction factor corresponding to this relative roughness and the Reynolds number can simply be determined from the Moody chart. To avoid the reading error, we determine it from the Colebrook equation ... [Pg.496]

Solving problems in chemical engineering and science often requires finding the real root of a single nonlinear equation. Examples of such computations are in fluid flow, where pressure loss of an incompressible turbulent fluid is evaluated. The Colebrook [8] implicit equation for the Darcy friction factor, f, for turbulent flow is expressed... [Pg.24]

The Colebrook implicit equation for the Darcy friction factor, f, for turbulent flow is ... [Pg.52]

The Darcy friction factor is four times the Fanning friction factor, fp, i.e., fp = 4fp. For fully developed turbulent flow regime in smooth and rough pipes, the Colebrook [5] equation or the Chen [6] equation can be used. [Pg.157]

Values of k and k for various polymer/tube systems are given in Table 5.10. (Values of k and ki can be determined for a given polymer solution from laboratory measurements of pressure drop in smooth tubes at two flow rates in the turbulent range.) These values can be used with the model to predict friction loss for that solution at any Reynolds number in any size pipe. If the Colebrook equation for smooth tubes is used, the appropriate generalized expression for the friction factor is... [Pg.437]

Figure 4.2 gives the Moody Friction Factor Chart. This chart allows Ito be read as a function of pipe roughness, e, divided by pipe diameter (e/D, the so called relative roughness) and the Reynolds number (Re= Dvp/p), where p is the viscosity of the fluid. One can also solve the Colebrook equation iteratively to find f ... [Pg.81]

Problem Statement Use the Colebrook and Haaland equations to calculate the friction factor with e/D = 0.008 and Re = 8 X 10 . [Pg.82]

For laminar flow that is very simple because (as we discussed before) the laminar-flow part of the friction factor plot is simply /= 16/. For turbulent and transition flow, it is more difficult. The common friction factor plot (Fig. 6.10) is based bn the Colebrook equation [5]... [Pg.205]

The fully developed turbulent friction factor seems to be in disagreement with the Blasius equation for smooth microcharmels and with the Colebrook correlation for rough microchannels. [Pg.2861]

Colebrook proposed empirical equation for friction factor for both smooth and rough pipe is... [Pg.751]

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