Pressure drop correlations

FIG. 14-50 Pressure drop correlation for random packings, as presented hy Robbins. [Cbem. Eng. Progr., 87(1), 19 (1990). Reproduced with peimission of the Ameiican Institute of Chemical Engineers. Copytight 1990 AlChE. All fights reseroed. ] To convert inches H20/ft to mm H20/m, multiply by 83.31. 

X = Abscissa of Smith-Dresser-Ohlswager correlation, or abscissa of Norton Generalized Pressure Drop Correlation, or Fluor vessel sizing separation factor or evaporator temperature, °F... 

Although Sutherland did not obtain an equation for total tray pressure drop, correlation at this time indicates that it follows the effective head concept of Hughmark. This is a limited evaluation because the data available did not indicate any clear liquid heights over about 0.75 in. 

Figures 9-21B and -21C are the earliest generalized pressure drop correlations (GPDC) proposed and have been used for many industrial plant design. Progressively, Figures 9-21E-H are more recent correlations. These charts will be discussed in a later section.

Figure 9-21B. Recent generalized pressure drop correlation. Note v = viscosity of liquid in centipoise. Used by permission of Norton Chemical Process Products Corp.

Figure 9-21F. Strigle s latest generalized pressure drop correlation. Note G = gas mass velocity, Ib/ft -sec. Used by permission of Strigle, R. F. Jr., Packed Tower Design and Applications Random and Structured Packings, 2nd ed. Gulf Publishing Co., (1994) p. 19.

Figure 9-21G. Generalized pressure drop correlation for non-foaming systems for IMTP metal random packing. Parameter of curves is pressure drop in inches of water/foot packed height. Numbers in parentheses are mm of water/meter of packed height. Used by permission of Norton Chemical Process Products Corp., Bull-IHP-1, 12/91 (1987).

Figure 9-34D. Pressure drop correlation at flood point for use with Table 9-33. Used by permission of Zenz, F. A., Chemical Engineering, Aug. (1953) p. 176 all rights reserved.

Y = ordinate in the generalized pressure drop correlation, = G F tl)UL°-2/pGPLgc u = viscosity, centipoise p = density, Ib/ft ... 

Revised Packed Tower Pressure Drop Correlation Constants for Towers Operating Below Flooding Region... 

Leva, M., "Reconsider Packed-Tower Pressure-Drop Correlations, Chem. Eng. Progress, V. 88, No. 1 (1992), p. 65. 

Figure 10-148 presents a recommended pressure drop correlation for low-fin tubes in shells and is based on clean tube pressure drop with no dirt sealing the leakage clearances between tubes and baffle holes or baffle-to-shell clearances. A fouled condition pressure drop may be an indeterminate amount greater. The authors state that this University of Delaware correlation has some lactors built in that limit the deviations to a relatively small range. Figure 10-148 has... 

Chenoweth, J. M. and Martin, M. W. Trans. Am. Soc. Mech. Eng., Paper 55 PET-9 (1955). A pressure drop correlation for turbulent two-phase flow of gas-liquid mixtures in horizontal pipes. 

Friedel L (1979) Improved friction pressure drop correlations for horizontal and vertical two-phase pipe flow. In 3rd International European Two-Phase Group Meeting, Ispra, Italy, 1979, vol 18, issue 7... 

Table 6.7 Pressure drop correlations. Reprinted from Qu and Mudawar (2003a) with permission... 

The column cross-sectional area and diameter for the selected pressure drop can be determined from the generalised pressure-drop correlation given in Figure 11.44. 

Figure 11.44. Generalised pressure drop correlation, adapted from a figure by the Norton Co. with permission...

Figure 8-11. Alternate generalized pressure drop correlation.30... 

The constants in the heat transfer and pressure drop correlations are functions of the fluid physical properties, volumetric flowrate, tube size and pitch. In preliminary design, it is reasonable to assume either 20 mm outside diameter tubes with a 2 mm wall thickness or 25 mm outside diameter tubes with 2.6 mm wall thickness. The tube pitch is normally taken to be pj = l.25do- A square tube pitch configuration can be assumed as a conservative assumption. Baffle cut can be assumed to be 0.25 in preliminary design. 

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