Chapter 10A

10A. Total pressure Drop using Equation 10.15 and 10.16 Back to Main

This page is used to determine the change in pressure for the flow of an incompressible liquid in a section of line of fixed diameter where no work is done, using Equation 10.16.

Where: d = internal line diameter

V =fluid velocity = (Equation 10.17)

q = flow rate in volumetric or mass terms

r = density

gc = mass/force conversion constant

g = gravitational force

L = length of line

DX = change of elevation

f = dimensionless factor

Determine f (dimensionless factor) by the equation

(10.15)

Where: C1 =

C2 =

Re = (Equation 10.8)

The units are defined as those listed on page 321. To carry out the total pressure drop calculation the Liquid viscosity, Pipe length, Pipe elevation, Liquid density, Inside diameter, Flow rate, and Pipe relative roughness of the fluid must be entered into their entry space. To do so use the mouse to click the curser in their entry space and input the data. Once this has been done, select Run to execute the solution.

# Definitions and Explanations

Viscosity is defined in Screen 3I

If the pipe is not on an incline, Pipe length is the total length of the pipe in the horizontal direction from beginning to end.

If the pipe is on a incline

L

Y

X

Where: Y = distance from the bottom of the pipeline to the top of the pipeline in

the vertical direction.

X = distance from the beginning of the pipeline to the end in the horizontal direction.

L = pipe length

Pipe elevation is the distance of the pipe from the top of the pipeline to the bottom, in the vertical direction.

L

Y Y = Pipe elevation

X

If the liquid were flowing downhill, Pipe elevation would be a negative number.

The inside diameter of the pipe is the length from one inner edge of the pipe to another inner edge of the pipe on the exact opposite side.

Flow rate is the flow rate of the fluid.

Pipe relative roughness is determined by the Friction Factors Using Moody Correlation graph (Figure 10.1) which combines the Colebrook transition between the smooth pipe equation and the fully turbulent zone.

f - Friction Factor = Vs Re - Reynolds Number

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