文档介绍：Pocket Guide to Chemical Engineering
by Carl R. Branan
· ISBN: 0884153118
· Pub. Date: November 1999
· Publisher: Elsevier Science & Technology Books
Introduction
This pocket guide contains selected rules of thumb and
shortcut design methods meant to travel into the field as
well as the office, even when the "office" is a hotel room. It
contains updates on certain fast-moving technology and
new material not found elsewhere. Miniaturization and easy
retrieval of information are stressed. Those on the go can
produce reasonable results quickly when using this book as
a basic source.
Carl Branan
E1 Paso, Texas
1
Fluid Flow
GENERAL
Two of the most useful and basic equations are
2
U
Ah=~ (1-1)
2g
Au 2
AP (V) + ~ + AZ + E=0 (1-2)
2g
where Ah = head loss in feet of flowing fluid
u - velocity in ft/sec
g = ft/sec 2
P = pressure in lb/ft 2
V = specific volume in ft3/lb
Z = elevation in feet
E = head loss due to friction in feet of flowing fluid
2 Pocket Guide to Chemical Engineering
In Equation 1-1 Ah is called the "velocity head." This
expression has a wide range of utility not appreciated by
many. It is used "as is" for
1. Sizing the holes in a sparger
2. Calculating leakage through a small hole
3. Sizing a restriction orifice
4. Calculating the flow with a pitot tube
With a coefficient it is used for
1. Orifice calculations
2. Relating fitting losses
3. Relief valve sizing
4. Heat exchanger tube leak calculations
For a sparger consisting of a large pipe having small
holes drilled along its length, Equation 1-1 applies directly.
This is because the hole diameter and the length of fluid
travel passing through the hole are similar dimensions. An
orifice, on the other hand, needs a coefficient in Equation 1-
1 because hole diameter is a much larger dimension than
length of travel (say ~ in. for many orifices). Orifices will