Conversions. The equation for converting feet of head to pounds per
square inch is:
P = H x SPGR
or
H = 2.31 x P
2.31
SPGR
Where:
P = pressure in PSI
H = Head (in feet of fluid)
SPGR = Specific gravity
2.31 = Conversion constant
We found out in the first part of this class that all products produce a
different pressure at different heights. In the equation, the specific
gravity compensates for the different products and the constant 2.31 takes
care of the feet of head (hd)or the PSI.
Example: SPGR =.8448
Head = 250 ft
P = 250 x .8448 =91 PSI
2.31
H = 2.31 X 91 =249 ft/hd
844
PART C DESIGN FUEL
Design fuel: Fuels most likely to be transported by military pipeline are
motor gasoline, JP-4, and diesel fuel. Properties of these fuels will be
found in MIL-HDBK-200 (Federal specifications) and gravity range in Table 6-
1. With such a wide variation, specific gravity becomes an important factor
in the design of military pipelines. The heaviest fuel making up 24 percent
or more of the total requirement will be taken as the design fuel.
Viscosity: Viscosity is a measure of the relative ease or difficulty with
which a liquid can be made to flow. It is the internal force (resistance)
or opposition to flow. Viscosity can be expressed as kinematic viscosity or
dynamic viscosity. For our purposes in the U.S. Army we will use kinematic
viscosity. The units of kinematic viscosity are centistokes and feet
squared per second. The viscosity, in units of centistokes (cs), is found
by using Figure 1-1. If the units of feet squared per second are desired,
then the conversion factor of 92,900 cs equals one foot squared per second
is used.
Example:
To convert 20 cs to cubic ft/sec use, the following formula:
y
=
Kinetic
=
20
=
0.000215285
92,900
92,900
12-8
QM 5099
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