| Bingham
plastic |
A
fluid
that
behaves
in
a
Newtonian
fashion
but
with
a
requirement
that
some
stress
to
set
it
in
motion
. |
| Best
Efficiency
Point
(B.E.P.) |
The
point
on
a
pump's
performance
curve
that
corresponds
to
the
highest
efficiency. |
| Casing |
The
body
of
the
pump
which
encloses
the
impeller,
syn
volute
. |
| Cavitation |
The
sudden
collapse
of
gas
bubbles
due
to
the
sudden
pressure
increase. |
| Centrifugal
force |
A
force
associated
with
a
rotating
body.
In
the
case
of
a
pump,
the
rotating
impeller
pushes
fluid
on
the
back
of
the
impeller
blade,
imparting
circular
and
radial
motion.
A
body
that
moves
in
a
circular
path
will
has
a
centrifugal
force
associated
with
it. |
| Control
volume |
The
limits
imposed
for
the
theoretical
study
of
a
system.
The
limits
are
usually
set
to
intersect
the
system
at
locations
where
conditions
are
known
(syn
system
boundary). |
| Datum
plane |
A
reference
plane.
A
conveniently
accessible
known
surface
from
which
all
vertical
measurements
are
taken
or
referred
to. |
| Delta
(D
) |
A
Greek
symbol
used
to
express
a
difference
between
two
terms.
For
example,
D
H
means
that
the
variable
H
is
the
difference
of
two
other
terms
such
as
H1
and
H2. |
| Dilatant |
The
property
of
a
fluid
whose
viscosity
increases
with
strain
or
displacement. |
| Discharge
Static
Head |
The
difference
in
elevation
between
the
liquid
level
of
the
discharge
tank
and
the
centerline
of
the
pump.
This
head
also
includes
any
additional
pressure
head
that
may
be
present
at
the
discharge
tank
fluid
surface. |
| e.g |
Exemplar
gracia,
for
example
in
latin. |
| Enthalpy |
A
thermodynamic
property
of
a
fluid.
The
enthalpy
of
a
fluid
consists
of
the
energy
associated
with
the
fluid
at
a
microscopic
level
(related
to
the
temperature
of
the
fluid)
plus
the
energy
present
in
the
form
of
pressure
at
the
inlet
and
outlet
of
the
system. |
| Equipment |
Refers
to
any
device
in
the
system
other
than
pipes,
pipe
fittings
and
isolation
valves. |
| Equipment
pressure
head
difference |
The
difference
in
pressure
head
between
the
outlet
and
inlet
of
an
equipment. |
| Friction |
The
force
produced
as
reaction
to
movement.
All
fluids
produce
friction
when
they
are
in
motion.
The
higher
the
fluid
viscosity,
the
higher
the
friction
force
for
the
same
flow
rate.
Friction
is
produced
internally
as
one
layer
of
fluid
moves
with
respect
to
another
and
also
at
the
fluid
wall
interface. |
| Friction
head
difference |
The
difference
in
head
required
to
move
a
mass
of
fluid
from
one
position
to
another
at
a
certain
flow
rate
within
a
piping
system.
It
is
also
the
specific
energy
required
to
overcome
friction
in
the
system. |
| Head |
Specific
energy
or
energy
per
unit
weight
of
fluid,
the
unit
of
head
is
a
distance
in
feet
or
meters. |
| Heat
loss |
The
heat
lost
by
a
system
or
the
heat
lost
due
to
friction. |
| Heat
transfer |
The
heat
lost
or
gain
by
a
system. |
| i.e. |
Id
est,
"that
is"
in
latin. |
| Impeller |
The
rotating
element
of
a
pump
which
imparts
movement
and
pressure
to
a
fluid. |
| Internal
energy |
A
thermodynamic
property.
The
energy
associated
with
a
substance
at
a
molecular
level. |
| Iteration |
A
method
of
solving
an
equation
by
trial
and
error.
An
iteration
technique
is
used
to
solve
equations
where
the
unknown
variable
cannot
be
explicitly
isolated.
A
frequently
used
technique
is
the
Newton-Raphson
method. |
| Kinetic
energy |
A
thermodynamic
property.
The
energy
associated
with
the
mass
and
velocity
of
a
body. |
| Laminar |
A
distinct
flow
regime
that
occurs
at
low
Reynolds
number
(Re
<2000).
It
is
characterized
by
particles
in
successive
layers
moving
past
one
another
without
mixing. |
| Mercury
(Hg) |
A
metal
which
remains
liquid
at
room
temperature.
This
property
makes
it
useful
when
used
in
a
thin
vertical
glass
tube
since
small
changes
in
pressure
can
be
measured
as
changes
in
the
mercury
column
height.
The
inch
of
mercury
is
often
used
as
a
unit
for
negative
pressure. |
| Moody
diagram |
A
graphical
representation
of
the
laminar
and
turbulent
(Colebrook)
flow
equations. |
| Negative
pressure |
Pressure
that
is
less
than
the
pressure
in
the
local
environment,
syn
vacuum. |
| Net
Positive
Suction
Head
(N.P.S.H.) |
The
head
in
fluid
column
height
absolute
as
measured
or
calculated
at
the
pump
suction
flange,
less
the
vapor
pressure
(converted
to
fluid
column
absolute)
of
the
fluid. |
| Newtonian |
A
fluid
whose
viscosity
is
independent
of
the
rate
of
shear.
In
addition,
a
linear
relationship
between
the
rate
of
shear
and
the
tangential
stress
between
layers
characterize
it. |
| Operating
point |
The
point
which
intersects
the
system
curve
and
the
performance
curve
and
corresponds
to
the
flow
and
head
required
for
the
process. |
| Performance
curve |
A
curve
of
Total
Head
vs.
flow
for
a
specific
pump
model
and
impeller
diameter
(syn
characteristic
curve,
water
performance
curve). |
| Pipe
roughness |
A
measurement
of
the
average
height
of
peaks
producing
roughness
on
the
internal
surface
of
pipes.
Roughness
is
measured
in
many
locations
and
then
averaged.
It
is
usually
defined
in
micro-inches
RMS
(root
mean
square). |
| Potential
energy |
A
thermodynamic
property.
The
energy
associated
with
the
mass
and
height
of
a
body
above
a
reference
plane. |
| Pressure |
The
application
of
external
or
internal
forces
to
a
body
producing
tension
or
compression
within
the
body.
In
a
fluid
only
compression
(no
tension)
is
possible. |
| Pressure
head |
The
specific
energy
of
pressure
(equal
to
p/g
). |
| Pseudoplastic |
The
property
of
a
fluid
whose
viscosity
decreases
with
rate
of
shear. |
| Rheopectic |
The
property
of
a
fluid
whose
viscosity
increases
with
time. |
| Shut-off
head |
The
Total
Head
corresponding
to
zero
flow
on
the
pump
performance
curve. |
| Specific
gravity |
The
ratio
of
the
density
of
a
fluid
to
that
of
water
at
standard
conditions. |
| Strain |
The
ratio
between
the
absolute
displacement
of
a
reference
point
within
a
body
to
a
characteristic
length
of
the
body. |
| Stress |
In
this
case
refers
to
tangential
stress
or
the
force
between
the
layers
of
fluid
divided
by
the
surface
area
between
them. |
| Suction
Static
Head |
The
difference
in
elevation
between
the
liquid
level
of
the
fluid
source
and
the
centerline
of
the
pump.
This
head
also
includes
any
additional
pressure
head
that
may
be
present
at
the
suction
tank
fluid
surface. |
| Suction
Static
Lift |
The
same
definition
as
the
Suction
Static
head.
This
term
is
only
used
when
the
pump
centerline
is
above
the
suction
tank
fluid
surface. |
| Siphon |
A
system
of
piping
or
tubing
where
the
exit
point
is
lower
than
the
entry
point
and
where
some
part
of
the
piping
is
above
the
free
surface
of
the
fluid
source. |
| System |
The
system
as
referred
to
in
this
book
includes
all
the
piping
with
or
without
a
pump,
starting
at
the
inlet
point
(often
the
fluid
surface
of
the
suction
tank)
and
ending
at
the
outlet
point
(often
the
fluid
surface
of
the
discharge
tank). |
| System
Curve |
A
plot
of
Total
Head
vs.
flow
that
satisfies
the
system
requirements. |
| System
equation |
The
equation
for
Total
Head
vs.
flow
for
a
specific
system
(syn
system
curve). |
| System
requirements |
The
parameters
that
determine
Total
Head,
that
is:
friction
and
the
system
inlet
and
outlet
conditions
(i.e.
velocity,
elevation
and
pressure). |
| Thixotropic |
The
property
of
a
fluid
whose
viscosity
decreases
with
time
(see
Appendix
A). |
| Total
Dynamic
Head |
Identical
to
Total
Head.
This
term
is
no
longer
used
and
has
been
replaced
by
the
shorter
Total
Head. |
| Total
Head |
The
difference
between
the
head
at
the
discharge
and
suction
flange
of
the
pump
(syn
Total
Dynamic
Head.
pump
head,
system
head). |
| Total
Static
Head |
The
difference
between
the
discharge
and
suction
static
head
including
the
difference
between
the
surface
pressure
of
the
discharge
and
suction
tanks.
It
is
also
the
specific
potential
energy
of
the
system
if
we
do
not
consider
the
pressure
head
in
the
discharge
or
suction
tank. |
| Turbulent |
A
type
of
flow
regime
characterized
by
the
rapid
movement
of
fluid
particles
in
many
direction
as
welt
as
the
general
direction
of
the
overall
fluid
flow. |
| Vacuum |
Syn
negative
pressure. |
| Vapor
pressure |
The
pressure
at
which
a
liquid
boils
at
a
specified
temperature. |
| Velocity
Head
difference |
The
difference
in
velocity
head
between
the
outlet
and
inlet
of
the
system. |
| Viscosity |
A
property
from
which
a
fluid's
resistance
to
movement
can
be
evaluated.
The
resistance
is
caused
by
friction
between
the
fluid
and
the
boundary
wall
and
internally
by
the
fluid
layers
moving
at
different
velocities. |
| Volute |
syn
casing. |
| Work |
The
energy
required
to
drive
the
fluid
through
the
system. |
| Yield
Dilatant |
(see
Appendix
A). |
