ESSOM COMPANY LIMITED
Section 2: Theory
12
2
.
4 Formula
▪
Turbine Input, W
i
Turbine input power of water flow to turbine for one unit weight of water is,
3
2
4
f
2
2
f
kg
liter
1 min
1
m
cm
N
10
9.81
min
60 sec
1000 liter
kg
m
cm
i
W
Q
p
1.635
i
W
Qp
(
2. 7
)
Where
:
i
W
=
Turbine input, Watts
Q
=
Flow rate, lpm
p
=
Turbine inlet pressure, kg
/
cm
2
▪
Turbine Output, W
o
Turbine output is normally measured by dynamometer
.
f
N
rev
2 radian(dimensionless)
min
kg
9.81
m.
kg
min
rev
60sec
f
o
W
F
r
n
1.0273
o
W
Frn
(
2. 8
)
Where
:
o
W
=
Turbine output, Watts
F
=
Net force on the mechanical or hydraulic dynamometer, kg
r
=
dynamometer radius, m
n
=
dynamometer speed, rev
/
min
If torque
(
T
F r
)
on the dynamometer is directly measured in Newton
-
meter
(
N
-
m
)
radian(dimensionless)
min
N m 2
min
60sec
o
W
T
n
0.10472
o
W
Tn
(
2. 9
)
Where
:
T
=
Torque, N
.
m
▪
Turbine Efficiency,
Turbine output power
100% =
100%
Turbine input power
o
i
W
W
(
2. 10
)
In case of the turbine being used for driving electric generator, the efficiency of the generator must be included in the
overall efficiency of the combined turbine
-
generator unit
.
Power output of AC generator can be measured by a wattmeter
.
100% =
100%
100%
Turbine input
Electrical output
power
e
i
i
W
VI
W
W
(
2. 11
)
Where
:
o
=
Overall Efficiency,
%
e
W
=
Electrical Output, Watts
V
=
Output voltage, V
I
=
Output Current, A
