ESSOM COMPANY LIMITED
Part 3: Experiment
19
TEST RESULTS - TURBINE PERFORMANCE CURVES
Test results are commonly expressed in the form of curves plotting on graph paper
.
They are known as “Turbine
Performance Curves or Characteristic Curves”
.
In plotting the curves, basic characteristics of turbine performances taken directly from the recording data and data of
calculated results are used
.
Calculations of the results such as turbine output power, turbine input power, and turbine
efficiency are done by applying formulae and principles of turbine theory in Article 3
(
see sample of calculations for a
test run in Article 6
).
Recommended performance curves to be plotted are as follows
:
▪
Torque vs
.
Speed at Various Flow Rates or Nozzle Pressures
.
Torque
(
T
)
is plotted on the vertical axis and speed
(
n
)
is plotted on the horizontal axis of the graph
.
It may be
observed that the higher the torque, the slower the speed
.
▪
Turbine Inlet Pressure vs
.
Flow Rate
.
Pressure
(
P
)
is plotted on the vertical axis and flow rate
(
Q
)
is plotted on the horizontal axis of the graph
.
It may be
observed that the higher the flow rate, the lower the pressure
.
▪
Turbine Output Power vs
.
Speed at Various Flow Rates or Nozzle Pressures
.
Turbine output power
(
W
o
)
is plotted on vertical axis and speed
(
n
)
is plotted on the horizontal axis of the graph
.
It
may be observed that the maximum output is at a medium speed
.
▪
Turbine Efficiency vs
.
Speed at Various Flow Rates or Nozzle Pressures
.
Turbine efficiency
(
)
is plotted on the vertical axis and speed
(
n
)
on the horizontal axis of the graph
.
It may be
observed that the maximum efficiency is at a medium speed
.
▪
Turbine Racing Characteristic Curves
-
No Load Condition
.
Speed
(
n
)
is plotted on the vertical axis vs
.
turbine inlet pressure
(
P
)
on the horizontal axis when the turbine is
running without any engagement of the mechanical dynamometer operation
(
brake arms are fully released
).
