1. KALI CHARAN NIGAM INSTITUTE OF
TOPICS – MULTISTAGE CENTRIFUGAL PUMPS
-- MODEL TESTING OF CENTRIFUGAL PUMPS
FLUID MECHANICS AND FLUID MACHINE (KME302)
BY : DEEPAK KUMAR YADAV
2. MULTISTAGE CENTRIFUGAL PUMPS
If a centrifugal pump consists of two or more
impellers, the pump is called a multistage
The impellers may be mounted on the same shaft
or on different shafts.
A multistage pump is having the following two
1. To produce a high head (Impeller are connected in
2. To discharge a large quantity of liquid(Impeller are
connected in parallel)
3. MULTISTAGE CENTRIFUGAL PUMPS
FOR HIGH HEADS
For developing a high head, a number of impellers are
mounted in series or on the same shaft as shown in fig.
The water from suction
pipe enter 1st impeller
at inlet and is discharge
at outlet with increased
The water with increased
pressure from the outlet
of the 1st impeller is taken
to the inlet of the 2nd
Impeller with the help of
4. MULTISTAGE CENTRIFUGAL PUMPS
FOR HIGH HEADS
At the outlet of the 2nd impeller, the pressure of
water will be more than the pressure of water at
the outlet of the 1st impeller.
If more impeller are mounted on the same shaft,
the pressure at the outlet will be increased.
Let n = Number of identical impellers mounted on
the same shaft.
Hm= Head developed by each impeller
Then Total head developed = n. Hm
The discharge passing through each impeller is
5. MULTISTAGE CENTRIFUGAL PUMPS
FOR HIGH DISCHARGE
For obtaining high discharge, the pump should be
connected in parallel as shown in fig.
Each of the pumps lifts
the water from a common
pump and discharge water
to a common pipe to
which the delivery pipes
of each pump is connected.
Each of the pump is working
against the same head.
7. MODEL TESTING OF CENTRIFUGAL
Before manufacturing the large sized pumps, their
models which are in complete similarity with the
actual pumps are made.
Tests are conducted on the models and
performance of the prototype are predicted.
The complete similarity between the model and
actual pump will exist if the following conditions
1. Specific speed of model = Specific speed of prototype
8. MODEL TESTING OF CENTRIFUGAL
2.Tangential velocity (u) is given by
3. Discharge is given by