Euler's equation H_{e} =
U_{2}V_{u2}/g assumes infinite no of vanes and
radial entry into impeller eye, (V_{u1} = 0).According
to this equation, Euler's head depends on:

Answers

Impeller type, speed and outlet diameter

Impeller outlet vane angle, speed and outlet diameter

Impeller inlet and outlet diameter, speed and flow

None of the above

Qs2

For the pumping system
shown in the figure below, calculate the total head and the
power absorbed by the pump. Power absorbed is given by,
BkW = Q(m^{3}/hr.) x H(m) x specific gravity/(3.67
x efficiency(%))
Assume pump efficiency = 80%

Answers

30 m and 46 kW

32 m and 49 kW

35 m and 53.6 kW

30 kW and 4.6 kW

Qs3

A centrifugal pump generates a pressure
of 100 psi (a head of 231 ft = 100 psi x 2.31) when handling
clean water of specific gravity 1.0. What pressures and head
will this pump generate when pumping brine with sp. gr. 1.2
and kerosene with sp. gr. 0.8

The
affinity laws of centrifugal pumps suggest that pump capacity
varies directly with the impeller diameter, pump head as the
square of the diameter and power as the cube of the diameter
(assuming the efficiency is unchanged). The law holds good for
impeller trims limited by the pump specific speed, impeller
type and inlet diameter of the impeller. Assuming that the
affinity laws hold good for the impeller trim shown below,
what will be the capacity, head and efficiency for the current
operating point?

Answers

Q = 450 m^{3}/hr., H = 81 m, efficiency = 82% and power = 121 kW

Q = 405 ^{3}/hr., H = 72.9 m, efficiency = 73.8% and power = 109 kW

Q = 450 ^{3}/hr., H= 72.9 m, efficiency = 82% and power = 109 kW

Q = 405 ^{3}/hr., H = 81 m, efficiency= 82% and power = 109 kW

Qs5

A pump manufacturer has to test an
external fire fighting pump (for ship) of the following
specifications: Q = 2400 ^{3}/hr H = 150
m Efficiency = 86% Speed = 1800 rpm Medium - Sea
water (sp. gr. 1.03) Driver - Main Engine through power
take-off and gear box The manufacturer can test pump at his
works, using one of the test motors at six pole speed (1000
rpm synchronous). What will be the rated duty condition of the
pump at 1000 rpm at the test bed and what should be the rating
of the test motor. Test bed uses clean cold water (sp. gr. =
1.0) for testing.

Answers

Q = 1333 ^{3}/hr., H = 83.3 m, motor = 400 kW, 6 pole

Q = 1333 m^{3}/hr., H = 46.3 m, motor = 215 kW, 6 pole

Q = 740 m^{3}/hr., H = 83.3 m, motor = 215 kW, 6 pole

Q = 1200 ^{3}/hr., H = 37.5 m, motor = 160 kW, 6 pole

Qs6

The specific speed of an impeller is
expressed as N.xQ^{0.5}/H^{0.75}, where N =
speed, Q = flow in USgpm and H = head/stage in ft. Following
are four impellers for double suction split-case pumps with
their rated duties. What are their specific speeds (US units)?

Pump A

Pump B

Pump C

Pump D

Impeller- 5HS12

Impeller- 5HS12

Impeller- 5HS12

Impeller- 5HS12

Q = 1110 US gpm

Q = 1760 US gpm

Q = 2200 US gpm

Q = 3170 US gpm

H = 72 ft

H = 180 ft

H = 295 ft

H = 295 ft

N = 1450 rpm

N = 1480 rpm

N = 1480 rpm

N = 1480 rpm

Answers

Answer 1

Answer 2

Pump A - 900

Pump A - 975

Pump B - 975

Pump B - 1954

Pump C - 1263

Pump C - 1263

Pump D - 1954

Pump D - 840

Answer 3

Answer 4

Pump A - 1954

Pump A -1263

Pump B - 1263

Pump B -1954

Pump C - 975

Pump C - 975

Pump D - 840

Pump D- 900

Qs7

Referring to Fraser-Sabini efficiency
charts, the efficiencies of the four pumps listed in Qs no 6
are estimated to be as follows:

Answers

Answer 1

Answer 2

Answer 3

Answer 4

Pump A- 84%

Pump A- 83%

Pump A- 82%

Pump A- 81%

Pump B- 81%

Pump B- 78%

Pump B- 84%

Pump B - 67%

Pump C- 80.5%

Pump C- 84%

Pump C- 83%

Pump C - 85%

Pump D - 79%

Pump D- 80%

Pump D - 75%

Pump D - 72%

Qs8

Suction specific speed is an indicator
of the suction capability of a pump. It is also a measure of
suction energy of the pump & its permissible range of
operation. External fire pumps for ships (FiFi pumps) operate
at a single duty point and the typical duties are as follows:-

Pump A

Pump B

Pump C

Pump D

Q= 2400 m^{3}/hr

Q= 1200 m^{3}/hr

Q= 600 m^{3}/hr

Q= 300 m^{3}/hr

H= 150 m

H= 140 m

H= 140 m

H= 140 m

N= 1800rpm

N= 1800rpm

N= 1800rpm

N=2100rpm

The suction specific speed (Nss) is given by,
NxQ^{0.5}/(NPSHr)^{0.75} , where, N = speed
in rpm , Q = flow/eye in US gpm and NPSHr is in
ft.

What would be the expected NPSHr of pumps A, B, C
& D if all of them are double suction split-case single
stage pumps,considering that most commercially designed pumps
achieve Nss = 9000 (US units)?

Answers

Answer 1

Answer 2

Answer 3

Answer 4

Pump A - 17.2m

Pump A - 10.8m

Pump A - 6.4m

Pump A - 4.3m

Pump B - 10.8m

Pump B - 6.8m

Pump B - 4.1m

Pump B - 6.8m

Pump C - 6.8m

Pump C - 4.3m

Pump C - 2.5m

Pump C - 10.8m

Pump D - 5.3m

Pump D - 3.3m

Pump D - 2.0m

Pump D - 3.3m

Qs9

A ship-owner is considering installation
of two diesel engine driven external fire pumps on the ship
deck. Pump duty and suction conditions are as follows:- a)
Rated capacity of each pump - 600 m3/hr b) Rated head -
140 m. c) Static lift (minimum water level to pump center
line) = 3.0 m. d) Total losses in the pipe line (strainer,
bend, straight pipe, etc.) = 0.5 m. e) Vapor pressure =
0.6 m. f) Atmospheric pressure = 10.3 m.
g) Available
NPSH = 6.2 m (10.3 - 3.0 - 0.5 - 0.6 m)

The ship-owner
wants to maintain a safety ratio of 1.2 (NPSHa/NPSHr) to
prevent cavitation. What is the maximum speed at which he
can run a) an end suction pump b) a double suction
pump
(Consider that pumps operate at B.E.P at the
rated duties and that they have been designed for Nss =
9000 US units.)

Answers

Answer 1

Answer 2

Answer 3

Answer 4

End Suction- 2080 r.p.m

End Suction- 2080 r.p.m

End Suction- 1470 r.p.m

End Suction- 1667 r.p.m

Double Suction- 2080 r.p.m

Double Suction- 1470 r.p.m

Double Suction- 2080 r.p.m

Double Suction- 2370 r.p.m

Qs10

What is the NPSHa for the following
system: <br>(Given, vapor pressure of water at pumping
temperature is 0.5 m & suction vessel is open to
atmospheric pressure.)