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1131 practice sets · Page 40 of 57
In a single casing, multistage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by
designing new impeller
trimming the impeller size to the required size by machining
not possible
some other alterations in the impeller
According to fan laws, for the fans having constant wheel diameters, the power demand varies
directly as fan speed
square of fan speed
cube of fan speed
square root of fan speed
According to fan laws, for fans having constant wheel diameter, the pressure varies
directly as fan speed
square of fan speed
cube of fan speed
square root of fan speed
According to fan laws, for fans having constant wheel diameter, the air or gas capacity varies
directly as fan speed
square of fan speed
cube of fan speed
square root of fan speed
According to fan laws, at constant weight of air or gas, the speed, capacity and pressure vary
directly as the air or gas density
inversely as square root of density
inversely as density
as square of density
According to fan laws, at constant pressure, the speed capacity and power vary
directly as the air or gas density
inversely as square root of density
inversely as density
as square of density
According to fan laws, at constant speed and capacity, the pressure and power vary
directly as the air or gas density
inversely as square root of density
inversely as density
as square of density
Puck up the wrong statement about centrifugal pump
discharge a diameter
head a speed2
head a diameter
Power a speed
Overall efficiency of a centrifugal pump is the ratio of
Energy available at the impeller to the energy supplied to the pump by the prime mover
Actual work done by the pump to the energy supplied to the pump by the prime mover
Energy supplied to the pump to the energy available at the impeller
Manometric head to the energy supplied by the impeller per Newton of water
Indicator diagram of a reciprocating pump is a graph between
flow vs swept volume
pressure in cylinder vs swept volume
flow vs speed
pressure vs speed
A draft tube is not required for a
Francis turbine
Kaplan turbine
Pelton wheel turbine
None of the above
Casting of a centrifugal pump is designed so as to minimize
friction loss
cavitation
static head
loss of kinetic energy
Runaway speed of a hydraulic turbine is
full load speed
the speed at which turbine runner will be damaged
the speed if the turbine runner is allowed to revolve freely without load and with the wicket gates wide open
the speed corresponding to maximum overload permissible
Multi stage centrifugal pumps are used to
Give high discharge
Produce high heads
Pump viscous fluids
All the above
The angle of taper on draft tube is
greater than 15 degree
greater than 8 degree
greater than 5 degree
less than 8 degree
Multistage centrifugal pumps are used to obtain
high discharge
high head
pumping of viscous fluids
high head and high discharge
Reciprocating pumps are no more to be seen in industrial applications (in comparison to centrifugal pumps) because of
high initial and maintenance cost
lower discharge
lower speed of operation
necessity of air vessel
When a piping system is made up primarily of friction head and very little of vertical lift, then pump characteristics should be
horizontal
nearly horizontal
steep
first rise and then fall
When a piping system is made up primarily of vertical lift and very little pipe friction, the pump characteristics should be
horizontal
nearly horizontal
steep
first rise and then fall
Head developed by a centrifugal pump depends on
impeller diameter
speed
fluid density
a and b above
