WorksheetsDay 37-Oct 27-worksheet-Diploma-Turbines
Total questions: 15
Worksheet time: 10mins
The primary reason for limiting the divergence angle of a straight divergent draft tube to nearly 8° is to
Reduce friction losses
Avoid flow separation and eddy formation
Increase velocity at outlet
Prevent cavitation
A Pelton wheel does not require a draft tube because
The pressure at runner exit is above atmospheric
The jet strikes the bucket tangentially and leaves at atmospheric pressure
The casing maintains vacuum
Tailrace is at higher level
The specific speed of Kaplan turbine is high mainly because
It handles low head and low discharge
It handles high head and low discharge
It handles low head and high discharge
It handles high head and high discharge
The conversion of velocity head into pressure head in a reaction turbine happens
Inside the runner
In the penstock
In the draft tube
In the scroll casing
For maximum efficiency in Pelton turbine, the ratio of bucket speed to jet speed should be
(a)
A mixed flow turbine changes direction of flow from
Tangential to radial
Radial to tangential
Radial to axial
Axial to tangential
Reaction turbines operate completely under atmospheric pressure throughout the flow.
True
False
Assertion (A): The Kaplan turbine is provided with adjustable runner blades. Reason (R): It allows the turbine to maintain efficiency only at the design load.
Both A and R are true, and R is the correct explanation
Both A and R are true, but R is not the correct explanation
A is true but R is false
A is false but R is true
Expansion of water in the draft tube converts into .
kinetic energy, pressure energy
pressure energy, kinetic energy
potential energy, heat energy
kinetic energy, potential energy
Specific speed of a turbine increases as discharge ______ and head ______
(a)
A reaction turbine always requires a ______ and a ______.
casing, draft tube
nozzle, runner
valve, pipe
impeller, guide vane
Volumetric efficiency of a turbine is the ratio of ______ to ______.
actual water striking runner, water supplied at inlet
actual water striking runner, water discharged at outlet
water supplied at inlet, actual water striking runner
water supplied at inlet, water discharged at outlet
A turbine runs at 300 rpm under a head of 9 m. Find the unit speed Nu.
(a)
A turbine develops 720 kW under a head of 16 m. Find the unit power Pu.
(a)
For a reaction turbine, Q = 1.5 m3/s, H=12 m , overall efficiency=80% . Find output power.
(a)
