91. The friction present between the steam and the nozzle surfaces reduces the heat drop by
10 to 15 percent
15 to 25 percent
25 to 40 percent
40 to 60 percent
✅ The correct answer is option A.
Steam Nozzles and Turbines MCQs
92. The critical pressure ratio is given by (where p1 = Initial pressure of steam, and p2 = Pressure of steam at throat or critical pressure)
p1 p2
p1/p2
p2/p1
p1 + p2
✅ The correct answer is option C.
93. The purpose of governing in steam turbines is to
maintain the speed of the turbine
reduce the effective heat drop
reheat the steam and improve its quality
completely balance aga
✅ The correct answer is option A.
94. An impulse turbine as compared to a reaction turbine, for a given power has __________ row of blades.
equal
less
more
✅ The correct answer is option C.
95. The pressure compounded impulse turbine as compared to velocity compounded turbine require __________ number of stages.
same
less
more
✅ The correct answer is option C.
96. When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be
choked
underdamping
overdamping
none of these
✅ The correct answer is option B.
97. In a reaction turbine, when steam flows through the fixed blades,
pressure increases while velocity decreases
pressure decreases while velocity increases
pressure and velocity both decreases
pressure and velocity both increases
✅ The correct answer is option B.
98. The blade velocity coefficient is ratio of relative velocity of steam at outlet tip of the blade to the relative velocity of steam at inlet tip of the blade.
TRUE
FALSE
✅ The correct answer is option A.
99. The variation of steam pressure in the nozzle depends upon
velocity of steam
specific volume of steam
dryness fraction of steam
all of these
✅ The correct answer is option D.
100. The turbine blades do not change the direction of steam issuing from the nozzle.
TRUE
FALSE
✅ The correct answer is option B.