Steam and Gas Turbines Multiple Choice Questions on “Losses in Reaction Blade Passages”.
1. Passages in steam turbines are _______
a) convergent
b) divergent
c) convergent & divergent
d) none of the mentioned
Answer: a
Clarification: Passages in steam turbines are convergent so that steam expands.
2. The flow of steam through the nozzle is isoentropic.
a) True
b) False
Answer: b
Clarification: The flow of steam is not isoentropic.
3. In reaction turbines a pressure drop occurs between rotors and stator.
a) True
b) False
Answer: a
Clarification: Steam when leaving the stator changes its speed relative to the blade speed and pressure drop occurs.
4. Steam is directed towards rotor by _________
a) rotor vanes
b) moving blades
c) fixed blades
d) none of the mentioned
Answer: c
Clarification: Steam is directed by fixed vanes in steam turbine.
5. Losses that occur when steam is supplied from boiler to turbine is called as ___________
a) regulating loss
b) friction loss
c) gland loss
d) none of the mentioned
Answer: a
Clarification: When steam is supplied from boiler to turbine it passes through regulating valve and some energy loss is occurred while passing through regulating valve which is called as regulating loss.
6. Losses occurred while passing through blades are called as ________
a) efficient losses
b) blade friction loss
c) efficient & blade friction losses
d) none of the mentioned
Answer: b
Clarification: Blade friction loss are caused due to friction between blade and steam and loss occurs due to that friction.
7. Disc friction loss is due to ___________
a) churning action of disc
b) friction between blade and steam
c) pressure drop
d) none of the mentioned
Answer: a
Clarification: Blades re connected to the disc and there will be some amount of energy loss due to churning action of the disc.
8. For fixing blades and rotating components together ___________ are used.
a) bolt and nut
b) valve
c) glands
d) none of the mentioned
Answer: c
Clarification: Glands are used to fix blades and rotating components together.
9. Losses occurred at gap between glands are called as _________
a) valve losses
b) gland losses
c) valve & gland losses
d) none
Answer: b
Clarification: Gland losses are the losses that are occurred at the gap between the glands.
10. Kinetic energy that steam has while coming out of turbines is called as ________
a) residual loss
b) friction loss
c) gland loss
d) none of the mentioned
Answer: a
Clarification: Residual losses are the energy that steam contains while exiting the turbine. This energy cannot be used and hence it is called as residual losses.