Power Plant Engineering Practice Test 7

1. The critical pressure gives the velocity of steam at the throat ___________

equal to the velocity of sound

more than velocity of sound

less than the velocity of light

none of the mentioned

2. The efficiency of the open cycle gas plant is quite low. Why?

A lot of mechanical energy is used up by the compressor

Gas gets cooled before reaching the turbine wheels

Due to the presence of regenerator and absence of air pre heater

Both Gas gets cooled before reaching the turbine wheels and a lot of mechanical energy is used up by the compressor

3. The heat of combustion of a fuel __________

is always positive

is equal to the heat of formation

can't be known without calculating it

is always negative

4. The impulse reaction turbine has its driving force ___________

as a reaction force

none of the mentioned

as an impulsive force

partly as an impulsive force and partly as a reaction force

5. Presence of free moisture in coal during its high temperature carbonisation __________

increases the loss of fine coal dust from the ovens when charging

none of the mentioned

protects the volatile products from pyrolysis (cracking) in the presence of hot coke and hot oven walls

reduces the coking time

6. Rateau turbine is ____________

velocity compounded turbine

pressure-velocity compounded turbine

simple reaction turbine

pressure compounded turbine

7. A turbine is said to have an axial discharge when the steam leaves the blade tip at __________ to the direction of the blade motion.

90°

180°

270°

60°

8. Caking index of the coal blend used for the manufacture of metallurgical coke should be around __________

9. Which of these is a working fluid in the bottoming plant of a Brayton-Rankine combined plant?

Mercury

Water

Steam

Air

10. Multi-stage steam turbines are of the ___________

velocity compounded type

pressure compounded type

all of the mentioned

reaction type