Power Plant Engineering (2171910) MCQs

MCQs of Steam Nozzles

Showing 31 to 40 out of 41 Questions
31.

The supersaturated flow of steam through a nozzle as compared to a stable flow, the available heat drop

(a)

remains the same

(b)

increases

(c)

decreases

(d)

is unpredictable

Answer:

Option (c)

32.

The difference of supersaturated temperature and saturation temperature at that pressure is known as 

(a)

degree of supersaturation

(b)

degree of superheat 

(c)

degree of undercooling

(d)

none of these

Answer:

Option (c)

33.

For a convergent divergent nozzle, critical pressure ratio occurs when

(a)

velocity at exit becomes sonic

(b)

shock wave of occurs

(c)

nozzle efficiency is maximum 

(d)

increase in exit and inlet pressure ratio does not increase steam flow rate

Answer:

Option (d)

34.

For a convergent divergent nozzle, the mass flow rate remains constant if the ratio of exit and inlet pressures

(a)

is less then critical pressure ratio 

(b)

is equal to the critical pressure ratio 

(c)

is more then critical pressure ratio 

(d)

is infinity

Answer:

Option (c)

35.

Mack number is more than unity in the ____________ of a convergent divergent nozzle

(a)

Convergent potion 

(b)

Straight portion

(c)

Throat 

(d)

Divergent potion 

Answer:

Option (d)

36.

If a flow is to be continuously accelerated from a subsonic to a supersonic velocity in nozzle, it must 

(a)

convergent 

(b)

divergent

(c)

have throat 

(d)

have first divergent section and then convergent section

Answer:

Option (c)

37.

The discharge of steam in a convergent-divergent nozzle __________ after the throat (i.e. in the divergent portion of the nozzle)

(a)

remains constant

(b)

decreases

(c)

increases

(d)

can't predict

Answer:

Option (a)

38.

In a nozzle, whole frictional loss is assumed to occur between

(a)

inlet and thoroat

(b)

inlet and outlet

(c)

throat and exit

(d)

all of these

Answer:

Option (c)

39.

When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be

(a)

choked

(b)

underdamping

(c)

overdamping

(d)

none of these

Answer:

Option (b)

40.

Which of the following statement is correct?

(a)

The expansion of steam in a nozzle follows Rankine cycle

(b)

The friction in the nozzle increases the dryness fraction of steam

(c)

The pressure of steam at throat is called critical pressure

(d)

All of these

Answer:

Option (d)

Showing 31 to 40 out of 41 Questions