Which of the following is NOT an effect of supersaturation in steam flowing through a convergent-divergent nozzle?

Increase in specific volume of steam

Increase in the entropy of steam

Improvement in dryness fraction

Which of the following statement about metastable expansion of steam through a steam nozzle is FALSE?

It increases the discharge through the nozzle

Steam is undercooled to a temperature less than that corresponding to its pressure

Exit velocity of the steam is increased

Which of the following is the correct formula for calculating the supercooled temperature of steam, when steam metastable expansion of steam takes place inside a steam nozzle. (T2 Supercooled temperature, T1 Inlet temperature of steam)

( frac{T_2}{T_1} = ( frac{P_2}{P_1})^ frac{n}{n-1} )

( frac{T_2}{T_1} = ( frac{P_2}{P_1})^ frac{n+1}{n} )

( frac{T_2}{T_1} = ( frac{P_1}{P_2})^ frac{n}{n-1} )

( frac{T_2}{T_1} = ( frac{P_2}{P_1})^ frac{n}{n-1} )

It represents an Isobaric line, at which the condensation commences

It is an isothermal line, at which the condensation completes

Saturation line of water is also called Wilson line

It represents the limiting condition of undercooling at which the condensation begins

It represents an Isobaric line, at which the condensation commences

14 + Mcqs in Steam Nozzles Super Saturated Flow and Wilsons Line in Thermal Engineering Page 1 McqOptions

1.	Determine the exit pressure of steam if the steam enters a nozzle at 11 bar and 300 C. At the outlet it is observed that the specific volume of the steam is 0.86804 m³/kg. The expansion of steam is metastable.
A.	4 bar
B.	3 bar
C.	2 bar
D.	1 bar
Answer» D. 1 bar

Discussion

2.	Which of the following is NOT an effect of supersaturation in steam flowing through a convergent-divergent nozzle?
A.	Increase in specific volume of steam
B.	Increase in the entropy of steam
C.	Improvement in dryness fraction
D.	Increase in the enthalpy drop
Answer» E.

Discussion

3.	The point on the h-s diagram at which the condensation beings and normal conditions of thermal equilibrium are restored is said to be on _____
A.	wilson line
B.	saturation vapor curve
C.	constant dryness fraction line
D.	constant pressure line
Answer» B. saturation vapor curve

Discussion

4.	Which of the following statement about metastable expansion of steam through a steam nozzle is FALSE?
A.	It increases the discharge through the nozzle
B.	Steam is undercooled to a temperature less than that corresponding to its pressure
C.	Density of steam is increased
D.	Exit velocity of the steam is increased
Answer» E.

Discussion

5.	What is the value of index of expansion for supersaturated steam. (Pvⁿ=C, n is the index of expansion)
A.	1.300
B.	1.013
C.	1.135
D.	1.000
Answer» B. 1.013

Discussion

6.	Steam at 15 bar pressure and 250 C enters a convergent-divergent steam nozzle and leaves at 4 bar. The mass flow rate is 5 kg/s. Calculate the exit area of the nozzle if the expansion is metastable.
A.	0.00542187 m<sup>2</sup>
B.	0.0029147 m<sup>2</sup>
C.	0.036521 m<sup>2</sup>
D.	0.003265 m<sup>2</sup>
Answer» C. 0.036521 m<sup>2</sup>

Discussion

7.	Calculate the degree of supersaturation if steam at 10 bar 250 C is discharged at 2 bar by a convergent-divergent nozzle. Consider metastable steam expansion and negligible inlet velocity.
A.	5.65
B.	3.11
C.	2.15
D.	2.36
Answer» C. 2.15

Discussion

8.	Steam at 20 bar and 300 C enters a convergent-divergent steam nozzle and is discharged at 3 bar. Considering the effects of supersaturation calculate the degree of undercooling.
A.	36.65 C
B.	45.54 C
C.	23.32 C
D.	62.87 C
Answer» B. 45.54 C

Discussion

9.	Steam at 12 bar and 300 C enters a convergent-divergent steam nozzle and leaves at 3 bar. If the expansion of the steam is metastable, calculate the supercooled temperature.
A.	165 C
B.	143 C
C.	154 C
D.	120 C
Answer» C. 154 C

Discussion

10.	Which of the following is the correct formula for calculating the supercooled temperature of steam, when steam metastable expansion of steam takes place inside a steam nozzle. (T₂ Supercooled temperature, T₁ Inlet temperature of steam)
A.	( frac{T_2}{T_1} = ( frac{P_2}{P_1})^ frac{n}{n-1} )
B.	( frac{T_2}{T_1} = ( frac{P_2}{P_1})^ frac{n+1}{n} )
C.	( frac{T_2}{T_1} = ( frac{P_1}{P_2})^ frac{n}{n-1} )
D.	( frac{T_2}{T_1} = ( frac{P_2}{P_1})^ frac{n}{n-1} )
Answer» E.

Discussion

11.	Calculate the enthalpy drop steam enters a convergent-divergent nozzle at 11 bar and 250 C and leaves at 1 bar. The expansion is to be considered metastable.
A.	427031.34 kJ/kg
B.	55648.32 kJ/kg
C.	323654.25 kJ/kg
D.	158469.21 kJ/kg
Answer» B. 55648.32 kJ/kg

Discussion

12.	The sudden expansion of dry saturated steam in the absence of dust, doesn t lead to condensation until its density is about 8 times that of the saturated vapor of the same pressure.
A.	True
B.	False
Answer» B. False

Discussion

13.	Considering metastable expansion to be in effect, the flow of wet steam though a convergent-divergent nozzle shall result in a discharge slightly less than the calculated one.
A.	True
B.	False
Answer» C.

Discussion

14.	What is Wilson line?
A.	It is an isothermal line, at which the condensation completes
B.	Saturation line of water is also called Wilson line
C.	It represents the limiting condition of undercooling at which the condensation begins
D.	It represents an Isobaric line, at which the condensation commences
Answer» D. It represents an Isobaric line, at which the condensation commences

Discussion

Explore topic-wise MCQs in Thermal Engineering.

Determine the exit pressure of steam if the steam enters a nozzle at 11 bar and 300 C. At the outlet it is observed that the specific volume of the steam is 0.86804 m3/kg. The expansion of steam is metastable.

Which of the following is NOT an effect of supersaturation in steam flowing through a convergent-divergent nozzle?

The point on the h-s diagram at which the condensation beings and normal conditions of thermal equilibrium are restored is said to be on _____

Which of the following statement about metastable expansion of steam through a steam nozzle is FALSE?

What is the value of index of expansion for supersaturated steam. (Pvn=C, n is the index of expansion)

Steam at 15 bar pressure and 250 C enters a convergent-divergent steam nozzle and leaves at 4 bar. The mass flow rate is 5 kg/s. Calculate the exit area of the nozzle if the expansion is metastable.

Calculate the degree of supersaturation if steam at 10 bar 250 C is discharged at 2 bar by a convergent-divergent nozzle. Consider metastable steam expansion and negligible inlet velocity.

Steam at 20 bar and 300 C enters a convergent-divergent steam nozzle and is discharged at 3 bar. Considering the effects of supersaturation calculate the degree of undercooling.

Steam at 12 bar and 300 C enters a convergent-divergent steam nozzle and leaves at 3 bar. If the expansion of the steam is metastable, calculate the supercooled temperature.

Which of the following is the correct formula for calculating the supercooled temperature of steam, when steam metastable expansion of steam takes place inside a steam nozzle. (T2 Supercooled temperature, T1 Inlet temperature of steam)

Calculate the enthalpy drop steam enters a convergent-divergent nozzle at 11 bar and 250 C and leaves at 1 bar. The expansion is to be considered metastable.

The sudden expansion of dry saturated steam in the absence of dust, doesn t lead to condensation until its density is about 8 times that of the saturated vapor of the same pressure.

Considering metastable expansion to be in effect, the flow of wet steam though a convergent-divergent nozzle shall result in a discharge slightly less than the calculated one.

What is Wilson line?

Determine the exit pressure of steam if the steam enters a nozzle at 11 bar and 300 C. At the outlet it is observed that the specific volume of the steam is 0.86804 m³/kg. The expansion of steam is metastable.

What is the value of index of expansion for supersaturated steam. (Pvⁿ=C, n is the index of expansion)

Which of the following is the correct formula for calculating the supercooled temperature of steam, when steam metastable expansion of steam takes place inside a steam nozzle. (T₂ Supercooled temperature, T₁ Inlet temperature of steam)