Convergent nozzles are used in jet engines upto nozzle pressure ratio of _______

In the question two statements are given, followed by two conclusions, I and II. You have to consider the statements to be true even if it seems to be at variance from commonly known facts. You have to decide which of the given conclusions, if any, follows from the given statements. Statement I: No taps are nozzles Statement II: Some valves are taps Conclusion I: All nozzles are valves Conclusion II: All valves are nozzles

A

Only conclusion I follows

B

Only conclusion II follows

C

Both conclusions I and II follow

D

Neither conclusion I nor conclusion II follows

Nitrogen gas flows into a convergent nozzle at 200 kPa, 400 K and very low velocity. It flows out of the nozzle at 100 kPa, 330 K. If the nozzle is insulated find the exit velocity.

A

681.94 m/s

B

581.94 m/s

C

481.94 m/s

D

none of the mentioned

Convergent divergent nozzles used in rocket engines have _________ area ratio.

A

higher

B

lower

C

optimum

D

none of the mentioned

Dry and saturated steam at 11 bar pressure enters a convergent-divergent nozzle and is discharged at 2 bar. Determine the actual enthalpy drop if he efficiency of the nozzle is 96%.

A

254.56 kJ/kg

B

321.32 kJ/kg

C

288.14 kJ/kg

D

245.63 kJ/kg

The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency and h_d = Enthalpy or heat drop during expansion of steam in a nozzle)

A

V = 44.72 $${{\text{h}}_{\text{d}}}\sqrt {\text{K}} $$

B

V = 44.72 $${\text{K}}\sqrt {{{\text{h}}_{\text{d}}}} $$

C

V = 44.72$$\sqrt {{\text{K}}{{\text{h}}_{\text{d}}}} $$

D

V = 44.72 $${\text{K}}{{\text{h}}_{\text{d}}}$$

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

Under-damping

C

Over-damping

D

None of these

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

overdamping

B

underdamping

C

chocked

D

none of the mentioned

If the divergence angle for a conical nozzle is 30°, nozzle exit diameter is 30 cm, exit pressure is 10% more than the ambient pressure, mass flow rate is 14 kg/s and the jet exhaust velocity is 700 m/s, determine the total thrust of the engine under standard sea level operating conditions.

A

11.2 kN

B

12.9 kN

C

10.3 kN

D

9.8 kN

A nozzle is said to be a convergent nozzle

A

When the cross-section of the nozzle increases continuously from entrance to exit

B

When the cross-section of the nozzle decreases continuously from entrance to exit

C

When the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit

D

None of the above

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

None of these

Convergent nozzles are used in jet engines upto nozzle pressure ratio of _______

Related Questions