STEAM NOZZLES (2 marks)

Steam is expanded in a set of nozzles from 4 bar 300 deg. Celcius to 2 bar. What is the type of nozzle? Consider the isentropic index k=1.3.

• Convergent-divergent

• Convergent

• Data insufficient

• None of the above

Steam is expanded in a set of nozzles from 5 bar 300 deg. Celcius to 2 bar. If initial velocity is neglected and isentropic expansion is assumed, then find the minimum area (sq.cm) of the nozzles to flow 1.5kg/s of steam. Consider the isentropic index k=1.3.

• 22.97

• 12.32

• 07.03

• 09.15

The throat and exit areas of a convergent-divergent nozzle are 1100 sq.mm and 1650 sq.mm respectively. Dry saturated steam at 5 bar enters the nozzle at a velocity of 80 m/s. The exit pressure is 1.5 bar. Estimate the mass flow rate in kg/s. Assume isentropic flow up to the throat and take critical pressure ratio to be 0.58.

• 0.689

• 0.456

• 0.823

• 1.561

The throat and exit areas of a convergent-divergent nozzle are 1100 sq.mm and 1650 sq.mm respectively. Dry saturated steam at 5 bar enters the nozzle at a velocity of 80 m/s. The exit pressure is 1.5 bar. Assume isentropic flow up to the throat and take critical pressure ratio to be 0.58. Estimate the nozzle efficiency

• 45.4

• 67.1

• 59.3

• 50.1

Air having a flow rate of 3.6 kg/s at 7 bar and 170 deg.Celcius expands through a convergent-divergent nozzle into a space at 1.03 bar. Calculate the throat area (sq.mm) of the nozzle. Assume isentropic flow and neglect inlet velocity

• 1463

• 3645

• 2680

• 2185

Air having a flow rate of 3.6 kg/s at 7 bar and 170 deg.Celcius expands through a convergent-divergent nozzle into a space at 1.03 bar. Calculate the exit area (sq.mm). Assume isentropic flow and neglect inlet velocity

• 5134

• 4244

• 3645

• None of the above

The throat and exit areas of a convergent-divergent nozzle are 1280 sq.mm and 1600 sq.mm respectively. Dry saturated steam at 5 bar enters the nozzle at a velocity of 80 m/s. The exit pressure is 1.5 bar. Estimate the mass flow rate in kg/s. Assume isentropic flow up to the throat and take critical pressure ratio to be 0.58

• 0.689

• 0.459

• 0.958

• 0.632

The throat and exit areas of a convergent-divergent nozzle are 1280 sq.mm and 1600 sq.mm respectively. Dry saturated steam at 5 bar enters the nozzle at a velocity of 80 m/s. The exit pressure is 1.5 bar.Estimate the nozzle efficiency. Assume isentropic flow up to the throat and take critical pressure ratio to be 0.58

• 87.1

• 72.3

• 65.3

• 96.5

The value of critical pressure ratio for superheated steam is

• 0.546

• 0.500

• 0.556

• 0.582

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