Free Printable Thermal Engg II (Unit I

1.

Nozzle efficiency is given by

a)

$\frac{h_1-h_{3s}}{h_1-h_3}$

b)

$\frac{h_1-h_3}{h_1-h_{3s}}$

c)

$\frac{h_1-h_3}{h_{1s}-h_3}$

d)

$\frac{h_{1s}-h_3}{h_1-h_3}$

2.

In the figure shown,

a)

Frictional loss in divergent portion

b)

Frictional loss in convergent portion

c)

No frictional loss

d)

Frictional loss in both in convergent and divergent portion

3.

During expansion of steam in a nozzle as shown in figure, the condition of steam at throat i.e. at state 2 is

a)

Wet

b)

Saturated

c)

Supersaturated

d)

Superheated

4.

$\frac{mv_2}{V_2}$ With respect to the nozzle shown, this equation gives ____________ (Note m - mass flow rate)

a)

Area of nozzle at throat

b)

Area of nozzle at exit

c)

Area of nozzle at inlet

d)

None of the above

5.

When inlet velocity is considered in a nozzle, the following equation can be used to calculate the velocity at throat

a)

$44.72\ \sqrt{h_1-h_2}$

b)

$44.72\sqrt{h_{01}-h_2}$

c)

$44.72\sqrt{h_2-h_1}$

d)

$44.72\sqrt{h_2-h_{01}}$

6.

During expansion of steam through a nozzle as shown in figure, the condition of steam at throat is

a)

Superheated

b)

Wet

c)

Saturated

d)

Supersaturated

7.

During expansion in a convergent - divergent nozzle, the enthalpy of steam under isentropic conditions:

at inlet section 1-1 is 3100 kJ/kg;

at throat section 2-2, 2900 kJ/kg and

at exit section 3-3, 2700 kJ/kg

If there is a frictional loss of 15 % of overall enthalpy drop in divergent portion, What would be the enthalpy at exit.

a)

2770 kJ/kg

b)

2640 kJ/kg

c)

2760 kJ/kg

d)

2670 kJ/kg

8.

During expansion in a convergent - divergent nozzle, the enthalpy of steam under isentropic conditions:

at inlet section 1-1 is 3100 kJ/kg;

at throat section 2-2, 2900 kJ/kg and

at exit section 3-3, 2700 kJ/kg

If there is a frictional loss of 50 kJ in divergent portion, What would be the enthalpy at exit.

a)

2650 kJ/kg

b)

2750 kJ/kg

c)

2950 kJ/kg

d)

2850 kJ/kg

9.

In the figure, superheated steam at state 1, after reaching state a, expands under supersaturated condition. The temperature of steam at state b is

a)

Equal to $T_{sat}$ at $p_2$

b)

Greater than $T_{sat}$ at $p_2$

c)

Less than $T_{sat}$ at $p_2$

d)

None of the above

10.

The degree of supersaturation is

a)

$\frac{p_b}{p_{b_{sat}}}$

b)

$\frac{p_{b_{sat}}}{p_b}$

c)

$\frac{p_2}{p_b}$

d)

$\frac{p_b}{p_2}$

Thermal Engg II (Unit I - Quiz 2)

Total questions: 10

Worksheet time: 5mins

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