#### Steam Boilers and Engines

1

The boiler efficiency is given by (where m = Total mass of water evaporated into steam in kg/h, mf = Mass of fuel in kg/h, C = Calorific valve of fuel in kJ/kg of fuel, h = Total heat of steam in kJ/kg, and hf1 = Sensible heat of feed water in kJ /kg)

A. (m_f .C)/(m_s (h - h_(f1)))
B. (m_f .C)/(m_s (h + h_(f1)))
C. (m_s (h - h_(f1)))/(m_f .C)
D. (m_s (h + h_(f1)))/(m_f .C)

2

Which of the following is correct ? (where pa = Actual mean effective pressure, pm = Theoretical mean effective pressure, and K = Diagram factor)

A. P_a = P_m //K
B. P_a = P_m xx K
C. P_a = K//P_m
D. P_a = P_m + K

3
The draught (in mm of water), for maximum discharge of flue gases through the chimney, is given by (where H = Height ot the chimney in metres, and T1 = Absolute temperature of air outside the chimney in K)

A. (T_1)/(88.25H)
B. (88.25 H)/(T_1)
C. (T_1)/(176.5H)
D. (176.5 H)/(T_1)

4

Willian's law states that the steam consumption per hour provided with a throttled governor is proportional to (where I.P. = Indicated power)

A. (1)/(I.P)
B. (1)/(I.P)^2
C. I.P
D. I.P^2

5

When the total heat of steam is h kJ/kg and the sensible heat of feed water is hf1 kJ/kg, then the factor of evaporation is given by

A. (h - h_(f1))/(2257)
B. (h + h_(f1))/(2257)
C. (h xx h_(f1))/(2257)
D. none of these