Steam Boilers and Engines


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)`


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`

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)`



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`


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