Steam Boilers and Engines

1: The boiler efficiency is given by (where m = Total mass of water evaporated into steam in kg/h, m_f = 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 h_f1 = 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)`

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2: Which of the following is correct ? (where p_a = Actual mean effective pressure, p_m = 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`

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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)`

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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`

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5

When the total heat of steam is h kJ/kg and the sensible heat of feed water is h_f1 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

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