The temperature of flue gases was observed to be 350°C with a chimney (natural draught) of 45 m. The same draught was developed using an induced draught fan and the temperature of the flue gases was measured to be 150°C. The mass of air supplied for complete combustion of 1 kg of fuel is 20 kg. The ambient temperature is 30°C. Assuming cp = 1.004 kJ/kg for flue gases calculate the efficiency of chimney.

The temperature of flue gases was observed to be 350°C with a chimne

1.	The temperature of flue gases was observed to be 350°C with a chimney (natural draught) of 45 m. The same draught was developed using an induced draught fan and the temperature of the flue gases was measured to be 150°C. The mass of air supplied for complete combustion of 1 kg of fuel is 20 kg. The ambient temperature is 30°C. Assuming cp = 1.004 kJ/kg for flue gases calculate the efficiency of chimney.
A.	0.21%
B.	0.56%
C.	1.23%
D.	0.11%
Answer» B. 0.56%

Discussion

No Comment Found

Related MCQs

Determine the ambient temperature if the temperature of flue gases inside the chimney is 363°C and the 20 kg of air is supplied for complete combustion of 1 kg of fuel. The discharge though the chimney is maximum.
A chimney is used to develop natural draught of 20 mm of water. The ambient temperature is 30°C. Determine the chimney height if the discharge though the chimney is maximum.
The temperature of flue gases was observed to be 350°C with a chimney (natural draught) of 45 m. The same draught was developed using an induced draught fan and the temperature of the flue gases was measured to be 150°C. The mass of air supplied for complete combustion of 1 kg of fuel is 20 kg. The ambient temperature is 30°C. Assuming cp = 1.004 kJ/kg for flue gases calculate the efficiency of chimney.
A boiler has a chimney of height 45 m. The ambient temperature is 25°C. The temperature of the hot gases inside chimney is 330°C. Calculate the draught in terms of column of water if it is given that discharge through the chimney is maximum.
A chimney of height 45 m is full of hot gases at temperature 330°C. If the discharge through the chimney is maximum, determine the draught in terms of column of hot gases. The ambient is 25°C.
Determine the temperature of hot gases inside the chimney if the temperature of cold air outside is 27°C and 20 kg of air is required for complete combustion of 1 kg of fuel. It is given that the discharge though the chimney is maximum.
A chimney of height 25 m is used to provide natural draught. The ambient temperature is 25°C and the temperature of the hot gases inside the chimney is 352°C. If the discharge though the chimney is maximum determine the mass of air supplied per kg of fuel burnt.
The draught produced by the chimney is due to the difference in densities between the column of hot gases inside the chimney and the cold air present outside.
The frictional resistance offered to the flow of flue gases by the grate and gas passages result in draught losses.
What is the ratio of draught in terms of column of hot gases to the chimney height when the discharge though chimney is maximum?

Discussion

No Comment Found

Related MCQs

Reply to Comment