Draught produced by a tall chimney due to density difference between hot flue gas inside the Chimney and atmospheric air outside the chimney is more appropriately known as the __________ draught.

The ratio of the energy required to produce the artificial draught (expressed in meters head or J/kg of flue gas) to the mechanical equivalent of extra heat carried away per kg of flue gases due to natural draught, is known as

A

Efficiency of the boiler

B

Efficiency of the chimney

C

Efficiency of the fan

D

Power of the boiler

Thermal conductivity based continuous flue gas analyser makes use of varying thermal conductivity of the constituents of flue gases. Which of the following constituents of flue gases has the maximum thermal conductivity?

A

CO₂

B

N₂

C

O₂

D

CO

The draught produced by steel chimney as compared to that produced by brick chimney for the same height is

A

Less

B

More

C

Same

D

May be more or less

The draught produced, for a given height of the chimney and given mean temperature of chimney gases

A

decreases with increase in outside air temperature

B

increases with increase in outside air temperature

C

remains the same irrespective of outside air temperature

D

may increase or decrease with increase in outside air temperature

For the same draught produced the power of induced draught fan as compared to forced draught fan is

A

less

B

more

C

same

D

not predictable

Power required in case of forced draught as compared to induced draught (for the same draught produced) is

A

Same

B

Less

C

More

D

Either more or less; depends on the flue gas density

The air pressure at the fuel bed is reduced below that of atmosphere by means of a fan placed at or near the bottom of the chimney to produce a draught. Such a draught is called

A

Natural draught

B

Induced draught

C

Forced draught

D

Balanced draught

The velocity of flue gases (V) through the chimney under a static draught of (H') metres is given by

A

$${\text{V}} = \sqrt {2{\text{gH}}'} $$

B

$${\text{V}} = \sqrt {\frac{{2{\text{g}}}}{{{\text{H}}'}}} $$

C

$${\text{V}} = \frac{{{\text{H}}'}}{{\sqrt {2{\text{g}}} }}$$

D

$${\text{V}} = 2{\text{g}}\sqrt {{\text{H}}'} $$

The draught produced by chimney of given height at given outside temperature

A

decreases if the chimney gas temperature increases

B

increases if the chimney gas temperature increases

C

remains same irrespective of chimney gas temperature

D

may increase or decrease

Smoke density of the flue gas going out of the chimney is measured by a

A

Polarograph

B

Thermal conductivity meter

C

Photo electric cell

D

Chromatograph

Draught produced by a tall chimney due to density difference between hot flue gas inside the Chimney and atmospheric air outside the chimney is more appropriately known as the __________ draught.

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