What is the ratio of draught in terms of column of hot gases to the chimney height when the discharge though 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.

A

45 m

B

35 m

C

25 m

D

39 m

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

A

$$\frac{{{{\text{T}}_1}}}{{88.25{\text{H}}}}$$

B

$$\frac{{88.25{\text{H}}}}{{{{\text{T}}_1}}}$$

C

$$\frac{{{{\text{T}}_1}}}{{176.5{\text{H}}}}$$

D

$$\frac{{176.5{\text{H}}}}{{{{\text{T}}_1}}}$$

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.

A

Natural

B

Induced

C

Forced

D

Chimney

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.

A

True

B

False

Determine the height of chimney above grate level. Where diameter of chimney is 1.75m and produces a draught of 1.8cms of water. Temperature of flue gases is 290oC. The flue gases formed per kg of fuel burnt are 23kg. Neglect the losses and assume atmospheric temperature as 20oC?

A

H = 23.28m

B

H = 18.56m

C

H = 32.77m

D

H = 41.92m

For maximum discharge through a chimney, the condition is that height of hot gas column producing the draught should be

A

One-half the height of chimney

B

Equal to the height of chimney

C

Two times the height of chimney

D

Four times the height of chimney

Determine the height of the chimney to produce a static draught of 22mm of water if the mean flue gas temperature in chimney is 290oC and ambient temperature in boiler house is 20oC. The gas constant for air is 29.26Kgm/Kgk and for chimney flue gas is 26.2 Kgfm/Kgk. Assume reading as 760mm of mercury?

A

38.42m

B

42.55m

C

45.84m

D

44.03m

Consider the following Column A and Column B in which the names of microorganisms are given in Column A and the groups to which they belong are given in Column B: Column A Column B (a) Aspergillus (i) Algae (b) Lactobacillus (ii) Bacteria (c) Paramecium (iii) Fungi (d) Spirogyra (iv) Protozoa (v) Virus The correct match of the items of Column A with that of Column B is

A

a - iii, b - ii, c - iv, d - v

B

a - ii, b - iii, c - iv, d - i

C

a - iii, b - ii, c - iv, d - i

D

a - v, b - iii, c - ii, d - iv

Two centrifugal pumps P and R are available for use in a pipe flow system and their head-discharge characteristics are as follows. Pump P Pump R Discharge (cumecs) Head (m) Discharge (cumecs) Head (m) 0 40 0 45 0.12 35 0.14 40 0.2 28 0.24 35 0.3 18 0.3 28 The following statements (S1, S2, and S3) pertain to the head and discharge values during actual operation. Neglect losses in the system. Which of the following statements are correct? S1: When the two pumps P and R are connected in parallel, the discharge is 0.36 cumecs corresponding to a head of 35 m. S2: When the two pumps P and R are connected in parallel, the discharge is 0.36 cumecs corresponding to a head of 70 m. S3: When the two pumps P and R are connected in series, the discharge is 0.3 cumecs corresponding to a head of 46 m.

A

S2 only

B

S1 and S3

C

S1 and S2

D

S2 and S3

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

What is the ratio of draught in terms of column of hot gases to the chimney height when the discharge though chimney is maximum?

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