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For a given ambient air temperature with increase in the thickness of insulation of a hot cylinderical pipe, the rate of heat loss from the surface would

CHEMICAL ENGINEERING, Heat Transfer /
Question: For a given ambient air temperature with increase in the thickness of insulation of a hot cylinderical pipe, the rate of heat loss from the surface would
[A].

decrease

[B].

increase

[C].

first decrease and then increase

[D].

first increase and then decrease

Answer: Option D

Explanation:

No answer description available for this question.

For a given ambient air temperature with increase in the thickness of insulation of a hot cylinderical pipe, the rate of heat loss from the surface would Read More »

CHEMICAL ENGINEERING, Heat Transfer

Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is

CHEMICAL ENGINEERING, Heat Transfer /
Question: Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is
[A].

finned tube heat exchanger with air inside and steam outside.

[B].

finned tube heat exchanger with air outside and steam inside.

[C].

shell and tube heat exchanger with air inside tubes and steam on shell side.

[D].

shell and tube heat exchanger with air on shell side and steam inside tubes.

Answer: Option B

Explanation:

No answer description available for this question.

Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is Read More »

CHEMICAL ENGINEERING, Heat Transfer

A fluid is flowing inside the inner tube of a double pipe heat exchanger with diameter ‘d’. For a fixed mass flow rate, the tube side heat transfer co-efficient for turbulent flow conditions is proportional to

CHEMICAL ENGINEERING, Heat Transfer /
Question: A fluid is flowing inside the inner tube of a double pipe heat exchanger with diameter ‘d’. For a fixed mass flow rate, the tube side heat transfer co-efficient for turbulent flow conditions is proportional to
[A].

d0.8

[B].

d-0.2

[C].

d-1

[D].

d-1.8

Answer: Option B

Explanation:

No answer description available for this question.

A fluid is flowing inside the inner tube of a double pipe heat exchanger with diameter ‘d’. For a fixed mass flow rate, the tube side heat transfer co-efficient for turbulent flow conditions is proportional to Read More »

CHEMICAL ENGINEERING, Heat Transfer

A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2.°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be

CHEMICAL ENGINEERING, Heat Transfer /
Question: A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2.°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be
[A].

greater than that for uninsulated steam pipe.

[B].

less than that of the uninsulated steam pipe.

[C].

equal to that of the uninsulated steam pipe.

[D].

less than the steam pipe with 5 cms insulation.

Answer: Option B

Explanation:

No answer description available for this question.

A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2.°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be Read More »

CHEMICAL ENGINEERING, Heat Transfer

If the baffle spacing in a shell and tube heat exchanger increases, then the Reynolds number of the shell side fluid

CHEMICAL ENGINEERING, Heat Transfer /
Question: If the baffle spacing in a shell and tube heat exchanger increases, then the Reynolds number of the shell side fluid
[A].

remains unchanged.

[B].

increases.

[C].

increases or decreases depending on number of shell passes.

[D].

decreases.

Answer: Option D

Explanation:

No answer description available for this question.

If the baffle spacing in a shell and tube heat exchanger increases, then the Reynolds number of the shell side fluid Read More »

CHEMICAL ENGINEERING, Heat Transfer

In a laboratory test run, the rate of drying was found to be 0.5 x 10-3 kg/m2.s, when the moisture content reduced from 0.4 to 0.1 on dry basis. The critical moisture content of the material is 0.08 on a dry basis. A tray dryer is used to dry 100 kg (dry basis) of the same material under identical conditions. The surface area of the material is 0.04 m2/kg of dry solid. The time required (in seconds) to reduce the moisture content of the solids from 0.3 to 0.2 (dry basis) is

CHEMICAL ENGINEERING, Heat Transfer /
Question: In a laboratory test run, the rate of drying was found to be 0.5 x 10-3 kg/m2.s, when the moisture content reduced from 0.4 to 0.1 on dry basis. The critical moisture content of the material is 0.08 on a dry basis. A tray dryer is used to dry 100 kg (dry basis) of the same material under identical conditions. The surface area of the material is 0.04 m2/kg of dry solid. The time required (in seconds) to reduce the moisture content of the solids from 0.3 to 0.2 (dry basis) is
[A].

2000

[B].

4000

[C].

5000

[D].

6000

Answer: Option C

Explanation:

No answer description available for this question.

In a laboratory test run, the rate of drying was found to be 0.5 x 10-3 kg/m2.s, when the moisture content reduced from 0.4 to 0.1 on dry basis. The critical moisture content of the material is 0.08 on a dry basis. A tray dryer is used to dry 100 kg (dry basis) of the same material under identical conditions. The surface area of the material is 0.04 m2/kg of dry solid. The time required (in seconds) to reduce the moisture content of the solids from 0.3 to 0.2 (dry basis) is Read More »

CHEMICAL ENGINEERING, Heat Transfer