A metal wire of 0.01 m dia and thermal conductivity 200 W/m.K is exposed to a fluid stream with a convective heat transfer coefficient of 100 W/m2.K. The Biot number is ______________?

Byadmin March 3, 2019August 24, 2021

A metal wire of 0.01 m dia and thermal conductivity 200 W/m.K is exposed to a fluid stream with a convective heat transfer coefficient of 100 W/m2.K. The Biot number is ______________?

A. 5.6
B. 0.025
C. 3.5
D. 0.0035

Chemical Heat Transfer

Thermal diffusivity is given by__________________?

Thermal diffusivity is given by__________________?

A. k/ρCp
B. ρCp/k
C. μCp/a
D. μ/hCp

Read More Thermal diffusivity is given by__________________?
Chemical Heat Transfer

In a gas-liquid shell and tube heat exchanger, the_________________?

In a gas-liquid shell and tube heat exchanger, the_________________?

A. Presence of a non-condensable gas decreases the condensing film co-efficient
B. Gases under high pressure are routed through the tube side, because high pressure gases are
corrosive in nature
C. Gases to be heated/cooled is normally routed through the shell side, because the corrosion
caused by the cooling water or steam condensate remain localised to the tubes
D. All A, B. & C.

Read More In a gas-liquid shell and tube heat exchanger, the_________________?
Chemical Heat Transfer

The purpose of providing expansion bellows in the shell of tubular exchanger is to _____________________?

The purpose of providing expansion bellows in the shell of tubular exchanger is to _____________________?

A. Increase the heating load
B. Impart structural strength
C. Account for the uneven expansion of shell and tube bundles
D. Facilitate increase of shell length, if needed

Read More The purpose of providing expansion bellows in the shell of tubular exchanger is to _____________________?
Chemical Heat Transfer

Nucleate boiling is promoted ___________________?

Nucleate boiling is promoted ___________________?

A. On polished surfaces
B. On rough surfaces
C. In the absence of agitation
D. None of these

Read More Nucleate boiling is promoted ___________________?
Chemical 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______________________?

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

Read More 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 Heat Transfer

In a shell and tube type heat exchanger, the floating tube bundle heat arrangement is used________________?

In a shell and tube type heat exchanger, the floating tube bundle heat arrangement is used________________?

A. In low range of temperature differences
B. In high range of temperature differences
C. Because of its low cost
D. To prevent corrosion of the tube bundles

Read More In a shell and tube type heat exchanger, the floating tube bundle heat arrangement is used________________?

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