Related Questions

__________ number is sometimes used in place of Grashoff number in free convection heat transfer.
A Stanton
B Brinkman
C Rayleigh
D Nusselt
Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the
A Surrounding temperature
B Average temperature of the fin
C Temperature of the fin end
D Constant temperature equal to that of the base
The scales form in heat exchanges after a period of operation and provide additional resistance to heat transfer with some heat transfer coefficient . The reciprocal of this scale heat transfer coefficient is called .
A scaling factor
B forming factor
C resisting factor
D fouling factor
The length of each side of square A is increased by 100 percent to make square B. Again the length of each side of square B is increased by 50 percent to make square C. By what percent is the area of square C greater than the sum of the areas of square A and B?
A 75%
B 80%
C 85%
D 90%
The Grashoff number is defined as the ratio of the
A Buoyancy to inertial forces
B Buoyancy to viscous forces
C Inertial to viscous forces
D Buoyancy to surface tension forces
The length of each of square A is increased by 100 percent to make square B.Again the length of the each side of square B is increased by 50 peacent to make square C.By of the area df square A and B?
A 75%
B 80%
C 85%
D 90%
A small square region inside a larger square is shaded. The diagonal of the larger square is three times the diagonal of the small square in length. What fraction of the area of the larger square is not shaded?
A 1/9
B 1/3
C 2/3
D 8/9
For a slab supported on its four edges with corners held down and loaded uniformly, the Marcus correction factor to the moments obtained by Grashoff Rankine’s theory
A Is always less than 1
B Is always greater than 1
C Can be more than 1
D Can be less than 1
For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area
A Increases
B Decreases
C Remains constant
D Passes through a maxima
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

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