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.Management Sciences
Category: Chemical Heat Transfer
In a shell and tube heat exchanger, the height of 25 percent cut baffles is equal to (where, D = inside diameter of shell) ?
A. 0.25 D
B. 0.50 D
C. 0.75 D
D. None of these
Prandtl number is the ratio of________________?
A. Momentum diffusivity to mass diffusivity
B. Momentum diffusivity to thermal diffusivity
C. Thermal diffusivity to mass diffusivity
D. Thermal diffusivity to momentum diffusivity
Pick out the correct equation ?
A. jH = (St)(Pr)2/3 = f/2
B. jH = (St)(Pr)1/3 = f/2
C. jH = (St)2/3(Pr) = f/2
D. jH = (St)1/3(Pr) = f/2
For large heat transfer area requirement, shell and tube heat exchanger is preferred, because it________________?
A. Occupies smaller space
B. Is more economical
C. Is easy to operate and maintain
D. All A., B. and C.
Tube expansion allowances exist in _____________ heat exchanger?
A. Multipass fixed tube sheet
B. U-tube
C. Single pass fixed tube sheet
D. None of these
Film boiling occurs at ________________ pressure?
A. Atmospheric
B. Sub-atmospheric
C. Negative
D. Very high
Which of the following is the most controlling factor for the rate of bubble detachment from the hot solid surface ?
A. Liquid density
B. Liquid viscosity
C. Hot surface temperature
D. Interfacial tension
The wavelength at which the maximum monochromatic emissive power occurs for a black body, is (where, T = absolute temperature of the black body)?
A. αT
B. α × 1/T
C. α T4
D. Independent of T
Convective heat transfer, in which heat is transferred by movement of warmed matter is described by___________________?
A. Fourier’s law
B. Newton’s law of cooling
C. Fick’s law
D. None of these
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