Search
.Management Sciences
Category: Chemical Heat Transfer
When vaporisation takes place directly at the heating surface, it is called________________?
A. Film boiling
B. Nucleate boiling
C. Vapour binding
D. None of these
An ejector is used to__________________?
A. Increase pressure
B. Increase temperature
C. Remove condensate
D. None of these
The heat transfer by radiation from a mild steel surface is to be reduced by reducing the emissivity of the surface. This can be best achieved by__________________?
A. Painting the surface black
B. Painting the surface white (with aluminium paint)
C. Giving the surface a mirror finish
D. Roughening the surface
Steam economy in case of a triple effect evaporator will be _________________?
A. 1
B. < 1
C. > 1
D. Between 0 and 1
During crystallisation, formation of crystal can occur in ______________ solution only?
A. Saturated
B. Supersaturated
C. Under-saturated
D. All A., B. and C.
Double pipe heat exchangers are preferably useful, when____________________?
A. High viscosity liquid is to be cooled
B. Requirement of heat transfer area is low
C. Overall heat transfer co-efficient is very high
D. A corrosive liquid is to be heated
Boiling point elevation of a solution of NaOH _____________________?
A. Increases rapidly with temperature rise
B. Is almost independent of temperature
C. Is almost independent of pressure
D. Both B. and C
A diathermanous substance _______________ the thermal radiation completely?
A. Absorbs
B. Reflects
C. Transmits
D. None of these
Nusselt number (for forced convection heat transfer) is a function of the _____________ number?
A. Prandtl
B. Reynolds
C. Both A. & B.
D. Neither A. nor B.
Recent Comments