A. Film boiling
B. Nucleate boiling
C. Vapour binding
D. None of these
Related Mcqs:
- When vaporisation takes place through a blanketting film of gas, the phenomenon is termed as ___________________ boiling?
A. Pool
B. Nucleate
C. Transition
D. Film - The actual temperature drop across the heating surface of an evaporator depends on the_______________?
A. Liquid depth over the heating surface
B. Solution being evaporated
C. Pressure difference between the steam chest and the vapor space above the boiling liquid
D. All A., B. and C. - The actual temperature drop across the heating surface in an evaporator depends on the_________________?
A. Feed
B. Depth of liquid over heating surface
C. Pressure difference between steam chest and vapour space
D. All A., B. and C. - An equipment which converts the latent or sensible heat of one fluid into the latent heat of vaporisation of another, is called a_________________?
A. Boiler
B. Heat exchanger
C. Recuperator
D. Regenerator - It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/kg.K. The rate at which the heat has to be supplied in (kJ/min) to the evaporator is____________________?
A. 3.06 × 105
B. 6.12 × 105
C. 7.24 × 105
D. 9.08 × 105 - Rate of heat transfer by vaporisation from pools of water is affected by the ____________________?
A. Nature of heating surface and distribution of bubbles
B. Surface tension of water
C. Viscosity of water
D. All A., B. and C. - In case of _______________ boiling, the liquid temperature is below the saturation temperature and the boiling takes place in the vicinity of the heated surface?
A. Nucleate
B. Local
C. Pool
D. Saturated - The interchange factor for radiation heat transfer from surface ‘x’ to surface ‘y’ in case of an infinite parallel planes with emissivities εx & εy is given by_______________?
A. εx + εy
B. εx . εy
C. 1/εx + 1/εy
D. (εx + εy)/( εx + εy – εx . εy) - 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 - The local surface conductance for laminar film condensation on vertical surface is (where, t = film thickness) _________________?
A. ∝ t
B. ∝ 1/t
C. ∝ √t
D. Independent of ‘t’
