Process Heat Transfer Mid - II, November - 2014

1.Heat transfer takes place accompanied by phase change, which is normally known as
  • Conduction
  • vaporization
  • both
  • none of the above
Answer: C
2.Condensation can be classified into __________
  • 2
  • 3
  • 1
  • 4
Answer: A
3.____ is characterized by a thin liquid film forming over the entire surface
  • Film wise condensation
  • drop wise condensation
  • both
  • all of the above
Answer: A
4.For laminar film condensation on vertical surface the local surface conductance
  • Is directly propositional to the film thickness
  • Changes inversely with the film thickness
  • Iis independent of the film thickness.
  • Varies as the square root of the film thickness
Answer: B
5.For laminar film condensation on vertical surface, the film thickness __________
  • Remains constant from top to bottom
  • Cumulatively decreases from top to bottom
  • Cumulatively increases from top to bottom
  • The surface conductance increases from top to bottom
Answer: C
6.The peak heat flux in a boiling curve is called ______________
  • The burnout point
  • the Leiden frost point
  • the boiling point
  • the nusselt point
Answer: A
7.Heat exchangers are used in _____________________
  • Condensers and boilers in steam plant
  • radiators
  • intercoolers and pre heaters
  • all of the above
Answer: D
8.Capacity of an evaporation defined as __________
  • The number of kilograms of solvent vaporised per hour
  • The number of kilograms of solvent vaporised per kilograms of steam fed to the evaporator
  • The number of kilograms of steam consumed
  • none of the above
Answer: A
9.Economy of an evaporator is defined as _________
  • Number of kilograms of steam consumed/hour
  • Number of kilograms of steam consumed/kilogram of solvent vaporized
  • Both
  • The no. of kilograms of solvent vaporized per kilograms of steam fed to the evaporators
Answer: D
10.Heat transfer by radiation is described by ____
  • Newtonian‘s law of cooling
  • Fick’s law
  • Fourier’s law
  • Stefan- Boltzmann law
Answer: D
11.Thermal conductivity of a material has the units of _______________
Answer: w/m.k
12.The use of 1-2 shell and tube heat exchanger is not recommended whenever the LMTD correction factor is less than ________________
Answer: 0.75
13.Agitated film evaporators are generally used for ____________________
Answer: Viscous heat sensitive products
14.Steam economy of a single evaporator is always ___________________
Answer: >1
15.In a multiple effect evaporator with forward feed ___________________
Answer: Feed flows from higher pressure to lower pressure
16.The boiling point of a solution is affected by _______________
Answer: Increase in evaporating capacity
17.Absorptivity of the perfect black body is ________________
Answer: 1
18.Reflectivity of the perfect black body is ________________
Answer: 0
19.View factors is important in the analysis of problem involving heat transfer by _________
Answer: Radiation
20.________________ law is the monochromatic emissive power for black body radiation
Answer: Plank’s law