Theory Questions
Completion requirements
- Explain the various types of evaporators used in chemical industry. Give figures wherever possible.
- Discuss the advantage and limitations of dimensional analysis. Derive a correlation equation for natural convection heat transfer.
- Define the number of transfer units and discuss its importance in rating heat exchanger performance.
- Define Fourier number, Biot number in heat conduction problems and state their physical significance.
- Define thermal diffusivity and discuss the effect of thermal diffusivity on the rate of heat propagation.
- Explain film boiling, nucleate boiling and sub-cooled boiling.
- Write a note on maximum heat flux and critical temperature drop.
- Show that absorptivity of a radiating body is equal to its emissivity.
- Discuss the main laws of block body radiation.
- Define view factor and discuss its importance.
- Discuss Grashof number and Rayleigh's number in natural convection process.
- Discuss various theoretical and empirical equations available to predict natural convection heat transfer coefficient.
- State Dittus-Boelter equation and Colburn equation for heat transfer and discuss their application.
- Indicate the various methods of improving the overall efficiency of evaporators.
- Derive an expression for view factor between an elemental surface and finite surface.
- Discuss the operation and advantages of a multiple effect evaporator.
- Discuss the operation and working of a vapor compression evaporator with high pressure steam jet compression.
- Derive Nusselt equation for condensation of pure saturated vapors on a vertical tube.
- Explain the terms "Black body" and "Grey body" with reference to radiant heat transfer.
- Discuss briefly the difference between film-wise and drop-wise condensation. What are the methods employed to promote drop-wise condensation?
- Discuss briefly the phenomenon of nucleate and film boiling. Explain with a neat diagram the various zones of boiling.
- Define LMTD and explain the reason for which this concept is introduced in heat exchanger design. Explain why correction factors are being used when applying this technique for the design of multi-pass heat exchangers.
- Condensing equipments are always designed for film-wise condensation - why?
- Explain the effects of boiling point elevation and hydrostatic head on evaporator capacity.
Last modified: Monday, 5 August 2024, 7:44 PM