by 1.What are the important parts of thermal power plant?
- BOILER
- FURNACE
- TURBINE
- HEAT EXCHANGER
- COOLING TOWER
2.What is meant by heat transfer process? Write its 3 types.
- Transfer of heat from one place to another place, Which occurs as a result of a temperature difference
- Conduction
- Convection
- Radiation.
3. Write any 2 important differences between conduction and convection.
* Conduction
- Heat transfer in bodies due to fixed molecules.
- This take place is solid bodies.
* Convection
- Heat transfer in bodies due to moving molecules.
- This take place in flawed liquid of gas
4.Write Fourier law of heat conduction and explain the terms in it.
- q conduction = -kA x (∆T /∆ x )
where A the cross- sectional area
∆T temperature difference ( T1-T2)
between the two surfaces separated by a distance Δx
5.What is meant by natural convection heat transfer process?
- is the heat transfer process where the heat transfer takes place due to the natural temperature difference or density difference and no external forces are employed for the fluid movement.
6.Write and explain the terms in the formula for calculating the radiation heat transfer process ( Name the law )
- q emitted = εσ . AT4
where A is the surface area, T is the temperature of the body,
σ is a constant called Stefan-Boltzmann constant, equal to 5.67×10-8 W/m2K4, and ε is a material property called emissivity.
The emissivity has a value between zero and 1.
7. Write briefly about a) Laminar flow b) Turbulent flow c) Parallel flow c) Counter flow.
- Laminar flow: which the fluid particles move in regular path.
- Turbulent flow: is the one in which the fluid particles move in zig-zig path
- Parallel flow: is the one where the 2 fluid steams move parallel to each other.
- Counter flow: the one where the fluid steams move opposite to each other.
8. Name the various types of heat exchangers.
- Parallel flow heat exchanger.
- Recuperation heat exchanger.
- Plate heat exchanger.
- Counter flow
- Regenerative
- Shell& tube heat exchanger.
- Cross flow heat exchanger.
- Direct& indirect contact
- Double pipe heat exchanger
9.Write the expansion of LMTD.
- Log-mean temperature difference (ΔTlm )
10. Write the 2 limitations of Plate heat exchangers.
- Plate exchangers are limited when high pressures, high temperatures, or aggressive fluids are present.
- Because of this problem these type of heat exchangers have only been used in small, low pressure applications such as on oil coolers for engines.
11. Write 4 important parts of a shell and tube heat exchanger.
- Shell
- tubes
- rear header
- front header
– baffles
- tubes sheet
