FACT Chemical Engineering Heat Transfer Model Questions
1. Loss of heat from unlagged steam pipe to the ambient air is by
(d) all (a), (b) & (c) (Ans)
2. Fourier's law applies to the heat transfer by
(c) conduction (Ans)
(d) all (a), (b) & (c)
3. Fourier's law of heat conduction applies to .......... surfaces.
(c) both (a) and (b) (Ans)
(d) neither (a) and (b)
4. Unsteady state heat conduction occurs, when
(a) temperature distribution is independent of time
(b) temperature distribution is dependent on time (Ans)
(c) heat flows in one direction only
(d) three dimensional heat flow is concerned
5. What is the unit of thermal conductivity ?
(a) Kcal/hr.m2 0C
(b) Kcal/hr.m. 0C (Ans)
6. The unit of heat transfer co-efficient is
(a) BTU/hr.ft2 0F (Ans)
7. Which of the following is correct ?
(a) Rate = Driving force * Resistance
(b) Driving force = Rate * Resistance (Ans)
(c) Resistance = Driving force * Rate
(d) Rate = Resistance/Driving force
8. An insulator should have
(a) low thermal conductivity (Ans)
(b) high thermal conductivity
(c) less resistance to heat flow
(d) a porous structure
9. Heat flux through several resistance in series in analogous to the current flowing through several
(a) resistances in parallel
(b) capacitors in series
(c) resistances in series (Ans)
(d) none of these
10. The overall resistance for heat transfer through a series of flat resistance, is the ..... of the resistances.
(b) geometric mean
(d) sum (Ans)
11. Which of the following has the highest thermal conductivity ?
(d) Silver (Ans)
12. Which area is used in case of heat flow by conduction through a cylinder ?
(a) Logarithmic mean area (Ans)
(b) Arithmetic mean area
(c) Geometric mean area
(d) None of these
13. For heat flow through very thick walled cylinder, use ............ mean radius.
(b) logarithmic (Ans)
(d) either (a) or (c)
14. What is the logarithmic mean of r1 and r2 ?
(a) r1 - r2/ln r1/r2 (Ans)
(b) r1 - r2/ln r2/r1
(c) r2 - r1/ln r1/r2
(d) r1 - r2/ - ln r1/r2
15. What is Nusselt number ?
(b) hD/k (Ans)
16. Prandtl number is given by
(c) Cp.μ/k (Ans)