1. When vaporisation takes place directly at the heating surface, it is called
2. Steam consumption in kg/hr in case of an evaporator is given by (where, C & E are capacity the economy of the evaporator respectively)
3. Reynold's analogy states that
4. With increase in temperature, the thermal conductivity of non-metallic amorphous solids
5. Fourier's law applies to the heat transfer by
6. Shell side pressure drop in a shell and tube heat exchanger does not depend upon the
7. In the equation Q = UAΔt; Δt is
8. With increase in porosity, the thermal conductivity of a solid substance
9. For an ideal black body
10. In Joule's experiment, an insulated container contains 20 kg of water initially at 25°C. It is stirred by an agitator, which is made to turn by a slowly falling body weighing 40 kg through a height of 4 m. The process is repeated 500 times. The acceleration due to gravity is 9.8 ms-2. Neglecting the heat capacity of agitator, the temperature of water (in °C) is
11. Fouling factor
12. In case of vertical tube evaporator, with increase in liquor level, the overall heat transfer co-efficient
13. The steam ejector is used to
14. For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area
15. The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are
16. Hot water (0.01 m3 /min) enters the tube side of a counter current shell and tube heat exchanger at 80°C and leaves at 50°C. Cold oil (0.05 m3/min) of density 800 kg/m3 and specific heat of 2 kJ/kg.K enters at 20°C. The log mean temperature difference in °C is approximately
17. In a heat exchanger, floating head is provided to
18. Leidenfrost point is a term concerned with the
19. A process stream of dilute aqueous solution flowing at the rate of10 Kg.s-1 is to be heated. Steam condensate at 95°C is available for heating purpose, also at a rate of 10 Kg.s-1. A 1 - 1 shell and tube heat exchanger is available. The best arrangement is
20. Heat produced when a steady state current, I passes through an electrical conductor having resistance, 'R' is
21. Convective heat transfer co-efficient in case of fluid flowing in tubes is not affected by the tube length/diameter ratio, if the flow is in the __________ zone.
22. The actual temperature drop across the heating surface in an evaporator depends on the
23. Which of the following is not used as a medium for high temperature heating ?
24. Presence of a non-condensing gas in a condensing vapour
25. Kirchoff s law applies to __________ radiation.