Chemical Heat Transfer Quiz 3

1 / 50

**Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the__________?**

2 / 50

**For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it___________?**

3 / 50

**Film boiling is usually not desired in commercial equipments, because______?**

4 / 50

**For hot feed, forward feeding as compared to backward feeding results in _______ economy?**

5 / 50

**For an ideal black body________?**

6 / 50

**Fruit juice (a heat sensitive material) can be concentrated in a _____ evaporator?**

7 / 50

**Heat exchanger tubes are never made of__________?**

8 / 50

**For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area_____?**

9 / 50

**Heat flux is the time rate of heat transfer per unit________?**

10 / 50

**Grashoff number is given by_________?**

11 / 50

**Finned tube heat exchangers___________?**

12 / 50

**Fourier?s law of heat conduction applies to ______ surfaces?**

13 / 50

**For small temperature difference, the heat transfer rate as per Newton?s law of cooling is proportional to (where, ?t = excess temperature) ?**

14 / 50

**For gases, the thermal conductivity increases with temperature rise. For liquids, with increase in concentration, its thermal conductivity generally ?**

15 / 50

**Film boiling occurs at _________ pressure?**

16 / 50

**For evaporation of viscous solution in a multiple effect evaporator, the preferred feeding scheme is __________?**

17 / 50

**For what value of Prandtl number, St = f/2 ?**

18 / 50

**For a given ambient air temperature with increase in the thickness of insulation of a hot cylindrical pipe, the rate of heat loss from the surface would ?**

19 / 50

**For concentrating an aqueous solution of a material like anhydrous Na2SO4, whose solubility decreases with rise in temperature, the most suitable evaporator is a ________ evaporator?**

20 / 50

**For a cold dilute feed to produce thick viscous liquor, backward feeding as compared to forward feeding results in_______?**

21 / 50

**Fouling factor for a heat exchanger is given by (where, U1 = heat transfer co-efficient of dirty surface U2 = heat transfer co-efficient of clean surface) ?**

22 / 50

**For heat flow through very thick walled cylinder, use ___________mean radius?**

23 / 50

**For a perfectly transparent surface (like gases), the______?**

24 / 50

**For a fluid flowing in an annulus space, the wetted perimeter for heat transfer and pressure drop are___________?**

25 / 50

**Heat flux, as defined in heat flow is analogous to ________ in electricity flow?**

26 / 50

**Heat flux increases with temperature drop beyond the Leiden frost point in the plot of heat flux vs. temperature drop for a boiling liquid, because_____?**

27 / 50

**For the same heat transfer area and the terminal conditions, the ratio of the capacities of a single effect evaporator to a triple effect evaporator is__________?**

28 / 50

**Fresh orange juice contains 12% (by weight) solids and the rest water 90% of the fresh juice is sent to an evaporator to remove water and subsequently mixed with the remaining 10% of fresh juice. The resultant product contains 40% solids. The kg of water removed from 1 kg fresh juice is___________?**

29 / 50

**Harmonic mean temperature difference is given by__________?**

30 / 50

**For what value of Prandtl number, the Col-burn analogy is valid ?**

31 / 50

**For a counter current heat exchanger with Ti h = 80?C, T?c = 60?C, T?h = 50?C and Ti c = 30?C, and the temperature difference between the two streams being the same everywhere along Z, the direction of flow of hot fluid. The temperature profile should satisfy_____?**

32 / 50

**Fouling factor_______?**

33 / 50

**For a laminar flow of fluid in a circular tube, ?h1? is the convective heat transfer co-efficient at velocity ?V1?. If the velocity is reduced by half and assuming the fluid properties are constant, the new convective heat transfer co-efficient is_________?**

34 / 50

**For a multipass shell and tube heat exchanger, the LMTD correction factor is always_________?**

35 / 50

**Heat produced when a steady state current, I passes through an electrical conductor having resistance, ?R? is_____?**

36 / 50

**For condensation of pure vapors, if the heat transfer co-efficients in filmwise and drop-wise condensation are respectively hf and hd, then___________?**

37 / 50

**Forced circulation evaporators are useful for the concentration of viscous, salting and scale forming liquors. Which of the following is a forced circulation evaporator ?**

38 / 50

**For large heat transfer area requirement, shell and tube heat exchanger is preferred, because it_________?**

39 / 50

**Fourier?s law applies to the heat transfer by___________?**

40 / 50

**Heat sensitive materials can be concentrated in an evaporator employing________?**

41 / 50

**Film condensation is promoted on a/an _________ surface?**

42 / 50

**Extremely large or small volumes of fluids are generally best routed through the shell side of a shell and tube heat exchanger, because of the_________?**

43 / 50

**Heat exchangers operating, when the asymptotic range is reached, ?**

44 / 50

**For specified tube outside diameter, higher BWG means higher_____?**

45 / 50

**For turbulent flow in a tube, the heat transfer co-efficient is obtained from the Dittus- Boelter correlation. If the tube diameter is halved and the flow rate is doubled, then the heat transfer co-efficient will change by a factor of_________?**

46 / 50

**Forced circulation evaporators are normally used for concentrating liquids having _____?**

47 / 50

**Grashoff number, which is defined as g . ? (Ts ? T?) ?2. L3/?2, is proportional to the ratio of buoyancy force to _____ force?**

48 / 50

**Heat flux through several resistances in series in analogous to the current flowing through several_______?**

49 / 50

**For a liquid in laminar flow through a very long tube, when the exit fluid temperature approaches the wall temperature, the equation to be used is_______?**

50 / 50

**For ________ Prandtl number values, the heat conduction will be negligible in the buffer zone?**

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