Chemical Heat Transfer Quiz 3

Heat exchanger tubes are never made of__________?

Film condensation is promoted on a/an _________ surface?

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

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

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__________?

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

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_____?

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

Grashoff number is given by_________?

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

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___________?

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

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_________?

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

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

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

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___________?

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?

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

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

Heat sensitive materials can be concentrated in an evaporator employing________?

Harmonic mean temperature difference is given by__________?

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

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

Film boiling occurs at _________ pressure?

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

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_____?

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

Fouling factor_______?

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

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

For an ideal black body________?

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_______?

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

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

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

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

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

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_________?

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) ?

Fourier?s law applies to the heat transfer by___________?

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

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 ?

Finned tube heat exchangers___________?

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

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_________?

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

For specified tube outside diameter, higher BWG means higher_____?

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

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