Chemical Heat Transfer Quiz 3

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_______?

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

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_________?

Fouling factor_______?

Heat sensitive materials can be concentrated in an evaporator employing________?

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_____?

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

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

For specified tube outside diameter, higher BWG means higher_____?

For an ideal black body________?

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

Film condensation is promoted on a/an _________ surface?

Grashoff number is given by_________?

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

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 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_________?

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

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__________?

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___________?

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

Film boiling occurs at _________ pressure?

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

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

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) ?

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

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

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

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

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

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 ?

Heat exchanger tubes are never made of__________?

Finned tube heat exchangers___________?

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

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

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

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

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

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

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

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

Fourier?s law applies to the heat transfer by___________?

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

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?

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

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

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

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

Harmonic mean temperature difference is given by__________?