Online Chemical Engineering Test - Heat Transfer Test 1

Bulk of the convective heat transfer resistance from a hot tube surface to the fluid flowing in it, is

The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe, where the wall heat flux is constant, is

Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter)

The equation, , corrosponds to __________ analogy.

'Fouling factor' used in the design of a multipass shell and tube heat exchanger is a

Log mean temperature difference (LMTD) cannot be used, if

The heat transfer by radiation from a mild steel surface is to be reduced by reducing the emissivity of the surface. This can be best achieved by

Pick out the wrong statement.

A composite flat wall of a furnace is made of two materials 'A' and 'B'. The thermal conductivity of 'A' is twice of that of material 'B', while the thickness of layer of 'A' is half that of B. If the temperature at the two sides of the wall are 400 and 1200°K, then the temperature drop (in °K) across the layer of material 'A' is

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

Three solid objects of the same material and of equal mass-a sphere, a cylinder (length = diameter) and a cube are at 500°C initially. These are dropped in a quenching bath containing a large volume of cooling oil each attaining the bath temperature eventually. The time required for 90% change in temperature is the smallest for

When does the heat generated by fluid friction becomes appreciable compared to the heat transferred between the fluids ?

The film co-efficient between condensing vapour and metal wall increases with

A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer co-efficient for air will vary in the ratio of

The equation, (N_St x N^2/3_Pr) = f/2, is the __________ analogy.

__________ heat exchanger is used for chilling oil to be dewaxed.

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

Vibrations in the tubes of a shell and tube heat exchanger is induced due to the

At constant temperature, the thermal conductivities of gases __________ with rise in pressure.

Heat exchanger tubes are never made of