In a boiling curve, the peak heat flux is called the _____________ point?

A. Nusselt
B. Leidenfrost
C. Boiling
D. Burnout

Evaporator tubes are generally_____________________?

A. Horizontal
B. Vertical
C. Inclined
D. Random

Which characteristic of a fluid is not important in deciding its route in a shell and tube heat exchanger ?

A. Corrosiveness
B. Fouling characteristic
C. Viscosity
D. None of these

In a single effect evaporator, the economy is________________?

A. 1
B. < 1
C. > 1
D. None of these

In counter flow compared to parallel flow, ?

A. LMTD is greater
B. Less surface area is required for a given heat transfer rate
C. Both A. and B.
D. More surface area is required for a given heat transfer rate

In case of heat transfer by conduction in a hollow cylinder, ______________ mean area is used to calculate the heat transfer rate?

A. Geometric
B. Arithmetic
C. Logarithmic
D. Either A., B. or C.

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_________________?

A. Cube
B. Cylinder
C. Sphere
D. Equal for all the three

Which of the following parameters of the fluid is not very important, while deciding its route in a shell and tube heat exchanger ?

A. Corrosiveness & fouling characteristics
B. Pressure
C. Viscosity
D. Density

Critical value of the _____________ number governs the transition from laminar to turbulent flow in free convection heat transfer?

A. Grashoff
B. Reynolds
C. Both ‘a’ & ‘b’
D. Prandtl & Grashoff

Which of the following has maximum thermal conductivity ?

A. Iron
B. Coal
C. Nitrogen
D. Tar