The automobile radiator is a heat exchanger of
A. parallel flow type
B. counter flow type
C. cross flow type
D. regenerator type
Answer C
The centrifugal compressors are generally used for refrigerants that require
A. small displacements and low condensing pressures
B. large displacements and high condensing pressures
C. small displacements and high condensing pressures
D. large displacements and low condensing pressures
Answer D
The humidity ratio or specific humidity is the mass of water vapour present in
A. 1 m³ of wet air
B. 1 m³ of dry air
C. 1 kg of wet air
D. 1 kg of dry air
In free convection heat transfer transition from laminar to turbulent flow is governed by the critical value of the
A. Reynold's number
B. Grashoff's number
C. Reynold's number, Grashoff's number
D. Prandtl number, Grashoff's number
Which of the following statements is wrong?
A. The heat transfer in liquid and gases takes place according to convection
B. The amount of heat flow through a body is dependent upon the material of the body
C. The thermal conductivity of solid metals increases with rise in temperature
D. Logarithmic mean temperature difference is not equal to the arithmetic mean temperature difference.
