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________________?

Related Mcqs:

The ratio of velocity head to tube side return loss in case of a multipass shell and tube heat exchanger is ________________?

A. 2 B. 1/2 C. 4 D. 1/4...

Overall heat transfer co-efficient of a particular tube is U1. If the same tube with some dirt deposited on either side has coefficient U2, then_________________?

A. U1 = U2 B. U2 > U1 C. U1 > U2 D. U1 = dirt factor – U2...

It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/kg.K. The rate at which the heat has to be supplied in (kJ/min) to the evaporator is____________________?

A. 3.06 × 105 B. 6.12 × 105 C. 7.24 × 105 D. 9.08 × 105...

The left face of a one dimensional slab of thickness 0.2 m is maintained at 80°C and the right face is exposed to air at 30°C. The thermal conductivity of the slab is 1.2 W/m.K and the heat transfer co-efficient from the right face is 10 W/m2.K. At steady state, the temperature of the right face in °C is____________________?

A. 77.2 B. 71.2 C. 63.8 D. 48.7...

In an interphase heat transfer process, the equilibrium state corresponds to equality of temperature in the two phases, while the condition for equilibrium in an interphase mass transfer process is equality of___________________?

A. Concentrations B. Chemical potentials C. Activity co-efficients D. Mass transfer co-efficients...