A plane wall is 20cm thick with an area perpendicular to heat flow of 1m2 and has a thermal conductivity of 0.5W/mK. A temperature difference of 100°C is imposed across it. What is the ratio of heat flow?

An insulating material with a thermal conductivity k = 0.12W/mK is used for a pipe carrying steam. The local coefficient of heat transfer to the surrounding h = 4 W/m²K. In order to provide effective insulation, what should be the minimum outer diameter of the pipe?

A plane slab of 100mm thickness generates heat. It is observed that the temperature drop between the center and its surface to be 50°C. If the thickness is increased to 200mm the temperature difference will be ___________

As the temperature increases, the thermal conductivity of a gas ____________

Hot air at 50°C. If the forced heat transfer convection is 75 W/m²K, the heat gain rate gain rate by the plate through an area of 2m² will be _____

Which of the following non-dimensional numbers is used for transition from laminar flow to turbulent flow in the free convection?

Which non-dimensional numbers relates the thermal boundary layer and hydrodynamic boundary layer?

The laminar boundary layer occurs when a cold fluid over a hot plate. In which of the following positions, the temperature gradient assumes zero value?

The characteristic length for computing Grashoff number of horizontal cylinder is ___________

In laminar developing flow through a pipe with constant wall temperature, the magnitude of the pipe wall inner surface convective heat transfer coefficient shall be maximum at the:

For a fluid with Prandtl number Pr>1, momentum boundary layer thickness?