1. Air at 1 atm and 27°C flows across a 12 mm diameter sphere at a velocity of 4 m/s. A small heater inside the sphere maintains the surface temperature at 77°C. Calculate the rate of heat loss from...

1. Air at 1 atm and 27°C flows across a 12 mm diameter sphere at a velocity of 4 m/s. A small heater inside the sphere maintains the surface temperature at 77°C. Calculate the rate of heat loss from the sphere.

2. Calculate the heat transfer coefficient for water flowing through a 25 mm diameter tube at the rate of 1.5 kg/s, when the mean bulk temperature is 40°C. For turbulent flow of a liquid take

where all properties are evaluated at the mean bulk temperature.