N2 flows through an insulated horizontal tube at steady state. With an inlet temperature of 150°C and a velocity change from 2 m/s to 50 m/s, what is the exit temperature?

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.