Heat Transfer T...

The inner surface of a nickel-steel cylinder (k = 19 W/mK) of inner diameter = 1 cm and outer diameter = 7 cm is maintained at a constant temperature of 110°C, while the outer surface is held at 50°C. Calculate the heat lost per meter length of the pipe (in kW).

A pipe of 25 mm outer diameter carries steam. The heat transfer coefficient between the cylinder and the surrounding is 5 W/m²K. It is proposed to reduce the heat lost from the surrounding pipe by adding insulation having a thermal conductivity of 0.05 W/mK. Which of the following statements is true?

A long slender bar has one of its end in a furnace and has reached a steady-state condition. The temperature at 25 cm from the furnace was found to be T. If now the heat transfer coefficient is increased to ‘n’ times such that the same temperature is now found at a location of 15 cm, then calculate the value of nⁿ.

A rod of length 25 cm and diameter 20 mm is connected between two walls which are maintained at a temperature of 353 K and air at 298 K flows over the rod. If the thermal conductivity of the rod is 250 W/mK and the convective heat transfer coefficient is 40 W/m²K, then calculate the temperature at the center of the rod (℃).