The air passage for cooling a gas turbine vane can be approximated as a tube of 3-mm diameter and 75-mm length. The operating temperature of the vane is 650°C, and air enters the tube at 427°C.

(a) For an air flow rate of 0.18 kg/h, calculate the air outlet temperature and the heat removed from the vane.

(b) Generate a plot of the air outlet temperature as a function of flow rate for 0.1 < m < 0.6 kg/h. Compare this result with those for vanes having 2- and 4-mm-diameter tubes, with all other conditions remaining the same.