Question

Water is boiled at the rate of 25kg/h in a polished copper pan, 280mm in diameter at atmospheric pressure. Assuming nucleate boiling conditions calculate the temperature of the bottom surface of the pan.

Answer 1

$T_{sat }= 100 [C]\\ D = 0.28\ m\\ C_{sf }= 0.013$ “..for polished copper and water combination”

$h_{fg }= 2.256×10^6 J/kg$ “…heat of vapourization of water at 1 atm.”

$Q = \dfrac{25 × 2.256×10^6}{3600} W$ … "total heat supplied to boil 25 kg/h of water”

$q_s = \dfrac{Q }{(\pi ×D^2 / 4) }[W/m^2]$ ….."heat flux”

Thus, surface temp, $T_s = 112.2 °C$