Boiling heat transfer of Nitrogen in a thermosyphon condenser‐reboiler

An experimental investigation was conducted to determine the boiling heat‐transfer characteristics in a thermosyphon condenser‐reboiler of air‐separation plants. The test section was a plate‐fin heat exchanger of practical size of 0.106 m width and 2.56 m length. The testing fluid was nitrogen. Experiments were carried out within a range of pressure from 150 to 300 kPa, submergence from 1.95 to 2.80 m, and heat flux up to 11 kW/m 2 under constant wall‐temperature condition. The liquid superheat at the onset of boiling was rather significant. The boiling heat‐transfer coefficients obtained agreed well with Chen's correlation modified by Colburn's J factor within a mean deviation of 9.3%.