AN ELECTROCHEMICAL MASS TRANSFER INVESTIGATION IN THE PRESENCE OF SIMULTANEOUS SUBCOOLED POOL BOILING

摘要

Mass transfer rates were investigated in the presence of simultaneous subcooled pool boiling at a vertical cylindrical electrode using the electrochemical limiting diffusion current technique. Various concentrations of equimolar ferri/ferrocyanide (0.01-0.20M) in 0.5M NaOH electrolyte were used. The initial metal temperature was ≈500℃ and liquid subcooling was varied between 25 and 80℃. Transient temperature and limiting current histories were recorded following sudden immersion of the hot electrode and Schlieren photographs were taken for a range of electrode temperatures. In the nucleate boiling regime, the variation of mass transfer coefficient with temperature difference between electrode and electrolyte showed similar trends to the variation of heat transfer with temperature difference. Film boiling was briefly observed at low subcooling, eg. 27℃.