An experimental study of saturated pool boiling from downward facing and inclined surfaces

Pool boiling curves for inclinations of 0 deg (downward facing), 5, 10, 15, 30, 45, and 90 deg are obtained by quenching a 12.8-mm thick copper disk having a diameter of 50.8 mm in a pool of saturated water. Results show that nucleate boiling heat flux decreases as the angle of inclination is increased. However, the decrease in nucleate boiling heat flux with inclination is more pronounced at lower wall superheats. Conversely, the transition boiling heat flux and both q(CHF) and q(min), as well as the corresponding wall superheat, increase with surface inclination. The quenching time of a downward facing surface having an initial wall superheat of 160 K is about six times that for a 5-deg inclination and 23 times that for a 90-deg inclination. For all inclinations, quenching always begins at the lowermost position and propagates upward.