Abstract
This paper presents experimental results on the real value of the minimum-heat-flux (MHF) -point temperature for subcooled pool boiling of water from a horizontal cylinder and an advanced form of the correlation for subcooled film-boiling heat-transfer proposed in the previous paper. First, experiments to observe the collapse process of film boiling were conducted by using a high speed video. The experimental results show that the collapse mode is classified into the propagative collapse with a precursory local-collapse and the coherent collapse. Second, the propagation velocity of collapse front and the mean surface temperature upon the local collapse followed by the propagative collapse were measured. The experimental results show that, for higher propagation-velocities, the MHF-point temperature decreases and approaches the value upon coherent collapse which has only a slight dependence on liquid subcooling. Finally, an advanced form of the correlation for subcooled film-boiling heat-transfer reported in the previous paper is proposed. This equation is in good agreement with the present data of of water at subatmospheric pressures and the existing data of liquid sodium and freon R-11 at atmospheric pressure and pressurized water.
