SODIUM POOL BOILING HEAT TRANSFER.

A series of experiments on pool boiling heat transfer in sodium were carried out under pressures ranging from 0. 6 to 32 kPa. The effect of liquid head was systematically studied. Cylindrical test heaters of 7. 6 and 10. 7 mm in dia. and of 50 mm in heated length were used. The non-boiling heat transfer data showed slightly higher Nusselt numbers than those predicted by Kutateladze's correlation. The effect of liquid head was clarly seen on the stable nucleate boiling heat transfer. The effect was well explained as the effect of saturation temperature increase due to the liquid head. Taking the effect of liquid head into account, an empirical correlation of nucleate boiling heat transfer was presented. The effect of liquid head on the critical heat flux was firstly made clear. The effect of liquid head on the critical heat flux was well explained as the combined effects of the increase in liquid pressure and the resultant increase in subcooling. Critical heat fluxes for zero liquid head were calculated by extrapolating the experimental data and they were compared with the conventional formulas. An empirical formula to express these critical heat fluxes was presented.