Heat Transfer Performance of Liquid Sodium Open Thermosyphons

Abstract

Experimental studies are carried out on the heat transfer of open circular thermosyphons (the radius of length to radius are 6 and 10) using liquid sodium. The Nusselt numbers (N_ur) measured for liquid sodium are plotted against the Rayleigh number (R_ar) and the product of the R_ar and Prandtl number (P_r). These results cover a range of R_ar from 4×10² to 1.7×10⁵ or R_ar·P_r from 10 to 9.5×10³ and are compared to the previous results of mercury. It is shown that the arrangement of N_ur against R_ar·P_r is more appropriate than that against R_ar. The heat transfer of open thermosyphons for liquid sodium and mercury shows similar characteristics. The effect of convection flow on N_ur becomes significant over about 60 R_ar·P_r.