Experimental investigation of turbulent heat transfer to liquid sodium in the thermal entrance region of an annulus

An experimental investigation has been carried out for turbulent heat transfer to liquid sodium in the thermal entrance region as well as in the thermal fully developed region. The experiments were made with a step-function heat flux distribution in the inner wall of an annulus with the Reynolds number varying from 6000 to 60 000. the inner diameter of the channel was 17.2 mm and the outer diameter 31.8 mm. The velocity profile was fully developed at the start of heating. The experimental results were found to be in good agreement with the theoretical prediction. Finally, an empirical relation was obtained for the heat transfer in the fully-developed region.