Turbulent heat transfer to liquid sodium in the entrance region of a concentric annuli

In this paper an analytical solution and experimental investigation concerning the problem of turbulent heat transfer in an annuli with simultaneously developing velocity and temperature distribution under the condition of a constant wall heat flux were made. For the theoretical study the authors derived several groups of differential and integral equations which were solved, using a finite difference technique with help of computer codes. According to the asymptotic solutions the authors obtained some turbulent heat transfer relations. In the experiments, the inner diameter of the channel was 12.34mm and outer diameter was 19.00mm. The inner wall of the channel was provided with constant heat flux and the outer wall heat-insulated. The range of the parameters Re = 2 × 104 approximately 1.35 × 105; Pc = 128-854. It was found that the asymptotic solutions conformed very well with the experimental data obtained by the authors and others.