Thermal Influence on Steam Generator Heat Transfer Tube During Sodium-Water Reaction Accident of Sodium-Cooled Fast Reactor

Investigation of correlation diagram between heat transfer coefficient and void fraction under sodium–water reaction

“…Therefore, a low Reynolds k-e turbulent model [7] is implemented. It is mentioned that the present set of numerical method are the same with the previous work [5] in which the heat transfer coefficient on the tube surface is estimated directly from the numerical simulation. In the analysis, the fluid velocity and the void fraction nearby the heat transfer tube surface are given parametrically as the boundary condition.…”

“…In the boundary layer approximation theory [4,5], a tangential velocity profile is evaluated with a space derivative of non-dimensional flow stream function f 0 . The tangential velocity in the boundary layer u x is evaluated using boundary velocity u B as…”

“…On the contrary, an effective thermal conductivity should be taken into account instead of the volumetric average. For instance, the following Davis's equation [8] was applied in the previous work [5].…”

“…With regard to the boundary velocity, three cases of 0.5, 1.0 and 1.5 m/s are selected based on the previous work [5]. Figure 8 shows the comparison of the diagram between the effective thermal conductivity models.…”

“…The upper boundary of the fluid region is 2 mm above the tube surface that corresponds to the same position with T/ C-a (see Figure 2). Since the fluid region exists only near the tube surface, a boundary layer approximation [4,5] is applied as a numerical method.…”