Water-LBE flow similarity laws and their numerical experiments

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.

This paper studies theoretically and numerically flow similarity laws between water and lead-bismuth eutectic (LBE) liquid. It is associated practically with the problem how to use water to simulate experimentally natural convections in an LBE cooled reactor. It is revealed that Reynolds, Richardson and thermal power similarity laws can hold not only globally (in a sense of the global parameters) but also locally. The water model scale, power and other factors are determined by choosing the inlet and outlet temperatures, so that the local Reynolds numbers at these two points in the water experiment are equal to the corresponding LBE ones. Several cases are shown by the variation of the inlet temperature. There are two particular cases: (i) Froude numbers are equal additionally; (ii) the model scale is one to one. For the case of the model scale 1:1, the similarity solution is presented in detail. Numerical experiments of reactor flows of both water and LBE are carried out. They show that the theoretical similarity predictions can have deviations of 5% in Reynolds number and 10% in Richardson number. The reason for it is that flow patterns in the upper coolant plenum are different due to the much lower LBE Prandtl number than waters one.