A cold trap is one of the important components in the Fast Breeder Reactor (FBR) to control oxygen and hydrogen concentration of liquid sodium. For more accurate evaluation of the cold trap performance, we have started a research program to develop the evaluation method based on the 3D numerical analysis. Our evaluation method consists of two steps: one is a numerical analysis of sodium compound deposition on the mesh wires; the other is a numerical analysis of the sodium flow in the cold trap where the effect of the sodium compound deposition is considered as local pressure loss increment. In this study, we have focused on the development of the numerical analysis method of the sodium compound deposition on the mesh wires of the cold trap. As a numerical method, we have adopted the lattice Boltzmann method which is known to be useful for the flow simulation around the complex geometry like the mesh wires. In order to apply the lattice Boltzmann method to the sodium compound deposition simulation around the mesh wire, we proposed a low Reynolds number model and an impurity precipitation model for the conventional lattice Boltzmann method. The low Reynolds number model was validated by a comparison with a theoretical solution of the two-dimensional channel flow. To validate the impurity precipitation model, we conducted a precipitation experiment by using the supersaturated sucrose in the water instead of the liquid sodium with the oxygen and the hydrogen. The comparison between the experiment and the simulation showed good agreement regarding the pressure loss increment. From these results, we confirmed the accuracy of the low Reynolds number model and the impurity precipitation model. The accuracy of our models in the sodium condition will be confirmed in the future study.
Development of precipitation model with the use of the Lattice Boltzmann Method and its application for the rolling process
