The Influence of Multi-cellular Natural Convection Heat Transfer in the Oxide Pool of the Three-Layer Configuration

The experimental study was performed to confirm the effect of aspect ratio (H/R) of the oxide layer under the equivalent decay heat condition. We measured local heat transfer coefficients (hh) at the top plate, the curved side wall and the bottom plate for three different aspect ratios. The range of Ra'H was from 6.70×1010 to 5.13×1013. The Sc, which corresponds to Pr was 2,014. Based upon the analogy between heat and mass transfer, mass transfer experiments were performed in a copper sulfate– sulfuric acid (CuSO₄-H₂SO₄) electroplating system. This study investigated the influence of aspect ratios in the oxide layer on the heat load from the oxide layer to the upper light metal layer. The cooling condition of the bottom plate has little influence on the heat transfer of the top plate as the heat transfer at the top plate is much higher than that of the bottom plate. We confirmed that the heat load from the oxide layer to the upper light metal layer is varied depending on the flow patterns for the three-layer configuration. For large H/R forming the twin-cell, the upward heat ratios increased. However, for the small H/R forming the multi-cell, the increase of the upward heat ratios is nearly constant although the H/R decreases as the multi-cell flow distributes the heat concentrated at the upper light metal layer to the overall oxide layer.