泡沫铜强化石蜡相变蓄热特性的数值分析

通过构建泡沫金属内固液相变传热模型,对方腔蓄热单元中泡沫铜强化石蜡相变蓄热特性进行数值分析。数值模型采用考虑泡沫金属真实结构的等效导热系数通用模型,并兼顾石蜡在融化前后与金属骨架之间的热非平衡效应。通过求解模型得到方腔内石蜡固液界面演化规律与温度分布,进而对蓄热过程进行火用分析。结果表明:当前数值模型能较好地预测泡沫铜内固液相变传热;泡沫铜显著改善了石蜡相变的空间均匀性,减小了蓄热区温度梯度,使蓄热速率和火用效率得到有效提高。

Numerical Study on Phase Change Heat Storage Enhancement of Paraffin Using Copper Foam

In this work, phase change heat storage enhancement of paraffin using copper foam in a square cavity was numerically studied. A model for solid-liquid phase change heat transfer in metal foam was established. In the model, the effective thermal conductivity of metal foam was calculated using an analytical model considering the actual foam structure and with good application generality. The thermal non-equilibrium effect between metal skeleton and solid/liquid paraffin was also considered. The evolution of solid-liquid interface and temperature distribution in the cavity were numerically simulated and analyzed. The exergy performance of the phase change heat storage process was also discussed. It is shown that copper foam widens the phase change area of paraffin, and decreases the temperature gradient in the cavity. As a result, the related phase change rate and exergy efficiency are effectively promoted by introducing the copper foam into the paraffin.