闭孔泡沫铝有效热导率模型及传热模拟研究

Study on Effective Thermal Conductivity Modeling of Closed-cell Aluminum Foam and Heat Transfer Simulation

摘要:

有效热导率是表征闭孔泡沫铝热性能的重要参数,准确预测闭孔泡沫铝的有效热导率具有重要意义。本文基于已有的闭孔泡沫铝有效热导率模型,提出了一个改进模型,并采用数值模拟方法针对闭孔泡沫铝的非稳态传热过程进行了分析,基于温度场分布获得了有效热导率。结果表明与Lu模型相比,改进模型的预测精度更高；与文献中三个理论模型相比,改进模型具有更好的适用性及预测精度；当采用数值模拟方法计算有效热导率时,沿传热方向的胞孔数对有效热导率的预测精度影响较大；在保证泡沫铝胞孔数足够的条件下,数值模拟结果的精度最高；从成本及精度两方面考虑,改进模型有更好的适用性。

Abstract:

Effective thermal conductivity is a key parameter to characterize the thermal property of closed-cell aluminum foam. It is of great significance to predict the effective thermal conductivity of closed-cell aluminum foam. In this paper, based on the existing models for effective thermal conductivity of closed-cell aluminum foam, an improved model was proposed. Furthermore, the numerical simulation method was employed to analyze the unsteady heat transfer process of closed-cell aluminum foam. And the effective thermal conductivity was obtained from the distribution of temperature field. The results show that the improved model has higher prediction accuracy compared with Lu model. Besides, the improved model has better applicability and prediction accuracy compared with the three theoretical models from literature.The number of cells in the heat transferdirection has a great influence on the accuracy of the effective thermal conductivity by the numerical simulation method. The accuracy of numerical simulation is the highest when the number of cell holes is enough. Considering cost and accuracy, the improved model has better applicability.