泡沫铝通道内瞬态流动的平均换热系数

针对泡沫铝金属填充矩形通道内的对流换热开展了瞬态实验研究,分析了泡沫铝孔径(孔隙率)、流体流量(流速)等关键参数的影响。为了有效地处理实验数据,重新定义并推导了平均换热系数的计算公式,得到了泡沫铝通道内流动的平均换热系数,并引入了基于渗透率的雷诺数和达西数,确定了相关换热、流动准则数关系。实验研究表明,流速的增大有利于对流换热的强化:而平均换热系数对泡沫金属孔径较敏感;对于低孔隙率泡沫金属,渗透率成为影响换热强度的主要因素,相同或接近的孔隙率下,孔径越大,渗透率和达西数越大,越有利于换热,且压损减小。

Average Heat Transfer Coefficient for Transient Flow in Aluminum Foam-Filled Channels

Experimental research was performed on transient flow and heat transfer in a rectangular channel filled with aluminum foam metal, and key parameters such as foam pore size （porosity）, fluid flow （velocity） were analyzed. In order to analyze the experimental data effectively, the average heat transfer coefficient was redefined and deduced. Furthermore, non-dimensional Darey and Reynolds number based on the permeability were introduced. And the empirical equations describing convective heat transfer in AI foam-filled channel were finally obtained. Experimental results show that increasing flow rate can enhance convective heat transfer. The average heat transfer coefficient is relatively sen- sitive to the pore size. For low-porosity metal foam, permeability is the dominating factor on heat transfer. Under the condition of the same or approaching porosity, heat transfer can be enhanced by using metal foams of higher permeability and Darcy number, with the gain of a lower pressure drop.