节点在液态铝合金泡沫析液过程中的耗散作用分析

Study on Nodes'dissipative Effect on Foam Drainage During the Fabrication of Foamed Aluminum

液态金属泡沫是由大量气泡密集堆积在金属熔体中形成,本身处于非平衡态,可以看成是一种软物质。泡沫析液在微观上是液体在气泡间隙内的微流动过程,是影响泡沫稳定的主要因素之一。采用SurfaceEvolver(2.30)软件计算得到不同液体体积分数(含液率)时泡沫节点形状,然后利用CFD软件(FLUENT 6.2)计算了不同气液界面边界条件下节点的内部流场,并分析节点对泡沫析液过程的影响。通过建立节点在析液过程中流动能量耗散模型,计算液态金属铝泡沫析液速率与流量的关系,数值计算结果表明:平均速率u与流量Q的关系接近u∝Q0.5;流量Q与压力差Δp之间存在Δp∝log Q的关系。

Liquid metallic foams are typical forms of soft materials.Drainage means that liquid flows inside a micro-channel of foams,which is one of primary factors to liquid foams＇ stability.In this paper,a structural model of a single node with different liquid holdup was presented by Surface Evolver（2.30）.CFD（FLUENT） was used to compute the velocity field in a single node.The results suggested that average velocity u and mass flow rate Q is satisfied with the correction of u ∝Q^0.5 and the linear relationship between mass flow rate Q and pressure difference Δp is satisfied with the correction of Δp∝log Q approximately.