锌锅中低Pr流体混合对流的数值模拟

NUMERICAL SIMULATION OF MIXED CONVECTION FOR LOVW PRANDTL NUMBER FLUID IN GALVANIZING BATH

以带钢连续热镀锌生产工艺为背景,对抽象出的低Pr数流体混合对流流动和换热模型进行了数值模拟,给出了在不同Re、Ra及Ri时的流场和温度场。数值结果表明,当Re、Ra都不等于0时,在所考虑的参数范围内,流动和换热受自然对流和强制对流两种机理控制。Re不变,增大Ri,自然对流作用加强,并且当Ri增加到一定值时,流动和换热发生振荡。所给出的速度相图显示,对应不同的Re、Ra及Ri,流动和换热会出现稳态解、周期性振荡解和混沌。

A numerical computation is carried out to simulate fluid flow and heat transfer of mixed convection for low Prandtl number fluid, background of which is continuous galvanizing baths. The results show that when Re and Ra don＇t equal to O, fluid flow and heat transfer will be controlled by natural and forced convection mechanism. While Re is constant, the effect of natural convection mechanism will be augmented by increasing Ri. Meanwhile, an oscillatory flow turns up. The phase diagrams characterize steady flow, periodic oscillatory flow and chaos under different Re, Ra and Ri.