方腔内不同位置块状食品层流冷却数值研究

Numerical study of laminar cooling behavior in a cavity with square food at different positions

为了考察冷却器内不同位置食品的冷却行为,利用Ansys有限元软件的CFD模块对单侧冷却的方腔进行非稳态共轭传热分析,给出了冷壁面和食品表面的对流换热系数(h);结果表明,食品的放置位置不同,由于腔体内空气流动和对流换热的差异,会导致冷却过程中冷壁面h变化趋势有所不同,食品表面的h在冷却刚开始时变化强烈,且沿着表面呈"M"型变化,在食品拐角处会出现h的突变,除置于方腔上方的食品冷却速率较慢外,其余几种的冷却速率相差不大。

In order to explore the cooling behavior of food at different positions in a cavity, Ansys Computational Fluid Dynamics（CFD） software is used to analyze the transient conjugate heat transfer problem in a cavity with single side cooling. The local heat transfer coefficients （h） at cold wall and food surface are given. The results indicate that different change of h at cold wall in the cooling process was found in the cavity with different air flow and convective heat transfer. The value of h changed dramatically at initial stage and ＂M＂ -shape character was found along the food surface. Rapid change of h was found at all the four vertexes of square food during the cooling process. The cooling rates of food at different positions showed no noticeable difference except the top one, which cooled down slowly.