以啤酒为研究对象,基于COMSOL Multiphysics软件建立二维传热模型来模拟同体积的罐装啤酒与瓶装啤酒的巴氏杀菌过程。得出在2种包装形式下啤酒的巴氏灭菌过程都存在明显的自然对流现象,最慢加热区(SHZ)在受热过程中逐渐下移。在杀菌初始时,金属罐中最大流速可达77.89 mm/s,明显大于此时玻璃瓶内的最大速度。采用60℃-20 min巴氏杀菌程序结束后,金属罐中啤酒的最小的巴氏杀菌单元值(PU值)为14.84,最大与最小的PU值的差值为5.16,而玻璃瓶中最小PU值只有6.09,最大最小PU值的差值为11.71,反映了500 mL啤酒采用金属罐装杀菌不仅可以缩短杀菌时间,且可以有效减少因传热不均匀引起的过杀菌现象。

A two-dimensional heat transfer model was established to simulate thermal pasteurization process of beer in can and glass bottle based on COMSOL Multiphysics in this paper. It has been shown that the action of natural convection forces the slowest heating zone( SHZ) to migrate towards the bottom of the can and bottle as expected. The maximum magnitude of the velocity was found to be 77. 88mm / s at 30s in can,which was faster than the velocity in bottle at the same time. The minimum pasteurization unit( PU) value in can was 14. 84 in heating( 60℃ /20min) and the difference of PU value between maximum and minimum was 5. 16,while the minimum pasteurization unit( PU) value in bottle was 6. 09 and the difference of PU value between maximum and minimum was 11. 71,which indicated that the effect of thermal pasteurization in can was better than in bottle.