基于CFD技术的瓶装啤酒隧道式巴氏杀菌过程研究

Study on tunnel pasteurization of bottled beer based on CFD technology

通过数值模拟瓶装啤酒隧道式巴氏杀菌的过热阶段(巴氏杀菌加热部分的最后一个阶段),确定瓶中的冷核(slowest heating zone,SHZ),并运用L9(34)正交试验,分析喷淋水温度、喷口处喷淋水湍流强度以及瓶子的运行速度三因素对瓶中啤酒温度分布均匀性的影响。结果表明:冷核起先是位于瓶底,后向上移动,但不超过灌装高度的1/2;在加热至7min时,喷淋水温度、喷口处喷淋水湍流强度影响显著,瓶子的运行速度则不显著,试验的可能的最优条件:喷淋水温度为65℃,喷口处喷淋水湍流强度为3%,瓶子运行的速度为3mm/s。

In the industrial processing of beer, pasteurization is neces- sary the to guarantee its biological stability. The superheat phase （the last part of heating phase） was numerically simulated, in which the slowest heating zone （SHZ） inside the bottle was determined, and tben the influence of three parameters on the uniforn, ity of tern perature distribution inside the bottled beer during pasteurization, i. e. the temperature of spray water, the lurbulem intensity of spray water at the spray nozzles and the running velocity of bottles were analyzed using L9 （3^4 ） orthogonal experiments. The results indicated that SHZ lay at the bottom of tbe bottle at the beginning and then moved upward without exceeding 1/2 of filling beight of beer. Besides, after heating for 7 min, the temperature and the turbulent intensity of spray water at the spray nozzles affected tbe uniformity of temperature distributiou inside the bottled beer obviously, while the running velocity of hottle had no significant effect on it. Our results showed that the probable optimum condition was 65℃ temperature of spray water and 3% turbulent intensity of it at the spray nozzles as well as 3 mm/s running velocity of bottle.