基于包装材料冷链速冻食品微波复热温度场仿真研究

Simulation on Temperature Field of Microwave Reheating of Cold-chain Quick-frozen Food with Different Packaging Materials

目的解决微波复热冷链食品时包装材料及微波输入功率选择的问题。方法通过对照实验法,利用物理场仿真软件COMSOL Multiphysics 5.6来建立速冻食品微波复加热模型,模拟采用4种常见速冻食品外包装材料,在800 W功率下将一份初始温度为−18℃的速冻土豆泥通过微波复加热至65℃,研究升温过程中物块中心温度和时间速率曲线,以及物料达到目标温度时横切面温度场分布情况。然后在此基础上控制包装材料这个单一变量,分别改变输入功率和物料形状。结果铝箔制的包装材料中的物料微波加热速率最快,所用的时间为10 s;达到目标温度时,不同包装材料下,pp塑料制的物料体温度差最小,加热相对最均匀;不同形状下,菱形柱体的物料温度差最小,加热相对最均匀;不同微波功率下,6 kW微波功率实现目标温度消耗电能最少。结论铝箔制的包装材料微波加热速率最快,pp塑料制的包装材料微波加热物料受热均匀性最佳,菱形柱体形状的物料在微波加热时均匀性最佳,选择输入功率为6 kW时加热效益最大。

This study aims to solve the problems of packaging materials and microwave input power selection in microwave reheating cold chain food.COMSOL Multiphysics 5.6 was used to establish the microwave reheating model of quick-frozen food.The four kinds of common quick-frozen food outer packaging materials were simulated,and a quick-frozen mashed potato with an initial temperature of−18℃was reheated to 65℃by microwave under 800 W power.The temperature and time rate curves of the center of the block and the temperature distribution of the cross section when the material reached the target temperature were studied.Then on this basis,the single variable of packaging material was controlled to change the input power and material shape respectively.The time for the four materials of meal box packaging to reach 65℃was:447 s,10 s,525 s and 464 s.When the target temperature was reached,the material temperature difference of PP plastic packaging material is the smallest(5℃),and the ma-terial temperature difference of diamond column shape was the smallest(7℃).Achieving the target temperature at 6 kW microwave power consumes the least power(0.195 kW·h).The packaging material made of aluminum foil has the fastest microwave heating rate,the packaging material made of PP plastic has the best heating uniformity,and the materials in the shape of diamond column has the best uniformity during microwave heating.The heating benefit is the largest when the input power is 6 kW.