基于有限元模型的欧姆加热预煮鸡蛋凝固过程解析  

Finite element modelling and analysis of the solidification process of eggs using ohmic treatment

作　　者：李星恕[1,2] 李林灿 丁能顺 高圣东 李树旺 熊秀芳 LI Xingshu;LI Lincan;DING Nengshun;GAO Shengdong;LI Shuwang;XIONG Xiufang(College of Mechanical and Electronic Engineering,Northwest A&F University,Yangling 712100,China;Shaanxi Engineering Research Center for Agricultural Equipment,Yangling 712100,China)

机构地区：[1]西北农林科技大学机械与电子工程学院,杨凌712100 [2]陕西省农业装备工程技术研究中心,杨凌712100

出　　处：《农业工程学报》2023年第20期266-274,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(31972209);陕西省重点研发计划项目(2021NY-162,2021NY-059)。

摘　　要：针对传统的鸡蛋预煮方法升温条件不可控,蛋清、蛋黄凝固状态难以控制等问题,该研究通过试验明确了蛋壳导电性能,在此基础上建立并验证了欧姆加热预煮鸡蛋过程的有限元模型,研究了欧姆加热预煮鸡蛋过程中鸡蛋内部的温度分布,分析了欧姆加热对鸡蛋凝固过程的影响,明确了电场强度和摆放方向对鸡蛋内部升温速率与温度分布的影响。结果表明:欧姆加热条件下,蛋壳可近似视为绝缘体;欧姆加热预煮鸡蛋是壳外溶液在欧姆效应下温度升高,通过热传导作用来实现的;建立了欧姆加热预煮鸡蛋的有限元模型并进行验证,温度模拟值与实测值之间的相对均方根误差均小于5%;鸡蛋长轴沿垂直电极板方向摆放,有利于改善鸡蛋内部加热均匀性;可以通过控制欧姆加热条件确定鸡蛋的凝固状态,达到控制鸡蛋蛋清、蛋黄凝固时间及状态的目的。研究结果可为开发基于欧姆加热的鸡蛋预煮装置提供参考。Egg pre-cooking can usually use boiling water or steam to heat the eggs at present.However,it is difficult to accurately control the temperature of the heating medium.There is also a great variation in the solidification state of egg whites and yolks,even leading to the product quality in the subsequent egg processing.Therefore,it is very necessary for an egg precooked with a controllable heating temperature and an easily adjustable solidification state in egg production.Fortunately,Ohmic heating has been widely used to directly apply the current to the food during heating,particularly in food sterilization,defrosting,and steaming.The shorter heating times can also be obtained to reduce the temperature gradients,indicating better temperature control,compared with the conventional.In this study,ohmic heating was used to simulate the process of precooked eggs using the finite element method.The test system was established for the egg ohmic heating,including the power supply,temperature acquisition module,thermocouple,heating vessel,electrode plate,and PC.A comparison was implemented on the temperature rise history for the internal solution of eggshells with different conductivity during ohmic heating.It was found that the electrical conductivity of eggshells was basically zero.The finite element model was then developed and validated in the ohmic heating of pre-cooked eggs using COMSOL Multiphysics software.The electric field intensity was the main reason for the different temperatures around the eggs during ohmic heating.There were uniform distributions of internal temperature and electric field intensity in eggs under different heating conditions.A systematic analysis was then conducted to clarify the effects of the electric field and placement direction on the internal heating rate and temperature distribution of the egg during solidification.The results showed that the eggshell was considered an insulator under ohmic heating.The ohmic heating of pre-cooked eggs was achieved to increase the temperature of the so

关 键 词：有限元 模拟 温度分布 欧姆加热 鸡蛋预煮 鸡蛋凝固过程 

分 类 号：TS253.4[轻工技术与工程—农产品加工及贮藏工程]