摘要
欧姆加热利用食品物料本身的电阻抗来产生热量,是一种内加热方式,与传统加热方式相比,具有快速均匀的加热特点。但食品往往不是一个均匀体系,不同部位的电导率的差异也会造成欧姆加热升温的不均匀性,研究不均匀体系欧姆加热时的温度分布对于欧姆加热技术的开发利用有重要意义。本文利用有限元方法,模拟了含有绝缘体的物料的欧姆加热过程,并用实验进行了验证。结果表明,有限元模型能够很好地模拟欧姆加热过程,整个加热过程中,模拟预测的温度与实验测得温度接近,最大差值为8K。同时运用有限元模型模拟了绝缘体的位置和方位对温度场的影响,绝缘体在物料中的位置和方位影响物料中电流密度的分布,温度场最高点位置始终出现在电流密度最高的区域,而最低点与电流的加热作用和物料间的热传导作用有关。
As an internal heating means generating heat by using the inherent electrical resistance of the material to be treated, ohmic heating is faster and more uniform in heating compared with conventional heating techniques. However,inhomogeneities in heating may occur due to the difference in electrical conductivity in different parts of materials to be treated.It is crucial to investigate the temperature profile of in homogenous materials for heating process such as thermal sterilization. Experiments and finite elemental analysis were carried out to investigate ohmic heating of mimic food containing a insulate plate inside. It was revealed that finite element analysis could model ohmic heating with maximum 8K in temperature difference between simulation results and experimental data.The effect of position and orientation of insulate plate on the temperature distribution was studied as well and it was found that the hottest points always appeared in the area with the highest electric current density, while the location of the coldest points were determined by the local electric current densitv and thermal conductivity.
出处
《食品工业科技》
CAS
CSCD
北大核心
2010年第2期145-148,151,共5页
Science and Technology of Food Industry
关键词
欧姆加热
温度场
数学模型
电导率
ohmic heating
temperature field
mathematic model
electrical conductivity
