食品欧姆加热过程中不同电极形状的温度场分布的数值模拟

NUMERICAL SIMULATION OF TEMPERATURE FIELD DISTRIBUTION DURING FOOD OHMIC HEATING BY ELECTRODES WITH DIFFERENT SHAPES

为了了解5种不同电极板形状对食品欧姆加热中物料的温度场分布及加热效率的影响,建立了不同电极形状的欧姆加热三维模型,利用有限元的方法求解欧姆加热过程中模型的温度场和电场方程,模拟分析了矩形、圆形以及弧形电极的欧姆加热过程中的温度分布.结果表明:食品的欧姆加热过程中温度场的分布与电极的形状有很大的关系,弧形电极的欧姆加热过程中,电流密度的分布与电极的弧度有关,电极的曲率越大,电场线越密集,电势梯度增大,加热过程中温度场分布越不均匀;矩形与圆形电极的欧姆加热效果相同,其电场分布及加热效率都一致.

We studied the temperature field distribution and the heating efficiency of materials heated by five electrode plates with different shapes during food ohmic heating process,constructed the three-dimensional ohmic heating models for different electrodes,solved the temperature field equation and the electric field equation of the ohmic heating models by finite element methods,and simulated the temperature field distributions of the ohmic heating process of a rectangular electrode,a round electrode and an arc-shaped electrode.The results showed that the temperature field distribution of the food ohmic heating process had a strong relation with the electrode shape;the current density distribution was related with the radian of the electrode during the ohmic heating process of the arc-shaped electrode,that is to say,the larger electrode curvature resulted in denser electric field lines,larger potential gradient and more nonuniform temperature field distribution;and the rectangular electrode and the round electrode had the same ohmic heating effect,and the same electric field distribution and heating efficiency.