基于Fluent的纸浆模塑热压定型加热板温度均匀性分析

模内热压定型是纸浆模塑餐具生产过程中的一种常用干燥方式，它是将成型后获得的湿纸模胚在被模具挤压与抽真空的条件下进行加热。加热板作为热压定型机的热源，其工作表面的温度均匀性影响着制品的干燥质量。针对纸浆模塑热压定型过程中加热板的温度不均匀性问题，文中提出了一种联合仿真与正交试验的优化方法。首先，对加热板的工作过程进行分析，建立了加热板的传热模型；然后，基于Fluent对加热板进行温度场的数值模拟，根据温度场分布结果将油路结构中的高温区域与低温区域尽可能交错，设计了4种新的迷宫式油路结构；最后，以油路结构、油路平面高度、加热板厚度和油路截面直径设计了4因素4水平的正交试验，并进行了极差分析与方差分析。结果表明：在实际干燥过程中，工作表面的最高温度为224.47℃，最低温度为209.92℃，温度极差高达14.55℃，温度标准差为3.01℃；加热板厚度和油路直径的大小对温度极差的影响显著，油路结构对温度标准差的影响显著。基于以上分析改进了加热板的结构，与原设计方案相比，加热板工作表面的温度极差降至7.27℃，温度标准差降至1.09℃，保证了加热板温度的均匀性，提升了纸浆模塑产品的质量。

Analysis of Temperature Uniformity of Pulp Molding Hot Pressing Heating Plate Based on Fluent Simulation

In-mold hot-pressing is a common drying method in the production of pulp moulded tableware. The wet paper mold embryo obtained after moulding is heated under the condition of extrusion and vacuum. Heating plate is the heat source of hot-pressing machine, and the temperature uniformity of its working surface affects the drying quality of products. Aiming at the temperature non-uniformity of the heating plate in the process of pulp molding hot pressing, this paper proposed an optimization method which combined simulation and orthogonal experiment. Firstly, the working process of heating plate was analyzed and the heat transfer model of heating plate was established. Then, based on Fluent, the temperature field was simulated numerically. According to the results of temperature field distribution, the high-temperature area and low-temperature area in the oil circuit structure were staggered as far as possible, and four new labyrinth oil circuit structures were designed. Finally, an orthogonal test with 4 factors and 4 levels was designed based on the structure of oil circuit, the plane height of oil circuit, the thickness of heating plate and the section diameter of oil circuit, and the range analysis and variance analysis were carried out. The results show that during the actual drying process, the maximum temperature and minimum temperature of the working surface are 224.47 ℃ and 209.92 ℃, respectively, and the temperature range is as high as 14.55 ℃ and the temperature standard deviation is 3.01 ℃. The thickness of heating plate and the diameter of oil passage have a significant influence on the temperature difference, and the structure of oil passage has a significant influence on the temperature standard deviation. Based on the above analysis, the structure of heating plate was improved. Compared with the original design, the temperature range of the working surface of heating plate has been reduced to 7.27 ℃ and the temperature standard deviation has been reduced to 1.09 ℃, which ensures the uniformity of temperature of heating plate and improves the quality of pulp molded products.