挂面烘房湿度系统建模与验证

Modeling and Verification of Humidity System of the Room for Noodle drying

挂面烘房内的湿度是挂面干燥成形工艺过程中的重要物理量,其中湿度的自动调节对提高产品质量、生产效率和减轻工人劳动强度至关重要。为实现自动湿度控制,建立了挂面烘房湿度系统的动态模型。模型考虑了挂面脱水和风机排潮两个基本物理过程,它们分别通过水分蒸发和通风影响着湿度系统。根据从烘房正常生产条件下采集到的温湿度数据,通过系统辨识方法估计模型参数。利用大量实测数据对动态模型进行仿真,结果显示水蒸气密度和湿度的仿真值与实测值的均方根误差分别为1.04 g/m3、1.63%,证明了模型的准确性。最后分析了仿真结果,指出了现有风机排潮策略的不足和改进办法。

Humidity is of critical importance among the physical variables in the process of drying and shape-forming of vermicelli. The automatic regulation of humidity is certainly positive for the quality of the final product, the efficiency of the production line, and also for the save of tedious labor. Aiming at automatic control of humidity in the drying room, a dynamic model of the humidity system is established. Two physical processes in noodle drying are considered in the model, namely the process of dehydration of noodles and the process of humidity exhaust through fans. The both processes affect the humidity system through the investigation of water evaporation and moisture ventilation. The model parameters are estimated through system identification methods based on the data of humidity and temperature sampled from the drying room of the production line in normal working conditions. A large amount of measured data is used to simulate the model, and the results indicated that the root-mean-square errors between the simulated values and measured values of water vapor density and humidity are respectively 1.04 g/m3 and 1.63%, indicating the accuracy of the model. After analyzing the simulation results, the shortcomings of the existing dehumidification strategy of the fan and the improvement methods are pointed out.