芳纶纸高温压光过程冷却段的传热模拟研究

Heat Transfer Simulation of Cooling Phase in High Temperature Calendering Process of Aramid Paper

关键词:  芳纶纸  压光  传热  模拟

Key Words:aramid paper  calender  heat transfer  simulation

摘要:经过320℃高温压光的芳纶纸在出压区冷却过程中纸面温度会急剧变化，导致纸幅收缩会对卷曲造成不利影响。为探究芳纶纸出压区后的降温情况，利用牛顿冷却定律和对比参量公式推导出芳纶纸低速热压光过程中的传热方式，借助Matlab软件模拟计算了单辊加热下芳纶纸离开压区后的温度，并与纸张的实际温度测量值进行了对比。结果表明，在压光机车速10 m/min、压光温度320℃条件下，芳纶纸出压区后的热对流形式以自然对流为主；芳纶纸在出压区初期降温较明显，在1 m的特征长度内芳纶纸的温度降至50.2℃，在5 m的假设特征长度内，芳纶纸的温度降至室温。

Abstract:After being calendered at 320℃， the aramid paper would cool down quickly after exiting the pressure zone， resulting in paper shrinkage and affecting the winding process. The cooling process was simulated by Newton’s Cooling Law and the Contrast Parameter Formula， and the temperature of the paper after being heating and leaving pressing zone was calculated using the Matlab software.The experiments were executed to compare the simulated data with the actual results for validation of the simulation model. In these experiments， the pilotcalender machine operation conditions were controlled that only one roll was heated to 320℃ and the other roll was not heated. From the results， it could be concluded that the simulation program predicted very well the behavior of heat transfer in the aramid paper. The results also showed that the heat transfer after exiting the nip was dominated by natural convection when the speed of machine was 10 m/min. The temperature of the paper droped so quickly that it decresed to 50.2 ℃ when it left the nip only 1 meter and it would reached to room temperature when the distance was 5 meters.