摘要
雷击电弧热效应下风机桨叶夹层材料PVC和巴塞木的损伤机制尚不明晰。该文对PVC和巴塞木开展冲击大电流实验,发现在雷击电弧热效应下,PVC和巴塞木残余强度明显下降,且PVC下降速度更快。采用分子反应动力学仿真手段,对PVC和巴塞木的损伤机制进行研究,发现:冲击热场下,纤维素(巴塞木主要成分)大分子链逐渐断裂,聚合度呈波动下降,而PVC聚合度下降幅度比纤维素小。峰值温度为1498K时,PVC产气量远大于纤维素,而当峰值温度升至2998K时,纤维素产气量逐渐与PVC持平。纤维素分子通过氢键吸附较多水分子,在高温作用下水分受热膨胀成为纤维素损伤的关键因素,而PVC中水分含量较少。上述结果可为不同环境的风机叶片夹层材料优化选型提供参考。
Damage mechanism under lighting strikes of PVC and balsa wood which are used in the wind turbine blades remains unclear. Large current experiments were conducted on PVC and balsa wood. Stricken by lightning discharge, there was an apparent reduction in the residual strength of PVC and balsa wood, and the descending speed of PVC was larger than balsa wood. By the means of molecular reaction dynamic simulation, the damage mechanism of PVC aud balsa wood were elucidated. Cellulose in balsa wood was gradually split with the degree of polymerization （DP） indicating a wave-decrease tendency, while for PVC, there is no obvious reduction in the DP as that of cellulose. At a peak temperature 1 498 K, the gas production of PVC was much more than cellulose, while the temperature was increased to 2 998 K, the gas from cellulose pyrolysis reached the same level as PVC. In addition, much water in the air was prone to attach to cellulose by the H bond. If temperature was increased, water molecules expansion turned to be the principal factor to damage the cellulose fibers, while the density of hydrogen bond between PVC and water was much lower. The above results present useful reference for optimal selection of the sandwich structure materials of the wind turbine blades.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2017年第1期292-300,共9页
Proceedings of the CSEE
基金
国家自然科学基金国际合作重点项目(51420105011)~~
关键词
风机桨叶损伤
化学裂解
分子反应动力学
产气特性
水分子运动
damage of wind turbine blade
chemical pyrolysis
molecular reaction dynamics
gas product characteristics
water molecule movement
