Zeng Haoyu, Lu Chao, Zhang Li, Yang Tianran, Jin Ming, Ma Yuefeng, Liu Jiaping
School of Material Science and Engineering, Southeast University, Nanjing 211189, China.
Division of Science and Technology Management, China Three Gorges Corporation, Wuhan 430010, China.
Materials (Basel). 2022 Feb 17;15(4):1510. doi: 10.3390/ma15041510.
Temperature distribution in concrete is significant to the concrete structure's macro properties and different factors affect the heat transfer in concrete, and therefore influence the temperature distribution. This work established a three-dimensional transient heat transfer model coupled with various environmental factors, using the finite element method for calculating the results and real-measured data for testing accuracy. In addition, a sensitivity evaluation of various factors was conducted. Due to various environmental factors, the results revealed that the prediction of temperature distribution in concrete by the three-dimensional model had great accuracy with an error of less than 4%. A particular hysteresis effect of temperature response in the concrete existed. Considering heat transfer in different spatial directions, the model can predict the temperature change of each spatial point instead of the spatial surface in different depths, proving the shortcomings of a one-dimensional heat transfer model. A greater solar radiation intensity caused a more significant temperature difference on the concrete surface: the surface temperature difference in July was twice as significant as that in December. Wind speed had a cooling effect on the concrete surface, and stronger wind speed accompanied with a stronger cooling effect made the surface temperature closer to the ambient temperature. Material properties had different effects on the temperature distribution of the surface part and internal part: the specific heat capacity determined the speed of the outer layer temperature change while the thermal conductivity determined the speed of the inner layer temperature change.
混凝土中的温度分布对混凝土结构的宏观性能具有重要意义，不同因素会影响混凝土中的热传递，进而影响温度分布。本研究建立了一个与各种环境因素耦合的三维瞬态热传递模型，采用有限元方法计算结果，并使用实测数据检验准确性。此外，还对各种因素进行了敏感性评估。结果表明，由于各种环境因素的影响，三维模型对混凝土温度分布的预测具有很高的准确性，误差小于4%。混凝土中存在特定的温度响应滞后效应。考虑到不同空间方向的热传递，该模型可以预测每个空间点的温度变化，而不是不同深度的空间表面的温度变化，证明了一维热传递模型的不足。太阳辐射强度越大，混凝土表面的温差越显著：7月的表面温差是12月的两倍。风速对混凝土表面有冷却作用，风速越强，冷却效果越强，使表面温度更接近环境温度。材料性能对表面部分和内部部分的温度分布有不同影响：比热容决定外层温度变化的速度，而导热系数决定内层温度变化的速度。
