混凝土对流换热系数的风洞实验研究

A study on the convective heat transfer coefficient of concrete in wind tunnel experiment

提出混凝土表面对流换热系数的实验方案,试件的形式为圆管,从内部加热,安装在TJ-1风洞内,圆管的轴线与风向一致,风速调节范围为1m/s至25m/s,利用专门开发的实验控制系统全自动监控加热过程并自动记录数据。3个试件的实验结果有很好的一致性。实验结果表明,混凝土表面对流换热系数与风速、混凝土表面热辐射系数与温差之间均有很好的线性相关性。由实验结果回归分析得到混凝土表面受迫对流换热系数、混凝土表面热辐射系数、混凝土表面总热交换系数的计算公式,为混凝土结构温度效应分析中热工参数取值提供了依据。

An experimental method is developed for measuring the convective heat transfer coefficient of concrete surface. The test specimen is in the form of a circular tube, heated from inside, and installed longitudinally in a TJ-1 wind tunnel. The wind speed varies from 1 m/s to 25 m/s, the heating process is controlled and the test data recorded automatically via a specially developed control system. The test results of the three concrete tube specimens agree with each other very well. There exist linear correlations between the convective heat transfer coefficient of concrete surface and wind speed, the radiation coefficient of concrete surface and the temperature difference. The formulae for calculating the convective heat transfer coefficient, the radiation coefficient, and the total heat transfer coefficient of concrete surface are derived based on analyses of the experimental results.