寒旱地区混凝土箱形渡槽湿热耦合效应

针对冬季渡槽的湿热全耦合效应问题,避免渡槽在冬季输水过程中出现裂缝现象,以寒旱地区某渡槽为工程背景,利用湿热耦合传输理论分析,实测2023年1月5至1月20日的环境温度、环境湿度及风速,采用Fluent有限元软件建立了不同环境参数的混凝土箱形渡槽温度场、湿度场、湿热耦合场有限元模型。并分析不同工况对冬季渡槽的非耦合和全耦合状态下的温度效应的影响。分析结果表明,渡槽通水时冬季最不利温差为-14.7℃,不通水时为-6.3℃；渡槽通水时冬季最不利横向温差为-10.2℃,不通水时为-6.2℃；在湿度扩散过程中,沿板厚方向湿度由内向外逐渐减小,且吸水速度随时间的增大而减小；在湿热耦合过程中,全耦合场温度值小于非耦合场温度值,湿热全耦合作用的挠度变化值小于湿热非耦合作用下的挠度变化值,湿热耦合作用的拉应力小于湿热非耦合作用下的拉应力值,因此,湿热全耦合作用对渡槽结构变形有利。

Wet heat effect of concrete box aqueduct in cold and arid areas Simulation analysis

Aiming at the problem of moist and thermal coupling effect of winter aqueduct, the finite element model of temperature field, humidity field and humid heat coupling field of concrete box aqueduct with different environmental parameters is established by using Fluent finite element software. Taking an aqueduct in Northwest China as an example, the ambient temperature, ambient humidity and wind speed from January 5 to January 20, 2023 were measured, and the influence of different working conditions on the temperature effects of the aqueduct in the uncoupled and fully coupled state in winter was analyzed. The analysis results show that The most unfavorable temperature difference in winter when the aqueduct is open to water is -14.7 °C and -6.3 °C when it is not water; the most unfavorable transverse temperature difference in winter when the aqueduct is open to water is -10.2 °C and -6.2 °C when no water is not connected; in the process of humidity diffusion, the humidity in the direction of plate thickness gradually decreases from inside to outside, and the water absorption rate decreases with the increase of time; in the process of moist and thermal coupling, the temperature value of the fully coupled field is less than the temperature value of the non-coupling field, the deflection change value of the fully coupling action of humidity and heat is less than the deflection change value under the non-coupling of humidity and heat, and the tensile stress of the moist and thermal coupling action is less than the tensile stress value under the non-coupling of moist heat, therefore, the full coupling of humidity and heat is beneficial to the deformation of the aqueduct structure.