基于COMSOL模型的黑土农耕地剖面冻结水热耦合分析  

Hydrothermal Coupling Analysis of Freezing Process of Black Soil Farmland Profile Based on COMSOL Model

作　　者：蒋瑶钰 王彬[1] 陈祖明 王文刚 JIANG Yaoyu;WANG Bin;CHEN Zuming;WANG Wengang(School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083)

机构地区：[1]北京林业大学水土保持学院,北京100083

出　　处：《水土保持学报》2023年第6期187-193,共7页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(41977060)。

摘　　要：为量化分析典型黑土农耕地在冻结过程中的剖面水热耦合特征,以东北典型黑土区耕层土壤为研究对象,通过室内单土柱模拟试验,并结合COMSOL Multiphysics模型PDE模块,实现黑土冻结过程中温度场与水分场的耦合求解。结果表明:(1)COMSOL模型可实现黑土剖面冻结过程的水热耦合分析,温度场(R~2=0.83,RMSE=0.91℃)与水分场拟合效果(R~2=0.88,RMSE=0.02 cm/cm^(3))均较好,可满足拟合精度需要;(2)黑土农耕地剖面温度的变化速率呈先快速冷却后缓慢趋于稳定的变化趋势,且越接近冷端,土壤温度下降至稳定阶段的速率越快;(3)黑土农耕地剖面水分场在冻结过程中呈明显的水分重分布现象,且在冻结峰面呈现暖端聚集速率快[0.000 93~0.001 00 cm/(cm^(3)·h)]而冷端反之[0.000 34~0.000 42 cm/(cm^(3)·h)]的冰晶聚集现象。研究结果可为黑土冻结水热运移规律分析提供技术支持,并为黑土冻融—水力复合侵蚀机理研究和剖面水热动态模拟提供理论基础。To quantitatively analyze the coupling characteristics of water and heat in the profile of typical black soil cultivated land during the freezing process,the topsoil in the typical black soil region in NE China was taken as the research object.Through indoor single soil column simulation experiments and combination with COMSOL Multiphysics model PDE module,the coupling solution of temperature field and moisture field during black soil freezing process was achieved.Results showed that:(1)The COMSOL model could realize the hydrothermal coupling analysis of the freezing process of black soil profile,and the fitting effect of temperature field(R2=0.83,RMSE=0.91℃)and water field(R2=0.88,RMSE=0.02 cm/cm^(3))was good,which could meet the fitting accuracy requirements.(2)The temperature change rate of black soil cultivated land profile exhibited a trend of rapid cooling followed by a slow approach to stability,and the closer to the cold end,the faster the rate at which soil temperature decreased to the stability stage.(3)The frozen black soil cultivated land profile underwent significant water redistribution during the freezing process.An ice crystal aggregation phenomenon was observed at the warm end,which occured at a fast rate,while the cold end showed the opposite phenomenon[0.00034~0.00042 cm/(cm^(3)·h)].The research results can provide technical support for analyzing the water heat transport law of frozen black soil,as well as a theoretical basis for the study of the mechanism of frozen thawing and hydraulic composite erosion of black soil profiles and dynamic simulation of water-heat in profiles.

关 键 词：水热耦合 温度场 水分场 冻融侵蚀 

分 类 号：S157.1[农业科学—土壤学]