基于COMSOL Multiphysics的不同水头压力下水热耦合分析

Hydrothermal Coupling Analysis under Different Head Pressures Based on COMSOL Multiphysics

摘要: 冻土的水热耦合问题一直是冻胀融沉的主要原因之一，涉及到土壤中水分的迁移、热量的传递以及相变过程。在多年冻土和季节冻土区，由于环境因素的影响，冻土路基容易发生不均匀沉降、冻胀融沉等灾害，这些灾害都与水分迁移、相变以及温度变化息息相关。为了解决冻土水热耦合问题，本文通过COMSOL Multiphysic软件建立水热耦合的二维模型，研究不同水头压力作用下同一时间段温度和压力的影响、对流出边界总热通量的影响、对总液态水体积的影响，以及对最低温度的影响进行分析，模拟了3种不同水头压力的工况。结果表明：同一时间段的温度和压力随着水头压力的增加而变化；流出边界离开系统的总热通量也随着水头压力的增大而增大；不同工况下水头梯度越大，冰块融化速度越快，达到总液态水体积最大值的时间越短。

Abstract: The hydrothermal coupling problem of frozen soil has always been one of the main reasons for frost heave and thaw settlement, involving the migration of water in the soil, heat transfer, and phase change process. In permafrost and seasonal permafrost areas, due to environmental factors, permafrost roadbeds are prone to disasters such as uneven settlement, frost heave and thaw settlement, which are closely related to water migration, phase change, and temperature changes. In order to solve the problem of hydrothermal coupling in permafrost, this paper establishes a two-dimensional model of hydrothermal coupling using COMSOL Multiphysic software. The influence of temperature and pressure at the same time period under different head pressures, the influence on the total heat flux at the outflow boundary, the influence on the total liquid water volume, and the influence on the minimum temperature are studied. Three different head pressure working conditions are simulated. The results show that the temperature and pressure during the same time period change with the increase of head pressure; The total heat flux leaving the system at the outflow boundary also increases with the increase of head pressure; The larger the head gradient under different working conditions, the faster the melting rate of ice, and the shorter the time to reach the maximum total liquid water volume.