双热源作用下土壤高温热湿迁移数值模拟

SIMULATION OF HIGH-TEMPERATURE HEAT AND MOISTURE MIGRATION IN SOIL WITH DOUBLE HEAT SOURCES

建立双热源作用下低饱和度土壤高温热湿迁移过程的数学模型,并进行数值求解,其中考虑固相颗粒间水蒸气迁移的影响。结果表明,随着热源温度增加,砂土温度呈整体升高趋势,同时湿度变化也十分剧烈,其中热源附近的湿度呈先快速减小后逐渐增大趋势;而远离热源处的湿度呈先增大后逐渐减小趋势。与砂土相比,粘土的温度场和湿度场变化较微弱。随着热源间距增大,土壤温度场达到稳定的时间有所延长,且土壤湿度峰值的出现时间整体向后推迟。当砂土和粘土的初始饱和度分别在20%和30%附近时,水蒸气迁移效应会明显缩短土壤温度场达到稳定的时间;而当土壤趋向于干燥或饱和状态时,上述效应呈逐渐减弱趋势。

Considering the thermal vapor diffusion, a numerical model describing high-temperature heat and moisture migration in soil with double heat sourees was built and solved. Results showed that with the increase of the heat souree temperature, the temperature tends to be higher and the moisture content varies dramatieally in sand. Especially, the moisture content near the heat source decreases quickly and then grows gradually, while the moisture content far from the heat source grows at first and then decreases gradually. Compared with the sand, the temperature and moisture content in clay vary weakly. With the increase of the distance between two heat sources, the time reaching the steady soil temperature as well as the peak soil moisture content becomes longer. It is found that when the initial saturation is about 20% for sand and 30% for clay, respectively, the vapor diffusion effeet can greatly reduce the time reaching a steady soil temperature. When the soil tends to be dry or saturated, the above effect tends to be weakened.