黄土土柱加热加速蒸发的试验模拟研究

Abstract

Abstract:The water vapor diffusion can be enhanced by the heating from municipal solid waste, and significantly impact the evaporation process in the earthen final cover. The parameters associated with the water vapor diffusion are usually measured by using the instantaneous profile method. This method is very time-consuming because the drying process lasts a long time. In this study, a bottom heating method is proposed to accelerate the drying process in a loess soil column. A constant temperature of 70 °C is applied at the bottom of the soil column. The thermo-hydraulic response of the loess is monitored along the soil column. A numerical model is developed to simulate the coupled thermo-hydraulic process. The numerical model is used to back analyze the tortuosity τ of the loess for vapor diffusion and the parameter a of an empirical evaporation function. We found that the bottom heating accelerated the drying process of the soil column by almost 22 d compared with the conditions without heating under the same evaporation boundary. Before Day 15, the proportions of the enhanced vapor flux in the total water loss were higher than 50%, dominating the evaporation process. The experimental and numerical study demonstrated that the proposed heating method is able to obtain the parameters of vapor diffusion more efficiently than the conventional method.

Effects of clay content on the volumetric behavior of loess under heating-cooling cycles

“…In the field, temperatures within earthen final covers vary in a wide range. According to previous studies (Dach and Jager, 1995;Liu XC et al, 2016), the soil temperature in an earthen final cover could increase to approximately 70 °C due to the heat generated by the waste decomposition. On the other hand, as a typical semi-arid climate region, the atmospheric temperature in northwestern China varies from subzero to several dozen degrees Celsius.…”

Development of BAS2 for determination of evaporative fluxes

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