Model experimental study on the influence of moist air on the hydrothermal properties of open crushed rock layers
Warming and humidification trend of the Qinghai-Xizang Plateau is becoming increasingly severe,and the water vapor mass fraction in the air seasonally varies,resulting in changes in air physical parameters,enthalpy values,etc.,which may indirectly affect the heat transfer process of the crushed rock structural em-bankment.This paper analyzes the hydrothermal characteristics inside the crushed rock layer in dry and wet air under the same pressure conditions based on model experiments and air thermodynamics theory.The results indi-cate that under isobaric conditions,the temperature difference between dry and moist air is positively correlated with water vapor mass fraction,and the changing rate in water vapor mass fraction is 8%lower than the varying rate of temperature difference.The surface sensible heat flux of crushed rock considering the thermal influence of vapor was calculated based on the surface energy balance method,and it was found that the difference in sensi-ble heat flux under the two air conditions is also positively correlated with water vapor mass fraction.At this time,the changing rate of water vapor mass fraction is 9.8%higher than the varying rate of sensible heat flux difference.After sunrise,the convective heat transfer difference between dry and moist air and the deep-layer rock mainly depends on the relative humidity of the air.After sunset,due to the large temperature difference be-tween dry and moist air,it is mainly influenced by the temperature difference.When the water vapor mass frac-tion is at a low level,the changing rate in enthalpy difference between dry and moist air is about 87%higher than the changing rate in water vapor mass fraction,and the changing rate in enthalpy difference is about 21%higher than the rate of change in water vapor mass fraction.This phenomenon becomes more pronounced as the water vapor mass fraction decreases.The research results are of great significance for evaluating and predicting the long-term thermal stability of crushed rock structural embankment considering humid air conditions in permafrost regions.
crushed rock embankmenthydrothermal characteristicsmodel experimentsenthalpysensible heat flux
NETL
NSTL
万方数据
