饱和多孔介质中颗粒释放-迁移问题的理论求解

Theoretical solution of particle release-transport in saturated porous media

饱和多孔介质中颗粒释放迁移特性的研究在地下污染物处置、地下水开采、核废料处置、城市固体废弃物填埋等方面有很重要的研究意义.对经典的颗粒迁移模型进行修正,建立一种饱和多孔介质中颗粒释放-迁移模型,给出点源和线源形式下的瞬时释放和释放浓度按指数规律衰减情况的解析解.分析了线源浓度按指数规律衰减情况的弥散系数、衰减系数、线源宽度、时间和距离等的影响机理.研究结果表明:随着时间或距离增大,多孔介质中迁移颗粒的浓度先增大后减小.弥散系数越大,迁移颗粒的浓度峰值越小.其次,衰减系数对迁移颗粒的浓度有较大的影响,衰减系数越大,相应的浓度峰值越小.另外,经典模型未在沉积动力方程中考虑弥散作用的影响,使得经典模型的预测结果普遍偏小.

Particle release and transport in saturated porous media is of great significance in underground pollutants treatment, groundwater exploration, nuclear waste disposal and municipal solid waste landfill. A modified model for particle release and transport was developed, and specific solutions to instantaneous release and concentration decay for point source and line source were given. The solution of concentration decay were analyzed to determine the influences of dispersion coefficient, attenuation coefficient, line source width, time and space. The research shows that the particle concentration increases first and then decreases with the increasing of time or distance. The peak concentration decreases with dispersion coefficient. Besides, attenuation coefficient affects the particle concentration. The peak concentration decreases with attenuation coefficient. Additionally, the effect of the dispersive flux was not taken into account in the classic deposition equation, leading to a lower predicted result.