在部分和斯麦克石中扩散和气体流动力学.
Jerry P Owusu1,2, Konstantinos Karalis2, Nikolaos I Prasianakis1
1Laboratory for Waste Management, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland.
概括
分子动力学模拟揭示了像He,H2,CO2,Ar和CH4这样的气体如何通过部分和的粘土迁移. 粘土毛孔中的气体扩散和分离取决于和度,毛孔宽度和温度.
科学领域:
- 地质化学 地质化学
- 材料科学 材料科学 材料科学
- 化学工程是化学工程的重要组成部分.
背景情况:
- 粘土是核废物处理的关键自然和人工障碍.
- 从废物降解中产生的气体需要通过粘土屏障进行迁移,以防止压力增加.
- 部分和土中的气体迁移涉及通过水膜和气体充满的孔隙的运动.
研究的目的:
- 为了研究不同和度下的Na-montmorillonite中相孔中的气体分子流动性 (He,H2,CO2,Ar,CH4).
- 为了评估部分和粘土中孔液的水力动力学行为.
- 了解气体在富含水和富含气体的阶段之间的分割,以及其对环境因素的依赖.
主要方法:
- 经典分子动力学 (MD) 模拟以确定气体扩散系数和分区.
- 不平衡分子动力学 (NEMD) 模拟用于研究不同动态状态下的气体流动性和粘度.
- 开发Bosanquet类型方程,以根据孔状特征预测气体扩散和粘度.
主要成果:
- 气相中的气体扩散随着孔隙宽度的增加而增加,接近散装扩散.
- 在水膜中的气体扩散在散装相中保持不变,但在非常薄的膜中发生变化.
- 气体分离与散装相相似,取决于温度和气体分子量;在微观尺度上,滑动边界条件是必要的.
结论:
- 粘土屏障中的气体迁移是复杂的,受到和,孔隙结构和流体相相互作用的影响.
- 分子动力学模拟为纳米规模的气体运输机制提供了关键的见解.
- 开发的Bosanquet类型方程可以帮助建模地质仓库中的气体运输.
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