Mathematical and Experimental Studies of Dispersion in Porous Media

横向扩散的准确定量评估在水文地质、环境工程和其他领域至关重要，因为这一过程会影响溶质稀释和反应物的混合。在许多情况下，生化反应的速度取决于横向弥散系数。这项研究的主要目标是开发和测试一种新的实验室测量横向色散的方法。虽然已有实验室测量多孔介质中横向弥散的方法，但它们都是基于直接测量这一量的概念，由于横向弥散系数很小，这是非常困难的。所提出的方法是基于从测量的量得出的横向色散与其成反比的推断。这项工作将开发和测试一种测量均匀同位素多孔介质中横向色散的装置。我们将测量螺旋流场中的泰勒弥散系数。较小的横向色散意味着较大的泰勒色散系数，很容易从穿透曲线中推断出令人满意的精度。将通过实验和数学模型对装置内的流动和传输进行评估。此外，我们还将对几种松散的多孔介质进行实验，以评估分散性随颗粒大小和分布、填料类型以及其他变量的变化情况。

0001441KitanidisThe accurate quantitative evaluation of transverse dispersion is crucial in hydrogeology, environmental engineering, and other fields because of the way this process affects solute dilution and mixing of reactants. In many cases, the rate of biochemical reactions depends on the transverse dispersion coefficient. The primary objective of this research is to develop and test a new laboratory method for measuring transverse dispersion. Although there are methods for the laboratory measurement of transverse dispersion in porous media they all are based on the concept of measuring this quantity directly, which is very difficult because transverse dispersion coefficients are small. The proposed method is based on the inference of transverse dispersion from measurements of a quantity is inversely proportional to it. This work will develop and test a device for measurement of the transverse dispersion in homogeneous isotopic porous media. We will measure the Taylor dispersion coefficient in a spiral flow field. A small transverse dispersion means a large Taylor dispersion coefficient that is easy to infer with satisfactory accuracy from the breakthrough curve. The flow and transport in the device will be evaluated through experiments and mathematical modeling. Additionally, we will perform experiments with several unconsolidated porous media in order to evaluate the behavior of dispersivity with grain size and distribution, type of packing, and other variable.