Mixing Rules at Pore and Fracture Junctions

小行星9405837 我们建议使用一个数学模型和实验室实验来阐明混合规则在孔隙体或裂缝交界处的规模。 传统的模型假设示踪剂或污染物进入这些连接点之一，或者混合良好，或者沿着出油管通过连接点。 提出了一个元胞自动机数值模型和一个有机玻璃加工实验微观模型来研究这些限制之间存在一系列混合规则的假设。 Peclet数将用于在导致充分混合规则的扩散控制和污染物永远不会离开出油管的平流控制之间的流动中定位。 孔隙或裂缝交界处的佩克莱数定义为平均平流速度乘以孔隙/裂缝尺寸，再除以扩散系数。 在高速度和高佩克莱特数时，在分流线上几乎没有混合，产生平流控制。 在小速度和Peclet数扩散占主导地位，导致完全混合。 我们假设，这些限制之间的过渡跨越约一个数量级的Peclet数，并发生在附近的Peclet数为1。 格子气体自动机（LGA）和/或格子玻尔兹曼方法将用于数值模拟流动和运输的同时。 这些方法在Peclet数接近1时效果良好，但已经开发了一种新的算法来有效地模拟非均匀流体的稀溶液，以便在大范围内经济地改变Peclet数，同时保持雷诺数恒定。 实验方法采用有机玻璃的物理微观模型的路口，由四个相交的渠道。 为了适应预期范围的Peclet数，低雷诺数，和合理的实验时间常数，通道和流速必须相当小。 在低流速和Peclet数下，实验对泄漏、温度波动和其他问题非常敏感。 我们建立了一个实验的初步版本，以阐明和解决这些问题。 元胞自动机模拟和物理微观模型将被用来探索混合与不同的组合进入和退出流量，并与不同的结的几何形状。 然后，我们将与其他研究人员合作，将规则应用于多孔系统的渗流网络模型和各种裂缝网络系统，以确定混合规则的空间分布，以及它们对机械和宏观分散计算的影响。 通过合作，我们将在网络中模拟混相驱替实验，混合，不混合和自适应混合规则，以进一步研究混合条件的范围。

9405837 Wilson We propose to use a mathematical model and laboratory experiments to elucidate the mixing rule at the pore body or fracture junction scale. Traditional models have assumed that tracers or contaminants entering one of these junctions are either well mixed, or follow flowlines through the junction. A cellular automata numerical model and a machined Lucite experimental micromodel are proposed to investigate the hypothesis that there is a range of mixing rules between these limits. The Peclet number would be used to position in flow between diffusion control leading to the well mixed rule, and advection control, with contaminants never leaving a flowline. A pore or fracture junction Peclet Number is defined as the mean advective velocity times pore/fracture size, divided by the diffusion coefficient. At high velocities and high Peclet Numbers there is little mixing across the dividing stream line, yielding advective control. At small velocities and Peclet numbers diffusion dominates, resulting in complete mixing. We hypothesize that the transition between these limits spans about an order of magnitude of Peclet numbers, and occurs near a Peclet number of 1. Lattice gas automata (LGA) and /or lattice Boltzman methods will be used to numerically simulate flow and transport simultaneously. These methods work well for Peclet numbers near one, but a new algorithm has been developed to efficiently model dilute solutions of non-homogeneous fluids in order to economically vary Peclet number over a large range, while holding Reynolds number constant. The experimental approach employs a Lucite physical micromodels of a junctions, consisting of four intersecting channels. In order to accommodate the expected range of Peclet numbers the low Reynolds number, and reasonable experimental time constants, the channels and flow rates must be quite small. At low flow rates and Peclet numbers the experiment is very sensitive to leaks, temperature fluctua tions, and other problems. We built a preliminary version of the experiment to elucidate and solve each of these problems. The cellular automata simulations and the physical micromodel will be used to explore mixing with different combinations of entering and exiting flow rates, and with different junction geometries. We will then work with other investigators to apply the rules to percolation network models of porous systems, and various fracture network systems, to determine the spatial distribution of mixing rules, and their effect on mechanical and macro-dispersion calculations. Through collaborations we will simulate miscible displacement experiments in the networks, with mixing, no-mixing and adaptive mixing rules, to further investigate the range of mixing conditions.