Joint impact of the scaling and hysteresis on the NAPLs flow simulation
Hung-Hui Chen1, Liang-Cheng Chang2, Hsin-Yu Shan3
Abstract
The hysteresis of capillary pressure versus saturation (P-S) relation is an important constitutive relation in multiphase flow and the scaling rule for P-S relation is widely used to predict P-S relations in the simulation of NAPLs. This research examined the performance of the scaling rule on predicting the P-S relationship, and then studied the joint impact of the scaling and hysteresis on the multiphase NAPL flow simulation. Various experimental P-S values of distinct fluid-pairs were compared with the scaled P-S curves using the scaling rule. The comparison indicates that the prediction of P-S is more accurate when the water-air P-S curve is used to scale other P-S curves. The joint impact of the scaling and hysteresis on NAPLs flow simulation was then investigated by numerical simulation studies. The NAPL Simulator was used to simulate the outcome of several scenarios based on a system with water-NAPL-air in a hypothetical sand tank. For both gasoline and TCE, the difference of the injected NAPL volume between no hysteresis and hysteresis simulations over a given time period was the smallest when the water-air P-S curve was used to scale other P-S curve. Results of this study are valuable references for predicting the distribution of NAPLs using simulation.
Keywords: NAPL; Hysteresis; scaling rule
1. Introduction
The contamination of groundwater caused by including organic solvents, such as trichloroethylene (TCE), tetrachloroethylene (PCE) and other petroleum-based products has raised inevitable concerns because of its serious threat to human health. Most of these organic solvents are liquid phases in the subsurface with no solubility in water and are known as non-aqueous phase liquids (NAPLs). These NAPLs or their solutions, even at low concentrations they still can have severe effects on human health...