Experiment And Study Of Bimolecular Reactive Transport And Scale Dependence In A Single Fracture

The current large-scale human engineering activities are closely related to the bedrock fissure water,resulting in many groundwater environment problems,which have caused serious impacts and can lead to disastrous consequences.The quantization of reactive solute transport is an important precondition for the efficient repair of groundwater environment pollution in bedrock,there are still?over-prediction?and?long tail?and model parameter rule problems.To solve these problems,In this paper,we take the bimolecular reactive as an example,the aniline and 1,2-napthoquinone-4-sulfonic acid were used as the chemical reactants.Large-scale laboratory experiments and numerical simulations were carried out,and coupled with the advection-dispersion equation?ADE?and the TPL model.Summarized the experimental results in this paper,the main conclusions were drawn:?1?The results indicated that the laws of flow are non-Fickian flow in the experimental conditions,which can be simulated well using the equation of Forchheimer.?2?Under the condition of non-darcy flow,the solute transport in a non-fickian way,the phenomenon of?long tail?is becoming more and more obvious with the decrease of velocity,solute transport distance and narrow aperture increases.?3?The ADRE model can fit the bimolecular reactive experimental value,however,the non-Fickian phenomenon of product can not be simulated well.The TPL model is better than ADRE model to fit the non-Fickian phenomenon of NQAB,better coupling of these two models is what needs to be studied further.?4?At the same aperture and the same velocity,the value of D,?₀ and m increases with the increase of solute transport distance.Under the condition of the same aperture and the same transport distance,the value of D,?₀ increases with the increase of flow velocity,while the parameter m has an opposite trend.At the same flow velocity and the aperture,the values of the parameters D and?₀ generally decrease as the flow velocity increase,while the parameter m has an opposite trend.?5?Sensitivity analysis showed that the ADRE model was most sensitive by the parameters m and?₀,and the hydrodynamic dispersion coefficient D has relatively insensitive to the model.The hydrodynamic dispersion coefficient D and the parameters D have the same rule of change,by replacing the model parameters with the dispersion coefficient,the fitting accuracy and speed of ADRE can be improved.