二維多物種反應化學傳輸半解析解

A SEMI-ANALYTICAL MODEL FOR SIMULATING TWO-DIMENSIONAL MULTISPECIES REACTIVE TRANSPORT

陳瑞昇(Jui-Sheng Chen) ； 凃佑霖(You-Lin Tu) ； 張正弘(Cheng-Hung Chang) ； 王聖瑋(Sheng-Wei Wang)

《農業工程學報》 66卷1期 (2020/03) Pp. 2-10

https://doi.org/10.29974/JTAE.202003_66(1).0001

摘要

耦合一階序列降解／衰變反應的多物種移流－延散方程式可用來預測放射性核種、氮、含氯溶劑等降解性或衰變性污染物在地下水系統中遷移的行為。文獻中可發現的解析解主要是針對一維地下水系統，然而多維度解析解更是具真實世界的實用性。文獻中可發現多維度解析解，但主要考慮有限域地下水系統，有限域解析解通常包含無窮級數的累加，使得該解析解的數值耗時且低效率。因此本研究發展一個全新的二維半無限域半解析解模式，所發展的半解析解模式與文獻中二維有限域解析解模式來驗證，結果顯示兩個模式所得結果相當吻合，驗證了解的正確性與準確性。此外，所發展的半解析解模式的計算時間只有二維有限域解析解模式的1/7。本研究發展的半解析解模式為精確且高效率計算的模擬降解性或衰變性污染物遷移的工具。

關鍵字

半解析解 ； 有限域 ； 半無限域 ； 降解 ； 衰變

並列摘要

Multispecies advection-dispersion equations coupled with sequential first-order decay reactions is widely to predict the plume migration behaviors of degradable or decaying contaminants such as radionuclides, nitrogen and chlorinated solvents in the groundwater system. Although researchers attempted to develop analytical solutions to coupled advection-dispersion equations, the available analytical solutions in the literature are mostly derived for a one-dimensional transport system. Analytical solutions for multi-dimensional coupled multispecies transport are important and needed for real world application, whereas only relatively rare analytical solutions for a finite-domain transport system were derived. The solutions for transport in a finite domain generally involves a summation of infinite series expansions, making numerical evaluations of the solutions always time-consuming and inefficient. This study presents a novel semi-analytical model for rapid simulating two-dimensional plume migrations of all the members in a decay chain. The verification of the developed model is established by an excellent agreement between the derived model and with an analytical model in the literature derived for a finite domain. Moreover, the computational time for numerical evaluations of the derived solution is only 1/7 of the computational time for the solution derived for a finite domain. The derived semi-analytical model is an accurate and computationally efficient tool for simulating plume behaviors of degradable and decaying contaminants.

並列關鍵字

Semi-analytical ； Finite domain ； Semi-infinite domain ； Degradation ； Decay