A Multiscale Finite Element Framework for Reactive Contaminant Transport in Heterogeneous Porous Media

2008 ◽  
Author(s):  
K. B. Nakshatrala ◽  
A. J. Valocchi
Keyword(s):  
Reactive Transport ◽  
Chemical Species ◽  
Interfacial Area ◽  
Heterogeneous Porous Media ◽  
Major Influence ◽  
Small Scale ◽  
Full Resolution ◽  
Scale Heterogeneity ◽  
Reactive Pollutant ◽  
Reservoir Description

Mixing of chemical species across plume boundaries has a major influence upon the fate of the reactive pollutant in the subsurface. Small-scale heterogeneity leads to irregular plume boundaries which enhances mixing-controlled reactions through increasing the interfacial area of the plume. Therefore, it is crucial to capture this small-scale heterogeneity in order to properly model reactive transport. Unfortunately, computational limitations do not permit full resolution of the smallest scales of heterogeneity as the size of geomodels used for reservoir description typically exceeds by several orders of magnitude the capabilities of conventional reservoir simulators. Thus, it is necessary to use a coarse numerical grid, particularly for the cases with a large number of reactive species.

scholarly journals Modelling of kinetic interface sensitive tracers reactive transport in 2D two-phase flow heterogeneous porous media

2019 ◽  
Vol 85 ◽  
pp. 07003 ◽  
Author(s):  
Alexandru Tatomir ◽  
Dejian Zhou ◽  
Huhao Gao ◽  
Alexandru-Nicolae Dimache ◽  
Iulian Iancu ◽  
...  
Keyword(s):  
Reactive Transport ◽  
Interfacial Area ◽  
Breakthrough Curves ◽  
Heterogeneous Porous Media ◽  
Contaminant Removal ◽  
Geothermal Systems ◽  
Two Phase ◽  
Gas Recovery ◽  
Two Fluids ◽  
Oil Gas

Fluid-fluid interfacial area plays an important role for mass- and energy-transfer processes across the interface which is relevant in several hydrogeological and engineering applications, e.g. enhanced oil-gas recovery, CO2 storage in geological formations, unconventional geothermal systems, contaminant removal, etc. Kinetic interface sensitive tracers were designed to determine the size of the interface between two fluids by undergoing hydrolysis at the fluid-fluid interface. This study investigates by means of numerical modelling the influence of heterogeneity on the KIS tracer breakthrough curves in six idealized scenarios (S1-S6). It is an extension of the previous work conducted in “one-dimensional” column experiments by Tatomir et al. (2018) [1]. The changes in interfacial area are created by inclusion of heterogeneities at the Darcy-scale. The results show that KIS tracers can be used in two-dimensional experimental setup and can provide information about the size and dynamic evolution of interfacial area. Therefore, this is a first step for the dimensioning of an experimental flume.

scholarly journals Transformation of organic micropollutants along hyporheic flow in bedforms of river-simulating flumes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anna Jaeger ◽  
Malte Posselt ◽  
Jonas L. Schaper ◽  
Andrea Betterle ◽  
Cyrus Rutere ◽  
...  
Keyword(s):  
Microbial Community ◽  
Hydrodynamic Model ◽  
Reactive Transport ◽  
Water Quality Management ◽  
River Sediments ◽  
Small Scale ◽  
Organic Micropollutants ◽  
Specific Behavior ◽  
Hyporheic Flow ◽  
Scale Heterogeneity

AbstractUrban streams receive increasing loads of organic micropollutants from treated wastewaters. A comprehensive understanding of the in-stream fate of micropollutants is thus of high interest for water quality management. Bedforms induce pumping effects considerably contributing to whole stream hyporheic exchange and are hotspots of biogeochemical turnover processes. However, little is known about the transformation of micropollutants in such structures. In the present study, we set up recirculating flumes to examine the transformation of a set of micropollutants along single flowpaths in two triangular bedforms. We sampled porewater from four locations in the bedforms over 78 days and analysed the resulting concentration curves using the results of a hydrodynamic model in combination with a reactive transport model accounting for advection, dispersion, first-order removal and retardation. The four porewater sampling locations were positioned on individual flowpaths with median solute travel times ranging from 11.5 to 43.3 h as shown in a hydrodynamic model previously. Highest stability was estimated for hydrochlorothiazide on all flowpaths. Lowest detectable half-lives were estimated for sotalol (0.7 h) and sitagliptin (0.2 h) along the shortest flowpath. Also, venlafaxine, acesulfame, bezafibrate, irbesartan, valsartan, ibuprofen and naproxen displayed lower half-lives at shorter flowpaths in the first bedform. However, the behavior of many compounds in the second bedform deviated from expectations, where particularly transformation products, e.g. valsartan acid, showed high concentrations. Flowpath-specific behavior as observed for metformin or flume-specific behavior as observed for metoprolol acid, for instance, was attributed to potential small-scale or flume-scale heterogeneity of microbial community compositions, respectively. The results of the study indicate that the shallow hyporheic flow field and the small-scale heterogeneity of the microbial community are major controlling factors for the transformation of relevant micropollutants in river sediments.

scholarly journals PROOST: object-oriented approach to multiphase reactive transport modeling in porous media

2015 ◽  
Vol 18 (2) ◽  
pp. 310-328 ◽  
Author(s):  
P. Gamazo ◽  
L. J. Slooten ◽  
J. Carrera ◽  
M. W. Saaltink ◽  
S. Bea ◽  
...  
Keyword(s):  
Reactive Transport ◽  
Chemical Species ◽  
Object Oriented ◽  
Object Oriented Programming ◽  
Transport Modeling ◽  
Reactive Transport Modeling ◽  
Hydrodynamic Processes ◽  
Object Oriented Approach ◽  
Transport Problems ◽  
Oriented Approach

Reactive transport modeling involves solving several nonlinear coupled phenomena, among them, the flow of fluid phases, the transport of chemical species and energy, and chemical reactions. There are different ways to consider this coupling that might be more or less suitable depending on the nature of the problem to be solved. In this paper we acknowledge the importance of flexibility on reactive transport codes and how object-oriented programming can facilitate this feature. We present PROOST, an object-oriented code that allows solving reactive transport problems considering different coupling approaches. The code main classes and their interactions are presented. PROOST performance is illustrated by the resolution of a multiphase reactive transport problem where geochemistry affects hydrodynamic processes.

Small-scale heterogeneity in carbon dioxide, nitrous oxide and methane production from aggregates of a cultivated sandy-loam soil

2008 ◽  
Vol 40 (9) ◽  
pp. 2468-2473 ◽  
Author(s):  
Benjamin K. Sey ◽  
Ameur M. Manceur ◽  
Joann K. Whalen ◽  
Edward G. Gregorich ◽  
Philippe Rochette
Keyword(s):  
Carbon Dioxide ◽  
Nitrous Oxide ◽  
Methane Production ◽  
Sandy Loam ◽  
Sandy Loam Soil ◽  
Small Scale ◽  
Scale Heterogeneity ◽  
Loam Soil

scholarly journals Identification of candidate soil microbes responsible for small-scale heterogeneity in strawberry plant vigour

2016 ◽  
Vol 15 (9) ◽  
pp. 2049-2058 ◽  
Author(s):  
Feng WEI ◽  
Rong FAN ◽  
Thomas Passey ◽  
Xiao-ping HU ◽  
Xiangming Xu
Keyword(s):  
Soil Microbes ◽  
Small Scale ◽  
Strawberry Plant ◽  
Plant Vigour ◽  
Scale Heterogeneity

scholarly journals A Comparison of Isolated and Ducted Fixed-Pitch Propellers under Non-Axial Inflow Conditions

Aerospace ◽  
2020 ◽  
Vol 7 (8) ◽  
pp. 112
Author(s):  
Michael Cerny ◽  
Christian Breitsamter
Keyword(s):  
Flow Field ◽  
Unmanned Aerial Vehicles ◽  
Systematic Investigation ◽  
Major Influence ◽  
Small Scale ◽  
Highly Efficient ◽  
Strong Interest ◽  
Aerial Vehicles ◽  
Inflow Conditions ◽  
Fixed Pitch

A strong interest in highly-efficient, small-scale propeller configurations can be recognized, especially due to the currently growing number of and usage possibilities for unmanned aerial vehicles (UAVs). Although a variety of different propulsion concepts already exist on the market or are discussed in the literature, there is still a demand for a systematic investigation to compare such configurations, in particular, small-scale propellers with a fixed pitch, which are analyzed in this work. Therefore, different configurations of small-scale propellers with a fixed pitch are analyzed in this paper. They were operated as isolated single propellers and as ducted propellers in a cylindrical wing. Furthermore, due to their flight envelope, UAVs are likely to operate at highly inclined inflow conditions and even under reverse inflow. These non-axial inflow conditions have a major influence on the flow field around a propeller. In order to investigate this influence, all analyses were performed at a range of inflow angles in relation to the propeller axis from αdisc=0° to 180°.

Sign in / Sign up

Export Citation Format

Share Document