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1
Becker, Bernhard P., and Holger Schüttrumpf. "An OpenMI module for the groundwater flow simulation programme Feflow." Journal of Hydroinformatics 13, no. 1 (March 19, 2010): 1–12. http://dx.doi.org/10.2166/hydro.2010.039.
Повний текст джерелаАнотація:
The OpenMI standard defines an interface that allows time-dependent models to exchange data at runtime. The migration of a flow simulation programme to OpenMI compliance usually requires changes in the source code or even a reorganisation of the programme sequence. Users of commercial flow simulation programmes depend on the software producer if they want to couple their models according to the OpenMI standard. We describe how we made the groundwater flow simulation programme Feflow OpenMI compliant without changing the source code: an OpenMI-compliant control application communicates with Feflow via remote procedure calls. A basic prerequisite for applying this method is an entry point into the flow simulation programme that allows to modify the model data during runtime and to implement the remote procedure calls. Feflow meets this requirement as it provides the interface manager (IFM). The mode of operation is explained with a simple test case including an inundation model and a Feflow groundwater model.
2
Karmakar, Shyamal, Alexandru Tatomir, Sandra Oehlmann, Markus Giese, and Martin Sauter. "Numerical Benchmark Studies on Flow and Solute Transport in Geological Reservoirs." Water 14, no. 8 (April 17, 2022): 1310. http://dx.doi.org/10.3390/w14081310.
Повний текст джерелаАнотація:
Predicting and characterising groundwater flow and solute transport in engineering and hydrogeological applications, such as dimensioning tracer experiments, rely primarily on numerical modelling techniques. During software selection for numerical modelling, the accuracy of the results, financial costs of the simulation software, and computational resources should be considered. This study evaluates numerical modelling approaches and outlines the advantages and disadvantages of several simulators in terms of predictability, temporal control, and computational efficiency conducted in a single user and single computational resource set-up. A set of well-established flow and transport modelling simulators, such as MODFLOW/MT3DMS, FEFLOW, COMSOL Multiphysics, and DuMuX were tested and compared. These numerical simulators are based on three numerical discretisation schemes, i.e., finite difference (FD), finite element (FE), and finite volume (FV). The influence of dispersivity, potentially an artefact of numerical modelling (numerical dispersion), was investigated in parametric studies, and results are compared with analytical solutions. At the same time, relative errors were assessed for a complex field scale example. This comparative study reveals that the FE-based simulators COMSOL and FEFLOW show higher accuracy for a specific range of dispersivities under forced gradient conditions than DuMuX and MODFLOW/MT3DMS. FEFLOW performs better than COMSOL in regard to computational time both in single-core and multi-core computing. Overall computational time is lowest for the FD-based simulator MODFLOW/MT3DMS while the number of mesh elements is low (here < 12,800 elements). However, for finer discretisation, FE software FEFLOW performs faster.
3
Leiter, Augustin. "A Software Tool Developed for Simplified Numerical Modeling of Thermal Conduction around Distorted Geothermal Boreholes." Advanced Engineering Forum 21 (March 2017): 529–34. http://dx.doi.org/10.4028/www.scientific.net/aef.21.529.
Повний текст джерелаАнотація:
The geometric characteristics of multiple geothermal boreholes organized in a geothermal system affect its thermal efficiency. The location of boreholes and their verticality and straightness is often distorted during drilling process. This distortion then degrades thermal properties of such a system. To study this phenomenon a specialized software tool was developed for numerical modeling based on a simplified mathematical model. This paper describes software tool briefly and presents some initial numerical models of basic borehole arrangements solved by this tool. Paper also contains a verification calculated by specialized software FEFLOW.
4
Iwanek, Małgorzata, and Paweł Suchorab. "The assessment of water loss from a damaged distribution pipe using the FEFLOW software." ITM Web of Conferences 15 (2017): 03006. http://dx.doi.org/10.1051/itmconf/20171503006.
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5
Zhao, Chengyi, Yuchao Wang, Xi Chen, and Baoguo Li. "Simulation of the effects of groundwater level on vegetation change by combining FEFLOW software." Ecological Modelling 187, no. 2-3 (September 2005): 341–51. http://dx.doi.org/10.1016/j.ecolmodel.2004.10.019.
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6
Ren, Jian Min, Yang Yang, and Xing Wei Hu. "Application of GIS and FEFLOW in Forecasting Groundwater Flow Field of Minqin Basin." Advanced Materials Research 368-373 (October 2011): 2128–31. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.2128.
Повний текст джерелаАнотація:
Conditions were considered of complex geology and the hydrogeology of Minqin, the 3d numerical simulation model of groundwater system was built by FEFLOW software in the study area. Author found that hydrogeologic parameters which have been debugged many times corresponded with the hydrogeology prospecting results well. Verification results show that the model has better simulation effect and higher reliability in checking the model. Facts show that prediction of groundwater flow field has high reliability in the study area.
7
Anbergen, Hauke, Wolfram Rühaak, Jens Frank, and Ingo Sass. "Numerical simulation of a freeze–thaw testing procedure for borehole heat exchanger grouts." Canadian Geotechnical Journal 52, no. 8 (August 2015): 1087–100. http://dx.doi.org/10.1139/cgj-2014-0177.
Повний текст джерелаАнотація:
The amount of research conducted on geothermal energy as a source for heating and cooling demands of buildings, as well as for electrical energy production, has increased substantially in the past decades. The simulation of freezing and thawing is important for geothermal applications involving ground coupled heat pumps. One area of research is the development of grout cements for borehole heat exchangers (BHE). In many cases, BHEs are operated at temperatures below 0° C due to manifold reasons. Hence, the simulation of freezing and thawing cycles (FTC) is important for such geothermal applications, especially in cold regions. Recently, a testing device for measuring and quantifying the influence of FTC stresses on the mechanical integrity and hydraulic properties of BHE grouts was developed (Anbergen, published in 2014). The testing procedure simulates the downhole in situ conditions as confining radial earth pressure, freezing, and thawing directions from the inside to the outside and under saturated conditions. The hydraulic conductivity can be measured in axial flow direction. Thus, statements regarding the susceptibility of grouts against cyclic freezing and thawing stresses can be made. These results differ substantially from earlier findings, as in situ boundary conditions were not simulated sufficiently. For the verification of the procedure’s thermal process, temperature logs were recorded using thermocouples and thermography imaging. The thermal process was simulated using the finite element method (FEM) groundwater, heat, and mass modeling software FEFLOW. FEFLOW is a common software solution for thermohydraulic coupled groundwater applications with mass transport, as well as geothermal applications. However, up until now, the program could not yet simulate phase changes between solid and liquid phases. To enable the program for such simulations, a plug-in was developed. To do this, a C++ code was written and coupled to the simulation routine of the FEM software. The code is based on a modification of the material parameters of fluid and the incorporation of the latent heat effects in the fluid heat capacity. A linear and an exponential approach for the latent heat release were implemented and benchmarked. The code was verified using different analytical solutions and other FEM codes. Finally, the experimental results of the test procedure could be successfully computed using the new plug-in. Thus, it is now possible to compute phase changes with FEFLOW for geothermal applications as well as other applications like permafrost research.
8
Pan, Jun, Yang Liu, and Te Leng. "Analysis of Influence of Estuary Artificial Wetland on Water Environmental Capacity." Advanced Materials Research 726-731 (August 2013): 1441–44. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.1441.
Повний текст джерелаАнотація:
The model of artificial wetland is designed using the data of hydrology and water quality, to analyze influence of estuary wetland on water environmental capacity in Yangguan-river. The change of concentration of COD and TN is simulated by inputting the model to FEFLOW software. Environmental capacity is calculated on condition that sewage plant is discharging upstream. The result shows that, water quality and environmental capacity are improved by wetland. Environmental capacity of COD can meet the water quality target, but TN cant meet the target because of the high background concentration. This conclusion can be used to formulate or modify the environmental protection and plan.
9
Kumar Sahu, Suvendu, Kamalesh Mondal, Gobinath M, and D. C.Jhariya. "Application of groundwater transport modelling in groundwater development and management: a review." International Journal of Advanced Geosciences 7, no. 1 (May 5, 2019): 47. http://dx.doi.org/10.14419/ijag.v7i1.25905.
Повний текст джерелаАнотація:
Groundwater is one of the very sensible natural resource and to protect its quality there is need of proper management system. Groundwater modelling is very advance method for the simulation, forecasting and set remediation strategy to protect the ground-water system, it is an emerging field in groundwater study. So many scientists and researchers are working on this to prepare a groundwater management strategy and to improve the efficiency of the model. For solving the different groundwater related issues, it is important to select proper model. For the accuracy of the model result, it needs to have proper idea about the model, procedure of model run and selection of model basing on the problems. There are a smaller number of modelling software like SWAT, MODFLOW, MT3DMS, RT3D, MT3D, FLUXOS, CXTFIT, FEFLOW, Retraso-Code-Bright etc. Sometimes coupled models are also preferable as per the problem. This paper based on review of the general characteristics of different transport modelling software, methodology of the model development and its application in the different issues related to groundwater development and management.
10
Bian, Kai, Shi Lei Chen, Xue Yuan Li, and Ying Wang Zhao. "Numerical Simulation of Seepage Field in Aquifer under the Coal Seam." Advanced Materials Research 955-959 (June 2014): 3120–24. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.3120.
Повний текст джерелаАнотація:
In order to figure out seepage field in aquifer under the coal seam, the geology and hydrogeology conditions systematically of study area were analyzed, hydrogeological conceptual model was generalized, mathematical model was built, seepage field of the Taiyuan limestone aquifer was simulated with software Feflow. Simulation results show that hydrogeological parameters of Taiyuan limestone aquifer change greatly in different partitions. The model also indicates the heterogeneity of karst fissure of Taiyuan limestone aquifer. The drainage quantity is from the Ordovician limestone aquifer besides supplying from runoff of upstream and capture excretion of downstream. The research is an attempt to simulate the seepage field in aquifer under coal seam, to some extent, it also provides a technical basis for safe coal mining and as a reference for simulation constructions of three-dimensional groundwater flow models in similar coal mines.
11
Li, Mingwei, Zhifang Zhou, Hailong Huang, and Jianxin Liao. "Estimation of Hydraulic Diffusivity of a Confined Limestone Aquifer at the Xiluodu Dam." Geofluids 2022 (September 5, 2022): 1–10. http://dx.doi.org/10.1155/2022/8732415.
Повний текст джерелаАнотація:
Hydraulic diffusivity is a fundamental parameter in studying groundwater flow. An analytical solution for groundwater flow within a finite-length one-dimensional aquifer has been introduced. This analytical solution simplifies the river water level (RWL) by a piecewise linear function, accurately describing the arbitrary variation pattern. An inversion method for hydraulic diffusivity has been provided based on the analytical solution. Then, the method was employed to estimate the hydraulic diffusivity of a limestone aquifer in the Xiluodu reservoir and was verified by the FEFLOW software. The parameter sensitivity increases with the RWL fast increasing and reaches its peak value when the RWL approaches the maximum value. Given the sensitivity analysis, great attention should be paid to the stage when RWL fluctuates drastically for estimating hydraulic diffusivity. The proposed method is flexible to conditions that lack observation data or RWL fluctuating drastically.
12
Pasanen, A. H., and J. S. Okkonen. "3D geological models to groundwater flow models: data integration between GSI3D and groundwater flow modelling software GMS and FeFlow®." Geological Society, London, Special Publications 408, no. 1 (September 28, 2016): 71–87. http://dx.doi.org/10.1144/sp408.15.
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13
Cheng, Yu Fei, Yuan Hong Li, Xiang Quan Hu, Jun De Wang, and Shu Chao Lu. "The Study of Groundwater Modeling of Plain Area in Shiyang River Basin - I Groundwater System Conceptual Model Construction." Advanced Materials Research 937 (May 2014): 632–38. http://dx.doi.org/10.4028/www.scientific.net/amr.937.632.
Повний текст джерелаАнотація:
In order to construct the groundwater numerical simulation model, the study area was determined on the basis of the geological and hydrogeological conditions. Taking Feflow as operating platform, combining GIS with Surfer software, a study area of the structure of three-dimensional aquifer model was established, realizing the 3D visualization of a large area of the complex geological content. Combined with the hydrogeological conditions, three-dimensional geological structure of the model further generalization. The result showed that the aquifer of the vertical was generalized into the unconfined aquifer; based on the characteristics of lithology, structure, parameters and distribution of recharge and discharge in groundwater system, the study area groundwater system was characterized by isotropic saturated-unsaturated numerical flow model, and the equilibrium composition of the elements was analysed in study area, the partition of the aquifer hydrogeological parameters was divided, lay the foundation for groundwater numerical model simulation.
14
Liu, Yi, and Xiao Min Mao. "Influence of Boundary Conditions on Modeling Seawater Intrusion into Coastal Aquifer." Advanced Materials Research 250-253 (May 2011): 3074–78. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.3074.
Повний текст джерелаАнотація:
Numerical simulation is an essential tool for investigation of seawater intrusion in coastal aquifer. For most groundwater modeling software, boundary condition along the beach is required. But it was normally assumed due to the uncertainty in the seawater – freshwater interface. Using FEFLOW, a groundwater simulation software based on finite element method, we investigated the intrusion scope and the exiting point of groundwater outflow under various boundary conditions. Seven cases were designed, among which three cases with boundary conditions of a freshwater layer over seawater, three cases with a triangle freshwater zone between seawater and the beach, and the last one without freshwater at the seawater boundary. Results showed that the last case has the longest intrusion scope. The scope of seawater intrusion is determined by both the horizontal water head gradient along the bottom of the aquifer and the vertical water head gradient along the beach. Both higher horizontal gradient and lower vertical gradient result in larger intrusion scope. In some circumstances, the vertical gradient has greater impact on seawater intrusion than the horizontal gradient, and act as the main power inhibiting seawater intrusion.
15
Widomski, Marcin K., Iwona Pawelec, Ajay Kumar, and Grzegorz Łagód. "Numerical modelling of water percolation through mortar-based connection of concrete pipes." MATEC Web of Conferences 252 (2019): 05014. http://dx.doi.org/10.1051/matecconf/201925205014.
Повний текст джерелаАнотація:
This paper presents an attempt to numerical modelling of water seepage through the connection of two concrete pipes, commonly used in the past in construction of sanitary and stormwater sewerage systems, sealed by three types of different cement-based mortars. The 2D numerical calculations were made by means of the commercial modelling software FEFLOW, WASY-DHI, especially popular in soil and environmental science. The required input data for the developed numerical model, including saturated hydraulic conductivity and retention characteristics of tested mortars, were obtained during the conducted laboratory measurements. The hydraulic characteristics of the applied concrete pipe were based on literature. The assumed boundary conditions reflected the concrete sewerage pipe filled by water to the height of 10 cm and the matric suction pressure of soil below the sand bed. Our numerical calculations showed diversified seepage intensity and accumulated volume of percolating water for the three tested mortars. The observed differences were in our opinion related to sand/cement ratio of each mortar. The higher sand content, the higher volume of seepage was noted.
16
Rastorguev, I. A., L. N. Mukhina, and D. A. Ermakova. "Software DHI Feflow and Processing Modflow in Solving Groundwater Flow Problems for HPP Projects Design and Reconstruction in a Complex Geological and Hydrogeological Environment." Power Technology and Engineering 55, no. 2 (July 2021): 172–78. http://dx.doi.org/10.1007/s10749-021-01337-9.
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17
Iwanek, Małgorzata, Paweł Suchorab, and Zbigniew Suchorab. "FEM simulation of water lost through damaged household water connection." MATEC Web of Conferences 252 (2019): 05008. http://dx.doi.org/10.1051/matecconf/201925205008.
Повний текст джерелаАнотація:
The problem of water supply pipe’s failures is one of the most onerous for water distribution network’s (WDN) operators. Multiple actions undertaken to detect, minimise and eliminate the phenomenon of water losses are mainly focused on financial aspect of lost water. However, at some point, the further minimisation of water losses is unprofitable due to reaching the economic level of water leakages. In WDNs failures analysis the biggest emphasis is put on damages of main pipes and distribution pipes, while failures of household water connections are often neglected. That is because the most typical water losses in household connections are hard-to-detect background leakages with relatively small water outflow. Still, in a long-time perspective, such leakages can cause significant water losses. The aim of this paper was to evaluate the parameters of water lost through damaged household water connection (volume, velocity, suffosion conditions). The basis for the analysis were laboratory investigations and a numerical simulation of a pipe failure using the FEFLOW v. 5.3 software. The results of the simulation, compared with laboratory tests results, enabled to state that, contrary to the widespread practice, leakages from household connections cannot be ignored.
18
Pandian, Rajaveni Sundara, Indu Sumadevi Nair, and Elango Lakshmanan. "Finite element modelling of a heavily exploited coastal aquifer for assessing the response of groundwater level to the changes in pumping and rainfall variation due to climate change." Hydrology Research 47, no. 1 (May 16, 2015): 42–60. http://dx.doi.org/10.2166/nh.2015.211.
Повний текст джерелаАнотація:
Coastal aquifers are always under threat of seawater intrusion due to over-extraction of groundwater. The objective here is to assess aquifer response to variation in pumping and rainfall recharge due to projected climate change by groundwater modelling in a heavily exploited aquifer. Finite element groundwater flow modelling was carried out from March 1988 to December 2030 using FEFLOW software. Steady state calibration was done to match observed and simulated groundwater head by varying aquifer parameters within the allowable range. Transient state calibration was carried out during the period March 1988 to December 2002. The calibrated model was validated by comparing the simulated and observed groundwater head from January 2003 to December 2012. Groundwater head was predicted for a period until 2030 under eight different scenarios of changes in pumping and rainfall recharge. This prediction indicated that 10% increase of recharge and 10% decrease of pumping causes 3 m and 6 m increase in groundwater head in upper and lower aquifers, respectively, by the end of 2030. Groundwater recharge can be increased by rejuvenation of existing surface water bodies, check dams and construction of proposed check dams. Thus, increase of groundwater recharge and decrease in well field pumping is achievable to restore this heavily exploited coastal aquifer in another 20 years.
19
Cappellari, Davide, Leonardo Piccinini, Alessandro Pontin, and Paolo Fabbri. "Sustainability of an Open-Loop GWHP System in an Italian Alpine Valley." Sustainability 15, no. 1 (December 23, 2022): 270. http://dx.doi.org/10.3390/su15010270.
Повний текст джерелаАнотація:
Shallow geothermal systems (SGSs) for building climatization represent an advantageous alternative to traditional air-conditioning systems, resulting in economic and environmental benefits. Installation of these systems requires knowledge of site-specific geological and hydrogeological conditions, which in feasibility studies are often evaluated only at the single plant scale, lacking a comprehensive view and risking not to guarantee the system sustainability over time. In this paper a methodology for the sustainable design of SGSs is presented. The methodology is developed from an example on the aquifer scale in Longarone (Belluno, Italy), where three groundwater heat pumps (GWHPs) were installed in an industrial area located in a mountain basin hosting a coarse-grained phreatic aquifer, characterized by sediments with high hydraulic conductivity and proximal to a large river (Piave River). Open-loop systems were first analyzed through numerical modeling using FEFLOW software, identifying peculiar features of the aquifer, due to its interaction with surface waters, and suggesting the possibility of its greater geothermal exploitation. Subsequently, a relationship between flow rates and thermal plume extensions was obtained, which is useful to providing support in the evaluation of potential interference with neighboring systems. The study at the aquifer scale proved representative of the system, highlighting the criticalities of the area, such as trends of aquifer temperature alteration, interference between plants, and thermal feedback.
20
Volpi, Giorgio, Fabien Magri, Francesca Colucci, Thomas Fisher, Mattia De Caro, and Giovanni B. Crosta. "Modeling Highly Buoyant Flows in the Castel Giorgio: Torre Alfina Deep Geothermal Reservoir." Geofluids 2018 (2018): 1–19. http://dx.doi.org/10.1155/2018/3818629.
Повний текст джерелаАнотація:
The Castel Giorgio-Torre Alfina (CG-TA, central Italy) is a geothermal reservoir whose fluids are hosted in a carbonate formation at temperatures ranging between 120°C and 210°C. Data from deep wells suggest the existence of convective flow. We present the 3D numerical model of the CG-TA to simulate the undisturbed natural geothermal field and investigate the impacts of the exploitation process. The open source finite-element code OpenGeoSys is applied to solve the coupled systems of partial differential equations. The commercial software FEFLOW® is also used as additional numerical constraint. Calculated pressure and temperature have been calibrated against data from geothermal wells. The flow field displays multicellular convective patterns that cover the entire geothermal reservoir. The resulting thermal plumes protrude vertically over 3 km at Darcy velocity of about7⁎10-8 m/s. The analysis of the exploitation process demonstrated the sustainability of a geothermal doublet for the development of a 5 MW pilot plant. The buoyant circulation within the geothermal system allows the reservoir to sustain a 50-year production at a flow rate of 1050 t/h. The distance of 2 km, between the production and reinjection wells, is sufficient to prevent any thermal breakthrough within the estimated operational lifetime. OGS and FELFOW results are qualitatively very similar with differences in peak velocities and temperatures. The case study provides valuable guidelines for future exploitation of the CG-TA deep geothermal reservoir.
21
Huo, Aidi, Xiaofan Wang, Yan Lyu, Yuxiang Cheng, Chunli Zheng, and Jinxi Song. "Simulation research on the reinjection temperature fields of deep geothermal wells based on real-scale experiment." Energy Exploration & Exploitation 37, no. 2 (October 25, 2018): 646–62. http://dx.doi.org/10.1177/0144598718807556.
Повний текст джерелаАнотація:
The utilization of aquifer energy is a new technology closely related to the development of injection and production well technologies. Accurately predicting the effective use of geothermal energy storage in a surrounding aquifer is of great significance. A developed theory of groundwater hydro-geothermal transfer is suggested by analyzing the general features of stored energy in aquifers together with the interactions between flow connections and thermal breakthroughs. Based on the water-heat transfer in an aquifer, a coupled numerical model of groundwater flow and heat transfer is established using FEFLOW software for an injection and production wells system in the city of Xianyang to simulate the flow and temperature field. The results show that the key for the formation of a flow connection is the hydraulic gradient. That is, whether the flow connection will occur can be judged quantitatively according to the hydraulic gradient. Flow connections occur more easily through greater flow quantities and quicker injection and pumping rates, which lead to earlier occurrences of thermal breakthroughs. At an operation time of 120 days, to prevent thermal breakthroughs in the production wells, the reasonable well spacing was between 180 and 200 m, and the optimal well spacing was 180 m. This method is of great significance for the calculation of reasonable distance between injection and production wells of geothermal tail water without thermal breakthroughs and the sustainable development of a groundwater environment.
22
Hałaj, Elżbieta, Leszek Pająk, and Bartosz Papiernik. "Finite Element Modeling of Geothermal Source of Heat Pump in Long-Term Operation." Energies 13, no. 6 (March 13, 2020): 1341. http://dx.doi.org/10.3390/en13061341.
Повний текст джерелаАнотація:
Model simulation allows to present the time-varying temperature distribution of the ground source for heat pumps. A system of 25 double U-shape borehole heat exchangers (BHEs) in long-term operation and three scenarios were created. In these scenarios, the difference between balanced and non-balanced energy load was considered as well as the influence of the hydrogeological factors on the temperature of the ground source. The aim of the study was to compare different thermal regimes of BHEs operation and examine the influence of small-scale and short-time thermal energy storage on ground source thermal balance. To present the performance of the system according to geological and hydrogeological factors, a Feflow® software (MIKE Powered by DHI Software) was used. The temperature for the scenarios was visualized after 10 and 30 years of the system’s operation. In this paper, a case is presented in which waste thermal energy from space cooling applications during summer months was used to upgrade thermal performance of the ground (geothermal) source of a heat pump. The study shows differences in the temperature in the ground around different Borehole Heat Exchangers. The cold plume from the not-balanced energy scenario is the most developed and might influence the future installations in the vicinity. Moreover, seasonal storage can partially overcome the negative influence of the travel of a cold plume. The most exposed to freezing were BHEs located in the core of the cold plumes. Moreover, the influence of the groundwater flow on the thermal recovery of the several BHEs is visible. The proper energy load of the geothermal source heat pump installation is crucial and it can benefit from small-scale storage. After 30 years of operation, the minimum average temperature at 50 m depth in the system with waste heat from space cooling was 2.1 °C higher than in the system without storage and 1.6 °C higher than in the layered model in which storage was not applied.
23
Chen, Yanmei, Yu Zhang, Fang Xia, Zhao Xing, and Licheng Wang. "Impacts of Underground Reservoir Site Selection and Water Storage on the Groundwater Flow System in a Mining Area—A Case Study of Daliuta Mine." Water 14, no. 20 (October 18, 2022): 3282. http://dx.doi.org/10.3390/w14203282.
Повний текст джерелаАнотація:
The natural ecological conditions in the Shendong mining area in China are very fragile, and water resources are seriously lacking. As the production scale of the Shendong mine continues to expand, the demand for water for production and living is also increasing; however, the available surface and underground water is decreasing, and the water scarcity in the Shendong mine is becoming increasingly apparent. Obtaining water resources is a major technological challenge for green mining. The underground reservoir is a new type of underground water conservancy project, and the water shortage in China’s coal mine pits is resolved by underground reservoirs, which also makes a substantial contribution to the effective utilization of water resources. How the construction of underground reservoirs affects the groundwater system in a mining area has become one of the most important factors to consider when finding sites for underground reservoirs. In this study, we took the Daliuta Coal Mine as an example. A numerical model based on the hydrogeological conditions in the mining area was developed to determine the effects on groundwater using FEFLOW software via the finite element method. The model was used to analyze the impacts of coal seam mining thickness, overlying lithology, water-storage range and the water level of the underground reservoir on the groundwater flow system in the mining area. The results indicate that the thickness of the coal seam mining and the lithology of the overlying reservoir both had a significant effect on the upper aquifer system. The water-storage range and water level of the underground reservoirs were the main influences on the lower aquifer system. The results prove that underground reservoir storage had a good effect on water retention in the groundwater system in the mining area, and was able to achieve the desired result of storing groundwater and reducing water loss. It also had a positive feedback effect on the mining area’s environment.
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Randow, Jakob, Shuang Chen, Katrin Lubashevsky, Steve Thiel, Tom Reinhardt, Karsten Rink, Rüdiger Grimm, Anke Bucher, Olaf Kolditz, and Haibing Shao. "Modeling neighborhood-scale shallow geothermal energy utilization: a case study in Berlin." Geothermal Energy 10, no. 1 (February 3, 2022). http://dx.doi.org/10.1186/s40517-022-00211-9.
Повний текст джерелаАнотація:
AbstractNowadays, utilizing shallow geothermal energy for heating and cooling buildings has received increased interest in the building sector. Among different technologies, large borehole heat exchanger arrays are widely employed to supply heat to various types of buildings. Recently, a 16-borehole array was constructed to extract shallow geothermal energy to provide heat to a newly-developed public building in Berlin. To guarantee the quality of the numerical model and reveal its sensitivity to different subsurface conditions, model simulations were conducted for 25 years with two finite element simulators, namely the open-source code OpenGeoSys and the widely applied commercial software FEFLOW. Given proper numerical settings, the simulation results from OpenGeoSys and FEFLOW are in good agreement. However, further analysis reveals differences with respect to borehole inflow temperature calculation implemented in the two software. It is found that FEFLOW intrinsically uses the outflow temperature from the previous time step to determine the current inflow temperature, which makes it capable of much faster simulation by avoiding iterations within a single time step. In comparison, OpenGeoSys always updates the inflow and outflow temperature based on their current time step values. Because the updates are performed after each iteration, it delivers more accurate results with the expense of longer simulation time. Based on this case study, OpenGeoSys is a valid alternative to FEFLOW for modeling ground source heat pump systems. For modellers working in this field, it is thus recommended to adopt small enough time step size, so that potential numerical error can be avoided.
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Hałaj, Elżbieta, Leszek Pająk, and Bartosz Papiernik. "Simulation study of the Lower Cretaceous geothermal reservoir for aquifer thermal energy storage." Environmental Geochemistry and Health, October 28, 2021. http://dx.doi.org/10.1007/s10653-021-01130-7.
Повний текст джерелаАнотація:
AbstractThe aquifer thermal energy storage (ATES) has gained attention in several countries as an installation for increasing the energy efficiency of geothermal systems and the use of waste heat. The Lower Cretaceous reservoir is known as one of the most prospective for geothermal purposes in Poland. However, in the southern part of the Mogilno–Łódź Trough (Central Poland) is considered to have a lower geothermal potential. The aim of this paper is to study whether the Lower Cretaceous reservoir in this area is suitable for aquifer thermal energy storage. Prior to dynamic simulations in Feflow© software, a regional Petrel© static parametric model which includes a multidisciplinary approach was prepared. A methodology of fitting Petrel’s structural and parametrical model to Feflow requirements is provided within this paper. The performance simulation of 4 systems has been conducted for 30 years. Increasing precipitation potential is expected for aragonite and calcite along with a temperature increase, while silica precipitation carries a much smaller risk. The paper presents potential for ATES systems in the Lower Cretaceous reservoir of the study area with the best doublet location having thermal recovery ratio of 0.47 and 0.34 for 30 and 40 K temperature differential scenario. An imbalance in heat injection/production in the storage system can cause the reservoir to cool faster than in conventional geothermal heating installation. ATES can provide a successful geothermal reservoir boosting in the case of applying a balanced injection of waste heat.
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Gao, Yulong, Shengyan Pu, Chunmiao Zheng, and Shuping Yi. "An improved method for the calculation of unsaturated–saturated water flow by coupling the FEM and FDM." Scientific Reports 9, no. 1 (October 18, 2019). http://dx.doi.org/10.1038/s41598-019-51405-4.
Повний текст джерелаАнотація:
Abstract Numerical modeling of water movement in both unsaturated soils and saturated groundwater aquifers is important for water resource management simulations. The development of efficient numerical algorithms for coupling unsaturated and saturated flow has been a long-lasting challenge in hydrologic modeling, especially for regional-scale modeling. In this study, a new method coupling the Finite Element Method (FEM) and Finite Difference Method (FDM), FE-FDM, is developed to solve Richards equation for simulating unsaturated–saturated water flow. The FEM is adopted to discretize the governing equation in the horizontal direction, while the FDM is used in the vertical direction. This method combines the advantages of FEM in domain discretization, especially for complex computational domain, and the advantages of FDM in modeling simplicity and efficiency. The validity of the new method is demonstrated with three test cases that show that the FE-FDM solutions are accurate and are applicable for regional scale problems. In the test cases, the FE-FDM solutions are compared with experimental data and numerical results calculated with common software packages including FEFLOW and COMSOL. This study verified that the FE-FDM is applicable for simulating water flow in the unsaturated–saturated zone.
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Ghafoori, Yaser, Matej Maček, Andrej Vidmar, Jaromír Říha, and Andrej Kryžanowski. "Heat transfer by seepage in sand: Influence of saturated hydraulic conductivity and porosity." Acta hydrotechnica, June 1, 2021, 61–75. http://dx.doi.org/10.15292/acta.hydro.2021.05.
Повний текст джерелаАнотація:
Heat transfer within the soil is a complex process in the presence of seepage flow. In such conditions, the soil’s thermal behavior is influenced by the thermal and hydraulic properties of the medium as well as the initial conditions and boundary conditions to which the medium is subjected. This paper presents the experimental and numerical studies of heat transfer within the sand subjected to the seepage flow. It focuses on the influence of saturated hydraulic conductivity and the porosity of medium on the heat transfer process. The temperature distribution within the sand was monitored by the optical fiber Distributed Temperature Sensor (DTS). The experiment was performed on three types of silica-dominated sands with different saturated hydraulic conductivities and different Soil Water Characteristic Curve (SWCC). In addition to the experimental study, a coupled hydrothermal numerical model was designed in FEFLOW software and validated by comparing its results with the experimental measurements. To determine the influence of porosity and saturated hydraulic conductivity on heat transfer, we analyzed the numerical models for different values of porosity and saturated hydraulic conductivity. The numerical and experimental studies showed that the thermal velocity is higher in sand with higher saturated hydraulic conductivity and temperature declination occurs more quickly due to the heat convection process. Saturated sand with larger porosity has an overall higher heat capacity, wherefore the temperature declination started later in the measuring points but dropped down lower close to the temperature of the upstream water.
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Iwanek, Małgorzata. "Parameters characterizing leakages from damaged water pipes in the aspect of environmental security." Applied Water Science 12, no. 6 (April 15, 2022). http://dx.doi.org/10.1007/s13201-022-01641-3.
Повний текст джерелаАнотація:
AbstractLeakages from buried water pipes can result in suffosion posing a threat to the environment and the infrastructure existing in cities. Leakage of water from a pressure pipe into a soil susceptible to suffosion is a very complex phenomenon, characterized by a number of different parameters. Taking into account all parameters in the empirical tests of the buried water pipe leakage is practically impossible. Thus, it is necessary to select them so that on the one hand it is possible to perform a physical simulation of the phenomenon, and on the other to obtain reliable results of investigations. According to the Pareto principle, it can be stated that a small group of factors—about 20%—has a crucial impact on the phenomenon. Therefore, in empirical tests of water outflow from the underground water supply system, it is enough to consider 20% of the parameters affecting the analyzed phenomenon. The purpose of this work was to select these parameters. The selection was based on two types of research—literature research and computer simulations using the FEFLOW v. 5.3 software. The research allowed to select 4 out of 19 parameters which impact on the effects of the phenomenon of water outflow from pressure pipe to a soil susceptible to suffosion turned out to be the most essential: a pressure in the pipe, a leak area, a saturated conductivity coefficient of soil and an uniformity coefficient of soil.
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Ma, Jiuchen, Qian Jiang, Qiuli Zhang, Yacheng Xie, Yahui Wang, and Feiyu Yi. "Effect of groundwater forced seepage on heat transfer characteristics of borehole heat exchangers." Geothermal Energy 9, no. 1 (March 24, 2021). http://dx.doi.org/10.1186/s40517-021-00192-1.
Повний текст джерелаАнотація:
AbstractA system of borehole heat exchangers (BHEs) combined with pumping–injection wells is established in areas where the groundwater is shallow and the seepage velocity is weak. The pumping and injection wells are set on both sides of the BHEs. According to the three-dimensional unsteady-state heat transfer model in the aquifer, the convection–dispersion analytical solution of excess temperature is derived that considers groundwater-forced seepage and thermal dispersion effects and axial effect of the BHEs. Then, we use the dimensional analysis method and similarity criteria to build a controllable forced seepage sandbox. The software FEFLOW 7.1 is adopted and the simulation results are validated by the theoretical analysis and the indoor experiment test. On this basis, the numerical simulation is used to explore the influence of different pumping–injection flow volume on the Darcy flow velocity of the aquifer where the BHEs are located, as well as the average heat transfer efficiency and the heat transfer rates with borehole depth. The results show that when the pumping flow volume increases from 200 m3 day−1 to 1200 m3 day−1, the Darcy velocity correspondingly increases to about 10 times. The average heat efficiency coefficient of the BHEs is increased by 11.5% in cooling stage, and by 7.5% in heating stage. When the pumping–injection flow volume is 400–600 m3 day−1, the increment of heat transfer rates of the BHEs reaches 12.8–17.9 W m−1 and 3.6–4.2 W m−1 per unit of borehole depth during the cooling stage and heating stage, respectively, and then decreases as the flow volume increases gradually.