Application of the Focused Impedance Method (FIM) to Determine the Volume of an Object within a Volume Conductor
M. A. Kadir, S. P. Ahmed, G. D. Al Quaderi, R. Rahman, K. Siddique-e Rabbani
Department of Biomedical Physics & Technology, University of Dhaka, Dhaka, Bangladesh
Department of Physics, Jahangirnagar University, Savar, Dhaka, Bangladesh
Department of Physics, University of Dhaka, Dhaka, Bangladesh
Focused Impedance Method (FIM), a new technique of electrical impedance measurement having high sensitivity in the central region, can sense the change in transfer impedance of an object embedded at a shallow depth within a volume conductor of unchanging background conductivity, using electrodes at the surface. This paper presents a new method for measuring the volume of such an embedded object ...
T. Fong, M. Chui, and D. L. Freyberg
Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
Hydrological processes and components are intrinsically coupled, and thus must often be modeled as an integrated system. Unfortunately, although a few modeling codes are available, integrated hydrological modeling remains a challenge.The objective of this paper is to explore the feasibility of using COMSOL Multiphysics for integrated hydrological modeling; in particular, using the generic ...
R. Caulk, J. McCartney, E. Ghazanfari
University of Vermont, Burlington, VT, USA
University of Colorado, Boulder, CO, USA
In this study, a model of in-situ geothermal energy piles was constructed using COMSOL Multiphysics® software. Geothermal energy piles serve two purposes, first to transfer building load into the subsurface, but also to extract thermal heat from surrounding soils. This is achieved using a heat pump coupled with embedded heat exchangers. As a result, a multiphysics problem is introduced - heat ...
Coupling Heat Transfer in Heat Pipe Arrays with Subsurface Porous Media Flow for Long Time Predictions of Solar Rechargeable Geothermal Systems
P. Oberdorfer, R. Hu, M. Azizur Rahman, E. Holzbecher, M. Sauter, P. Pärisch
Applied Geology, Geoscience Centre, University of Göttingen, Göttingen, Germany
Institute for Solar Energy Research Hameln/Emmerthal (ISFH), Emmerthal, Germany
An increased share of renewable energies is regarded as an integral part of a strategy towards a sustainable future. With regard to the heat supply sector this may be achieved using solar thermal collectors or heat pump systems with borehole heat exchangers. During the last years solar thermal and geothermal systems have generally been installed separately. Now, several proposals are discussed in ...
Department of Chemical Engineering, University of Arkansas, Fayetteville, AR, USA
During the hydraulic fracturing process, there can be possible re-activation of closed/sealed faults and natural fractures in the formation, which may lead to changes in the boundary conditions of the reservoir. While study models of shale gas formations have utilized the concept of a closed reservoir in order to optimize the production of gas in the well-bore, this assumption cannot be adopted ...
E. Holzbecher, P. Oberdorfer, F. Maier, and Y. Jin
Georg-August Universität Göttingen
Geothermal heat production from deep reservoirs (5000-7000 m) is currently examined, not only in Germany. Our reference set-up consists of two pipes within a single borehole: one for pumping. We examine a design, where a single borehole splits into two legs at a certain depth. The two legs are connected by highly permeable geological, natural or artificial strata in the deep subsurface. The ...
E. Dagher, G. Su, T. S. Nguyen
Canadian Nuclear Safety Commission, Ottawa, ON, Canada
COMSOL® software was used to simulate the conductive heat transfer with phase change in the geological formations encompassed in permafrost surrounding a shallow thaw lake. The purpose of the simulation was to verify the adequacy of COMSOL to model such phenomena by comparing the COMSOL results to those obtained by another FEM model (Ling and Zhang, 2003). The graphical comparison of the ...
F. Bergeron, P. Pasquier
École Polytechnique de Montréal, Montréal, QC, Canada
Ground freezing techniques using liquid nitrogen are commonly used in order to increase the mechanical properties of the soils. This article presents a new ground heat exchanger using aluminum to increase the effective radius of the heat exchanger. Simulation results indicate that the current design generates a significant thermal short-circuit between the circulation pipes that must be ...
Full Coupling of Flow, Thermal and Mechanical Effects in COMSOL Multiphysics® for Simulation of Enhanced Geothermal Reservoirs
D. Sijacic, P. Fokker
TNO, Utrecht, The Netherlands
The effective modeling of enhanced geothermal systems (EGS) requires the coupling of geomechanics, fluid flow and thermal processes. An understanding of the complete system with these coupled processes is vital, not just for reservoir stimulation targeted at enhancing reservoir performance, but also for the understanding, prediction and prevention of induced seismicity. Thermal effects however ...
Modeling of Ultrasonic Transducers and Ultrasonic Wave Propagation for Commercial Applications Using Finite Elements with Experimental Visualization of Waves for Validation
D. R. Andrews
Cambridge Ultrasonics, Over, UK
Finite element (FE) modelling of ultrasonic propagation using COMSOL Multiphysics® simulations can be used to create images of waves. Unfortunately, in time-stepping solutions, it is possible for numerical instabilities to grow large and dominate the solution adversely. Any design of transducer that is based upon poorly-configured FE models is unlikely to perform as expected and will almost ...