Browsing NTNU Open by Author "Gjennestad, Magnus Aashammer"
Now showing items 1-12 of 12
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A combined fluid-dynamic and thermodynamic model to predict the onset of rapid phase transitions in LNG spills
Lervåg, Karl Yngve; Skarsvåg, Hans Langva; Aursand, Eskil; Ouassou, Jabir Ali; Hammer, Morten; Reigstad, Gunhild Allard; Ervik, Åsmund; Fyhn, Eirik Holm; Gjennestad, Magnus Aashammer; Aursand, Peder; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2020)Transport of liquefied natural gas (LNG) by ship occurs globally on a massive scale. The large temperature difference between LNG and water means LNG will boil violently if spilled onto water. This may cause a physical ... -
Fluid Meniscus Algorithms for Dynamic Pore-Network Modeling of Immiscible Two-Phase Flow in Porous Media
Sinha, Santanu; Gjennestad, Magnus Aashammer; Vassvik, Morten; Hansen, Alex (Peer reviewed; Journal article, 2021)We present in detail a set of algorithms for a dynamic pore-network model of immiscible two-phase flow in porous media to carry out fluid displacements in pores. The algorithms are universal for regular and irregular pore ... -
Modeling of Heat Transfer in Two-Phase Flow Using the Level-Set Method
Gjennestad, Magnus Aashammer (Master thesis, 2013)The implementation of a two-phase flow model, developed at SINTEF Energy Research and relying on the level-set method, was extended through the discretization and implementation of an advection-diffusion equation for ... -
Modelling of heat transport in two-phase flow and of mass transfer between phases using the level-set method
Gjennestad, Magnus Aashammer; Munkejord, Svend Tollak (Journal article; Peer reviewed, 2015)We describe mathematical models for heat transport and for mass transfer between phases due to vaporization and condensation. These models have been implemented in a framework for detailed two-phase flow calculations based ... -
Modelling of two-phase equilibrium, stability and steady-state flow in porous media
Gjennestad, Magnus Aashammer (Doctoral theses at NTNU;2020:364, Doctoral thesis, 2020)This thesis concerns fundamental aspects of coexistence and flow of two fluid phases within porous media. Specifically, the focus is on thermodynamic stability and equilibrium on the scale of a single pore and on macroscopic ... -
Onsager-symmetry obeyed in athermal mesoscopic systems: Two-phase flow in porous media
Winkler, Mathias; Gjennestad, Magnus Aashammer; Bedeaux, Dick; Kjelstrup, Signe; Cabriolu, Raffaela; Hansen, Alex (Peer reviewed; Journal article, 2020)We compute the fluid flow time correlation functions of incompressible, immiscible two-phase flow in porous media using a 2D network model. Given a properly chosen representative elementary volume, the flow rate distributions ... -
Performance analysis of heat and energy recovery ventilators using exergy analysis and nonequilibrium thermodynamics
Gjennestad, Magnus Aashammer; Aursand, Eskil; Magnanelli, Elisa; Pharoah, John George (Journal article; Peer reviewed, 2018)The increased attention to energy savings has contributed to more widespread use of energy recovery systems for building ventilation. We investigate the efficiency of such systems under different outdoor conditions using ... -
Rheology of high-capillary number two-phase flow in porous media
Sinha, Santanu; Gjennestad, Magnus Aashammer; Vassvik, Morten; Winkler, Mathias; Hansen, Alex; Flekkøy, Eirik Grude (Journal article; Peer reviewed, 2019)Flow of immiscible fluids in porous media at high capillary numbers may be characterized by an effective viscosity. We demonstrate that the effective viscosity is well-described by the Lichtenecker-Rother equation. Depending ... -
Stable and efficient time integration of a dynamic pore network model for two-phase flow in porous media
Gjennestad, Magnus Aashammer; Vassvik, Morten; Kjelstrup, Signe; Hansen, Alex (Journal article; Peer reviewed, 2018)We study three different time integration methods for a dynamic pore network model for immiscible two-phase flow in porous media. Considered are two explicit methods, the forward Euler and midpoint methods, and a new ... -
The spinodal of single- and multi-component fluids and its role in the development of modern equations of state
Aursand, Peder; Gjennestad, Magnus Aashammer; Aursand, Eskil; Hammer, Morten; Wilhelmsen, Øivind (Journal article; Peer reviewed, 2016)The spinodal represents the limit of thermodynamic stability of a homogeneous fluid. In this work, we present a robust methodology to obtain the spinodal of multicomponent fluids described even with the most sophisticated ... -
Thermodynamic modeling with equations of state: present challenges with established methods
Wilhelmsen, Øivind; Aasen, Ailo; Skaugen, Geir; Aursand, Peder; Austegard, Anders; Aursand, Eskil; Gjennestad, Magnus Aashammer; Lund, Halvor; Linga, Gaute; Hammer, Morten (Journal article; Peer reviewed, 2017)Equations of state (EoS) are essential in the modeling of a wide range of industrial and natural processes. Desired qualities of EoS are accuracy, consistency, computational speed, robustness and predictive ability outside ... -
Thermodynamic stability of volatile droplets and thin films governed by the disjoining pressure in open and closed containers
Gjennestad, Magnus Aashammer; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2020)Distributed thin films of water and their coexistence with droplets are investigated using a capillary description based on a thermodynamic fundamental relation for the film Helmholtz energy, derived from disjoining pressure ...