Blar i SINTEF Open på forfatter "Wilhelmsen, Øivind"
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The influence of concentration and temperature on the membrane resistance of ion exchange membranes and the levelised cost of hydrogen from reverse electrodialysis with ammonium bicarbonate
Raka, Yash Dharmendra; Bock, Robert; Karoliussen, Håvard; Wilhelmsen, Øivind; Burheim, Odne Stokke (Peer reviewed; Journal article, 2021) -
Minimum entropy production in a distillation column for air separation described by a continuous non-equilibrium model
Kingston, Diego; Wilhelmsen, Øivind; Kjelstrup, Signe (Journal article; Peer reviewed, 2020)In this work, we apply the rate-based model of Taylor and Krishna to describe the separation of air in a low-pressure, packed distillation column. By use of numerical optimization, we identify the temperature profile for ... -
Nonequilibrium thermodynamics of surfaces captures the energy conversions in a shock wave
Hafskjold, Bjørn; Bedeaux, Dick; Kjelstrup, Signe; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2020)A theory for the entropy production in a shock wave was developed using Gibbs’ excess properties in the framework of non-equilibrium thermodynamics (NET) of surfaces. The theory was used to analyze numerical results from ... -
Reducing the exergy destruction in the cryogenic heat exchangers of hydrogen liquefaction processes
Wilhelmsen, Øivind; Berstad, David Olsson; Aasen, Ailo; Nekså, Petter; Skaugen, Geir (Journal article; Peer reviewed, 2018) -
Structural, Mechanical, Electronic and Thermodynamic Analysis of Calcium Aluminum Silicate Crystalline Phases in Stone Wool Insulation Materials: A first-principles study
Ho, Thi H.; Ha, Do Tuong; Hoang, Nguyen-Hieu; Wilhelmsen, Øivind; Trinh, Thuat (Peer reviewed; Journal article, 2023)Stone wool materials have gained considerable attention due to their effectiveness as thermal and acoustic insulation solutions. The comprehension of crystal structure properties is pivotal in determining the overall ... -
The Nasal Geometry of the Reindeer Gives Energy-Efficient Respiration
Magnanelli, Elisa; Wilhelmsen, Øivind; Acquarone, Mario; Folkow, Lars; Kjelstrup, Signe (Journal article; Peer reviewed, 2016)Reindeer in the arctic region live under very harsh conditions and may face temperatures below 233 K. Therefore, efficient conservation of body heat and water is important for their survival. Alongside their insulating ... -
The Permselectivity and Water Transference Number of Ion Exchange Membranes in Reverse Electrodialysis
Zlotorowicz, Agnieszka; Strand, Robin Viktor; Burheim, Odne Stokke; Wilhelmsen, Øivind; Kjelstrup, Signe (Journal article; Peer reviewed, 2016) -
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 ... -
Theory and simulation of shock waves: Entropy production and energy conversion
Hafskjold, Bjørn; Bedeaux, Dick; Kjelstrup, Signe; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2021)We have considered a shock wave as a surface of discontinuity and computed the entropy production using nonequilibrium thermodynamics for surfaces. The results from this method, which we call the “Gibbs excess method” ... -
Thermodynamic properties of the 3D Lennard-Jones/spline model
Hafskjold, Bjørn; Travis, Karl; Bailey, Amanda H.; Hammer, Morten; Aasen, Ailo; Wilhelmsen, Øivind (Journal article; Peer reviewed, 2019)In the Lennard-Jones spline (LJ/s) model, the Lennard-Jones (LJ) potential is truncated and splined so that both the pair potential and the force continuously approach zero at rc 1:74 . It exhibits the same structural ... -
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 ... -
Thermodynamically consistent modeling of gas flow and adsorption in porous media
Gjennestad, Magnus Aashammer; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2024)In modeling of gas flow through porous media width adsorption, the thermodynamic properties of the adsorbed phase are usually approximated by those of the bulk liquid. Using non-isothermal, gaseous transport of moist air ... -
Tolman lengths and rigidity constants of multicomponent fluids: Fundamental theory and numerical examples
Aasen, Ailo; Blokhuis, Edgar M.; Wilhelmsen, Øivind (Journal article; Peer reviewed, 2018) -
Understanding the physical phenomena that occur inside heat exchanger for liquefaction of hydrogen
Wilhelmsen, Øivind; Skaugen, Geir; Berstad, David Olsson; Aasen, Ailo; Nekså, Petter (9782362150227;2017-3, Chapter; Peer reviewed, 2017) -
Using Fiber-Optic Sensors to Give Insight into Liquid-Solid Phase Transitions in Pure Fluids and Mixtures
Wahl, Markus Solberg; Wilhelmsen, Øivind; Hjelme, Dag Roar (Peer reviewed; Journal article, 2020)Fiber optic sensors offer a new and unique way to detect and analyze phase transitions, due to their small thermal mass and inert material. This paper presents and demonstrates a dual-sensor system to detect and analyze ...