Browsing NTNU Open by Author "Aasen, Ailo"
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A Study of Rotational Water Waves using Bifurcation Theory
Aasen, Ailo (Master thesis, 2014)This thesis is concerned with the water wave problem. Using local bifurcation we establish small-amplitude steady and periodic solutions of the Euler equations with vorticity. Our approach is based on that of Ehrnström, ... -
Accurate quantum-corrected cubic equations of state for helium, neon, hydrogen, deuterium and their mixtures
Aasen, Ailo; Hammer, Morten; Lasala, Silvia; Jaubert, Jean-Noël; Wilhelmsen, Øivind (Journal article; Peer reviewed, 2020)Cubic equations of state have thus far yielded poor predictions of the thermodynamic properties of quantum fluids such as hydrogen, helium and deuterium at low temperatures. Furthermore, the shape of the optimal α functions ... -
Bulk and interfacial thermodynamics of mixtures: From aqueous systems to ultracryogenic fluids
Aasen, Ailo (Doctoral theses at NTNU;2020:38, Doctoral thesis, 2020) -
Choice of reference, influence of non-additivity and present challenges in thermodynamic perturbation theory for mixtures
Hammer, Morten; Aasen, Ailo; Ervik, Åsmund; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2020)This work revisits the fundamentals of thermodynamic perturbation theory for fluid mixtures. The choice of reference and governing assumptions can profoundly influence the accuracy of the perturbation theory. The statistical ... -
Choked liquid flow in nozzles: crossover from heterogeneous to homogeneous cavitation and insensitivity to depressurization rate
Wilhelmsen, Øivind; Aasen, Ailo (Peer reviewed; Journal article, 2021)The critical mass flow rate is the maximum flow rate that can pass through a constrained geometry such as a nozzle. For liquid CO2, it has been shown that homogeneous relaxation models systematically underpredict the ... -
Curvature Corrections Remove the Inconsistencies of Binary Classical Nucleation Theory
Aasen, Ailo; Reguera, David; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2020)The study of nucleation in fluid mixtures exposes challenges beyond those of pure systems. A striking example is homogeneous condensation in highly surface-active water-alcohol mixtures, where classical nucleation theory ... -
Equation of state and force fields for Feynman-Hibbs-corrected Mie fluids. II. Application to mixtures of helium, neon, hydrogen and deuterium
Aasen, Ailo; Hammer, Morten; Müller, Erich; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2020)We extend the statistical associating fluid theory of quantum corrected Mie potentials (SAFT-VRQ Mie), previously developed for pure fluids [Aasen et al., J. Chem. Phys. 151, 064508 (2019)], to fluid mixtures. In this ... -
Equation of state and force fields for Feynman–Hibbs-corrected Mie fluids. I.Application to pure helium, neon, hydrogen, and deuterium
Aasen, Ailo; Hammer, Morten; Ervik, Åsmund; Müller, Erich A.; Wilhelmsen, Øivind (Journal article; Peer reviewed, 2019)We present a perturbation theory that combines the use of a third-order Barker–Henderson expansion of the Helmholtz energy with Miepotentials that include first- (Mie-FH1) and second-order (Mie-FH2) Feynman–Hibbs quantum ... -
Ice formation and growth in supercooled water–alcohol mixtures: Theory and experiments with dual fiber sensors
Wahl, Markus Solberg; Aasen, Ailo; Hjelme, Dag Roar; Wilhelmsen, Øivind (Peer reviewed; Journal article, 2020)Increased knowledge on fluid-solid phase transitions is needed, both when they are undesired and can impair processes operation, and when strict control is required in fields such as food technology, the pharmaceutical ... -
Optimization of Pipe Geometries with Entropy Production Minimization in Viscous Flow
Herlyng, Halvor (Master thesis, 2022)Hvordan termodynamiske irreversibiliteter i strømningen i ejektorer kan reduseres og hvordan optimalt design av ejektorer skal utføres er enda ikke helt forstått. Ejektorer er utstyr som brukes i forskjellige energiprosesser ... -
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)A present key barrier for implementing large-scale hydrogen liquefaction plants is their high power consumption. The cryogenic heat exchangers are responsible for a significant part of the exergy destruction in these plants ... -
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 models to accurately describe the PVTxy-behavior of water / carbon dioxide mixtures
Aasen, Ailo; Hammer, Morten; Skaugen, Geir; Jakobsen, Jana Poplsteinova; Wilhelmsen, Øivind (Journal article; Peer reviewed, 2017)Carbon dioxide/water (CO2/H2O) mixtures are of much interest in carbon capture and storage, atmospheric science, in the description of human lungs and in the processing of food and beverages. We present a comprehensive ... -
Thermodynamic properties of the 3D Lennard-Jones/spline model
Hafskjold, Bjørn; Travis, Karl; Bailey, Amanda H.; Hammer, Morten; Aasen, Ailo; Wilhelmsen, Øivind (Peer reviewed; Journal article, 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 ≈ 1.74σ. It exhibits the same structural ... -
Tolman lengths and rigidity constants from free-energy functionals – General expressions and comparison of theories
Rehner, Philipp; Aasen, Ailo; Wilhelmsen, Øivind (Journal article; Peer reviewed, 2019)The leading order terms in a curvature expansion of the surface tension, the Tolman length (first order), and rigidities (second order) have been shown to play an important role in the description of nucleation processes. ... -
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)The curvature dependence of the surface tension can be described by the Tolman length (first-order correction) and the rigidity constants (second-order corrections) through the Helfrich expansion. We present and explain ... -
Traveling gravity water waves with critical layers
Varholm, Kristoffer; Aasen, Ailo (Journal article; Peer reviewed, 2017)We establish the existence of small-amplitude uni- and bimodal steady periodic gravity waves with an affine vorticity distribution, using a bifurcation argument that differs slightly from earlier theory. The solutions ... -
Understanding the physical phenomena that occur inside heat exchanger for liquefactin of hydrogen
Wilhelmsen, Øivind; Skaugen, Geir; Berstad, David Olsson; Aasen, Ailo; Nekså, Petter (Chapter, 2017)Liquid hydrogen is an attractive solution for long-range distribution. The largest barriers for implementing large-scale hydrogen liquefaction plants are currently their high energy consumption and cost. The heat exchangers ...