Browsing NTNU Open by Author "Ervik, Åsmund"
Now showing items 1-20 of 27
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A consistent reduction of the two-layer shallow-water equations to an accurate one-layer spreading model
Fyhn, Eirik Holm; Lervåg, Karl Yngve; Ervik, Åsmund; Wilhelmsen, Øivind (Journal article; Peer reviewed, 2019)The gravity-driven spreading of one fluid in contact with another fluid is of key importance to a range of topics. These phenomena are commonly described by the two-layer shallow-water equations (SWE). When one layer is ... -
A review on wetting and water condensation - perspectives for CO2 condensation
Snustad, Ingrid; Røe, Ingeborg Treu; Brunsvold, Amy; Ervik, Åsmund; He, Jianying; Zhang, Zhiliang (Journal article, 2018)Liquefaction of vapor is a necessary, but energy intensive step in several important process industries. This review identifies possible materials and surface structures for promoting dropwise condensation, known to increase ... -
A robust method for calculating interface curvature and normal vectors using an extracted local level set
Ervik, Åsmund; Lervåg, Karl Yngve; Munkejord, Svend Tollak (Journal article, 2014)The level-set method is a popular interface tracking method in two-phase flow simulations. An often-cited reason for using it is that the method naturally handles topological changes in the interface, e.g. merging drops, ... -
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 ... -
CO2 Wetting on Pillar-Nanostructured Substrates
Wu, Jianyang; Snustad, Ingrid; Ervik, Åsmund; Brunsvold, Amy; He, Jianying; Zhang, Zhiliang (Peer reviewed; Journal article, 2020)CO2 capture by dropwise CO2 condensation on cold solid surfaces is a promising technology. Understanding the role of the nanoscale surface and topographical features of CO2 droplet wetting characteristics is of importance ... -
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 ... -
Comment on the level-set method used in ‘Numerical study on mobilization of oil slugs in capillary model with level set approach’
Ervik, Åsmund (Peer reviewed; Journal article, 2016)This is a comment on a 2014 paper by Dai and Wang. It is argued that the validation in Dai and Wang's paper is an artifact caused by the boundary conditions of the level-set function, meaning that the effects reported in ... -
Condensation heat transfer of CO2 on Cu based hierarchical and nanostructured surfaces
Snustad, Ingrid; Hollund, Lene; Ervik, Åsmund; Austegard, Anders; Brunsvold, Amy; He, Jianying; Zhang, Zhiliang (Peer reviewed; Journal article, 2021)Phase-change processes such as condensation are efficient means of heat transfer. However, condensation is also an energy-intensive process and extensive research is conducted to increase the heat transfer efficiency. ... -
Contact Angle and Condensation of a CO2 Droplet on a Solid Surface
Wu, Jianyang; Ervik, Åsmund; Snustad, Ingrid; Xiao, Senbo; Brunsvold, Amy; He, Jianying; Zhang, Zhiliang (Journal article; Peer reviewed, 2018)Anthropogenic release of carbon dioxide (CO2) is a major contribution to manmade increase in global warming. Carbon capture and storage (CCS) is a necessary technology for lowering CO2 emissions to an acceptable level that ... -
Coupled fluid-solid modelling of the valve dynamics in reciprocating compressors
Ervik, Åsmund; Saai, Afaf; Berstad, Torodd; Meyer, Ole; Tsuji, Takuma; Oku, Tatsuya; Hattori, Kazuhiro; Yamada, Kazuya; Delhaye, Virgile Roger; Nekså, Petter (Chapter, 2022)A novel method coupling computational fluid dynamics (CFD) and finite element method (FEM) was developed to account for the complex physics of the reciprocating compressor. The developed method is based on data exchange ... -
A detailed review on CO2 two-phase ejector flow modeling
Ringstad, Knut Emil; Allouche, Yosr; Gullo, Paride; Ervik, Åsmund; Banasiak, Krzysztof; Hafner, Armin (Peer reviewed; Journal article, 2020)Ejector-equipped vapor-compression systems for refrigeration and cooling, relying solely on (R744) as a natural working fluid, are perceived to be an eco-friendly and highly efficient solution for many applications. However, ... -
A detailed review on CO2 two-phase ejector flow modeling
Ringstad, Knut Emil; Allouche, Yosr; Gullo, Paride; Ervik, Åsmund; Banasiak, Krzysztof; Hafner, Armin (Peer reviewed; Journal article, 2020)Ejector-equipped vapor-compression systems for refrigeration and cooling, relying solely on (R744) as a natural working fluid, are perceived to be an eco-friendly and highly efficient solution for many applications. However, ... -
Development of an immersed boundary method for simulating contaminated fluid interfaces in two-phase flow
Lysgaard, Morten Olsen (Master thesis, 2015)This thesis covers the theory and implementation, verification and validation of an immersed boundary method for simulating the effect of an elastic membrane covering water drops in crude oil. First an introduction to ... -
Efficient Liquefaction of Carbon Dioxide on Superlyophobic Surfaces
Snustad, Ingrid; Ervik, Åsmund; Austegard, Anders; Reigstad, Gunhild Allard; He, Jianying; Zhang, Zhiliang; Brunsvold, Amy (Journal article, 2019)Liquefaction of CO2 is a necessary step in several parts of the carbon capture, transport and storage (CCS) chain, e.g. for processing for ship transport. By increasing the efficiency of condensation, a lower energy ... -
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 ... -
Experimental and computational studies of water drops falling through model oil with surfactant and subjected to an electric field
Ervik, Åsmund; Hellesø, Svein Magne; Munkejord, Svend Tollak; Müller, Bernhard (Chapter, 2014)The behaviour of a single sub-millimetre-size water drop falling through a viscous oil while subjected to an electric field is of fundamental importance to industrial applications such as crude oil electrocoalescers. ... -
Heat transfer characteristics of CO2 condensation on common heat exchanger materials, method development and experimental results
Snustad, Ingrid; Ervik, Åsmund; Austegard, Anders; Brunsvold, Amy; He, Jianying; Zhang, Zhiliang (Peer reviewed; Journal article, 2021)Understanding condensation of CO2 is essential for e.g designing compact heat exchangers or processes involved in Carbon Capture and Storage. However, a consistent experimental campaign for condensation of CO2 on common ... -
Influence of surfactants on the electrohydrodynamic stretching of water drops in oil
Ervik, Åsmund; Penne, Torstein Eidsnes; Hellesø, Svein Magne; Munkejord, Svend Tollak; Müller, Bernhard (Journal article; Peer reviewed, 2017)In this paper we present experimental and numerical studies of the electrohydrodynamic stretching of a sub-millimetre-sized salt water drop, immersed in oil with added non-ionic surfactant, and subjected to a suddenly ... -
Machine learning and CFD for mapping and optimization of CO2 ejectors
Ringstad, Knut Emil; Banasiak, Krzysztof; Ervik, Åsmund; Hafner, Armin (Peer reviewed; Journal article, 2021)In this study, a novel simulation-based algorithm for CO2 ejector design and performance evaluation is presented. The algorithm is based on an automated Computational Fluid Dynamics (CFD) workflow that can account for ... -
Mechanisms and enhancement of CO2 condensation heat transfer
Snustad, Ingrid (Doctoral theses at NTNU;2020:236, Doctoral thesis, 2021)The aim of this thesis is to increase the understanding of the mechanisms governing Carbon Dioxide (CO2) condensation, and in that way finding a pathway towards a higher condensation efficiency. Liquefaction of CO2 occurs ...