Browsing NTNU Open by Author "Johnsen, Sverre Gullikstad"

A Wall-Function Approach for Direct Precipitation/Crystallization Fouling in CFD Modelling

Johnsen, Sverre Gullikstad; Johansen, Stein Tore; Wittgens, Bernd (Chapter, 2015)

The main objective of this paper is to present a generic modelling framework, for the diffusive mass transport through the turbulent, reactive boundary layer of multi-component fluid mixtures that ...

An Analytical Mathematical Theoretical Study of Single-Well Push-Pull ”Echo” Tests

Johnsen, Sverre Gullikstad (Doktoravhandlinger ved NTNU, 1503-8181; 2007:122, Doctoral thesis, 2007)

Analysis of stream-line-based formulations is exercised to develop a stream-line based semi-analytical model for the single-well push-pull test, taking into account natural ground-water drift. The model is employed to ...

Capillary forces as a limiting factor for sawing of ultrathin silicon wafers by diamond multi-wire saw

Ryningen, Birgit; Tetlie, Pål; Johnsen, Sverre Gullikstad; Dalaker, Halvor (Peer reviewed; Journal article, 2020)

Succeeding with ultrathin silicon wafer sawing by diamond multi-wire saw, is not only a matter of optimization; the challenges of thin wafer production and the capability limit have not yet been fully understood. In this ...

CFD Simulations of Turbulent Flow in the Human Upper Airways

Aasgrav, Elin; Johnsen, Sverre Gullikstad; Simonsen, Are Johan; Müller, Bernhard (Chapter, 2017)

In this paper, investigations are conducted using Reynolds-averaged Navier-Stokes (RANS) turbulence models to investigate the importance of turbulence modelling for nasal inspiration at a constant flow rate of 250 ml/s. ...

Composition and Structure Analysis of Hard Grey Scale (HGS) Formed on Cold Surfaces Exposed to Aluminium Production Off-gas

Perez Clos, Daniel; Zedel, Hannes; Johnsen, Sverre Gullikstad; Nekså, Petter; Aune, Ragnhild Elizabeth (Peer reviewed; Journal article, 2022)

Hard grey scale (HGS) is a strongly adhering fouling material forming on solid surfaces impinged by off-gas generated in the pot cells of primary aluminium production plants. Even though associated maintenance costs have ...

Developing an immersed boundary method for compressible flow

Kristoffersen, Frederik; Larsson, Martin; Johnsen, Sverre Gullikstad; Schröder, Wolfgang; Müller, Bernhard Theodor (Journal article; Peer reviewed, 2023)

Development of a 3D sharp interface ghost node immersed boundary method (IBM) within a fluid solver based on the compressible Navier–Stokes equations is underway. The objective of the IBM is to accurately apply boundary ...

Digitalisering av energi sektoren

Oftedal, Sara; Rørvik, Eilif Søreide (Bachelor thesis, 2019)

Repsol er i ferd med å utvikle Nidaros feltet og vil lære av erfaringer gjort ved Kalvskinnet feltet. Erfaringene fra Kalvskinnet er at feltet hadde store produksjonstap knyttet til uplanlagte hendelser, og da spesielt ...

Enabling Efficient Heat Recovery from Aluminium Pot Gas

Clos, Daniel Perez; Andresen, Trond; Nekså, Petter; Johnsen, Sverre Gullikstad; Aune, Ragnhild Elizabeth (Chapter, 2017)

In the present work, previous studies carried out by the Norwegian aluminium industry and research centres with the aim of recovering heat from aluminium production off-gas, are reviewed. The main challenge in improving ...

Experimental Investigation of Rhinomanometry

Aanderaa, Lea Øvensen (Master thesis, 2021)

Formation of Hard Grey Scale (HGS) on the Surface of a Cold-finger in the Aluminium Production Industry

Clos, Daniel Perez (Doctoral theses at NTNU;2021:183, Doctoral thesis, 2021)

The present work has investigated the formation mechanisms of Hard Grey Scale (HGS) in a duct transporting the off-gas from aluminium production pot cells to the Gas Treatment Centre (GTC). For that purpose, a cooled fouling ...

Hardhetsreduksjon i varmepåvirket sone ved sveisereparasjon på utstyr i drift

Stegavik, Ståle Singstad; Kristensen, Jørgen; Stolpnes, Thomas (Bachelor thesis, 2020)

Denne rapporten tar for seg identifisering og testing av en mulig metode å gjennomføre sveisereparasjoner av korrosjonsskader på utstyr i drift på olje- og gassanlegg. Eksempler på slikt utstyr er rør og tanker. Bakgrunnen ...

Implementation, Demonstration and Validation of a User-Defined Wall Function for Direct Precipitation Fouling in Ansys Fluent

Johnsen, Sverre Gullikstad; Pääkkönen, Tiina; Johansen, Stein Tore; Keiski, Riitta; Wittgens, Bernd (Chapter, 2017)

In a previous paper (Johnsen et al., 2015) and presentation (Johnsen et al., 2016), we developed and demonstrated a generic modelling framework for the modelling of direct precipitation fouling from multi-component fluid ...

Investigation on scale formation in aluminium industry by means of a cold-finger

Clos, Daniel Perez; Nekså, Petter; Johnsen, Sverre Gullikstad; Aune, Ragnhild Elizabeth (Journal article; Peer reviewed, 2019)

A cylindrical fouling probe or “cold-finger” has been used to investigate fouling from aluminium production off-gas. The probe was located upstream from the off-gas cleaning system. Surface deposits have been collected for ...

Mathematical Modelling and Simulation of Flow in Collapsible Tubes

Akbar, Batool (Master thesis, 2022)

Obstruktiv søvnapné (OSA) er en tilstand som midlertidig blokkerer luftstrømmen gjennom de øvre luftveiene under søvn for de som er rammet. Denne vanlige tilstanden kan redusere søvn og livskvalitet, og til og med føre til ...

Measures to reduce emissions from offshore drilling units

Rølland, Kristina Nygaard; Øye, Vegar Hovdenakk; Godvindapillai, Shayangi (Bachelor thesis, 2020)

Hensikten med denne bacheloroppgaven har vært å studere hvordan Lundin Energy Norge AS sin lete- og produksjons aktivitet bidrar selskapets totale utslipp av CO2 og NOx, både i et historisk og fremtidig perspektiv, og for ...

Particle deposition characteristics in the formation of Hard Grey Scale (HGS) on cold surfaces exposed to aluminium production off-gas

Clos, Daniel Perez; Zedel, Hannes; Johnsen, Sverre Gullikstad; Nekså, Petter; Aune, Ragnhild Elizabeth (Peer reviewed; Journal article, 2021)

Hard Grey Scale (HGS) is a hard and strongly adhering fouling material that forms on solid surfaces impinged by the off-gas generated in the pot cells of aluminium production plants. Different theories on HGS formation ...