In today’s economy, it is important to have a sustainable business model where as little as possible goes to waste or finding solutions to create something useful out of by-products. Therefore, LKAB are looking to make a large investment into creating an infrastructure of several plants to turn tailings from the production of iron ore into usable products for several industries which LKAB has designated project ReeMAP (Rear Earth Elements and MonoAmmonium Phosphate). These products include phosphorus used in the production of food, gypsum used in the building industry and fluorine used in the chemical industry. One of the key ingredients in making these products is apatite, a calcium-phosphate crystal which is extracted from the tailings. The plant where the apatite is to be produced will be located close to the mining sites in Kiruna and Malmberget and then transported to the coast. The transportation can be caried out by rail carts which is how the iron ore is transported. Depending on the quantity of apatite that will be transported, a new rail track would need to be built which is a huge investment on top of the investment for the ReeMAP infrastructure. An alternative transportation method for the apatite is to use a pipeline that is pressurized by a series of pumps known as slurry transportation. This method of transporting material has been utilized in many countries around the world as it has shown to be a cost effective and more environmentally cautious method of transportation.  Slurry transportation comes with its own unique challenges, the major ones are making sure the slurry is well mixed and the solid particles do not deposit inside the pipeline and the other is the risk of freezing during a longer system shutdown. This has been studied using Computational Fluid Dynamics analysis in the software ANSYS Fluent. In addition, an overview calculation of the pressure losses to determine the number of pumps needed for the transportation has been conducted. The software ANSYS Fluent Multiphase was used to model the interaction of solid apatite particles with water and determine the volume concentration of apatite inside the pipeline. For the freezing of water inside the pipeline during a shutdown and stationary flow, the software ANSYS Fluent Solidification/Melting was used for the modelling.  The results from the flow model show that the apatite becomes pseudo-homogenous during the transportation, given that the particle size remains within a certain interval, which will deposit the correct amount of apatite at the outlet of the pipeline. The results from the freezing model shows that a shutdown of a few hours is possible without the risk of the water freezing inside the pipeline. With insulation, this time may be extended.

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This thesis evaluates two variants of Volumeof fluid method, namely Piecewise Linear Interface Construction (PLIC) and Multidimensional Tangent of Hyperbola for Interface Capturing (MTHINC) used in two-fluid simulations for interface tracking.Simulations of a single rising bubble in different conditions are performed aimed to assess the accuracy of the methods, and to check their convergence with grid size. The results show that both methods demonstrate convergence with mesh refinement, while PLIC captures the transient part of rising process of bubble more accurately than MTHINC in 2D case. / Denna avhandling utvärderar två varianter av metoden Volume of fluid för flerfas strömningar, nämligen Piecewise Linear Interface Construction (PLIC) och Multidimensional Tangent of Hyperbola for Interface Capturing (MTHINC) som används i tvåvätskesimuleringar för gränssnittsspårning.Simuleringar av en enda stigande bubbla under olika förhållanden utförs för att bedöma metodernas noggrannhet och för att kontrollera deras konvergens med gridsstorlek. Resultaten visar att båda metoderna visar konvergens med grid förfining, medan PLIC fångar den övergående delen av stigande bubbelprocess mer exakt än MTHINC i 2D-fall.

The aim of the thesis is to develop and validate subgrid-scale models that are relevant for large eddy simulations of complex flows including scalar mixing. A stochastic Smagorinsky model with adjustable variance and time scale is developed by adding a stochastic component to the Smagorinsky constant. The stochastic model is shown to provide for backscatter of both kinetic energy and scalar variance without causing numerical instabilities. In addition, new models for the subgrid-scale stress and passive scalar flux are derived from modelled subgrid scale transport equations. These models properly account for the anisotropy of the subgrid scales and have potentials wall bounded flows. The proposed models are validated in wall bounded flows with and without rotation and show potential or significantly improve predictions for such cases. / <p>QC 20100826</p>

Den största energiförlusten i ett rörsystem har vid flertal tillfällen bevisats vara friktionsförluster. Studien ämnar därför besvara om den typ av förluster kan minskas med hjälp av invändig behandling med superhydrofobisk coating.   Studien använder två småskaliga testanläggningar. Ett cirkulationssystem och en förenklad anläggning för friflödestest. På båda anläggningarna görs en fast installation av mätutrustning i direkt anslutning till ett 1,5m långt teströr, för att kalkylerad och uppmätt data inte skall påverkas av kringsystemen. Mätutrustning används för att kontrollera volymflöde, hastighet, temperatur och tryckfall. Insamlad data används sedan för att jämföra friktionsförluster före och efter invändig applicering av en superhydrofobisk coating.   Resultatet av studiens tester visar att den superhydrofobiska coating som använts, till skillnad från förväntat resultat, har en negativ effekt på flödet vid prövade applikationer och förlusterna ökade efter ytbehandling. / The greatest loss of energy in a pipe system has many times been proven to be frictional loss. This study with that in mind, will try to answer if this type of loss can be prevented using a superhydrophobic coating on the inside of a pipe.   This study uses two small-scale systems, one circulation system and one simplified system for freeflow testing. On both systems, measuring equipment is fixated close to the 1,5m test-pipe. Therefore, calculated and measured data is not distorted by the surrounding components. Measuring equipment is used to check volumetric flow, velocity, temperatures and differential-pressure. This data is later used to compare the frictional losses before and after applying the superhydrophobic coating.   The results, after completed tests are the opposite of the expected results. The coating that has been used for this study causes a negative effect and, in turn results in a substantial increase of frictional loss.

<p>Compressed air is a low efficiency media, and is thus very expensive to produce. This thesis work began by mind mapping how to create savings on the compressed air system at Billerud Skärblacka AB. Certain issues have been chosen for further studies.</p><p>In order to identify the consumption of compressed air at PM 8 and 9, several measurements were made. At PM 8 there were not found any pressure drop, only large pressure variations for short periods of time. The causes of these pressure variations were not established. At PM 9 a registered pressure drop of around 1 bar was found. The cause of the pressure drop at PM9 was not found. A solution for the pressure drop was presented, which also could give an opportunity to reduce the nominal pressure in the compressed air system. An idea for improvement of the compressed air system structure has also been presented.</p><p>A search for leakages on the compressed air system was carried out both at PM 8 and PM 9. Leakages at PM8 seem to be lower than at PM9. The search for leakages pointed out that those leakages on the compressed air system reduces the efficiency of the compressed air system.</p><p>There are some large scale consumers of compressed air at Billerud, for example one function at PM8 and the cleaning function of timber trucks. One idea for reducing electrical consumption is to replace compressed air with a high pressure fan at PM8. In the report more suggestions for saving electrical energy regarding the other large scale consumers are presented.</p>

<p>I detta arbete har vi med en litteraturstudie försökt påvisa vad en inblandad gas i oljan i ett hydrauliksystem har för betydelse för funktionen. Vi har använt information i traditionell facklitteratur samt i tidskrifter och vetenskapliga rapporter och upptäckt att problemen som uppkommer av inblandade gaser inte är väl kända. Dagens lösningar på problemen är nästan alltid kostsamma och handlar om att behandla symptomen. Vi har tittat på de olika fysikaliska data som gasen inverkar på i oljan, utifrån detta har vi analyserat vilka effekter detta har för ett hydrauliksystems funktion. Vi kommer att diskutera grundproblemet till kavitation och vanliga problem som ett hydrauliksystem ofta har. Vi har lyckats presentera resultat på att inblandad gas i oljan har en mycket stor inverkan på ett hydrauliksystem. Vi har kommit fram till att mycket av dagens problem med hydrauliksystem helt skulle kunna byggas bort om man tog större hänsyn till oljans förmåga att lösa in luft.</p>

The liquid steel sampling method is one of the commonly used procedures in monitoring the steelmaking process. Besides it can be used for analyzing the dissolved alloys, hydrogen content and oxygen content, it can be also employed to monitor the inclusion characteristics at the steelmakings. Here, a crucial point is that the steel sampler should be filled and the metal solidifies without changing the inclusion characteristics. Therefore, the objective of this work is to fundamentally understand the liquid steel sampling process by means of analyzing and modeling the two-phase flow during the sampler filling process, and verifying the mathematical model by using the experimental data. The present dissertation presents an experimental and theoretical study of the filling process of both the lollipop-shaped sampler and the rectangular-shaped sampler. Firstly, a physical modeling by using a water model has been carried out to fundamentally investigate the flow pattern inside the sampler vessels during its filling. The flow patterns were obtained by a PIV system. Then, a mathematical model has been built to theoretically understand the phenomena. The commercial CFD code was used. Here, different turbulence model have been compared between the realizable k-ε turbulence model and Wilcox k-ω turbulence model. It concludes that the Wilcox k-ω turbulence model agrees well with the PIV measurements.HH Thus, the preferred it was further employed to predict the turbulent flow inside the production lollipop-shaped sampler fillings. It is important to find that the average collision volume in the production steel sampler without solidification at filling is about 30 times higher than that in a ladle furnace. In the end, the whole sampling system was modeled. The initial solidification during the filling was taken into account. Focus was on the influence of the initial solidification on the inclusion concentrations. A discrete phase model was used to simulate the movement of inclusions in the liquid steel. Some selected different sized primary inclusions that exist in the ladles at a steelmaking process were simulated. The same method of studying the filling procedure of the lollipop-shaped sampler was further applied to comprehensively investigate the rectangular-shaped sampler. / QC 20100908

This thesis deals with the early stages of transition to turbulence in two different baseflows, namely the Falkner-Skan-Cooke boundary layer (FSC) and the asymptotic suction boundary layer (ASBL). Grid-generated turbulence is studied in order to characterise the isotropy levels, free-stream turbulence levels and characteristic length scales that will be present in the receptivity study. By varying the grids and their location it is possible to control the turbulence intensity level, Tu, and the integral length scale independently. Comparisons with other studies show that for increasing Re_M the isotropy levels and the rate of kinetic energy decay asymptotically approach the theoretical values. The FSC describes a a 3D boundary layer subjected to a pressure gradient. The FSC is stable to TS-waves, but becomes susceptible to both travelling and stationary crossflow disturbances. In the experiments the travelling modes were triggered using free-stream turbulence (FST) and the stationary modes were triggered using an array of cylindrical roughness elements. The receptivity phase to FST was linear as well as the initial growth. For high enough $Tu$ inside the boundary layer, nonlinear behaviour was observed further downstream. The stationary mode could only be triggered using tall roughness elements, with low heights resulting in no noticeable disturbances. The receptivity is found to be nonlinear for the roughness heights tested and the growth of the disturbances is exponential. For low levels of FST, Tu &lt; 0.25%, the travelling mode as well as the stationary mode grew. The ASBL is formed when uniform suction is applied to the surface of a porous plate with a flow over it. This baseflow is very stable to TS-waves, and was used to study the transient growth. For the ASBL, stationary disturbances were triggered using a spanwise array or cylindrical roughness elements. The velocity signals were decomposed using a spatial Fourier transform to study the growth of individual modes. The fundamental mode as well as some harmonics were seen to undergo transient growth, before finally decaying exponentially. Comparisons were made to the experimental data using optimal perturbation theory. The global optimals did not describe the transient growth effects well. The calculations were redone for suboptimal times and showed agreement with the experimental data, showing that optimal perturbation theory can describe transient growth if the initial disturbance state is known. / QC20100702

This is a Master Thesis done at the Swedish Defence Research Agency with the purpose to design and investigate how different geometries of a compression surface integrated with an intake affects the performance such as distortion, boundary layer diversion, pressure recovery and deceleration of speed. The work was divided in two parts. In the first part, CFD calculations using the FOI developed Edge 4.1 code were made for the compression surfaces alone. In the second part the most promising design was integrated with an intake. Two more bumps with the intake were modelled and the three geometries were compared to the intake without bump. Surface flow, deceleration of Mach number, pressure recovery, mass flow, boundary layer diversion, lift and drag were the factors chosen to be examined, boundary layer diversion and pressure recovery being the two most vital.