Numerous applications, such as meso-scale heat exchangers, Lab-on-Chip devices (LOC), different systems within pharmaceutical and food industry, monodispersed emulsion and several other microfluidic systems, include two-phase flow through a meso-scale T-junction. When two-phase gas-liquid flow passes through an asymmetric meso-scale T-junction, a mal-distribution occurs. The phenomenon has proven itself to be unavoidable in most cases. In some applications this phenomenon can put the operational system at risk, while in other applications it is actually preferred. The phenomenon is still far from thoroughly understood. Thus the objective of this thesis is to further investigate this mal-distribution phenomenon. Split ratio for plug flow at a meso-scale T-junction has been investigated. A model for prediction of the split ratio has been proposed. Physical ingredients for determination of the split ratio have been focused upon. Much of the conducted work is based on findings in the MSc thesis by Hong et al. (2011) who proved the importance of the bubble length when predicting the split ratio. Split ratio, bubble length and pressure has been measured through experimentation. The T-junction used in the conducted experiments has a main channel, referred to simply as the “main”. It is connected in a straight line with one outlet referred to as the “run”. The second outlet is connected perpendicularly to the main and the run, and is referred to as the “branch”. All channels have a square shaped cross section with a hydraulic diameter of . Water and air was used as working fluids. For all conducted experiments the flow field took on a plug flow pattern. The branch channel has been observed to be rich in gas for all cases, except when the flow rate in the run is high. The flux in the main also has to be low to reduce the viscous drag forces between the two phases and the inertial forces of the plug. For increasingly high total flow rate in the run, a turning point has been located. When the flow rate exceeds this point the run becomes rich in gas. In both extreme cases (high flow rate in the run and in the branch) separation occurs for sufficiently short bubbles. The occurrence of separation is also highly dependent on the total flux in the main. To retain separation the surface tension has to overcome the viscous drag forces acting on the interface between the two phases. In the centre regime, where bubbles always break up and a plug flow pattern occurs in both outlets, the split ratio shows a strict relation to the bubble length. This strict relation between the split ratio and the bubble length were also concluded upon in the MSc thesis by Hong et al. (2011). In the defined centre regime changes in superficial velocities showed to have a negligible effect on the split ratio in comparison to variation in the bubble length. Long bubbles yields a split ratio located closest to perfect distribution. Decreasing the bubble length yields an increase in the void fraction (gas) in the branch. A model for prediction of the split ratio has been proposed. It is primarily valid within the centre regime, and is based on the time and area averaged Bernoulli equation. The model takes the bubble length into account, and predicts the split ratio on the main assumption that an increased amount of energy is lost to friction and separation as the fraction of water in the branch is increased. This while keeping the total fluxes in each of the outlets constant. An anticipated trend has been located through evaluating the model against experimental data. Therefore the model has been concluded upon to be physically sound.

Rock Energy is a Norwegian company with a patented solution for drilling deep geothermal wells, for exploitation of deep geothermal energy from Hot Dry Rocks. The concept involves a drilled sub-surface heat exchanger, referred to as cross wells. The concept is well suited for production of heat for direct heat applications. In this thesis an analysis of the existing district heating plant at Oslo Airport Gardermoen has been conducted, together with examining possibilities of implementing geothermal energy as base load at the plant. A geothermal design that could meet the needs of the district heating plant has been established, and for evaluating the geothermal system in an environmental perspective an analysis based on LCA methodology has been conducted. Hafslund operates two district heating centrals at Gardermoen (Gardermoen heating central and a smaller mobile central) for which both have been analyzed to determine the potential for implementing deep geothermal energy as base load for the systems. Gardermoen heating central is connected to the airport and to the area close to the airport. This central is again connected to the mobile heating central, which is situated near the industrial estate south-east of the airport. Based on Hafslund’s production data from February 2011 to January 2012, a heat load duration curve for the two existing centrals have been established. When adding the two curves together the duration curve show a maximum load of 25,7 MW at present, and a yearly energy production of 74 GWh. The mobile central accounts for only 7,2% of the total load and heat production at present.Future heat demand in the Gardermoen area is expected to increase beyond existing capacity. Hafslund is therefore considering to increase the capacity of both their district heating centrals. The enlargement plans involves that the heating central will be expanded to a design load of 37,4 MW (24 MW at present), while the mobile central need to be increased to a design load of 15,2 MW (1,7 MW at present). Assessment of the geothermal installation showed that it is preferable to include the geothermal system in the base load of the mobile central. The additional geothermal capacity will cover 10 MW, and thus deliver 65% of the required heat load and 90% of the energy production from the mobile central. The geothermal installation was designed using the spreadsheet “Geocalc”. The outputs from Geocalc are used in an analysis of the environmental performance of the designed system through a Life Cycle Assessment (LCA). LCA introduces a technique to assess environmental impacts associated with all stages of a product’s life from “cradle to grave”. The report aims at giving normative results for the environmental impacts of a geothermal installation at Gardermoen. The method provides the ability to quantitatively compare results to other sources of heat provision processes for district heating. It is important to emphasize that the analysis has provided an overview of the potential environmental impact, and not necessarily the actual results of environmental consequences. The system analyzed has a thermal output of 10 MW, lifetime of 30 years, 5000 annual operating hours. The functional unit of district heating produced is kWh. The analysis is based on the main contributing processes to construction, operation and demolition of Rock Energy’s geothermal system. The district heating grid is not included in the analysis, as it is already in place at the site. Each contributing process has been systematically validated. It is however uncertainties associated with the data collection mainly due to contradictory information gathered. The information considered to be mostly uncertain is the energy consumption used for drilling purposes.Possible scenarios for the energy supply to drilling were established. These scenarios were simulated in a system model in Excel. The model is based on data and information gathered from existing literature, the database Ecoinvent, published reports and personal communication with drilling experts and specialists within the relevant fields of study. The results are assessed for the following impact categories: Climate change, metal depletion, fossil depletion, terrestrial acidification and freshwater eutrophication. The evaluated potential energy sources for the drilling operation are electricity from the Norwegian grid, electricity from the European grid, and diesel. The climate change category has especially been in focus when conducting the simulations and this category shows large spread in the results, from 0,9993 g CO2-eq/kWh for the best scenario to 23,6 g CO2-eq/kWh for the worst scenario. As expected, the analysis concludes that electricity from the Norwegian grid for the drilling is preferable. For a geothermal system in Europe, the results show that it would be advantageous to use diesel as energy supply for the drilling operation instead of European electricity mix, for which the emissions are doubled.For the metal depletion impact category, the variation of energy supply to drilling cause the least fluctuation. This is also the only impact category where the Norwegian electricity mix has higher impacts than for the diesel consumption. This can be explained by the infrastructure related to electricity transmission. The results of the study have been compared to other heat sources for district heating (waste incineration, biofuel and solar thermal). The comparison shows that from an LCA perspective geothermal energy based on Rock Energy’s concept is an environmentally friendly energy supplier for district heating. The studies compared are however based on varying assumptions, and thus a generalized conclusion cannot be drawn from this.

I denne masteroppgaven har det blitt gjennomført «fluid structure interaction» (FSI) simuleringer av modellturbinen fra Tokke, ved innløpsbetingelser som var rapportert å gjelde ved best driftspunkt. Simuleringsresultatene ble sammenlignet med laboratoriemålinger. Simuleringsresultatene viser at turbinene opererte nære, men ikke helt på beste driftspunkt, og at simuleringsresultatene er nesten like laboratoriemålingene. Virkningsgradsavviket mellom simuleringsresultatene og laboratoriemålingene 5.2%. Avviket i trykkhøyde mellom simuleringsresultatene og laboratoriemålingene er 0.2m. Dette tilsvarer et avvik på mindre enn én prosent. Avviket i trykkhøyde og virkningsgrad mellom simuleringsresultatene og laboratoriemålingene er små og simuleringsresultatene er derfor vurdert til å være tilfredsstillende.For å studere trykkpulsasjonene fra ledeskovlene, ble fire «steady state» FSI simuleringer gjennomført. For hver av simuleringene ble løpehjulet litt rotert i forhold til ledeapparatet. Dette ble gjort for å dekke en hel lastsyklus for løpehjulet. Deretter ble spenningen i to punkter i turbinbladet, som ble plassert i områder med stor spenning, studert for alle fire simuleringene. Den største dynamiske spenningen er 5.86Mpa, hvor den gjennomsnittlige spenningen er 18.42Mpa. Følgelig utgjør den dynamiske spenningen 31.8% av den totale spenningen. Det er liten forskjell i spenningsverdier mellom laboratoriemålingene og simuleringene. Forskjellene i maksimumsspenningene mellom simuleringsresultatene og lab- resultatene kan være på grunn av den lille forskjellen i målepunktlokasjonene, men også på grunnen av usikkerhet i «computational fluid dynamics» (CFD) og «finite element method» (FEM) simuleringene, men også måleusikkerhet. Likevel er det en sterk korrelasjon mellom simuleringer og laboratoriemålinger, og den ville blitt enda sterkere hvis finere mesh kunne blitt brukt, og et større lastområde ville blitt undersøkt. Mangel på datakraft var en begrensing for simuleringene. Både FSI simuleringsresultatene og laboratoriemålingene viser at dynamiske spenninger utgjør en stor prosentandel av de totale spenningene. Derfor, i tillegg til foreliggende parametere, burde energiselskapene vise kjøreplanen i spesifikasjonene til turbinprodusentene. Kjøreplanen ville gitt turbinprodusentene den nødvendige informasjonen slik at det kunne bli tatt høyde for dynamiske laster i turbindesign.

The goal with this master thesis was to establish Hill diagrams and improve a Kaplan turbine intended for use in Afghanistan. The turbine efficiency has been tested in setting 1 and 2. Turbine efficiency in setting 3 and 4 could not be tested because the runner blades interfere with the housing making it impossible to rotate the turbine. The efficiency was tested with an effective pressure head ranging from 2 to 8 meters. Best efficiency point was not reached because of limitations in the test rig making it impossible to reach a lower effective head. The best efficiencies tested in the two different settings are presented in the table below together with the uncertainty in the actual test point. All tests are done according to the IEC standard for model testing of hydraulic turbines. The computational fluid dynamics (CFD) simulations done on the inlet bend indicates that the bend should be rounded and flow controllers should be extended over the entire bend. This should be considered to get a more even velocity distribution at the inlet of the guide vane. An alternative placement of the lower bearing was designed but is discarded because of the disadvantages the modification leads to. High wear due to sand erosion on the seals causing high maintenance and costly stops makes the solution not optimal for use in water with high sand content. The runner blade design is checked against the design procedure presented by Professor Hermod Brekke in Pumper og Turbiner and found to be satisfying. It is concluded that time should rather be spent on optimizing the inlet of the turbine. Fluctuations in the measurements make it necessary to change the measuring equipment or search for error in the existing equipment before further tests can be carried out. In order to be able to test in setting 3 and 4 the runner needs to be placed while the blades are fixed in setting 4.

The aim with this thesis was to investigate moulds for composite production. A set of requirements needs to be established for such moulds. The requirements will then be used to find the right material and production method concerning the desired result. Different production methods and materials that can be used for moulds are presented.Two different master moulds were made using two different types of materials, ytong and aluminium. On each of these master moulds, has two types of carbon fibre prepreg been used to make moulds. After cure has the dimensional accuracy of these moulds been measured and compared with the CAD models. The accuracy has been one of KONGSBERG's main requirements. One of the two shapes of moulds was used to make parts in. These two parts have been measured after cure.Abaqus has been used to carry out an FE-analysis with simulations of spring due to cooling after cure.The measurements and the analysis shows the spring-in, but with some difference in the results.The two types of mould materials indicates good results for the shape and size they were tested on. They fulfill many of their requirements.

Pressure transients are caused by a change in the volumetric flow in a pipeline system, and can have severe consequences for rapid changes of the volumetric flow. A sudden closure of a valve is a common source of a pressure transient, and the pressure increase in front of the valve depends on the flow rate and the wave propagation velocity in the fluid and pipe. A gas-liquid mixture can have a very low wave propagation velocity, even for small air contents, and is effective in terms of damping due to the compressibility effects of the gas bubbles. With these alterations of the fluid properties the pressure transient will be weakened with reduced amplitude and an increased period, which are beneficial effects for the pipeline system.A simple experiment was carried out to investigate the practical solutions for the air injection system, and the results showed that the presence of air was beneficial in terms of a reduction of the amplitude and increased damping of the pressure transient. However, a few aspects should be revised in a refinement of the experiment. The air flow rate and duration were uncertain because of water accumulating in the air hose, and the timing of the gate valve closure was challenging.Simulations of various models of pipe systems were carried out in Flowmaster. The models are sufficient for simulation of ordinary pipes with a rapid closure of a valve, but fall short at modeling an air-water mixture. This is because only the reduced wave propagation is taken into account, and not the effects of the bubbles.

Many offshore installations are dependent on power generated by gas turbines and a critical issue is that these experience performance deterioration over time. Performance deterioration causes reduced plant efficiency and power output as well as increased environmental emissions. It is therefore of highest importance to detect and control recoverable losses in order to reduce their effect. This thesis project was therefore initiated to evaluate parameters for detecting performance deterioration in addition to document different aspects of gas turbine degradation and performance recovery. Compressor fouling is the largest contributor to performance deterioration. Investigating fouling was therefore the main focus of this study.In the present study the deterioration rates of four different gas turbines were evaluated. When choosing gas turbines it was emphasised to select gas turbines operating under equal conditions but with different washing procedures. In addition to offline washing two of the gas turbines had daily online washing routines and one of the gas turbines run idle wash every 1000 hour between each offline wash. Data was extracted from the monitoring software, TurboWatch, and loaded into Excel files. MATLAB scripts were created to handle the large amount of data and visualize performance trends. Series of two parameters were plotted against each other and the graphs were evaluated.The evaluation showed that an overall trend was that the gas turbine that had been running with online washing continuously over a long period of time had higher performance than the reference engine. For the second gas turbine a daily online washing procedure has recently started. The advantage with the evaluation of this gas turbine was that a good reference engine was available. The two engines were operating under quite similar conditions at the same location in addition to having equal filter systems. Some deterioration trends were possible to detect. For the first period both engines seemed to have quite equal deterioration trends. During the second period no clear trends were seen in corrected CDP and corrected EGT when evaluated for constant GG speed. The compressor efficiency had decreasing trends for both engines during the second period as well, but the compressor efficiency for machine 1 was overall higher during the period with online washing than the previous period. The borescope pictures taken after the first period with online washing showed good visual results. However, it is too premature to make a final decision regarding the exact performance gain of online washing. At the time the study was performed the engine had only been running online washing for one operating interval, and more investigation over longer time is recommended. For the engine running with idle wash it was not possible to conclude on the basis of the collected data. No clear deterioration trends were detected and investigations over longer time and several operating intervals are recommended. It is also important to be aware of the fact that the performance gain of idle wash needs to be much higher than for online washing in order for idle wash to be economically profitable. There are several uncertainties related to performance trends. These include inaccuracy in instrumentation, monitoring software, calibration etc. Due to the fact that all the gas turbines evaluated in this study only have standard instrumentation it caused additional uncertainty in the performance trends. One suggestion for further study is to initiate a test instrumented gas turbine into operation with sensors for measuring inlet pressure depression

Det første målet med denne masteroppgaven er å utvikle en prosedyre for å vakuumere, fylle og forsegle et varmerør (heat pipe). Varmerør benyttes for å transportere varme med lave temperaturdifferanser. Ved høye temperaturer er det fordelaktig å ta i bruk kalium som arbeidsmedium i varmerør. I denne rapporten er det utarbeidet en metode for sikker vakuumering, fylling og forsegling av et varmerør med kalium som arbeidsmedium. Det er i tillegg utviklet en prosedyre for hvordan hele prosessen skal gjennomføres. En turbomolekylærpumpe skal brukes for å generere vakuum, og sammen med varmeelement utgasse varmerøret. Et påfyllingskammer benyttes for å smelte og overføre kalium, mens induksjonssveising skal benyttes for å forsegle varmerøret. Med prosedyren som er utviklet er det ventet at man vil få et lekkasjefritt varmerør med veldig ren kalium som arbeidsmedium.Det andre målet med denne oppgaven er å utarbeide en numerisk beregningsmodell for strømning i porøse medium. Beregningsmodellen skal kunne vise effekten av ujevnt varmepådrag på strømningen i veken. Et høyt varmepådrag i et lite område av veken vil gi mye avdamping i dette området. Dette vil føre til at man får 3D strømning. På grunn av at tykkelsen til veken er veldig liten, er det ventet at man får lite variasjon i tykkelsesretningen, og modellen kan forenkles til 2D strømning. Beregningsmodellen som er utarbeidet benytter Darcys lov, i kombinasjon med kontinuitetsligningen for masse, for å beregne det stasjonære trykk- og hastighetsfeltet som oppstår på grunn av et varmepådrag. Varmepådraget kan være uniformt eller ujevnt.Fordelingen av varmefluksen har mye å si for total varmetransportkapasitet for veken. En varmedistribusjon som fører til en høy fluks øverst i veken vil gi en lavere total varmestrøm enn en tilsvarende varmedistribusjon der den høye fluksen er plassert nede i veken. Det er sett på mange ulike varmepådrag, og effekten disse varmepådragene har på vekekapasiteten.

Increased knowledge of the degassing process in separation of gas from oil is important in connection with development of subsea separation and boosting units for heavy oil fields. The focus in the thesis is on theory and equipment design for two-phase separation of oil and gas. A review of gravitational separators and compact separation technology with a focus on subsea installations is given first. An extensive literature review related to theory governing the degassing process is further presented. The effectiveness of the degassing process depends on the gas’ ability to migrate out of the oil. Bubble dynamics theory, especially correlations for calculation of a bubbles velocity in a liquid is therefore examined. Bubble size, fluid properties, especially liquid viscosity, and gas volume fraction in the liquid is decisive factors for the bubble velocity. A comparison of several correlations obtained in various literature is made to determine the best available for modeling degassing. Most of the correlations have a limited range of validity in terms of bubble size and Reynolds number. It is verified that they are highly inaccurate outside this range. A correlation developed to be valid for a large range of bubble sizes seems to predict bubble velocities reasonably well. Because of its large range of validity, this is chosen to be used in the development of a separator model. Some experimental work is performed on two liquids with different viscosity. It is verified that separation of gas in viscous liquids requires significantly more retention time for the smallest bubbles reach the liquid surface. Occasional deviations from the examined theory are observed, especially for the more viscous liquid. Based the chosen correlation for bubble velocity a simplified model for horizontal and vertical gravity separators is developed. Separator size, fluid properties, flow rate and distribution of bubbles are input parameters. The model calculates how much of the initial gas volume fraction that remains in the liquid after separation. Consequence of high liquid viscosity and distribution of bubble size and bubble distribution in the liquid are evaluated by use of the model. When the oil becomes very viscous is it important that separator and internals are designed to optimize the conditions for degassing. This implies among others an inlet device which provides an ability to control the bubble distribution and keep the size of bubbles as large as possible. Methods are suggested for increased effectiveness in degassing of heavy oils, by reducing viscosity, increase the coalescence rate and affecting the flow pattern. Separation of other phases and undesirable components is also important and may make it difficult to optimize the design for the degassing process. However, a separator should be efficient in all respects, making knowledge of the degassing process anyhow important. The thesis gives an overview of important parameters in the degassing process. Much work still remains to develop correlations and models which can give a more exact description of real systems. Continuous development in separator components and not at least compact separation technology is important to effectively be able to produce heavy oil, especially in terms of subsea installations.

Tatt for meg flere runder med forsøk og analyser. Tørking av muselever,-hjerte,-lunge,-nyre og -skjelett muskulatur ved +5ºC og -10ºC. Samt lagring ved +4ºC og -20ºC i fem måneder. Resultatene viste en sammenheng mellom lave temperaturer og høye verdier av RIN. De viste også en motsetning til tidligere resultater, med lavere RIN på prøver tørket ved +5ºC, samt uakseptable lave verdier ved lagring i kjøleskap. Dessuten var det en viss forskjell avhengig hvilket organ vi tørket og lagret.